This paper describes design of array force display for presentation of hardness distribution in an elastic object. The array force display is composed of an elastic plate and a linear actuator array. It provides a spatially continuous surface on which users can effectively touch virtual objects using any part of their bare hand. The elastic plate is made of rubber and sponge. When the actuator pushes the plate, its hardness increases. The user feels as if hard object is submerged in a soft object. The device is evaluated through experiments for palpation performance

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We have been developing a wearable robot that directly and physically supports human movement. A ldquomuscle suitrdquo for the arm that will provide muscular support for the paralyzed or those otherwise unable to move unaided is one example. Whereas low back pain is one of the most serious issue for the manual worker and in this paper, we focus on developing the support system for forward tilting of the upper body. In this paper, the concept and mechanical structure of the support system is shown. From the experimental result to keep forward tilting posture with load indicates our system is very effective for keeping forward tilting posture and it becomes clear that more than 60% reduction of muscular power is possible.

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In this paper, maneuverability measure of master control devices considering the musculo-skeletal model of operators is proposed. The original maneuverability measure of master arms considering the operator dynamics is extended by introducing a muscle tension space instead of the joint torque space of an operator so that the maneuverability is evaluated under a constant muscle stress condition which is related to muscle fatigue. Unidirectionality of muscle tension forces as well as the gravity effects acting on the master device and the operator arm are explicitly considered to get a correct evaluation. As a numerical example, the effect of a movable armrest installed on a master arm is evaluated based on the proposed measure. It is shown that the armrest is effective to reduce muscle fatigue by not only lowering the gravity loads for the operator but also reducing the gripping force necessary to maneuver the device. Experiments are also conducted to verify the result of this numerical example.

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In this paper we present a framework that allows the haptic rendering of interactions between the human hand and a virtual environment consisting of polygonal objects. The proposed solution creates a representation of the human hand through simple geometric primitives (spheres, cylinders etc.) and allows the fast collision detection and calculation of forces of interaction. The forces are calculated with precision and smoothness, especially at the fingertips, where the human haptic perception is more sensitive. The area of each contacted region is taken into account to correctly weigh the importance of each force we calculate. The objective is to give a simulation tool that will allow the use of exoskeletons for the human hand with an improved level of precision, which is necessary for the correct evaluation of these haptic devices and their efficient use.

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The system studied consists of a human operator, a stick driven by the force generated by the human hand, and a plant (e.g., a robotic arm) whose input comes from the stick. The system output is the position which is to be placed on a specific location by the human operator. The force from the stick output can be fed back (as a reflected force) and combined with the force applied by the human. The goal here is to study the effects of the reflected force feedback on the skills of the human operator. The recently induced probabilistic skill index is used to evaluate the performance of the operator performing specified tasks. The tasks are quantified by means of difficulty index. Four cases of different reflected feedback loops are studied. For each case, experimental data were collected when a human operator was performing a task of a known difficulty index. The probabilistic skill index is then used to quantify the effects of the reflected force feedback loop. Thus, this study provides evidence for evaluating the relative effects of the reflected forces on operator’s skills in the teleoperation

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