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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Haptic force feedback can be summarized as a system that provides a sense of feeling and the application of forces by a computer to a user. This type of feedback system was developed as a glove or master format in order to provide forces at the fingertips. As a core to the device, passive actuators were developed using magnetorheological fluid (MRF) and a novelexoskeleton mechanical power transmission system was designed utilizing rapid prototype parts. The fluid is a smart material that has the property of changing its viscosity when exposed to a magnetic field. By varying the intensity of electromagnets embedded within the fluid based actuators, the resistive forces of the actuators can be dynamically set. The entire system is lightweight, low power and easily portable. A completed system was tested to evaluate the usability of the device

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Patient engagement and effort are thought to be important for maximizing the therapeutic benefit of robot-assisted movement exercise after neurologic injury, but little is understood about how the audio-visual feedback presented during training affects engagement and effort. For the study reported here, we hypothesized that visual distraction would decrease engagement during robot-assisted movement training, but that appropriate auditory feedback would counteract this effect. Non-disabled participants (n = 10) participated in a common therapeutic exercise in which they attempted to track a moving target presented on a computer screen as a robotic exoskeleton compliantly assisted their arm movement. Introducing a simple visual distractor significantly increased both tracking error and the interaction forces between the participants and the robot. Introducing auditory feedback of tracking error reduced the effect of the visual distractor, decreasing tracking error and interaction forces toward normative values. If tracking error is taken as a surrogate measure of participant engagement, these results indicate that the presence of even a modest level of visual distraction in the training environment may decrease engagement, and thus present a hazard to the effectiveness of training. However, providing appropriate task feedback through the auditory system can reduce the effect of visual distractors. Therefore, an integrated design of the audio, visual, and haptic environment is important for optimizing robot-assisted movement training.

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A bidirectional force feedback dataglove actuated by pneumatic artificial muscles is introduced which has simpler exoskeleton structure and exerts bidirectional force only on the fingertips. Moreover, its fewer attachments can reduce the effect of the attachment looseness on the accuracy of position and force control. It meets all needs of virtual reality and the requirement of hand rehabilitation as well. Bidirectional force and movement are achieved by producing antagonistic torque with an antagonistic pair of pneumatic artificial muscles similar to the antagonistic muscles of human beings. The dataglove can support all four degrees of freedom measurement with the non-contact anisotropic magnetoresistive sensors. The cantilevered beam force sensor is integrated into the linkage of exoskeleton structure. A single PC-based control system is introduced. The dataglove can simulate the sensation of grasping rigid and elastic objects in virtual environment. At last, the clinic application in the rehabilitation of injured fingers is presented.

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