In this paper, we present an inexpensive force feedback virtual reality system using a 3-DOF five-bar-linkage manipulator. The direct drive manipulator has a gravity balanced structure. An implicit force control strategy is used to determine the virtual force feedback. The effects of virtual wall and virtual free space controllers are studied. A graphics system is developed to provide the visual feedback to the user. Experimental results are presented to show the user interaction with a virtual wall and a virtual object

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Adaptive tracking techniques are applied to pneumatic muscle actuators arranged in bicep and tricep configurations. The control objective is to force the joint angle to track a specified reference path. Mathematical models are derived for the bicep and tricep configurations. The models are nonlinear and in general time-varying, making adaptive control desirable. Stability results are derived, and the results of simulation studies are presented, contrasting the nonlinear adaptive control to a nonadaptive PID control approach.

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This paper proposes a polyarticular tendon drive system to simulate a variable stiffness of a human fingertip. The stiffness determines displacement of the fingertip when an external force is affected to it. The stiffness should be adjusted not only according to measurement precision of object’s dimensions in order to allow grasping position errors, but also according to tolerance of the assembly in order to allow position errors of assembly components. The variable stiffness therefore contributes to stable grasping and dexterous manipulation. A stiffness of a human fingertip in all directions increases as a grasping force of the human finger increases. The stiffness even in orthogonal direction to a grasping force increases in the same way. Through numerical simulations, feasible parameter settings of our proposed polyarticular tendon drive system are searched and then it is confirmed that the variable stiffness of a robotic finger driven by the proposed polyarticular tendon system is similar to the one of human finger through some experiments.

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In this article the design of a new upper limb rehabilitation system will be presented. A lightweight, modular, and portable system is achieved by the combination of electromyographic (EMG) control, functional electrical stimulation (FES), and the use of miniaturized flexible fluidic actuators (FFA) integrated in an elbow orthosis. First, the state of the art of upper limb rehabilitation devices will be discussed and requirements extracted. Then, the design concept of the new prototype upper limb training system will be presented. Subsequently, a miniaturized fluidically driven actuation system, including its mechatronical components, will be highlighted. Finally, an overview of the performance and function will be given.

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