The design of robotic orthoses focuses strongly on replicating kinematics of human limb. However, often sophisticated mechanisms which attempt at reproducing complex kinematics of human joints fails in adapting to geometrical variations of subjects sizes and eccentricities. One major that arises from this mismatching is an occurrence of hyperstaticity induced by the uncontrolled interaction forces. In this paper, we take the point of view of statics to investigate the force transmission problem, which is required for a fine force control. The main result of this study focuses on designing fixations between the orthosis and the human limb that provide additional degrees of freedom. The method involves two steps. Firstly, a set of possible solutions with respect to the isostaticity criterion is derived. Then, among these possible solutions, a set of design rules considering physiological aspects of transmitting forces to human limbs is used to select a preferred configuration. As an example, the method is applied to an existing 4 active DOF arm orthosis.

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This paper proposes a tendon driven system with antagonistic pairs of polyarticular tendons to simulate a variable stiffness of a human fingertip. The stiffness of a robot finger should be adjusted according to a situation that includes large position errors or collisions, because it tolerates errors of object positions and dimensions in assembly task and absorbs collision energy in hitting or catching task. The variable stiffness therefore contributes to stable grasping and dexterous manipulation. Besides, a stiffness of a human fingertip can be controlled by consciously contracting antagonist muscles when it does not contact anything such as in a preshaping phase. This study simplifies a tendon driven system of a human finger and then searches feasible parameter settings of the tendon driven system with antagonistic pairs of polyarticular tendons through numerical simulations. Finally it is experimentally confirmed that the proposed tendon driven system has similar stiffness to a human finger.

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This study presents a new method for the estimation of the dynamic impedance of multi-joint leg movements. The method is based on Multi Input Multi Output (MIMO) system identification techniques and is designed for continuous torque perturbations at the hip and knee joint. Preliminary results from this study indicate that MIMO system identification can successfully be used to estimate the hip and knee impedance and the interaction dynamics between both joints. It is also concluded that, in order to create a good model representation of the leg impedance, the effect of biarticular muscles needs to be taken into account. The obtained measures for joint impedance might be used for clinical assessment and follow up of patients, as well as for the development of supportive devices.

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This paper describes a system that provides a full body, digitally programmed, kinesthetic display for virtual reality applications. This design begins by providing a full six axis motion platform for each foot of the operator. From this base design, kneeling boards are added to support rolling, kneeling and prone postures; and a vertical feature presentation mechanism is appended which allows the operator to interact with realistic walls, windows, doors and other vertical obstacles features in his movement space. The design of this complex device was driven by a variety of requirements including the need for system modularity, enhanced safety and the need to emulate all significant physical activities

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