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This paper gives a new formulation to design adaptive structures through total energy optimization (TEO). This methodology enables the design of truss as well as tensegrity configurations that are equipped with linear actuators to counteract the effect of loading through active control. The design criterion is whole-life energy minimization which comprises an embodied part in the material and an operational part for structural adaptation during service. The embodied energy is minimized through simultaneous optimization of element sizing and actuator placement, which is formulated as a mixed-integer nonlinear programming problem. Optimization variables include element cross-sectional areas, actuator positions, element forces, and node displacements. For tensegrity configurations, the actuators are not only employed to counteract the effect of loading but also to apply appropriate prestress which is included in the optimization variables. Actuator commands during service are obtained through minimization of the operational energy that is required to control the state of the structure within required limits, which is formulated as a nonlinear programming problem. Embodied and operational energy minimization problems are nested within a univariate optimization process that minimizes the structure’s whole-life energy (embodied + operational). TEO has been applied to design a roof and a high-rise adaptive tensegrity structure. The adaptive tensegrity solutions are benchmarked with equivalent passive tensegrity as well as adaptive truss solutions, which are also designed through TEO. Results have shown that since cables can be kept in tension through active control, adaptive tensegrity structures require low prestress, which in turn reduces mass, embodied energy, and construction costs compared to passive tensegrity structures. However, while adaptive truss solutions achieve significant mass and energy savings compared to passive solutions, adaptive tensegrity solutions are not efficient configurations in whole-life energy cost terms. Since cable elements must be kept in tension, significant operational energy is required to maintain stable equilibrium for adaptation to loading. Generally, adaptive tensegrity solutions are not as efficient as their equivalent adaptive truss configurations in mass and energy cost terms.

This paper justifies the need for more research in the area of ‘assistive robotics’ and it describes the design and performance of a manipulator arm and gripper, mounted on an electric scooter, that can enable frail elderly and people with disabilities to collect and retrieve heavy objects, such as shopping items, located on high shelves. Known by the acronym ‘ESRA’, short for ‘Electric Scooter Robot Arm’, this device can be attached to a mobile vehicle like an electric scooter or an electric-powered wheelchair. This paper discusses the basic mechanical design of the ESRA manipulator and gripper, joint control, important design tools and failure analysis that were used for its development, and overall performance of the prototype arm. The object retrieval performance of this manipulator can also be enhanced using machine vision techniques for automatic object detection and gripper guidance. Different end-effector tools can be mounted on the end of the ESRA to enable the operator to perform a wide variety of common household chores and manipulation tasks.

This paper presents the design of a new miniature integrated haptic device consisting of a cutaneous, a thermal and a kinaesthetic module. To convey realistic tactile sensations in compact size, the cutaneous module is designed to include a 3 × 3 miniature pin-array display and an amplitude-modulated vibration generator. The pin-array display is intended to mimic both small-scale shapes and roughness of a virtual surface, and the vibration generator creates a variety of amplitude-modulated vibrations to replicate the continuous texture of a virtual environment. The pin-array module is constructed by miniature magnetic linear actuators, and the vibration generator is fabricated using a stacked multilayer piezo-actuator, flexure structures and supporting frames. To further convey the temperature and thermophysical properties of an object, the thermal module including a peltier element and a cooling jacket is integrated to the cutaneous module. In addition to tactile information, the kinesthetic information is equally important while perceiving objects. Thus, two kinaesthetic actuators operated by MR fluids are located on the control circuit board while supporting the cutaneous and thermal modules. The proposed design is sufficiently small to be installed into human-computer interface, and the integrated haptic device is able to enhance the sense of reality with combined haptic feedbacks while users interacts with graphical environments.

Humanitarian demining, the peaceful and non-explosive de-mining strategies, has been gaining worldwide acceptance lately. As the series of humanitarian demining, tele-operated mine detecting robot system was developed. This paper presents unique demining strategy of the demining robot system. There are two developed system called MIDERS-1 and MIDERS-2. The system is consisted of rough terrain mobile platform, multi degree of freedom manipulator, and the all-in-one mine detecting sensor module between ground penetrating radar and metal detector. We have focused that our cooperative demining procedure between the macroscopic and microscopic demining enhances the conventional human demining. With proposed methodology, the hardware configurations and functions are described.

The goal of this paper is to show EMG based system control applied to motorized orthoses. Through two biometrical sensors it captures biceps and triceps EMG signals, which are then filtered and processed by an acquisition system. Finally an output/control signal is produced and sent to the actuators, which will then perform the proper movement. The research goal is to predict the movement of the lower arm through the analysis of EMG signals, so that the movement can be reproduced by an arm orthosis, powered by two linear actuators.

In this paper, we have proposed a novel robotic knee device with a five-bar linkage to allow low impedance voluntary knee motions within a specified rotation range during swing phase and to assist knee extension motions during stance phase after reaching the boundary of the rotation range. The proposed device can provide free knee motions through the five-bar linkage with 2-DOF degree of freedom actuations by a patient's shank and a linear actuator, and can assist knee extension at any controlled knee angle during weight bearing by a geared five-bar linkage with 1-DOF actuation of the linear actuator. The kinematic transition between two modes can be implemented by contact mechanism of a circular structure knee joint and a linear link patella, and the resultant knee rotation range can be determined by the linear actuator. A weight optimization scheme with a simple genetic algorithm SGA is performed to increase portability of the proposed device and minimize the side-effects of increased link numbers as compared to existing four-bar mechanisms. The cost function is composed of sums of normalized total link lengths and normalized motor powers. The optimization results show that the total link length and motor power were reduced to 47% and 43% respectively, as compared to initial design. The proposed robotic knee device can provide a new rehabilitation mode for a stroke patient to allow safe and self-motivated overground walking with minimum concern of falling down.

A new type of electromagnetic linear actuator for vehicle active suspension was designed, with the characteristics of large stroke and force and fast response. Combined with the finite element analysis software, the effects of actuator structure parameters such as gap thickness, the secondary stainless steel thickness, the secondary copper thickness, permeability and conductivity of insulation stall on actuator thrust size and speed response were studied. And the effects of actuator power parameters such as voltage, frequency and load mode on actuator thrust size and speed response were also studied. The results show that the electromagnetic force is closely related to structural parameters such as the gap thickness, except for the conductivity of insulation stall. And the electromagnetic force is proportional to the square of the voltage, and first increases and then decreases with the frequency, getting the maximum at 20 Hz. The mathematic model of the actuator was also built up. Based on the simulation results, a prototype of electromagnetic linear actuator with appropriate parameters was developed. And the electromagnetic force test of the actuator was done. By comparison of the finite element simulation results and the experimental data, it shows the corresponding results are consistent, indicating that the design and analysis of the electromagnetic actuator is correct.

Modelling is considered to be an inherent part of design process of mechatronic devices and systems, in particular when solving problems of dynamics and accuracy of actuators and sensors. Mathematical software packages such as Matlab/Simulink are commonly used for this purpose. Engineers and designers who integrate mechanical components of devices under design, usually employ special computer software known as 3D CAD for creating three dimensional images. Typically it is used to generate technical drawings and layouts but its usability is more extensive. The paper presents ability of such software to support simulation where a linear stepping actuator is an example of a device under design.

Human adults know that usually, big objects are heavier than small ones if these objects are quite similar, in the same material for example. They have a general idea of the weight affordances about the every-day life objects. This paper presents a neural network architecture coupled with a simple linear actuator using force control, designed to use sensory-motor and visual informations during manipulation to learn how to recognize objects of different masses. After learning the association of sensory-motor informations through time with a particular object, our architecture can discriminate different masses and give relevant information for unknown objects, consequently, the objects are associated to some of their inferred physical properties.

In this paper, a human-computer interface equipped with self-uprighting feature and haptic feedback functionality as a PC peripheral is proposed. Device motion triggered by a user is sensed through embedded inertial sensors. Taking advantage of a mechanical structure incorporating a weighted bottom and mass symmetry, the device uses restorative uprighting force to right itself, making erratic motion once tipped over. The acceleration values are counterbalanced once yaw motion is applied by a user. The haptic feedback in this system is intended for both the realization of subtle detent effects and surface transmitting vibrations. Providing impulse tactile feedback according to gestural input, the device can function as a rotatable knob which is mechanically ungrounded. Moreover, surface transmitting vibration generated by linear actuators provides notifications of events important to the user in the form of ambient haptic feedback. With the utilization of the proposed features, it is expected that both intuitive information input and practical use of haptics in a desktop environment can be achieved.

The human vision system has visual functions for viewing 3D images with a correct depth. These functions are called accommodation, vergence and binocular stereopsis. Most 3D display system utilizes binocular stereopsis. We have developed a monocular 3D vision system with accommodation mechanism, which is useful function for perceiving depth. This vision unit needs an image shift optics for generating monocular parallax images. But conventional image shift mechanism is heavy because of its linear actuator. To improve this problem, we developed a light-weight 3D vision unit for presenting monocular stereoscopic images using a polypyrrole linear actuator.

The article deals with design and implementation of absolute linear position sensor for sensing of a ball screw position. The ball screw is one of the main parts in a linear actuator of the “Device for mechanical assessment of human body functional segments”. The proposed sensor is based on principle of sensing a position of a permanent magnet of family Hall IC (integrated circuit). The magnet is attached to the endstop of the moving ball screw. PCB (printed circuit board) with Hall IC are mounted to the casing of the linear actuator. Data acquisition is executed by an 8-bit microcontroller which provides the actual position of the ball screw via serial communication interface.

In order to quantitatively evaluate the dynamic changes in the texture of foods during chewing in humans, a robotic device is required to enable the reproduction of human chewing behaviour. The first step in designing such a device requires the jaw mechanism to be modeled and analysed through simulations. Following a biological examination of the muscles used in the process of mastication, it was determined that those responsible for chewing movements can be represented by a set of linear actuators. By placing these actuators between the mandible and the skull, according to human biological structure and functionality, a robotic model of parallel mechanism was identified. The physical dimensions and properties of the mechanism were measured from a model replica of the human skull. Simulations for the mandible movements with respect to given muscular actuations, and for the muscular actuations required for actual human chewing patterns, were conducted using the Matlab/SimMechanics toolbox and the SolidWorks/CosmosMotion, respectively.

The article presents approach to the control of a linear actuator of the Stewart platform. The proposed method is based on the state – space control with disturbance compensation. The controller itself has a structure with an input integrator and the disturbance compensation is provided by a torque observer. The whole controller design is based on a linear state-space model of the actuator with the disturbance.

The aforementioned robotic model of the masticatory system was refined in this section of the research, utilising substantially more data. This chapter presents both the design of, and data collected from such a masticatory robot of linear actuation. As a linear actuator was used to represent the muscle groups required for human mastication, the spatial placement between the mandible (moving plate) and the maxilla (ground plate) allowed both the line of action and attachment sites of each muscle to be followed. The design requirements for each actuation system were specified in terms of actuation range, velocity and acceleration, plus actuation force. These specifications were determined via firstly, inverse kinematics analysis, by application of simulation software, and secondly via jaw force analysis, by the application of Pythagorean Theorem. The end design of the physical linear actuation is made up of a rotary motor, a gear reduction train and a lead-screw. The challenges in relation to building an entire mastication robot are also discussed.

Ankle-Foot-Orthosis (AFO) is usually applied on affected leg of stroke patient with abnormal muscle tone. AFOs are usually made by thermoplastic material which cannot sustain prolonged mechanical force. Thus while walking with thermoplastic AFO, it could correct gait, but at the same time it would usually break down within several months’ usage. However, there were few studies concerning the test of AFOs. The purpose of this study was to develop a method for testing AFOs with cyclic walking and then validated its performance. A walking robot was designed as testing apparatus, which comprises foot, ankle joint and lower leg. The foot of robot could wear an AFO and is flexible on loading. Ankle joint of robot was constructed with 2 degrees of freedom (DOF) passive motions. Lower leg of robot was assembled with two servo motors and one linear actuator, which could drive leg and foot walking on the sagittal plane with 3-DOF. Four springs were selected to provide various stiffness for the ankle joint of robot, according to patient’s abnormal muscle tone. After loading gait data of one subject to robot as the target gait data, the robot would simulate his/her walking pattern including kinetics and kinematics behaviors. We analyzed 90 steps of the robot cyclic walking on a forceplate. The root mean square accuracy ± mean standard deviations of vertical ground reaction force, tilting angle of foot, and angle of ankle joint were 80.5N ± 9.5N, 1.9degree ± 0.5degree and 2.1degree ± 0.3degree, respectively, as compared to the target gait data. The walking robot showed good repeatability during walking, with low standard deviations as 1.3%, 0.8% and 1.8% of full scale respectively. In conclusion, the robot developed is a reliable tool for testing AFOs.

Dynamic bioreactor systems are widely used in heart valve tissue engineering as the means to apply defined mechanical stimuli on seeded myofibroblasts, thus promoting the development of sturdy yet elastic autologous tissue. Allowing for the delicate character of newly seeded cells as for the constant change of their mechanical properties over cultivation time, it is desirable to have a highly flexible dynamic bioreactor system adjustable to the changing demands. For this task a pulsatile bioreactor has been designed and built. This bioreactor renders possible the application of highly configurable pressure profiles on a heart valve and hence the simulation of the changing physiological environment of a growing heart valve. It consists of a pressure chamber where a PC-controlled linear actuator applies pulsatile pressure on the valve through a silicone membrane, and a reservoir chamber where several monitoring devices can be attached. Through the use of pressure sensors direct feedback to the actuator is possible and the development of the heart valve can be closely supervised. The system has been successfully tested on newly acquired porcine aortic and pulmonary valves.

Based on fundamental considerations concerning implantable valve actuating mechanisms and a review of recent low-energy actuators, we propose four concepts to adjust or switch an implantable valve. The Bellow-Concept makes use of a standard actuator and hermetic encapsulation with flexible bellows, where force can be transmitted by deflection of the bellows. The Shape-Memory-Alloy-Concept considers a biocompatible Shape-Memory-Alloy (SMA) actuator, which can be directly immersed in body liquids. The Stepper-Motor-Concept makes use of a hermetically encapsulated rotatory actuator, with the rotatory action being transmitted magnetically through the rigid encapsulation wall. Finally, the Magnetic-Spring-Concept proposes a hermetically encapsulated linear actuator and linear magnetic force transmission through the rigid encapsulation wall. We found the Magnetic-Spring-Concept the smallest and most simple one.

In our previous research, we addressed the problem of automating the design of passive radio-frequency (PRF) services. An optimal PRF surface is one that offers a maximum probability of localization at a minimum instrumentation cost, i.e., a minimum number of surface-embedded passive RFID transponders. Our previous results were based on the assumption that the signal distribution model of an individual RFID transponder can be approximated as a circle. The problem of automated PRF surface design was then formulated as the problem of packing a surface with circles of a given radius. However, in practice, this approach leads to some loss of optimality: some areas of the surface may not be covered or too many transponders may be required. More exact methods are need for verifying and constructing signal distribution models of surface-embedded RFID transponders that can be used by surface packing algorithms to optimize the design. In this paper, we present the design and implementation of a Cartesian robot for verifying and constructing signal distribution models of surface-embedded RFID transponders. A model is characterized by four high-level parameters: an RFID transponder, an RFID antenna, an RFID reader, and a surface type. The robot moves an RFID reader-antenna unit over a PRF surface, e.g. a carpet, and systematically collects readings for various antenna positions over the surface. The collected readings are subsequently processed to verify or construct signal distribution models. We describe experiments with the robot to verify the localization probability of automatically designed PRF surfaces. We also present experiments with the robot to verify and construct the signal distribution models of a specific RFID transponder.

In the paper an algorithm and computer software for the optimisation of error actuated control systems containing of an electromagnetic linear actuator is presented. The software consists of two main parts: (a) optimisation solver and (b) numerical model of the actuator. For the optimisation, the genetic algorithm (GA) has been used. The field discrete mathematical description is employed. The field-circuit model of the electromagnetic actuator includes: (a) the equation of a transient electromagnetic field, (b) equations which describe electric circuits of the system, including feedback, (c) the equation of mechanical motion and (d) the equation describing and the proportional-plus-integral-plus-derivative (PID) controller.

This paper presents a simulator's development. Its objective consists in training Colombian Navy soldiers. This device has three subsystems: A mobile platform, a graphical interface and a shooting device. The first was constructed by the connection of two linear actuators to a seat shaped, single user platform with two rotations over the horizontal axes. These actuators are activated by servomotors that are connected to a motion controller. Furthermore, the graphical interface permits the visualization of a realistic three dimensional world composed by a river, a firearm over a moving boat, targets and natural elements over the riversides. The software has the option of stereoscopic view and captures the shots provided by the third subsystem. The shooting device is the result of combining encoders with a cardan-type joint. It allows the aim movement in elevation and azimuth coordinates. Finally, preliminary tests of its potential use were conducted with satisfactory results.

We have been studying the new linear actuator for android using Halbach array of magnets. In this paper, the dynamic performances are computed by the 3-D finite element method and compared with the measurement of the prototype. As the result, both results are in good agreement, and the validity of the analysis is clarified. Moreover, the effectiveness of the proposed actuator is verified through the comparison with the conventional synchronous motor (shaft motor).

Pneumatic muscles have been used for a number of years as actuators in robotic systems, usually for those that mimic human actions. They are most commonly used in systems designed to aid physically handicapped people. Air muscles consist of an inflatable tube, usually neoprene rubber that is constrained by a nylon mesh. When compressed air is passed into the muscle, which is blocked at one end, the tube inflates, but the action of the enclosing mesh forces the tube to shorten. The resultant force is sued as a linear actuator.