In this paper we introduce the use of force feedback in conjunction with myoelectric control to establish an improved interface for a powered prosthetic limb. The force feedback is delivered through a single-axis exoskeleton worn about the elbow, while the EMG signal is derived from the biceps muscle. This combination is intended to produce a sense of effort in the biceps that is associated with the action of the motorized prosthetic gripper. The method engages both efferent and afferent signals innervating a functional muscle with the aim of realizing a muscle that is effectively biarticular. The controlling muscle spans one joint physiologically and a second, prosthetic joint functionally. Preliminary experiments have demonstrated that force feedback can substitute for vision during grasp and lift tasks.

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The hand force feedback system is an anthropomorphic haptic interface for the replication of the forces arising during grasping and fine manipulation operations. It is composed of four independent finger dorsal exoskeletons which wrap up four fingers of the human hand (the little finger is excluded). Each finger possesses three electrically actuated DOF placed in correspondence with the human finger flexion axes and a passive DOF allowing finger abduction movements. Each exoskeleton finger has three points of attachment to the operator’s finger (two for the thumb) at the middle of the phalanges. Mechanical fixtures guarantee that just a force perpendicular to the finger and in its sagittal plane is exchanged at each point of attachment. Such force component is sensed and it is actively controlled in feedback. The paper illustrates the design and testing of the controller for the thumbexoskeleton. First the mechanical system is analyzed and the features which influence the controller design, such as the presence of unidirectional tendon transmission, are modeled. Then haptic controllers, i.e. feedback controllers aiming at improving the performance of the device when used as a haptic interface for virtual environments or telemanipulation, are designed and tested experimentally. Finally the experimental results are discussed

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This paper outlines a novel approach of displaying multifingered tactile feedback information from remote and virtual environments. Miniature tactile fingertip modules are developed allowing multi-fingered integration into an already existing hand force exoskeleton for display of combined tactile and kinesthetic feedback. The tactile feedback comprises generation of both, vibrotactile and thermal stimuli directly at the operator’s fingertip where a multitude of human tactile receptors are located The proposed parallel configuration of integrated vibration and heat display with combined kinesthetic feedback actuators considers a novel approach towards the generation of holistic haptic sensations. Corresponding tactile rendering algorithms are presented computing realistic tactile stimuli of object properties from either remote real or virtual environments. Moreover the article discusses the design of a developed thermal and texture sensor with corresponding data processing algorithms for online identification of tactile object properties in a remote environment. The new quality of generated multi-fingered tactile feedback was evaluated in several experiments enabling a human operator performing exploratory tasks.

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This paper reports on the mechanical design of an active knee orthosis, powered by pleated pneumatic artificial muscles. The orthosis is intended as a proof-of-concept rehabilitation device for the assessment of mechatronical design principles and testing of different control strategies. The general focus of this research is on the development of a step rehabilitation robot prototype consisting of a powered exoskeleton for the lower limbs.

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This paper describes the control architecture for lower limbs rehabilitation robot system and its implementation. The system hasexoskeleton structure with 10 DOF (degrees of freedom) and is pneumatically actuated. The control strategy has been specifically designed in order to ensure a proper position control guiding patient’s legs along a fixed reference gait pattern. For this purposes Fuzzy controller with additional force compensator was developed. A numerical solution of the inverse kinematics problem based on video image analysis has been used. The controller was successively implemented and tested on embedded real-time PC104 system. Laboratory experiments without patient are carried out and the results are reported and discussed.

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