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Liquid crystal-based actuators are receiving increased attention for their applications in wearables and biomedical or surgical devices, with selective actuation of individual parts/fingers still being in its infancy. This work presents the design and realization of two gripper devices with four individually addressable liquid-crystal network (LCN) actuators thermally driven via printed graphene-based heating elements. The resistive heat causes the all-organic actuator to bend due to anisotropic volume expansions of the splay-aligned sample. A heat transfer model that includes all relevant interfaces is presented and verified via thermal imaging, which provides good estimates of dimensions, power production, and resistance required to reach the desired temperature for actuation while maintaining safe electrical potentials. The LCN films displace up to 11 mm with a bending force of 1.10 mN upon application of 0–15 V potentials. The robustness of the LCN finger is confirmed by repetitive on/off switching for 500 cycles. Actuators are assembled into two prototypes able to grip and lift objects of small weights (70–100 mg) and perform complex actions by individually controlling one of the device’s fingers to grip an additional object. Selective actuation of parts in soft robotic devices will enable more complex motions and actions to be performed.

Miniature actuators are utilized in various application fields, from robotics to medical devices, where compact dimensions, precise movements, and cost-effectiveness are crucial factors. Particularly for applications like braille displays, there is a critical demand for lightweight, portable, and affordable actuators to integrate into daily life for visually impaired people. However, existing actuation technologies such as electroactive polymers, electrorheological materials, and piezoelectric elements often do not meet the specific requirements of miniature actuators, especially for braille displays. Therefore, this study investigates the behavior of electrorheological fluids incorporated into polymer matrices of cellulose and proteins for miniature actuators to overcome the primary challenge of sedimentation through the structuring of the liquid. The gel formulations are tested in three distinct setups: the V-shaped, horizontal plates, and valve system. These experiments demonstrated immediate structural changes in the gel formulations, achieving reversible movement. Furthermore, the valve setup even enabled the analysis of the strength of the hardened mixtures by the resistance against applied air pressure. The results demonstrate that incorporating electrorheological fluids into polymer matrices is not only feasible but also preserves the characteristic behavior of electrorheological fluids under electrical field exposure. This behavior validates the applicability and suitability of modified electrorheological fluid mixtures in miniature actuators.

The requirements for high accuracy and throughput in next-generation data-intensive motion systems lead to situations where position-dependent feedforward is essential. This article aims to develop a framework for interpretable and task-flexible position-dependent feedforward through systematic learning with automated experimental design. A data-driven and interpretable framework is developed by employing Gaussian process (GP) regression, enabling accurate modeling of feedforward parameters as a continuous function of position. The data is efficiently collected and illustrated through an iterative learning control (ILC) algorithm. Moreover, a framework for experimental design in the sense of automatically determining the training positions is presented by exploiting the uncertainty estimates of the GP and the specified first-principles knowledge. Two relevant case studies show the importance and significant performance improvement of the approach for position-dependent snap feedforward for a simplified 1-D wafer stage simulation and experimental application to position-dependent motor force constant compensation in an industrial wirebonder.

El següent projecte presenta el procés complet d’ideació d’un actuador lineal electromecànic, des del disseny de cada peça i selecció del material juntament passant per l’elaboració dels plànols fins al càlcul dinàmic, relacions de transmissió i d’inèrcies. S’incorpora un apartat de comparativa entre actuadors hidràulics i pneumàtics amb els electromecànics. Es proposa un estudi de selecció d’unions cargolades estandarditzades ISO. Es discuteix sobre la millor opció motora per l’aplicació i per completar, es crea una fitxa tècnica d’especificacions del producte. Tot encaminat per la possible comercialització del disseny aquí presentat dirigit a una empresa capaç d’organitzar una producció en sèrie. També, s’ha inclòs en el treball un apartat d’anàlisi de tensions amb l’objectiu d’avaluar els esforços en peces en funció de les forces de treball aplicades utilitzant el programa de càlcul per elements finits Ansys. En últim lloc, es donen unes valoracions de millora en les conclusions i un pressupost de costs derivats del projecte d’enginyeria juntament amb una proposta d’utilització ergonòmica en les aplicacions industrials que més sovint pot ocupar., El siguiente proyecto expone el proceso completo de ideación de un actuador lineal electromecánico, desde el diseño de cada pieza con SolidWorks y selección de material junto con la creación de planos hasta el cálculo dinámico, relaciones de transmisión y de inercias. Se incorpora un apartado de comparativa entre actuadores hidráulicos y neumáticos con el electromecánico. Se propone un estudio de selección de uniones atornilladas estandarizadas ISO. Se discute sobre la mejor opción motora por la aplicación y al concluir, se crea una ficha técnica de especificaciones del producto. Todo encaminado por la posible comercialización del diseño aquí presentado dirigido a una empresa. También se ha incluido en el trabajo un apartado de análisis de tensiones con el objetivo de valorar los esfuerzos en piezas en función de las fuerzas de trabajo aplicadas utilizando el programa de cálculo por elementos finitos Ansys. Por último, se dan unas valoraciones de mejora en las conclusiones y un presupuesto de costes derivados del proyecto de ingeniería junto con una propuesta de utilización ergonómica en las aplicaciones industriales., The following project shows the complete process of designing an electromechanical linear actuator, from the design of each piece with SolidWorks and material selection along with the creation of plans to the dynamic calculation, transmission and inertia ratios. A comparison section is included between hydraulic and pneumatic actuators with electromechanical ones. A selection study of ISO standardized screwed joints is proposed. The best motor option for the application is discussed and at the end, a technical sheet of product specifications is created. All aimed at the possible commercialization of the design presented. A stress analysis section has also been included in the work with the objective of assessing the efforts in pieces based on the working forces applied using the Ansys finite element calculation program. Finally, there are evaluations of improvement in the conclusions and a budget of costs derived from the engineering project along with a proposal for ergonomic use in industrial applications.

The objective of this work was to develop an innovative LoRa-based platform that provides a low-cost and customizable solution for real-time monitoring of soil parameters. The system architecture was based on four levels: environmental (rural), sensors and actuators, communication network, and application, with the code made available for operation. The collected data were transmitted to data collection points using LoRa technology. The application level allowed for data storage, analysis, and visualization, enabling end-users to remotely monitor and control environmental measurement operations. With LoRa technology range tests, results indicated the capability to cover a maximum area between 95 and 120 hectares in the studied areas. Additionally, the collected data were sent to ThingSpeak.com and a mobile application called Thingsview. This demonstrated the efficiency and viability of LoRa technology for industrial communication sensor and IoT applications in rural environments, offering automation, increased efficiency, and savings in human resources for environmental monitoring tasks, El objetivo de este trabajo fue desarrollar una innovadora plataforma basada en LoRa que proporciona una solución económica y personalizable para la monitorización en tiempo real de parámetros del suelo. La arquitectura del sistema se basó en cuatro niveles: ambiental (rural), sensores y actuadores, red de comunicación y aplicación, con el código disponible para su funcionamiento. Los datos recopilados se transmitieron a puntos de recopilación de datos mediante la tecnología LoRa. El nivel de aplicación permitió el almacenamiento, análisis y visualización de datos, lo que permitió a los usuarios finales supervisar y controlar de forma remota las operaciones de medición ambiental. Con pruebas de alcance de tecnología LoRa, los resultados indicaron la capacidad de cubrir un área máxima de entre 95 y 120 hectáreas en las áreas estudiadas. Además, los datos recopilados se enviaron a ThingSpeak.com y a una aplicación móvil llamada Thingsview. Esto demostró la eficiencia y viabilidad de la tecnología LoRa para aplicaciones de sensores de comunicación industrial e IoT en entornos rurales, ofreciendo automatización, mayor eficiencia y ahorros en recursos humanos para tareas de monitorización ambiental.

This article mainly analyzes the correlation between the carrier energy in robotic arms, according to enhance its performance. This task is achieved because of the sensors/actuators based on nanostructures properties: short response time and high robustness, which proportionated the possibility to execute intricate instructions by the control subsystem of the robotic arm. Therefore, the instructions executed by the controller are supported by a polynomial design, this algorithm helped to evaluate every response signal as a consequence of the main control system, which was consequently by the short response time from the main sensors “flow (carrier energy) and speed of the robotic arm”, moreover, the advantage of the proposed system is given by the extra time obtained also to verify the stability of the robotic arm based in Lyapunov models correlated with Lagrange, as well as every equations were solved and organized by neural network., Este artículo analiza principalmente la correlación entre la energía portadora en brazos robóticos, en función de mejorar su rendimiento. Esta tarea se logra gracias a los sensores/actuadores basados en propiedades de nanoestructuras: corto tiempo de respuesta y alta robustez, lo que proporcionó la posibilidad de ejecutar instrucciones complejas mediante el subsistema de control del brazo robótico. Por lo tanto, las instrucciones ejecutadas por el controlador están sustentadas en un diseño polinómico, este algoritmo ayudó a evaluar cada señal de respuesta como consecuencia del sistema de control principal, lo que fue gracias al corto tiempo de respuesta de los sensores principales “flujo (energía portadora) y velocidad del brazo robótico”, además, la ventaja del sistema propuesto está dada por el tiempo extra que se toma también para verificar la estabilidad del brazo robótico basado en modelos de Lyapunov correlacionados con Lagrange, así como todas las ecuaciones fueron resueltas y organizadas por red neuronal.

The objective of this work was to develop an innovative LoRa-based platform that provides a low-cost and customizable solution for real-time monitoring of soil parameters. The system architecture was based on four levels: environmental (rural), sensors and actuators, communication network, and application, with the code made available for operation. The collected data were transmitted to data collection points using LoRa technology. The application level allowed for data storage, analysis, and visualization, enabling end-users to remotely monitor and control environmental measurement operations. With LoRa technology range tests, results indicated the capability to cover a maximum area between 95 and 120 hectares in the studied areas. Additionally, the collected data were sent to ThingSpeak.com and a mobile application called Thingsview. This demonstrated the efficiency and viability of LoRa technology for industrial communication sensor and IoT applications in rural environments, offering automation, increased efficiency, and savings in human resources for environmental monitoring tasks, El objetivo de este trabajo fue desarrollar una innovadora plataforma basada en LoRa que proporciona una solución económica y personalizable para la monitorización en tiempo real de parámetros del suelo. La arquitectura del sistema se basó en cuatro niveles: ambiental (rural), sensores y actuadores, red de comunicación y aplicación, con el código disponible para su funcionamiento. Los datos recopilados se transmitieron a puntos de recopilación de datos mediante la tecnología LoRa. El nivel de aplicación permitió el almacenamiento, análisis y visualización de datos, lo que permitió a los usuarios finales supervisar y controlar de forma remota las operaciones de medición ambiental. Con pruebas de alcance de tecnología LoRa, los resultados indicaron la capacidad de cubrir un área máxima de entre 95 y 120 hectáreas en las áreas estudiadas. Además, los datos recopilados se enviaron a ThingSpeak.com y a una aplicación móvil llamada Thingsview. Esto demostró la eficiencia y viabilidad de la tecnología LoRa para aplicaciones de sensores de comunicación industrial e IoT en entornos rurales, ofreciendo automatización, mayor eficiencia y ahorros en recursos humanos para tareas de monitorización ambiental.

This article mainly analyzes the correlation between the carrier energy in robotic arms, according to enhance its performance. This task is achieved because of the sensors/actuators based on nanostructures properties: short response time and high robustness, which proportionated the possibility to execute intricate instructions by the control subsystem of the robotic arm. Therefore, the instructions executed by the controller are supported by a polynomial design, this algorithm helped to evaluate every response signal as a consequence of the main control system, which was consequently by the short response time from the main sensors “flow (carrier energy) and speed of the robotic arm”, moreover, the advantage of the proposed system is given by the extra time obtained also to verify the stability of the robotic arm based in Lyapunov models correlated with Lagrange, as well as every equations were solved and organized by neural network., Este artículo analiza principalmente la correlación entre la energía portadora en brazos robóticos, en función de mejorar su rendimiento. Esta tarea se logra gracias a los sensores/actuadores basados en propiedades de nanoestructuras: corto tiempo de respuesta y alta robustez, lo que proporcionó la posibilidad de ejecutar instrucciones complejas mediante el subsistema de control del brazo robótico. Por lo tanto, las instrucciones ejecutadas por el controlador están sustentadas en un diseño polinómico, este algoritmo ayudó a evaluar cada señal de respuesta como consecuencia del sistema de control principal, lo que fue gracias al corto tiempo de respuesta de los sensores principales “flujo (energía portadora) y velocidad del brazo robótico”, además, la ventaja del sistema propuesto está dada por el tiempo extra que se toma también para verificar la estabilidad del brazo robótico basado en modelos de Lyapunov correlacionados con Lagrange, así como todas las ecuaciones fueron resueltas y organizadas por red neuronal.

Quadruped robots are versatile locomotion platforms capable of a variety of manipulation tasks. For each operating environment, the quadruped's choice of kinematic design, actuators, and end-effectors requires tuning and optimization. This research introduces geometrically enhanced designs for limb mechanisms and magnetic variable stiffness end-effectors for a ship-board quadruped platform, SORREL. The choice of kinematics in quadrupeds is highly dependent on the gait and certain leg designs might be more prone to waste power. Traditional robots, design their kinematics based on the actuator being a single unit consisting of a motor and a gearbox, overlooking the effects of their relative positions on the limb kinematics. A new method was developed for designing the leg kinematics by decoupling the design of the gearbox and the motor. This method gives more freedom in the design of the kinematics and allows for a wider range of configurations best fit for the required task. The quadruped leg design presented in this work has both actuators collocated at the hip in a parallel configuration; however, the gearbox of the knee motor is relocated from the hip to the knee joint. This seemingly simple modification significantly reduces the mechanical antagonism and motor losses and increases the stiffness of the leg. Quadrupeds perform manipulation and grasping through task-specific actuators. These actuators need to interact with the environment safely while maintaining accurate force control capabilities. More specifically, SORELL needs to be equipped with gripper modules to deal with varying tasks such as typing on keyboards, precision manipulation of electronics, and general pick and place. Most grippers used in manipulators are based on stiff positioned-controlled actuators which provide accuracy but require bulky and expensive Force/Torque (FT) sensors for force control. Additionally, traditional grippers struggle with delicate handling tasks and pose safety risks due

El TFG proposat consisteix en el redisseny d'un sistema de tancament de seguretat activat amb un fusible tèrmic i actuat mitjançant un actuador pneumàtic de simple efecte (sense pressuritzar) que permeti obrir o tancar (depenent de les necessitats del procés industrial) una vàlvula de bola de funcionament manual (amb palanca). Aquest equip es basa en un sistema comercial ja existent, del que s’han analitzat els punts febles i que s’han utilitzat per redissenyar un sistema similar que millori aquests punts i pugui fer-li competència. L’equip incorporarà diferents elements dissenyats per ser compatibles amb la gran majoria de vàlvules de bola i actuadors pneumàtics que es fabriquen i es venen al mercat europeu, amb la idea d'aconseguir un kit de tancament de vàlvules de bola quasi universal. S’ha basat el disseny de les diferents peces en un actuador i una vàlvula de bola de marca i model concrets, per tal de poder fer el primer prototip i els càlculs necessaris del sistema. Un cop dissenyades les peces i dimensionat el sistema (incloent-hi la selecció de material), s’han fet anàlisis d’elements finits a cada peça sotmesa a tensió fent servir l’eina bàsica d’anàlisi d’elements finits del programa Autodesk Inventor. Un cop analitzades, s’arriba a la conclusió que les tensions màximes de Von Mises obtingudes permeten mantenir per a totes les peces un factor de seguretat igual o superior a 1,25, donant com a vàlid el disseny del primer prototip., El TFG propuesto consiste en el rediseño de un sistema de cierre de seguridad activado con un fusible térmico y actuado mediante un actuador neumático de simple efecto (sin presurizar) que permita abrir o cerrar (dependiendo de las necesidades del proceso industrial) una válvula de bola de funcionamiento manual (con palanca). Este equipo se basa en un sistema comercial ya existente, del que se han analizado los puntos débiles y que se deben utilizar para rediseñar un sistema similar que mejore estos puntos y pueda hacerle competencia. El equipo incorporará diferentes elementos diseñados para ser compatibles con la gran mayoría de válvulas de bola y actuadores neumáticos que se fabrican y venden en el mercado europeo, con la idea de conseguir un kit de cierre de válvulas de bola cuasi universal. Se ha basado el diseño de las diferentes piezas en un actuador y una válvula de bola de marca y modelo concretos, para poder realizar el primer prototipo y los cálculos necesarios del sistema. Una vez diseñadas las piezas y dimensionado el sistema (incluyendo la selección de material), se han realizado análisis de elementos finitos en cada pieza sometida a tensión utilizando la herramienta básica de análisis de elementos finitos del programa Autodesk Inventor. Una vez analizadas, se llega a la conclusión de que las tensiones máximas de Von Misses obtenidas permiten mantener para todas las piezas un factor de seguridad igual o superior a 1,25, dando como válido el diseño del primer prototipo., The proposed TFG consists of the redesign of a safety closing system activated with a thermal fuse and actuated by means of a single-effect pneumatic actuator (without pressurization) that allows opening or closing (depending on the needs of the industrial process) a lever operated ball valve. This design is based on an already existing commercial system, the weak points of which have been analyzed and have been used to redesign a similar system that improves these points and can prove competititve. The equipment will incorporate different elements designed to be compatible with the vast majority of ball valves and pneumatic actuators that are manufactured and sold in the European market, with the idea of achieving an almost universal ball valve closing kit. The design of the different parts has been based on an actuator and a ball valve of a specific manufacturer and model, in order to be able to make the first prototype and the necessary calculations of the system. Once the parts were designed and the system dimensioned (including material selection), finite element analysis were performed on each part subjected to tension using the basic finite element analysis tool of the Autodesk Inventor program. Once analyzed, the conclusion reached is that the maximum Von Misses stresses obtained make it possible to maintain a safety factor equal to or greater than 1.25 for all parts, giving the design of the first prototype as valid.

Boom lifts are commonly utilized in various industries to provide safe and efficient access to elevated work areas. Recently, a boom-lift-mounted robot (BLMR) concept has been proposed, combining a boom lift and an industrial robot to facilitate enhanced levels of construction automation. However, boom lifts typically contain extendable large-scale, variable-stiffness structures, subject to complex nonlinear static deformation, and dynamic motion/gust-induced vibrations. These issues hinder the BLMR's precise and safe operation. To address these issues, this article proposed a static deformation compensation scheme and a vibration alleviation method based on the inertial measurement unit (IMU). The deformation exploits the measurement from a laser tracker, while the vibration compensation method synergistically exploits the extended Kalman filter of the IMU measurements at the tip and the robot motion's dynamic contribution to vibration under a real-time feedback framework. A telescope-type BLMR prototype is built to verify the proposed method. The proposed method is compared with a time-varying input shaper concerning the extension-dependent natural frequencies and damping ratios. Enhanced accuracy of the BLMR operation has been experimentally illustrated.

Den snabba tillväxten inom automation och robotik driver marknaden för linjära ställdon, med en förväntad årlig tillväxttakt (CAGR) på 8,9% från 2024 till 2030. För att möta de olika behoven behöver modulära och anpassningsbara designer skapas. Den nuvarande trenden inom detta område är programmering, precision och synkronisering. Ställdon kommer att spela en viktig roll i framtiden när behovet av robotapplikationer och smart styrning uppstår. Denna avhandling undersöker utvecklingen av synkroniserings mjukvara som använder en algoritm som justerar hastigheten, integrerad med CANopen-protokollet. Syftet är att hantera och säkerställa synkronisering mellan linjära ställdon inom inbyggda styrsystem. Huvudmålet är att uppnå exakt synkronisering mellan flera ställdon i ett CAN-nätverk. Mjukvaran är utvecklad i CAPL (CAN Access Programming Language) och utnyttjar CANopens PDO-tjänster på grund av deras effektivitet och prioriterade datakommunikation. Metoden innefattar implementering och testning av synkronisering algoritmen i både simulerade och verkliga miljöer, med verktyg som Matlab och CANanalyz för dataanalys. Resultaten visar att synkroniseringsprocessen effektivt justerade ställdonets hastigheter och uppfyller de initiala kriterierna. Slutsatserna bekräftar att den föreslagna metoden inte bara är genomförbar utan även tillämpbar i industriella sammanhang, med potential för ytterligare förbättringar genom integration av avancerade algoritmer som maskininlärning eller artificiell intelligens., The rapid growth in automation and robotics drives the linear actuator market, with an expected compound annual growth rate (CAGR) of 8.9% from 2024 to 2030. Modular and adaptable designs need to be developed. The current trend in this area includes programming, precision, and synchronisation. Actuators will play a significant role in the future as the demand for robotic applications and intelligent control increases. This thesis investigates the development of synchronisation software using a speed adjustment algorithm for integration with the CANopen protocol, aiming to manage and ensure synchronisation between linear actuators within an embedded control system. The principal objective was to achieve precise synchronisation across multiple actuators in a CAN network. The software was developed in CAPL (CAN Access Programming Language), and leverages the CANopen PDO service due to its efficiency and higher priority in data transmission. Methods involved implementing and testing the synchronisation algorithm in simulated and real-world environments, using tools such as Matlab and CANanalyz for data analysis. The results demonstrate that the synchronisation process effectively regulates actuator speeds, meeting the initial performance requirements. The conclusions confirm that the proposed method is feasible and applicable in industrial contexts, with the potential for further enhancement through advanced algorithms like machine learning or artificial intelligence.

We explore sim-to-real transfer of deep reinforcement learning controllers for a heavy vehicle with active suspensions designed for traversing rough terrain. While related research primarily focuses on lightweight robots with electric motors and fast actuation, this study uses a forestry vehicle with a complex hydraulic driveline and slow actuation. We simulate the vehicle using multibody dynamics and apply system identification to find an appropriate set of simulation parameters. We then train policies in simulation using various techniques to mitigate the sim-to-real gap, including domain randomization, action delays, and a reward penalty to encourage smooth control. In reality, the policies trained with action delays and a penalty for erratic actions perform nearly at the same level as in simulation. In experiments on level ground, the motion trajectories closely overlap when turning to either side, as well as in a route tracking scenario. When faced with a ramp that requires active use of the suspensions, the simulated and real motions are in close alignment. This shows that the actuator model together with system identification yields a sufficiently accurate model of the actuators. We observe that policies trained without the additional action penalty exhibit fast switching or bang–bang control. These present smooth motions and high performance in simulation but transfer poorly to reality. We find that policies make marginal use of the local height map for perception, showing no indications of predictive planning. However, the strong transfer capabilities entail that further development concerning perception and performance can be largely confined to simulation.

We explore sim-to-real transfer of deep reinforcement learning controllers for a heavy vehicle with active suspensions designed for traversing rough terrain. While related research primarily focuses on lightweight robots with electric motors and fast actuation, this study uses a forestry vehicle with a complex hydraulic driveline and slow actuation. We simulate the vehicle using multibody dynamics and apply system identification to find an appropriate set of simulation parameters. We then train policies in simulation using various techniques to mitigate the sim-to-real gap, including domain randomization, action delays, and a reward penalty to encourage smooth control. In reality, the policies trained with action delays and a penalty for erratic actions perform nearly at the same level as in simulation. In experiments on level ground, the motion trajectories closely overlap when turning to either side, as well as in a route tracking scenario. When faced with a ramp that requires active use of the suspensions, the simulated and real motions are in close alignment. This shows that the actuator model together with system identification yields a sufficiently accurate model of the actuators. We observe that policies trained without the additional action penalty exhibit fast switching or bang–bang control. These present smooth motions and high performance in simulation but transfer poorly to reality. We find that policies make marginal use of the local height map for perception, showing no indications of predictive planning. However, the strong transfer capabilities entail that further development concerning perception and performance can be largely confined to simulation.

We explore sim-to-real transfer of deep reinforcement learning controllers for a heavy vehicle with active suspensions designed for traversing rough terrain. While related research primarily focuses on lightweight robots with electric motors and fast actuation, this study uses a forestry vehicle with a complex hydraulic driveline and slow actuation. We simulate the vehicle using multibody dynamics and apply system identification to find an appropriate set of simulation parameters. We then train policies in simulation using various techniques to mitigate the sim-to-real gap, including domain randomization, action delays, and a reward penalty to encourage smooth control. In reality, the policies trained with action delays and a penalty for erratic actions perform nearly at the same level as in simulation. In experiments on level ground, the motion trajectories closely overlap when turning to either side, as well as in a route tracking scenario. When faced with a ramp that requires active use of the suspensions, the simulated and real motions are in close alignment. This shows that the actuator model together with system identification yields a sufficiently accurate model of the actuators. We observe that policies trained without the additional action penalty exhibit fast switching or bang–bang control. These present smooth motions and high performance in simulation but transfer poorly to reality. We find that policies make marginal use of the local height map for perception, showing no indications of predictive planning. However, the strong transfer capabilities entail that further development concerning perception and performance can be largely confined to simulation.

We explore sim-to-real transfer of deep reinforcement learning controllers for a heavy vehicle with active suspensions designed for traversing rough terrain. While related research primarily focuses on lightweight robots with electric motors and fast actuation, this study uses a forestry vehicle with a complex hydraulic driveline and slow actuation. We simulate the vehicle using multibody dynamics and apply system identification to find an appropriate set of simulation parameters. We then train policies in simulation using various techniques to mitigate the sim-to-real gap, including domain randomization, action delays, and a reward penalty to encourage smooth control. In reality, the policies trained with action delays and a penalty for erratic actions perform nearly at the same level as in simulation. In experiments on level ground, the motion trajectories closely overlap when turning to either side, as well as in a route tracking scenario. When faced with a ramp that requires active use of the suspensions, the simulated and real motions are in close alignment. This shows that the actuator model together with system identification yields a sufficiently accurate model of the actuators. We observe that policies trained without the additional action penalty exhibit fast switching or bang–bang control. These present smooth motions and high performance in simulation but transfer poorly to reality. We find that policies make marginal use of the local height map for perception, showing no indications of predictive planning. However, the strong transfer capabilities entail that further development concerning perception and performance can be largely confined to simulation.

We explore sim-to-real transfer of deep reinforcement learning controllers for a heavy vehicle with active suspensions designed for traversing rough terrain. While related research primarily focuses on lightweight robots with electric motors and fast actuation, this study uses a forestry vehicle with a complex hydraulic driveline and slow actuation. We simulate the vehicle using multibody dynamics and apply system identification to find an appropriate set of simulation parameters. We then train policies in simulation using various techniques to mitigate the sim-to-real gap, including domain randomization, action delays, and a reward penalty to encourage smooth control. In reality, the policies trained with action delays and a penalty for erratic actions perform nearly at the same level as in simulation. In experiments on level ground, the motion trajectories closely overlap when turning to either side, as well as in a route tracking scenario. When faced with a ramp that requires active use of the suspensions, the simulated and real motions are in close alignment. This shows that the actuator model together with system identification yields a sufficiently accurate model of the actuators. We observe that policies trained without the additional action penalty exhibit fast switching or bang–bang control. These present smooth motions and high performance in simulation but transfer poorly to reality. We find that policies make marginal use of the local height map for perception, showing no indications of predictive planning. However, the strong transfer capabilities entail that further development concerning perception and performance can be largely confined to simulation.

Den snabba tillväxten inom automation och robotik driver marknaden för linjära ställdon, med en förväntad årlig tillväxttakt (CAGR) på 8,9% från 2024 till 2030. För att möta de olika behoven behöver modulära och anpassningsbara designer skapas. Den nuvarande trenden inom detta område är programmering, precision och synkronisering. Ställdon kommer att spela en viktig roll i framtiden när behovet av robotapplikationer och smart styrning uppstår. Denna avhandling undersöker utvecklingen av synkroniserings mjukvara som använder en algoritm som justerar hastigheten, integrerad med CANopen-protokollet. Syftet är att hantera och säkerställa synkronisering mellan linjära ställdon inom inbyggda styrsystem. Huvudmålet är att uppnå exakt synkronisering mellan flera ställdon i ett CAN-nätverk. Mjukvaran är utvecklad i CAPL (CAN Access Programming Language) och utnyttjar CANopens PDO-tjänster på grund av deras effektivitet och prioriterade datakommunikation. Metoden innefattar implementering och testning av synkronisering algoritmen i både simulerade och verkliga miljöer, med verktyg som Matlab och CANanalyz för dataanalys. Resultaten visar att synkroniseringsprocessen effektivt justerade ställdonets hastigheter och uppfyller de initiala kriterierna. Slutsatserna bekräftar att den föreslagna metoden inte bara är genomförbar utan även tillämpbar i industriella sammanhang, med potential för ytterligare förbättringar genom integration av avancerade algoritmer som maskininlärning eller artificiell intelligens., The rapid growth in automation and robotics drives the linear actuator market, with an expected compound annual growth rate (CAGR) of 8.9% from 2024 to 2030. Modular and adaptable designs need to be developed. The current trend in this area includes programming, precision, and synchronisation. Actuators will play a significant role in the future as the demand for robotic applications and intelligent control increases. This thesis investigates the development of synchronisation software using a speed adjustment algorithm for integration with the CANopen protocol, aiming to manage and ensure synchronisation between linear actuators within an embedded control system. The principal objective was to achieve precise synchronisation across multiple actuators in a CAN network. The software was developed in CAPL (CAN Access Programming Language), and leverages the CANopen PDO service due to its efficiency and higher priority in data transmission. Methods involved implementing and testing the synchronisation algorithm in simulated and real-world environments, using tools such as Matlab and CANanalyz for data analysis. The results demonstrate that the synchronisation process effectively regulates actuator speeds, meeting the initial performance requirements. The conclusions confirm that the proposed method is feasible and applicable in industrial contexts, with the potential for further enhancement through advanced algorithms like machine learning or artificial intelligence.

This article presents the design of a control strategy for the Calais canal, a navigation canal located in a lowland area in northern France that is affected by tides. Moreover, the available actuators are discrete-valued and the hierarchy of operational objectives is time-varying. All these circumstances render water level regulation of the Calais canal a challenging problem. In view of this situation, the design of the overall control architecture is divided into a sequence of structured tasks, which are distributed among layers. The upper layer determines the current operating mode based on the analysis of several environmental and operational aspects. Information regarding the current mode is taken into account at the intermediate layer to select the appropriate optimization-based control problem, which is solved using lexicographic minimization. The optimal control setpoints are determined and sent to the lower layer, where scheduling problems are solved to select low-level control actions from a finite set to minimize the mismatch with respect to the optimal setpoints. Different realistic simulation scenarios are tested to demonstrate the effectiveness of the proposed approach., Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Transport Engineering and Logistics

Bulk nanoporous platinum (np-Pt) samples with a remarkably fine ligament size down to 2 nm and good mechanical robustness were fabricated for the first time by electrochemically dealloying Pt15Cu85 master alloy in 1 mol L−1 H2SO4 at 60 ℃. The as-prepared np-Pt shows an electrochemically active specific surface area as high as 25 m2/g due to the ultrafine nanostructure. The active surface area remains almost invariable even after 15% macroscopic compressive strain. Furthermore, np-Pt shows considerably high thermal stability due to the low surface diffusivity of Pt. Np-Pt is a promising surface- or interface-controlled functional material, particularly when excellent electrochemical and mechanical performance are necessary due to its high surface-to-volume ratio and mechanical robustness. This work demonstrated the potential application of np-Pt as an electrochemical actuation material. In-situ dilatometry experiments revealed that the surface adsorption–desorption of OH species on np-Pt causes significant strain variations. The proposed np-Pt electrochemical actuator shows an operating voltage down to 1.0 V, a large reversible strain amplitude of 0.37%, and a strain energy density of 1.64 MJ/m³.

Switched Reluctance Motors (SRMs) enable power-efficient actuation with mechanically simple designs. This paper aims to identify the nonlinear relationship between torque, rotor angle, and currents, to design commutation functions that minimize torque ripple in SRMs. This is achieved by conducting specific closed-loop experiments using purposely imperfect commutation functions and identifying the nonlinear dynamics via Bayesian estimation. A simulation example shows that the presented method is robust to position-dependent disturbances, and experiments suggest that the identification method enables the design of commutation functions that significantly increase performance. The developed approach enables accurate identification of the torque-current-angle relationship in SRMs, without the need for torque sensors, an accurate linear model, or an accurate model of position-dependent disturbances, making it easy to implement in production.

Age of Information (AoI) and delay are crucial performance metrics for Industrial Internet of Things (IIoT) applications not only to perform seamless actuation and control actions but also to enable self-organized and re-configurable manufacturing systems. A challenging task in heterogeneous IIoT networks is to minimize the AoI while maintaining a predefined delay constraint. In this work, we consider a Device-to-Device (D2D)-based heterogeneous IIoT network that supports two types of traffic flows, namely AoI-sensitive flow and delay-sensitive flow. First, we introduce a distributed backlog-aware random access protocol that allows the AoI-sensitive nodes to opportunistically access the channel based on the queue occupancy of the delay-sensitive node. Then, we develop an analytical framework to evaluate the average delay and the average AoI, and formulate an optimization problem to minimize the AoI under a given delay constraint. Finally, we provide numerical results to demonstrate the impact of different network parameters on the performance in terms of the average delay and the average AoI. We also give numerical solutions of the optimal parameters that minimize the AoI subject to a defined delay constraint., Forskningsprofilen NIIT

This thesis aims to provide a comprehensive reference on the effective integration of shape memory alloys into architectural design and design. Despite growing interest in SMAs for kinetic structures and adaptive facades, there is currently a fragmented understanding of how to leverage their unique properties in the built environment. Designers lack consolidated resources that map the capacities and limitations of different SMA materials and configurations with respect to functional objectives, manufacturing constraints, and performance goals. My research will gather dispersed knowledge across materials science, mechanics, and fabrication processes relevant to architectural SMAs. After conducting extensive research and different stages of prototyping, a final responsive wall piece will be designed and built that interacts with users responding to different stimuli including touch, sound, or distance. The outcome of this research on the integration of shape memory alloys (SMAs) into architectural design and construction can contribute significantly to designers and the field of architecture in several ways • Unlocking new design possibilities: • Facilitating interdisciplinary collaboration• Developing design guidelines and tools • Advancing responsive architecture• Inspiring future research and innovation

This paper introduces a wearable pneumatic actuator, designed for providing multiple types of tactile feedback using a single end-effector. To this end, the actuator combines a 3D-printed framework consisting of five 0.5 DOF soft silicon air cells with a pneumatic system to deliver a range of tactile sensations through a single end-effector. The actuator is capable of producing diverse haptic feedback, including vibration, pressure, impact, and lateral force, controlled by an array of solenoid valves. The design’s focus on multimodality in a compact and lightweight form factor makes it highly suitable for wearable applications. It can produce a maximum static force of 8.3 N, vibrations with an acceleration of up to 3.15 g, and lateral forces of up to 3.3 N. The efficacy of the actuator is demonstrated through two distinct user studies: one focusing on perception, where users differentiated between lateral cues and vibration frequencies, and another within a first-person shooter gaming scenario, revealing enhanced user engagement and experience. The actuator’s adaptability to body sites and rich multimodal haptic feedback enables it to find applications in virtual reality, gaming, training simulations, and more.

This paper introduces a wearable pneumatic actuator, designed for providing multiple types of tactile feedback using a single end-effector. To this end, the actuator combines a 3D-printed framework consisting of five 0.5 DOF soft silicon air cells with a pneumatic system to deliver a range of tactile sensations through a single end-effector. The actuator is capable of producing diverse haptic feedback, including vibration, pressure, impact, and lateral force, controlled by an array of solenoid valves. The design’s focus on multimodality in a compact and lightweight form factor makes it highly suitable for wearable applications. It can produce a maximum static force of 8.3 N, vibrations with an acceleration of up to 3.15 g, and lateral forces of up to 3.3 N. The efficacy of the actuator is demonstrated through two distinct user studies: one focusing on perception, where users differentiated between lateral cues and vibration frequencies, and another within a first-person shooter gaming scenario, revealing enhanced user engagement and experience. The actuator’s adaptability to body sites and rich multimodal haptic feedback enables it to find applications in virtual reality, gaming, training simulations, and more.

The characterization of vibrotactile perception is crucial to accurately configure haptic devices and create appropriate stimuli for improving user performance in human-machine interaction systems. This article presents a study aiming to determine the absolute and differential vibrotactile thresholds in different areas of the torso to develop reliable haptic patterns to be displayed using a haptic vest. In the `absolute threshold' experiment, we measure the minimum detectable vibration using a forced-choice task. Furthermore, in the `differential threshold' experiment, we measure the minimum frequency change needed for users to discriminate two successive vibrotactile stimuli using a vibration matching task. The first experiment does not show differences between absolute thresholds, opening up the possibility of setting a unique minimal vibration for creating haptic patterns. Similarly, the second experiment does not show differences between differential thresholds. Moreover, as these thresholds follow Weber's law, it is viable to estimate any upper or lower differential threshold for any reference stimulus using a K-value. These results are a first step for creating vibrotactile patterns over the torso with the employed eccentric rotating mass motors. Moreover, the whole study provides a method to obtain these psychophysical values since the usage of different motors can change these results., Depto. de Psicología Experimental, Procesos Cognitivos y Logopedia, Fac. de Psicología, TRUE, pub

The convergence of nano-, bio-, and information technologies is based on the understanding of complex hierarchical structures and systems, as well as on the material unity at the nanoscale and on technology integration from that scale. A growing interest in these technologies is a result of their potential to provide solutions to numerous societal challenges, such as advanced healthcare, environmental remediation, sustainable development, and adoption of cyber-physical systems based on the Internet of Things and the Internet of Systems. Taking into account that hybrid nanomaterials possess extraordinary physical and chemical properties derived from their size in the nanoscale, the aim of this work is to present the connection between processing parameters and multifunctional properties of nano scale hybrid materials, focusing on the study of ceramic-polymer structures before they can be nano-engineered into functional devices. The unique functionality of these nanostructures has enabled their applications in numerous devices such as: micro and nano-electro-mechanical systems (MEMS/NEMS), sensors, microactuators, surface acoustic wave devices, polymer electrolyte membrane fuel cells, switches, thermistors, resonators and filters, electrooptic devices, etc. In this study special attention has been paid to their applications in the fields of electronics, biotechnology, environmental protection and remediation.

The World Health Organization declared Alzheimer's disease and its care a global public health priority in 2021 due to its complexity and development, which affects the patient and their caregiver. Alzheimer's symptoms worsen daily, so the patient must have 24/7 care; between responsibilities, the caregiver must deal with arduous tasks, from bathing the patient to managing the behavioral symptoms. By carrying out a systematic mapping, it was possible to identify that, despite the profuse information about Alzheimer's and its care, there is no concise source of information that allows the development of integrated systems that support the care of patients with Alzheimer's. This paper is presented OntoCaimer, which is an ontology that synthesizes the recommendations and preventive actions for most of the symptoms of the different stages of Alzheimer's. OntoCaimer integrates concepts related to sensors, actuators, and measurement, making it possible to use it as a basis for the development of systems that support patient care digitally through alerts or with the use of actuators to support patient care. OntoCaimer allows automating a group of variables associated with recommendations or preventive actions such as weight, environment, and feeding schedules, among others, which would support patient care, reduce caregiver tasks, and serve as a knowledge base for the scientific community and the development of systems that implement electronic systems or simulations before their implementation., La Organización Mundial de la Salud declaró en el 2021 al Alzheimer y su cuidado como prioridad de salud pública a nivel mundial debido a su complejidad y desarrollo, que afecta al paciente y su cuidador. Los síntomas del Alzheimer empeoran día a día, por lo que el paciente debe tener un cuidado 24/7; entre las responsabilidades, el cuidador debe lidiar con arduas tareas, desde bañar al paciente hasta manejar sus síntomas comportamentales. A pesar de la profusa información acerca del Alzheimer y su cuidado, no se cuenta con una fuente concisa de información que permita desarrollar sistemas integrados que soporten el cuidado de pacientes con Alzheimer. En este artículo se presenta OntoCaimer, una ontología que sintetiza las recomendaciones y acciones preventivas para la gran mayoría de los síntomas de las diferentes etapas del Alzheimer, asimismo, OntoCaimer integra conceptos relacionados con sensores, actuadores y medición, haciendo posible su uso como base para el desarrollo de sistemas que apoyen el cuidado de los pacientes, de manera digital –a través de alertas–, o con el uso de actuadores, todo con el fin de dar soporte al cuidado de los pacientes. OntoCaimer permite automatizar un grupo de variables asociadas a las recomendaciones o acciones preventivas como el: peso, ambiente, horarios de alimentación, entre otros, lo que permitiría apoyar el cuidado del paciente, disminuir las tareas del cuidador y servir como base de conocimiento para la comunidad científica y el desarrollo de sistemas que implementen sistemas electrónicos o simulaciones antes de su implementación.

Direct ink writing (DIW) is a promising additive manufacturing (AM) technique in the field of microsystems technology due to the potential for high detail resolution and the wide choice of materials suitable for the technique. In this study, inks of polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) as well as composite inks with reduced graphene oxide (PVDF-TrFE-rGO) were developed and adapted for continuous flow DIW. The composite PVDF-TrFE-rGO inks achieved percolation after 1.5 wt% and electrical conductivity of 2.8 S/cm at the highest loading investigate in this study (7 wt%). The inks were successfully printed with minimum nozzle diameter of 40 & mu;m on different substrates including glass, metal and a nitrile elastomer. It was also demonstrated that the inks can be used to create a fully 3D-printed piezoelectric device with the predicted response, i.e. the fabrication technique did not deteriorate the functionality of the device. The conductive composite ink was successfully utilized as an effective electrode in the device. It was therefore demonstrated that by combining materials, such as the composite PVDF-TrFE-rGO ink and the co-polymer PVDF-TrFE with additive manufacturing techniques, the fabrication of low-cost, versatile devices can be achieved.

Direct ink writing (DIW) is a promising additive manufacturing (AM) technique in the field of microsystems technology due to the potential for high detail resolution and the wide choice of materials suitable for the technique. In this study, inks of polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) as well as composite inks with reduced graphene oxide (PVDF-TrFE-rGO) were developed and adapted for continuous flow DIW. The composite PVDF-TrFE-rGO inks achieved percolation after 1.5 wt% and electrical conductivity of 2.8 S/cm at the highest loading investigate in this study (7 wt%). The inks were successfully printed with minimum nozzle diameter of 40 & mu;m on different substrates including glass, metal and a nitrile elastomer. It was also demonstrated that the inks can be used to create a fully 3D-printed piezoelectric device with the predicted response, i.e. the fabrication technique did not deteriorate the functionality of the device. The conductive composite ink was successfully utilized as an effective electrode in the device. It was therefore demonstrated that by combining materials, such as the composite PVDF-TrFE-rGO ink and the co-polymer PVDF-TrFE with additive manufacturing techniques, the fabrication of low-cost, versatile devices can be achieved.

Direct ink writing (DIW) is a promising additive manufacturing (AM) technique in the field of microsystems technology due to the potential for high detail resolution and the wide choice of materials suitable for the technique. In this study, inks of polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) as well as composite inks with reduced graphene oxide (PVDF-TrFE-rGO) were developed and adapted for continuous flow DIW. The composite PVDF-TrFE-rGO inks achieved percolation after 1.5 wt% and electrical conductivity of 2.8 S/cm at the highest loading investigate in this study (7 wt%). The inks were successfully printed with minimum nozzle diameter of 40 & mu;m on different substrates including glass, metal and a nitrile elastomer. It was also demonstrated that the inks can be used to create a fully 3D-printed piezoelectric device with the predicted response, i.e. the fabrication technique did not deteriorate the functionality of the device. The conductive composite ink was successfully utilized as an effective electrode in the device. It was therefore demonstrated that by combining materials, such as the composite PVDF-TrFE-rGO ink and the co-polymer PVDF-TrFE with additive manufacturing techniques, the fabrication of low-cost, versatile devices can be achieved.

The objective of this bachelors thesis is to conduct a comprehensive analysis of the communication subsystems in the UHF, S, and X bands of the 3Cat-8 mission. This mission aims to develop a satellite under the CubeSat standard that allows the study of different physical phenomena, such as the effects of auroral emissions on wave propagation through the ionosphere. Furthermore, this project also includes the design of an S-band patch antenna, both to understand the design of a space application antenna and to implement it on the same satellite and compare it with other commercial options. In addition, the polar orbit described by the satellite results in limited opportunities for data downlink, making it necessary to design and dimension magnetic actuators to enable the satellite to point towards the ground station. This document addresses the study, design, and manufacturing of these elements in order to enable the satellite to aim its antennas at the ground station. Overall, this work represents a significant contribution to the 3Cat-8 mission. Throughout this project, various activities encompassing the fields of aerospace engineering and telecommunications have been carried out.

Direct ink writing (DIW) is a promising additive manufacturing (AM) technique in the field of microsystems technology due to the potential for high detail resolution and the wide choice of materials suitable for the technique. In this study, inks of polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) as well as composite inks with reduced graphene oxide (PVDF-TrFE-rGO) were developed and adapted for continuous flow DIW. The composite PVDF-TrFE-rGO inks achieved percolation after 1.5 wt% and electrical conductivity of 2.8 S/cm at the highest loading investigate in this study (7 wt%). The inks were successfully printed with minimum nozzle diameter of 40 & mu;m on different substrates including glass, metal and a nitrile elastomer. It was also demonstrated that the inks can be used to create a fully 3D-printed piezoelectric device with the predicted response, i.e. the fabrication technique did not deteriorate the functionality of the device. The conductive composite ink was successfully utilized as an effective electrode in the device. It was therefore demonstrated that by combining materials, such as the composite PVDF-TrFE-rGO ink and the co-polymer PVDF-TrFE with additive manufacturing techniques, the fabrication of low-cost, versatile devices can be achieved.

This work focuses on how to implement modern online-reactive control strategies developed for robots with backdrivable actuators on robots with conventional high gear ratio, position controlled motors. The vast majority of robots today have motors like this. Robots with torque-controlled proprioceptive actuators which are backdrivable and have high torque density are currently being developed. However, there are still many situations in which robots with more traditional position-controlled, high gear-ratio actuators are more appropriate. For example, since actuator weight scales exponentially with size while torque scales linearly, it is still cost-prohibitive to use torque control for robots that are large and or very tall. In addition, backdrivable actuators typically require low latency communication to function and consume much more current than high gear ratio actuators because they are dampening motion during operation. Both restrictions can make these motors prohibitively difficult to use and expensive to obtain. For these reasons, research on robots with non-backdrivable actuators is still valuable. Many of the basic assumptions made for control systems are violated when using these actuators; with the intent to develop robots capable of dynamic, robust locomotion, we will attempt to categorize these obstacles, record the attempts to overcome them, explain why or why not the interventions were successful and finally, recommend paths of inquiry for future work. Contributions from this thesis project include creation of a bipedal robotic platform for locomotion experiments, multiple gait generators for bipedal robots with non-backdrivable actuators which were tested on physical hardware, investigation of methods to compensate for non-backdrivability during locomotion and several principles for designing control systems for dynamic, stable locomotion. Supplemental media included: - dcm-disturbance-rejection-sim.mp4 - dcm-omnidirectional-walking-sim.mp4 - model

Submillimeter-scale electrically driven micromotors have the potential to revolutionize micro-robotic systems, but difficulties in their fabrication processes and unknown physical phenomena prevent their development. In this paper, we propose a submillimeter-scale rotary piezoelectric ultrasonic motor with the smallest stator (0.41 mm × 0.41 mm × 0.25 mm) reported to date. The micromachining technologies enable the creation of tiny components. A micromanipulator that can control a small amount of adhesive of sub-milligram order engenders success in manufacture of the stator. Several experiments clarify the submillimeter-scale physical behaviors, such as the admittance and the quality factor. With appropriate piezoelectric materials, submillimeter-scale ultrasonic motors are built and characterized using a rotor with 0.15 mm diameter. The motor with typical hard PZTs demonstrated maximum torque of 5.4 nNm and a maximum angular velocity of 714 rad/s at an applied voltage with amplitude of 44.8 Vp-p. Furthermore, another motor with single-crystal PMN-PT piezoelectric elements presented the possibility of low-voltage actuation. These submillimeter-scale ultrasonic motors were compared with existing comparable-size micromotors.

Urged by a close future perspective of a traffic flow made of a mix of human-driven vehicles and automated vehicles (AVs), research has recently focused on studying the traffic flow characteristics of Adaptive Cruise Controls (ACCs), the most typical AV. However, in most works, the ACC system is studied under a simplifying and unrealistic assumption, or the ACC system modeled is inaccurate. This paper proposes a general hierarchical control system to model ACC systems with several assumptions based on the deficiencies above. Moreover, a field experiment was conducted, and the corresponding experimental data was used to verify the proposed hierarchical control system and assumptions. In addition, string stability is explored along with sensitivity analyses of control parameters based on an example under the constant time gap policy. The results show that different upper-level controller parameters have different delays, where the delay of the speed is negligible; the introduction of actuator delay and lag in the lower-level controller can significantly improve the model goodness of fit. Furthermore, optimizing the delay and lag in the lower-level controller can significantly enhance the string stability of ACCs than optimizing the control parameters., Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Electronic Instrumentation

Interconnections in modern systems make them vulnerable to adversarial attackers both by corrupting communication channels and compromising entire subsystems. The field of secure state estimation (SSE) aims to provide correct state estimation even when an unknown part of the measurement signals is corrupted. In this letter, we propose a solution to a novel generalized SSE problem in which full subsystems can be compromised, corrupting both the actuation and measurement signals. For a full system with p measurements, the proposed sliding mode observer (SMO)-based solution allows for up to p attack channels which can be arbitrarily distributed amongst attacks on actuation and measurement signals. This is a much larger class of attacks than considered in the existing literature. The method is demonstrated on 10 interconnected mass-spring-damper subsystems., Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Team Riccardo Ferrari

Wearable vibrotactile actuators are non-intrusive and inexpensive means to provide haptic feedback directly to the user's skin. Complex spatiotemporal stimuli can be achieved by combining multiple of these actuators, using the funneling illusion. This illusion can funnel the sensation to a particular position between the actuators, thereby creating virtual actuators. However, using the funneling illusion to create virtual actuation points is not robust and leads to sensations that are difficult to locate. We postulate that poor localization can be improved by considering the dispersion and attenuation of the wave propagation on the skin. We used the inverse filter technique to compute the delays and amplification of each frequency to correct the distortion and create sharp sensations that are easier to detect. We developed a wearable device stimulating the volar surface of the forearm composed of four independently controlled actuators. A psychophysical study involving twenty participants showed that the focused sensation improves confidence in the localization by 20% compared to the non-corrected funneling illusion. We anticipate our results to improve the control of wearable vibrotactile devices used for emotional touch or tactile communication., Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public., Human-Robot Interaction

Liquid crystalline polymers are attractive materials for untethered miniature soft robots. When they contain azo dyes, they acquire light-responsive actuation properties. However, the manipulation of such photoresponsive polymers at the micrometer scale remains largely unexplored. Here, uni- and bidirectional rotation and speed control of polymerized azo-containing chiral liquid crystalline photonic microparticles powered by light is reported. The rotation of these polymer particles is first studied in an optical trap experimentally and theoretically. The micro-sized polymer particles respond to the handedness of a circularly polarized trapping laser due to their chirality and exhibit uni- and bidirectional rotation depending on their alignment within the optical tweezers. The attained optical torque causes the particles to spin with a rotation rate of several hertz. The angular speed can be controlled by small structural changes, induced by ultraviolet (UV) light absorption. After switching off the UV illumination, the particle recovers its rotation speed. The results provide evidence of uni- and bidirectional motion and speed control in light-responsive polymer particles and offer a new way to devise light-controlled rotary microengines at the micrometer scale.

The convergence of nano-, bio-, and information technologies is based on the understanding of complex hierarchical structures and systems, as well as on the material unity at the nanoscale and on technology integration from that scale. A growing interest in these technologies is a result of their potential to provide solutions to numerous societal challenges, such as advanced healthcare, environmental remediation, sustainable development, and adoption of cyber-physical systems based on the Internet of Things and the Internet of Systems. Taking into account that hybrid nanomaterials possess extraordinary physical and chemical properties derived from their size in the nanoscale, the aim of this work is to present the connection between processing parameters and multifunctional properties of nano scale hybrid materials, focusing on the study of ceramic-polymer structures before they can be nano-engineered into functional devices. The unique functionality of these nanostructures has enabled their applications in numerous devices such as: micro and nano-electro-mechanical systems (MEMS/NEMS), sensors, microactuators, surface acoustic wave devices, polymer electrolyte membrane fuel cells, switches, thermistors, resonators and filters, electrooptic devices, etc. In this study special attention has been paid to their applications in the fields of electronics, biotechnology, environmental protection and remediation.

In hyperthermia for cancer treatments, tumors are heated to improve the outcome of radio-and chemotherapies. Using extracorporeal high-intensity focused ultrasound (HIFU) transducers, the heating can be applied noninvasively, accurately, and with high acoustic power. The heating location can be changed by electronic beam steering, within the transducer’s small local heating range, and by mechanically repositioning the transducer, which effectively shifts the local range to enable the treatment of larger tumors. An important problem is the selection of the sonication points, i.e., the discrete locations reachable by electronic beam steering, and the admissible mechanical transducer positions, which must be performed prior to treatment, and can be seen as an actuator selection problem. Clearly, the selected sonication points and transducer positions have a major impact on the achievable tumor temperatures, and their number is directly related to the controller’s complexity and, thereby, real-time feasibility. To address this challenging problem, this brief presents a target-conformal optimization-based actuator placement procedure, designed to assist the clinician in enabling maximum treatment quality using only a limited number of sonication points and transducer positions. The method is computationally tractable, and takes into account the specific tumor geometry and tissue properties.

Conventional bending sensors mainly utilize electrical, chemical, or optical signals to control the bending action of the soft pneumatic bending actuator. Recently, image processing techniques have emerged as an alternative for detecting such bending movements. However, their fabrication process and measurement methodology still remain intricate. In this article, a novel vision-based bending sensor for the pneumatic network (PneuNet) actuator based on ArUco marker detection is proposed. The fabrication of the proposed sensor is simplified through the use of 3-D-printed or outsourced parts, making the proposed sensor’s design and fabrication much easier. The PneuNet is connected to a rotating disk featuring an ArUco marker via an inextensible Kevlar cable. Thus, the bending of the PneuNet is converted to the one degree of freedom (DoF) rotation of the ArUco marker, which can then be monitored by the camera module. Experiments show that a linear correlation between the bending and ArUco marker angles is characterized despite the hysteresis of the PneuNet, proving the proposed sensor’s usability. Moreover, control of multiple actuators is feasible as long as the markers are within the field of view (FOV) of the camera module. Finally, based on the mechanical detection method of the sensor, tracking of the PneuNet’s tip displacement upon the exertion of external force is also showcased to utilize the proposed sensor’s versatility further.

Liquid crystalline polymers are attractive materials for untethered miniature soft robots. When they contain azo dyes, they acquire light-responsive actuation properties. However, the manipulation of such photoresponsive polymers at the micrometer scale remains largely unexplored. Here, uni- and bidirectional rotation and speed control of polymerized azo-containing chiral liquid crystalline photonic microparticles powered by light is reported. The rotation of these polymer particles is first studied in an optical trap experimentally and theoretically. The micro-sized polymer particles respond to the handedness of a circularly polarized trapping laser due to their chirality and exhibit uni- and bidirectional rotation depending on their alignment within the optical tweezers. The attained optical torque causes the particles to spin with a rotation rate of several hertz. The angular speed can be controlled by small structural changes, induced by ultraviolet (UV) light absorption. After switching off the UV illumination, the particle recovers its rotation speed. The results provide evidence of uni- and bidirectional motion and speed control in light-responsive polymer particles and offer a new way to devise light-controlled rotary microengines at the micrometer scale. © 2023 Wiley-VCH GmbH.

[Resumen] Los actuadores blandos, es decir, los fabricados con materiales altamente deformables, tienen un gran potencial en aplicaciones biomédicas, debido principalmente a su bajo coste y peso, reducido tiempo de respuesta, facilidad de fabricación, alto grado de maniobrabilidad que ofrecen y seguridad en términos de biocompatibilidad. El objetivo de este proyecto es desarrollar un catéter robótico a pequeña escala con una punta dirigible para realizar cirugías cardiacas. Como primer paso para validar el concepto, este trabajo se centra en el diseño de un actuador hidráulico blando para controlar la dirección de la punta del catéter. Las simulaciones por elementos finitos permiten predecir con precisión el complejo comportamiento de los materiales hiperelásticos, lo que facilita el diseño y la optimización del uso de materiales. En este trabajo se emplean simulaciones en COMSOL Multiphysics para, por un lado, conocer cómo evoluciona el actuador bajo las deformaciones tridimensionales y, por otro, optimizar la geometría del actuador en términos de desplazamiento de la punta para una presión determinada. Asimismo, se describe el método de fabricación de los primeros prototipos., [Abstract] Soft actuators, i.e., those made of highly deformable materials, have great potential in biomedical applications, mainly due to their low cost and weight, reduced response time, ease of fabrication, high degree of maneuverability and safety in terms of biocompatibility. The objective of this project is to develop a small-scale robotic catheter with a steerable tip to perform cardiac surgery. As a first step to validate the concept, this work focuses on the design of a soft hydraulic actuator to control the direction of the catheter tip. Finite element simulations allow accurate prediction of the complex behavior of hyperelastic materials, which facilitates design and optimization of material usage. In this work, simulations in COMSOL Multiphysics are used to understand how the actuator evolves under three-dimensional deformations and to optimize the actuator geometry in terms of tip displacement for a given pressure. The manufacturing method of the first prototypes is also described.

The convergence of nano-, bio-, and information technologies is based on the understanding of complex hierarchical structures and systems, as well as on the material unity at the nanoscale and on technology integration from that scale. A growing interest in these technologies is a result of their potential to provide solutions to numerous societal challenges, such as advanced healthcare, environmental remediation, sustainable development, and adoption of cyber-physical systems based on the Internet of Things and the Internet of Systems. Taking into account that hybrid nanomaterials possess extraordinary physical and chemical properties derived from their size in the nanoscale, the aim of this work is to present the connection between processing parameters and multifunctional properties of nano scale hybrid materials, focusing on the study of ceramic-polymer structures before they can be nano-engineered into functional devices. The unique functionality of these nanostructures has enabled their applications in numerous devices such as: micro and nano-electro-mechanical systems (MEMS/NEMS), sensors, microactuators, surface acoustic wave devices, polymer electrolyte membrane fuel cells, switches, thermistors, resonators and filters, electrooptic devices, etc. In this study special attention has been paid to their applications in the fields of electronics, biotechnology, environmental protection and remediation.

Safety is crucial for quadrotor flight, especially when the system suffers one rotor loss and disturbance. To enable quadrotors to survive in these worst cases, this paper proposes a Simultaneous Planning And Execution (SPAE) system strategy. First, the Euler angles under different equilibrium states are solved to ensure the feasibility of the control input when the quadrotors encounters rotor loss and disturbance. Based on the admissible Euler angle solutions, an emergency control strategy is proposed to realize desired angles by recalculating the desired trajectory and the disturbance observer. Meanwhile, this control strategy sacrifices the yaw angle control to handle further underactuation of the system caused by complete rotor failure. In addition to rotor losses, unsafe flight caused by actuator saturation is considered in the SPAE strategy where the planning and execution are simultaneous. As a decision maker, the planning considers the current disturbances and constraints of actuators, then generates a feasible trajectory for controller execution. As an executor of the decision, the controller feedback estimated disturbance information to the trajectory planning, which can help trajectory planning make admissible decisions consistent with the current situation. As a result, the actuator saturation caused by the underestimation of disturbance can be avoided under a feasible regenerated trajectory. Extensive simulations and experiments prove the validity of the proposed SPAE strategy. IEEE

The very recent concept of metaverse highlights the importance of virtual reality (VR) and augmented reality (AR), which associates with a wide variety of applications in entertainment, medical treatment, and human-machine interfaces. The current VR/AR technologies mainly rely on visual interaction, while immersive experience in VR and AR highly demands sensational feedback, such as haptic and temperature with noticeable quality in wearable or even skin-integrated formarts. In this article, we report a wearable and flexible haptic interface based on electromagnetic vibrotactile actuators with high wearability and stability. By adopting double layers of copper (Cu) coils at the top and bottom of the magnetic disc, an enhanced electromagnetic field can be generated. Additionally, the intensity of the haptic feedback can be modulated according to sensed pressure in the virtual world by adjusting the value of power input and frequency. The actuator exhibits high stability and tolerance upon environmental, cyclic, and impact resistance tests. Finally, the actuators are developed into the soft VR interfaces for mounting on forearms, fingers, and hands to verify their superiority over conventional haptic actuators in the aspects of performance and applications. © 2014 IEEE.

Direct ink writing (DIW) is a promising additive manufacturing (AM) technique in the field of microsystems technology due to the potential for high detail resolution and the wide choice of materials suitable for the technique. In this study, inks of polyvinylidene fluoride-trifluoroethylene (PVDF-TrFE) as well as composite inks with reduced graphene oxide (PVDF-TrFE-rGO) were developed and adapted for continuous flow DIW. The composite PVDF-TrFE-rGO inks achieved percolation after 1.5 wt% and electrical conductivity of 2.8 S/cm at the highest loading investigate in this study (7 wt%). The inks were successfully printed with minimum nozzle diameter of 40 & mu;m on different substrates including glass, metal and a nitrile elastomer. It was also demonstrated that the inks can be used to create a fully 3D-printed piezoelectric device with the predicted response, i.e. the fabrication technique did not deteriorate the functionality of the device. The conductive composite ink was successfully utilized as an effective electrode in the device. It was therefore demonstrated that by combining materials, such as the composite PVDF-TrFE-rGO ink and the co-polymer PVDF-TrFE with additive manufacturing techniques, the fabrication of low-cost, versatile devices can be achieved.