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Some recent studies have addressed a class of human-machine coordination employing ldquovirtual fixtures,rdquo which are computer-generated walls or guides presented through haptic devices for assisting precise path tracing and for preventing the entry to specified regions. This paper presents the concept and control algorithms of a new class of virtual(More)
The purpose of this study is to establish a method of virtual-reality-mediated motion/force teaching from human teacher to human " teachee ". For effective teaching , position and force information of the teacher's action have to be communicated to the teachee. Position information is easy to display, but force information is difficult to display by(More)
High-gain PID position control, which is widely used with industrial robots, involves some risks in cases of abnormal events, such as unexpected environment contacts and temporal power failures. This paper proposes a new position control method to achieve both accurate, responsive tracking during normal operation and smooth, overdamped recovery from a large(More)
This article describes a computationally efficient formulation and an algorithm for tetrahedral finite-element simulation of elastic objects subject to Saint Venant-Kirchhoff (StVK) material law. The number of floating point operations required by the algorithm is in the range of 15% to 27% for computing the vertex forces from a given set of(More)
Friction force is cumbersome in numerical simulations due to its discontinuity at zero velocity. Fixed-step simulation techniques are especially desirable for control purposes, such as haptic friction rendering and friction compensation. Previous techniques have difficulties especially in numerical robustness and extensibility to multidimensional cases.(More)
Human-machine cooperative systems have been proposed. Most of them consider carrying, positioning and assembling tasks. Precise tracking tasks are also required in factories. However, an assist system for tracking task has not been studied well. In this paper, we aim to realize the human-machine system that assists a tracking task. In order to achieve the(More)
This paper introduces a device for enhancing detection of surface undulation through active touch. This device, which we call a “tactile contact lens,” is composed of a sheet and numerous pins arranged on one side of the sheet. Experimental results show that a small bump on a surface can be detected more accurately through this device than by(More)
High-gain proportional-integral-derivative (PID) position control involves some risk of unsafe behaviors in cases of abnormal events, such as unexpected environment contacts and temporary power failures. This paper proposes a new position-control method that is as accurate as conventional PID control during normal operation, but is capable of slow,(More)