In order to eliminate the drawbacks of conventional force feedback gloves, a new type of master hand has been developed. By utilizing three ¿four-bar mechanism joint¿ in series and wire coupling mechanism, the master finger transmission ratio is kept exact 1:1.4:1 in the whole movement range and it can make active motions in both extension and flexion direction. Additionally, to assure faster data transmission and near zero delay in master-slave operation, a digital signal processing/field programmable gate array (DSP/FPGA-FPGA) structure with 200 ¿s cycle time is designed. The operating modes of the master hand can be contact or non-contact, which depends on the motion states of slave hand, free motion or constrained motion. The position control employed in non-contact mode ensures unconstrained motion and the force control adopted in contact mode guarantees natural contact sensation. To evaluate the performances of the master hand, an master-slave control experiment based on force-position control method between the master hand and DLR/HIT hand is conducted. The results demonstrate this new type master hand can augment telepresence.

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We address an exoskeletal type haptic device which helps the human actively feel the sense of touch in palmar and dorsal directions. The device consisting of two finger-like parts taken by thumb and index finger, is designed in modular type to expand easily for five fingers. The proposed device is semi-directly driven by ultrasonic motors which have high power-to-weight ratio, and it provides haptic feedback to each joint of fingers. Methods for measuring the angular displacements and torques of the fingers are proposed and basic experiments are performed to verify the effectiveness of the system

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It is well-known that virtual reality (VR) is a powerful and promising computer-based technology for the motor recovery in stroke patients. The importance of using VR into arm rehabilitation has coined it as clinical VR; where its main sake is to improve the recovery process of post-stroke patients. In this regard, physical therapy and occupational therapy are provided by such technology. As we shall see into this contribution, interesting clinical VR applications have been designed for handling effectively the brain plasticity in chronic stroke patients. To this end, we use the so-called Light¿Exoskeleton which has been presented for arm-robotic therapy such that it serves as the kinesthetic feedback stimulator for assisting the patient during the rehabilitation sessions.

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This Paper describes the design of the ESA Human Arm Exoskeleton, which has been developed to enable force-feedback telemanipulations with redundant robotic arms. It is described, how several shortcomings of previous telemanipulation systems were eradicated, to meet the system requirements for a lightweight, easy wearable and comfortable system. The patented novelties towards prior arm exoskeletons are enlightened, and the methodology is shown, according to which the system was designed. The prototype, which has been developed at ESTEC is described in detail, outlining the special features of the design. The paper will also refer to the strengths of the Research and Development (R&D) base in Europe, derived from significant national and ESA programs and a judicious cross-fertilisation with R&D in non-space domains.

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Our new Limpact exoskeleton is mechanically based on the design of the passive Dampace and will be powered by rotational hydro-elastic actuators (rHEAs), using impedance control. In this paper we describe the design of the rHEA, which is a novel, custom-designed combination of a rotational hydraulic actuator and a symmetric torsion spring. The rHEA can also be used as a springless hydraulic actuator for stiffer admittance control, or for isometric large-torque measurements of up to 100 Nm, by locking specific components in the design. Our implementation of HEA required alterations to the existing theoretical models to account for (1) our long flexible tubes between the valve and cylinder, and (2) the influence of the pressure feedback on the valve flow. These newly adapted models gave the best fits on the frequency response functions from our open- and closed-loop identification experiments, and might even provide a better fit for the data in the original publication of the theoretical models. Multi-sine identification showed the torque-tracking bandwidth restricted to 18 Hz for a constant spectral-density reference signal of 20 nm, mostly due the transport delays in the long flexible tubes. The measured torque resolution was better then 0.01 Nm. The delivered torque resolution was below 1 Nm, although at those small amplitudes, the output signal was accompanied by significant phase lead indicating some unaccounted for non-linearities in the actuator. When manipulated manually by forefinger and thumb, almost no distortion torques were felt during minimal-impedance and virtual-spring control. The symmetric torsion spring proved difficult to model correctly, and finding the best design became an iterative process. The spring in the prototype, used for the measurements as reported in this study, had a stiffness and maximum torque below those theoretically calculated, limiting the desired output to 22 Nm. With our latest spring design for the actuators in the Limpact, t- — he maximum output torque is increased to 50 Nm.

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