For haptic devices, compensation of the robot’s gravity is a frequent strategy with the aim to reduce interaction forces between robot and human in zero-impedance control. However, a closer look at the composition of these interaction forces may reveal that the net effect of uncompensated gravitational components of the robot actually reduces interaction forces during dynamic movements, because inertial and gravitational components at least partially compensate each other. This is the case in lower extremity exoskeletons, where less user force is necessary to swing the robot’s leg when gravity helps. Here, we go one step further by shaping optimal passive dynamics for arbitrary haptic devices. The proposed method of generalized elasticities uses conservative force fields to improve haptic transparency for certain movements types. In an example realization, these force fields are generated by elasticities spanning multiple joints. Practical experiments with the Lokomat lower extremity exoskeleton show the success of the proposed method in terms of reduced interaction torques and more physiological user motion compared to gravity compensation.

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This work presents a novel wearable exoskeleton capable of moving the human wrist for rehabilitation or assistive purposes. The purpose of the device is to grant autonomy to individuals suffering from medical conditions such as frailty, spinal cord injury (SCI), stroke or other motor diseases. The device can be operated in two modes. The rehabilitation mode of the device moves the hand in a predefined manner and records the electromyography (EMG) signals for analysis. The assistive mode uses EMG signals to identify the intention of the user and the helps in the movement of the hand by supplying the assistive force. Principal Component Analysis (PCA) along with artificial neural networks is employed for EMG pattern recognition. Different aspects to this are currently under study and the initial design and test results for the device are discussed.

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A functionality test at the level of individual muscles may be effective for neuromuscular function tests. This paper proposes a novel computational method for neuromuscular function test planning using an individual muscle force control technique assisted by a rehabilitation robot. The algorithm will systematically compute an adequate amount and direction of force that a subject needs to exert, e.g., by his/her hand, to induce a desired muscle activation pattern of target muscle forces. A wearable robot with actuators (an exoskeleton robot, or a power-assisting device) is utilized to assist/resist the subject’s joint torques. This paper presents a basic concept and preliminary simulation results. The simulation results justify the use of the wearable actuators in terms of the accuracy of muscle-level control during planned motor tasks.

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Dataglove is an important interface device for dexterous interactions with virtual environments, which should be calibrated before used. Calibration is the initialization of dataglove and establishes a mapping from the sensor values to the joint angles of an articulated hand. For the exoskeleton dataglove, we build a measurement model of the finger flexion angle for human hand based on the theory of four-bar-linkage motion stabilization. The four postures obtained by the standard block are used to calibrate the parameters of the dataglove that are solved by the genetic algorithms (GA). The calibration based on GA has competitive merits, namely, insusceptibility to getting trapped in local extremum and no need of initial values. Experiment verifies that the method is simple and the result is accurate

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This paper presents a new design of an arm exoskeleton using shape memory alloy wires and springs embedded in fabric and taking the form of a sleeve. The device is intended to facilitate everyday life tasks by providing the user with an easily operated lift aiding device. The “SMA Aiding Sleeve” will bring extra lifting power to various classes of users (medical and non-medical). This paper presents the details of the design including the hardware and control scheme. The prototype preliminary tests provide encouraging results in terms of controllability and actuation. The results demonstrate the feasibility of position control.

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