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This study focuses on the crucial need for effective control strategies design for linear electromechanical actuators (EMA), which are essential components in industrial automation. While the PI controller is commonly used due to its simplicity and versatility in various control scenarios, its effectiveness is limited by its complex tuning process, which requires significant time and effort to achieve the optimal performance. To address this issue, the paper focuses on employing metaheuristic approaches that are Spiral Dynamic Algorithm (SDA) and Artificial Bee Colony (ABC) to fine tune the PI parameters for controlling the position of EMA. The simulation results, implemented in MATLAB Simulink, show that PI-SDA and PI-ABC produce better performances with minimal steady-state error, reduced overshoot, faster settling time and rise time. Hardware-in-the-loop (HIL) testing proves the effectiveness of the controller's performance in real-world scenarios. PI-SDA achieved a steady-state error of 0.0623, zero overshoot, faster rise time of 1.6956 s, and faster settling time of 7.2166 s. As for validation, PI-ABC showed similar results in HIL environment with a steady-state error of -0.0314, an overshoot of 5.0007%, a rise time of 1.3805 s, and a settling time of 9.1002 s. These results highlight the effectiveness of metaheuristic methods in real-world implementation and outperform the traditional heuristic approaches.

A pneumatic piezoelectric linear actuator (PPLA) is proposed, which possesses the advantages of low power consumption, environmental friendliness, and high linearity of positioning. The prototype of the PPLA consists of a piezoelectric gas pump with serial chambers and a cylinder. The piezoelectric gas pump with serial chambers is designed with a wedge valve and flexible support structure, which results in high output performance and meets the working requirements of pneumatic linear actuators. Prototypes of PPLA are designed and manufactured. Experiments are conducted to investigate the effect of chamber height, driving voltage, and driving frequency on the performance of the PPLA. The experimental results indicate that increasing the chamber height enhances the output performance of the PPLA. At 250 Vpp and 120 Hz, the PPLA achieves a maximum output velocity of 16.62 mm/min and is able to handle a maximum load of 11 N. Additionally, an injection simulation experiment using zebrafish embryos is conducted, which confirms the high control accuracy and linearity of the PPLA. The experiment demonstrates the potential application of the PPLA in the field of cell manipulation. [ABSTRACT FROM AUTHOR]

Magnetic shape memory alloys (MSMA) have significant potential for industrial applications, especially in fast-switching linear actuators. Besides the eponymous active magnetic shape memory effect, they are characterized by a significant hysteresis owing to the material-inherent twinning stresses. In conventional MSMA push-actuators, twinning stresses represent an energy loss. However, energy efficient concepts embrace them as a multistable holding force, which is especially beneficial for applications such as robotic grippers, clamping devices, and valves. To actively use the MSM effect in both push and pull directions, perpendicular magnetic fields are required. In this paper, we introduce a novel excitation setup using highly anisotropic pole shoes to generate the necessary fields with unprecedented efficiency. This concept allows customization to provide an inherent bias force in any direction, tailored to specific use cases. A demonstrator based on our approach is realized for a balanced push-pull actuator and analyzed extensively both simulatively as well as experimentally. Simulations were performed with COMSOL Multiphysics, integrating nonlinear magnetics and mechanics with a model based on homogenized twin bands from prior research. The nonlinear switching patterns predicted by the simulations were validated through optical investigations of the physical demonstrator using digital image correlation. The results confirm the dynamic, efficient, and multistable performance of the actuator, even under small disturbances.

This paper presents the design, modeling, and simulation of a compact Electromagnetic Linear Actuator (ELA) and its application to a linear motion mechanism. The proposed actuator consists of a coil and a permanent magnet and can generate a linear motion when an alternating current is applied to the coil. Its overall dimensions are 20 mm (W) $\times15$ mm (H) $\times15$ mm (D) while the weight is 7 g. The proposed actuator can be controlled in terms of position using an open-loop system. A mathematical model is created for the proposed actuator, and theoretical analysis is performed to examine the actuator dynamic model. The simulation results are validated experimentally by manufacturing a physical prototype. Therefore, the proposed actuator generates an electromagnetic force of 0.1 N at 10 V (0.07 A), then our actuator able to achieve a displacement of 0.2 mm. Moreover, the experimental resonance frequency is measured at 70 Hz and the bandwidth of 80 Hz. Finally, the overall system performance is evaluated by integrating the developed actuator into the linear motion mechanism. We investigate the stick-slip motion of the linear mechanism without feedback control, dedicating sufficient time to both the slip phase and the stick phase. The experimental results show that the linear motion mechanism travels with speed 6 mm $s^{-1}$ with a frequency of 30 Hz.

In recent decades, significant research efforts have been devoted to studying various types of actuators. Of particular interest are soft actuators based on electroactive polymers, which offer low operating voltage, light weight, and fast response. In this study, we demonstrate the feasibility of a soft linear actuator fabricated from polypyrrole (PPy), an electroactive polymer that is easy to synthesize, cost-effective, and biocompatible. By optimizing the polymerization conditions, the operation condition and environment, we were able to achieve improved and stable actuator performance. Furthermore, we developed a new actuator-contained component with a flexible counter electrode to build an actuator that operates in air. This approach enabled us to build small and lightweight actuators that operate in air, with a diameter of 5 mm, resembling artificial muscles. Our resulting miniaturized and integrated linear PPy-based actuators can be driven at low voltages (±1.5 V), making them suitable for use in various parts of the body. As such, this actuator holds significant potential for a wide range of applications in the fields of soft electronics, drug delivery, artificial organs, and muscles, as well as a component material for portable medical sensors and devices. [ABSTRACT FROM AUTHOR]

The preliminary test results of a novel robotic hand rehabilitation device aimed at treatment for the loss of motor abilities in the fingers and thumb due to stroke are presented. This device has been developed in collaboration with physiotherapists who regularly treat individuals who have suffered from a stroke. The device was tested on healthy adults to ensure comfort, user accessibility, and repeatability for various hand sizes in preparation for obtaining permission from regulatory bodies and implementing the design in a full clinical trial. Trials were conducted with 52 healthy individuals ranging in age from 19 to 93 with an average age of 58. A comfort survey and force data ANOVA were performed to measure hand motions and ensure the repeatability and accessibility of the system. Readings from the force sensor (p < 0.05) showed no significant difference between repetitions for each participant. All subjects considered the device comfortable. The device scored a mean comfort value of 8.5/10 on all comfort surveys and received the approval of all physiotherapists involved. The device has satisfied all design specifications, and the positive results of the participants suggest that it can be considered safe and reliable. It can therefore be moved forward for clinical trials with post-stroke users. [ABSTRACT FROM AUTHOR]

Sitting in traffic congestion for hours in a posture that requires recurrent actions of manually pressing the pedal and braking excessively can result in fatigue, especially on the driver's leg and back. This fatigue can have long-term implications and adversely affect the driver's health. Thus, this paper aims to model and develop a control system that utilizes a linear actuator to replace the leg activities involved in pressing and releasing the brake pedal. This approach, combined with the implementation of a PID controller, offers a novel solution to control the vehicle speed by integration with the linear actuator that focus on low-speed driving condition. The design process begins with creating a 3D model using SolidWorks to visualize the movement of the linear actuator and Pedal subsystem. This model is then connected to Matlab-Simulink, where a PID controller is implemented and integrated into the electrical circuit to control the actuator's movement. Integration with the vehicle dynamic model enables a comprehensive analysis of the system's behavior on the vehicle dynamics. This research compares the trial and error method with the Matlab tuner for implementing the PID controller. The performance of the system will be evaluated based on the steady state error, overshoot, rise time, and settling time. The results demonstrate that the Matlab tuner outperforms trial and error method by achieving a faster response and significantly reducing steady state error during robustness testing. With the integration of the linear actuator, the system is capable of tracking the desired speed and has the potential to replace the leg activities involved in pressing and releasing the brake pedal. For future work, validating the proposed mechanism with a physical prototype of the linear actuator and pedal using hardware-in-the-loop techniques poses a challenge, as hardware constraints may vary with different environments. [ABSTRACT FROM AUTHOR]

Navigating a mobile robot through a curve path is a difficult task in both on-road and off-road navigation. This research provides a hardware and software platform to address this issue. Two types of research have been conducted in this paper. First, a hardware platform consisting of a Linear Actuator-based steering mechanism is implemented to hold the steering at the desired angle. Second, the curvature information from Google Maps path data is collected and used to improve the existing Pure Pursuit algorithm, which is known as the curve-aware Pure Pursuit (C-PP) algorithm, which navigates a mobile robot in both on-road and off-road (with scattered small obstacles) environments. The mobile robot is navigated using C-PP and steering is controlled by a Linear Actuator. The results taken in real-time and simulation show that the proposed algorithm for on-road and off-road environments has lower longitudinal and lateral RMSE values compared to the existing algorithms.

This article examines a new linear oscillating actuator (LOA) design that uses rectangular-shaped core materials and permanent magnets (PMs). The primary objective of the paper is to examine a novel LOA topology with a rectangular-shaped core and PMs as an alternative to the tubular LOA. A static core material is housed between the mover’s components and two stator cores with two coils, each of which is placed on either side of the mover. The dimensions of all the parameters are swept for optimization and the optimal parameter dimension is chosen based on the optimal value of the electromagnetic (EM) force. An analysis is done for output results like EM force and stroke. Parameters like input current, EM force and stroke-to-current ratio are investigated for different frequencies of the input electrical loading to demonstrate the significance of resonance operation. EM force per PM mass of the investigated design of LOA is 67 percent higher than that of a conventional rectangular-shaped LOA. Additionally, the EM force density of the proposed design is 23.8 percent higher than that of the conventional design of LOA. Furthermore, the stroke of the proposed LOA is also feasible and more than most of the designs of the LOA. Additionally, the proposed design of the LOA is simple in structure, low-cost, and feasible for fabrication.

A type of automated manual transmission gearshift system that uses two linear actuators to perform gearshift events is presented. The shifting mechanism can be made simpler by using linear actuator to drive the shift fork directly. The mathematical model of the actuator is built and analyzed. Coordinated control of the engagement and disengagement processes is created based on a detailed analysis of the gearshift process in order to shorten the shift time. The force characteristics test reveals the nonlinear output characteristics. The precise displacement control need for coordinated control and stable control requirement for the shifting operation are satisfied by a linear extended state observer based controller. To verify the novel gearshift system and the control method, a test bench and control system are constructed. The results of the simulations indicate that the displacement control's accuracy is enhanced. As the speed difference reaches 500 r/min, the testing results demonstrate a noticeably reduced of shift force fluctuation and jerk generated during the gearshift process, from 20 m/s3 to 3.1 m/s3. With the improved gearshift system and control method, the gearshift coordinated control can also save 25 ms of shift time.

In recent years, further improvements in the performance of internal combustion engines to reduce environmental burden have been demanded. The combustion state of an engine is affected by the parameters of the dynamic valve system, such as the opening/closing timing and the lift of the intake and exhaust valves. Therefore, we investigate an electromagnetic valve-drive system in this study. Two models are created to improve the magnetic circuit and increase thrust. To investigate the thrust characteristics of these actuators, an electromagnetic field analysis is conducted using the finite element method. Meanwhile, to investigate the effect of the yoke material on the thrust, an electromagnetic field analysis is performed based on materials with different saturation magnetic flux densities and magnetic permeabilities. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper proposes a novel control technique for motion control of a linear hydraulic actuator, in which actuator reference position and velocity profiles are generated analytically. The proposed algorithm parameterizes an eight-term exponential function based on initial, middle, and final boundary conditions. Nominal and off-nominal disturbance forces applied against the actuator are completely included to shape the desired system reference. This new scheme can create the reference pump rotational speed required to accurately control the presented system with no closed-loop commands and with excellent performance characteristics. Moreover, unlike the traditional hydraulic actuator control algorithms, the presented methodology is able to successfully respond to a wide range of disturbance forces while satisfying steady state conditions. The results showed that, the proposed controller steers the system to the steady state desired value within about 0.1 second only and with zero percent overshoot in terms of the reference input and about 2 percent for the disturbance input. Numerical results using the Monte-Carlo simulation method confirmed the effectiveness and the robustness of the new algorithm despite wide range of disturbance forces. [ABSTRACT FROM AUTHOR]

Masticatory robots are an effective in vitro performance testing device for dental material and mandibular prostheses. A cable-driven linear actuator (CDLA) capable of bidirectional motion is proposed in this study to design a masticatory robot that can achieve increasingly human-like chewing motion. The CDLA presents remarkable advantages, such as lightweight and high stiffness structure, in using cable amplification and pulley systems. This work also exploits the proposed CDLA and designs a masticatory robot called Southeast University masticatory robot (SMAR) to solve existing problems, such as bulky driving linkage and position change of the muscle’s origin. Stiffness analysis and performance experiment validate the CDLA’s efficiency, with its stiffness reaching 1379.6 N/mm (number of cable parts n = 4), which is 21.4 times the input wire stiffness. Accordingly, the CDLA’s force transmission efficiencies in two directions are 84.5% and 85.9%. Chewing experiments are carried out on the developed masticatory robot to verify whether the CDLA can help SMAR achieve a natural human-like chewing motion and sufficient chewing forces for potential applications in performance tests of dental materials or prostheses. [ABSTRACT FROM AUTHOR]

This article presents the design and implementation of a linear actuator based on NiTi Shape Memory Alloys with temperature and position measurements based on a magnetic sensor array and a set of thermistors. The position instrumentation is contact free to avoid friction perturbations; the position signal conditioning is carried out through the calculation of the response of each magnetic sensor, selecting the closest sensor to ensure accurate results on the full range of movement. Experimental results validate the accuracy of the position sensing with a competitive behaviour. [ABSTRACT FROM AUTHOR]

Actuators with clutch mechanisms have advantages in safety, backdriveability, and controllability for human-coexistence robots. This paper presents a large force actuator using electro-adhesive gels, which are functional materials controlled by the magnitude of an electric field. The developed actuator can generate and continuously control a force over 560 N and resist with a small force when de-energized. The number of electro-adhesive gel disks is drastically increased to increase the generative force. This paper reports the structural plan for the new actuator and experiments to investigate its basic characteristics. Based on the experimental results, an actuator model is identified for the future design of its control system. This paper contributes to the development of a clutch-type linear actuator with a large generative force, maintaining safety and a high force-to-weight ratio. It also addresses the problem of high-voltage power supply costs for electro-rheological and electro-adhesive materials. [ABSTRACT FROM AUTHOR]

Copyright of Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent decades, significant research efforts have been devoted to studying various types of actuators. Of particular interest are soft actuators based on electroactive polymers, which offer low operating voltage, light weight, and fast response. In this study, we demonstrate the feasibility of a soft linear actuator fabricated from polypyrrole (PPy), an electroactive polymer that is easy to synthesize, cost-effective, and biocompatible. By optimizing the polymerization conditions, the operation condition and environment, we were able to achieve improved and stable actuator performance. Furthermore, we developed a new actuator-contained component with a flexible counter electrode to build an actuator that operates in air. This approach enabled us to build small and lightweight actuators that operate in air, with a diameter of 5 mm, resembling artificial muscles. Our resulting miniaturized and integrated linear PPy-based actuators can be driven at low voltages (±1.5 V), making them suitable for use in various parts of the body. As such, this actuator holds significant potential for a wide range of applications in the fields of soft electronics, drug delivery, artificial organs, and muscles, as well as a component material for portable medical sensors and devices.

The preliminary test results of a novel robotic hand rehabilitation device aimed at treatment for the loss of motor abilities in the fingers and thumb due to stroke are presented. This device has been developed in collaboration with physiotherapists who regularly treat individuals who have suffered from a stroke. The device was tested on healthy adults to ensure comfort, user accessibility, and repeatability for various hand sizes in preparation for obtaining permission from regulatory bodies and implementing the design in a full clinical trial. Trials were conducted with 52 healthy individuals ranging in age from 19 to 93 with an average age of 58. A comfort survey and force data ANOVA were performed to measure hand motions and ensure the repeatability and accessibility of the system. Readings from the force sensor (p < 0.05) showed no significant difference between repetitions for each participant. All subjects considered the device comfortable. The device scored a mean comfort value of 8.5/10 on all comfort surveys and received the approval of all physiotherapists involved. The device has satisfied all design specifications, and the positive results of the participants suggest that it can be considered safe and reliable. It can therefore be moved forward for clinical trials with post-stroke users.

This study developed an ankle rehabilitation device for post-stroke patients. First, the research models and dynamic equations of the device are addressed. Second, the Sliding Mode Controller for the ankle rehabilitation device is designed, and the device's response is simulated on the software MATLAB. Third, the ankle rehabilitation device is successfully manufactured from aluminum and uses linear actuators to emulate dorsiflexion and plantarflexion exercises for humans. The advantages of the device are a simple design, low cost, and mounts onto rehabilitative equipment. The device can operate fast through experiments, has a foot drive mechanism overshoot of 0°, and a maximum angle error of 1°. Moreover, the rehabilitation robot can operate consistently and is comfortable for stroke patients to use. Finally, we will fully develop the device and proceed to clinical implementation.

Obtaining powered linear movement over a long range of motion is a common yet challenging task, as the majority of linear actuators have limited ranges of motion as determined by their functioning mechanisms. In this paper, the authors present a novel belt-based self-actuated linear drive (B-SALD), in which a self-powered moving platform slides on a slotted track with essentially unlimited range of motion (only limited by the length of the track). Unlike the traditional rack-and-pinion mechanism, the B-SALD system uses a double-sided timing belt as the power-transmitting element. With the teeth on its inner surface, the belt interacts with a timing pulley for its own circulation; with the teeth on its outer surface, the belt interacts with a linear rail with parallel slots and drives the translation of the moving platform. The unique functioning mechanism generates multiple distinct advantages: no lubrication is required; the slotted track is simple and inexpensive to manufacture; and it provides an inherent compliance to buffer shock loading. With the experiments conducted on a preliminary prototype, it has been demonstrated that the B-SALD is able to provide accurate positioning and continuous motion control, an overall mechanical efficiency of 70% over the majority of the load range, and the capability of generating large force output in the desired manner. [ABSTRACT FROM AUTHOR]

People with knee disorders often find it difficult to perform common mobility tasks, such as stand–sit–stand motions. High knee torque is required to complete such transitions, as the chances of toppling increase during these motions. Most of the existing conventional approaches, such as wheelchairs and crutches, have failed to provide complete independence to the users. Conversely, contemporary systems like lower body exoskeletons which are bulky, complex, and expensive do not specifically target the knee joint instead of assisting other joints. Hence, there is a need to aid the knee joint using a robotic knee exoskeleton capable of accurately providing the desired knee torque. In the present work, to assist the user in performing the stand–sit–stand motions, an electromyography sensor-based four-bar knee exoskeleton actuated by a linear actuator is proposed. The modeling of the complete exoskeleton is developed using bond graph technique, as the components exist in different energy domains and it is possible to frame a dynamic bond graph model using only kinematic equations. The prototype is fabricated, and experiments are carried out on an artificial limb to prove the efficacy of the design of the current knee exoskeleton. The assistive torque developed by the actuator at the knee joint of the exoskeleton is found to be suitable to assist the wearer. As a result, little effort is required by the wearer for performing the stand–sit–stand motions. The rotation of the thigh link of the developed exoskeleton was found to be suitable for performing the stand–sit–stand activity. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper presents a hybrid linear actuator using screw clamp operation principle. The actuator mainly consists of a hollow electromagnetic torque motor located between two clamping nuts, two hollow cylindrical shaped piezoelectric stacks symmetrically configured at two ends of the actuator and a feed-screw (also considered as the mover of the actuator) assembled throughout all the parts. The torque motor is symmetrically connected to two clamping nuts via two torsion coupling springs located at either end of the motor spindle. Two piezoelectric stacks can work independently to propel the opposing loads, which effectively take advantage of the anti-compression and non-tensile characteristics of piezoelectric element. The special feature of the actuator is the screw clamp mechanism, the operation of which involves intermittent rotation of two nuts (driven by the torque motor) on a feed-screw to achieve the bi-direction piezoelectric motion accumulation. Furthermore, the application of feed-screw could decrease the actuator's sensitivity to wear, in order to realize a rigid self-locking and thus ensure the actuator's holding capacity. A prototype was fabricated and the experimental results show that the no-load speed, maximum thrust, and peak power of the actuator were 20 mm/s, 280 N, and 1.54 W, respectively. [ABSTRACT FROM AUTHOR]

Parallel manipulators are playing a significant role in robotic applications for the last few decades due to their merits over the serial manipulators. In this paper, kinematic analysis for the 3-RPR planar parallel manipulator having three degrees of freedom through a simple geometric approach is presented. The aim of the study presented here consist of two parts: improving the reachable workspace and investigating the positional error at platform due to link tolerance. The reachable workspace is estimated at various magnification ratios of manipulator at different position and orientation of tool point. The geometric approach is applied to calculate the workspace. The validation of kinematic results is carried out through the Computer-Aided Drafting (CAD) model. The positional error at platform and deviation in workspace due to tolerance on the link length are studied. The link tolerance results due to manufacturing and assembly constraints. The positional error for variation in link tolerance is presented. The proposed method is capable of quantification of maximum reachable workspace as well as worst error for the given tolerance value. The manipulator with highest possible accuracy over largest workspace area can be obtained applying proposed method as an optimized design. [ABSTRACT FROM AUTHOR]

This paper presents an analysis and design of linear quadratic regulator for reduced order full car suspension model incorporating the dynamics of the actuator to improve system performance, aims at benefiting: Ride comfort, long life of vehicle, and stability of vehicle. Vehicle's road holding or handling and braking for good active safety and driving pleasure and keeping vehicle occupants comfortable and reasonably well isolated from road noise, bumps, and vibrations are become a key research area conducted by many researchers around the globe. Different researchers were tested effectiveness of different controllers for different vehicle model without considering the actuator dynamics. In this paper full vehicle model was reduced to a minimal order using minimal realization technique. The entire system responses were simulated in MATLAB/Simulink environment. The effectiveness of linear quadratic regulator controller was compared for the system model with and without actuator dynamics for different road profiles. The simulation results were indicated that percentage reduction in the peak value of vertical and horizontal velocity for the linear quadratic regulator with actuator dynamics relative to linear quadratic regulator without actuator dynamics was 28.57%. Overall simulation results were demonstrated that proposed control scheme has able to improve the effectiveness of the car model for both ride comfort and stability. [ABSTRACT FROM AUTHOR]

Currently, energy demand is more significant than ever due to population growth and advances in recent technologies. In order to supply more energy while maintaining a healthy environment, renewable energy resources are employed. This paper proposes a novel solar-driven shape memory alloy thermomechanical actuator as an eco-friendly solution for solar thermal applications. The proposed actuator was assessed numerically and experimentally. The numerical tests showed that the designed actuation mechanism's inner temperature has a minimum variation per day of about 14 °C and a temperature variation of 19 °C for most days of the year, which allows for proper activation and deactivation of the actuator. As for the experimental tests, the presented actuation mechanism achieved a bi-directional force of over 150 N, where the inner temperatures of the actuator were recorded at about 70.5 °C while pushing forces and 28.9 °C while pulling forces. Additionally, a displacement of about 127 mm was achieved as the internal temperature of the actuator reached 70.4 °C. The work presented adds to the body of knowledge of a novel solar-based self-driven actuation mechanism that facilitates various applications for solar thermal systems. [ABSTRACT FROM AUTHOR]

Linear actuators are widely used in all kinds of industrial applications due to being devices that convert the rotation motion of motors into linear or straight traction/thrust motion. These actuators are ideal for all types of applications where inclination, lifting, traction, or thrust is required under heavy loads, such as wheelchairs, medical beds, and lifting tables. Due to the remarkable ability to exert forces and good precision, they are used classic control systems and controls of high-order. Still, they present difficulties in changing their dynamics and are designed for a range of disturbances. Therefore, in this paper, we present the study of an electric linear actuator. We analyze the positioning in real-time and attack the sudden changes of loads and limitation range by the control. It uses a general-purpose control with self-tuning gains, which can deal with the essential uncertainties of the actuator and suppress disturbances, as they can change their weights to interact with changing systems. The neural network combined with PID control compensates the simplicity of this type of control with artificial intelligence, making it robust to drastic changes in its parameters. Unlike other similar works, this research proposes an online training network with an advantage over typical neural self-adjustment systems. All of this can also be dispensed with the engine model for its operation. The results obtained show a decrease of 42 % in the root mean square error (RMSE) during trajectory tracking and saving in energy consumption by 25 % . The results were obtained both in simulation and in real tests. [ABSTRACT FROM AUTHOR]

Linear electromagnetic actuators realizing periodic oscillations have gained significant importance in the compressor and pump technology. This is due to the need of compact drive units to increase the power density of modern pumps and compressors. This work presents an energy-based control approach for harmonic oscillations of linear electromagnetic drives and analyzes the functionality and performance of the oscillation control for periodic actuator movements up to 250 Hz. To obtain a more robust control behavior, the control structure needs to be decoupled, with an amplitude and phase component using a periodical harmonic carrier function. This approach avoids a standstill of the actuator by constantly triggering an oscillation at the fundamental frequency of the mechanical system. The presented control approach is especially beneficial for oscillatory systems which need to adapt their oscillation frequency to mechanical loads. [ABSTRACT FROM AUTHOR]

This article presents a convex inner approximation approach for mixed ${H}_2$ / ${H}_\infty$ control of a flexure-based nanopositioning system. Generally for such positioning systems, the inevitable existence of model mismatch renders it often times difficult-to-achieve satisfying system performance. Additionally, it is essential to also note that the high-order resonances typically presented are prone to be activated if the controller is not designed appropriately, especially in the case when the control input variation arising from the design is unnecessarily drastic. Therefore, to circumvent the above undesirable possibilities, this work aims to improve the tracking performance with a suitable controller design that effectively suppresses the control input variation. Furthermore, despite the existence of model uncertainties, it is shown that it is possible for a subset of stabilizing controller gains to be characterized appropriately via convex inner approximation, which then further facilitates the determination of the controller by means of convex optimization. Rather importantly, this approach provides a performance guarantee with an optimized limiting bound to the $H_2$ -norm level (which assures optimal behavior for the system), and also concurrently limits the $H_\infty$ -norm level within a prescribed attenuation level (which satisfies a prescribed robustness measure). Finally, numerical optimization and comparative experiments are carried out for demonstrative purposes. [ABSTRACT FROM AUTHOR]

This study developed an ankle rehabilitation device for post-stroke patients. First, the research models and dynamic equations of the device are addressed. Second, the Sliding Mode Controller for the ankle rehabilitation device is designed, and the device's response is simulated on the software MATLAB. Third, the ankle rehabilitation device is successfully manufactured from aluminum and uses linear actuators to emulate dorsiflexion and plantarflexion exercises for humans. The advantages of the device are a simple design, low cost, and mounts onto rehabilitative equipment. The device can operate fast through experiments, has a foot drive mechanism overshoot of 0°, and a maximum angle error of 1°. Moreover, the rehabilitation robot can operate consistently and is comfortable for stroke patients to use. Finally, we will fully develop the device and proceed to clinical implementation. [ABSTRACT FROM AUTHOR]