This paper describes the design and development of a new actuator with adjustable stiffness (AwAS) which can be used in robots which are necessary to work close to or physically interact with humans, e.g. humanoids and exoskeletons. The actuator presented in this work can independently control equilibrium position and stiffness by two motors. The first motor controls the equilibrium position while the second motor regulates the compliance. The novelty of the proposed design with respect to the existing systems is on the principle used to regulate the compliance. This is done not through the tuning of the pretension of the elastic element as in the majority of existing system but by controlling the fixation of the elastic elements (springs) using a linear drive. An important consequence of this approach is that the displacement needed to change the stiffness is perpendicular to the forces generated by the springs, thus this helps to minimize the energy/power required to change the stiffness. This permits the use of a small motor for the stiffness adjustment resulting in a lighter setup. Experimental results are presented to show the ability of AwAS to control position and regulate the stiffness independently.

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To harness the increased dexterity and sensing capabilities in advanced prosthetic device designs, amputees will require interfaces supported by novel forms of sensory feedback and novel control paradigms. We are using a motorized elbow brace to feed back grasp forces to the user in the form of extension torques about the elbow. This force display complements myoelectric control of grip closure in which EMG signals are drawn from the biceps muscle. We expect that the action/reaction coupling experienced by the biceps muscle will produce an intuitive paradigm for object manipulation, and we hope to uncover neural correlates to support this hypothesis. In this paper we present results from an experiment in which 7 able-bodied persons attempted to distinguish three objects by stiffness while grasping them under myoelectric control and feeling reaction forces displayed to their elbow. In four conditions (with and without force display, and using biceps myoelectric signals ipsilateral and contralateral to the force display,) ability to correctly identify objects was significantly increased with sensory feedback.

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The E-GRIP grasping device enables a wearer, with limited manual strength and dexterity, to grip implements with handles such as golf clubs, brooms, rakes, and shovels. Grip strength is achieved by unique usage of externally located shape memory metal wires. The device is also voice controlled for hands free operation

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Rehabilitation robotics specializes in designing machines, such as exoskeletons, which can be utilized to restore function in patients recovering from physical trauma. The proposed Assistive Rehabilitation Arm Orthosis (A.R.A.O.) is designed to restore function and rehabilitate patients suffering from muscular diseases as well as mild-stroke. Clinical studies have shown that task-based repetitive training can improve motor abilities and enhance functional performance in those recovering from stroke. The proposed design improves on the popular four bar linkage systems used in many modern orthoses by incorporating a dynamic feedback system that actuates elastic elements, allowing users to lift heavier objects, while still remaining portable. The dynamic feedback system incorporates force-sensing resistors in conjunction with a linear actuator to vary the tension in the tension bands. The device not only allows patients to perform day-to-day lifting tasks but also has the potential for use in rehabilitation.

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This research aims to develop a portable haptic master hand with 20 degrees of freedom (DOF). Master hands are used as haptic interfaces in master-slave systems. A masterslave system consists of a haptic interface that communicates with a virtual world or an end-effector for tele-operation, such as a robot hand. The thumb and fingers are usually modeled as a serial linkage mechanism with 4 DOF. So far, no 20 DOF master hands are developed that can exert perpendicular forces on the finger phalanges during the complete flexion and extension motion. In this paper, the design and development of a portable 4 DOF haptic interface for the index finger is presented. The concept utilizes a mechanical tape brake at the rolling-link mechanism (RLM) for passive force feedback. The systematic Pahl and Beitz design approach is used as an iterative design method. Important design requirements are; perpendicular forces on the finger phalanges, low friction mechanism, easy to control, no backlash, high backdrivability and lightweight

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