Browsing by Author "Fang, CJ"

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A performance criterion for the depth estimation of a robot visual control system
(2001)
Fang, CJ
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Lin, SK
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電控工程研究所
;
Institute of Electrical and Control Engineering
In this paper we propose a performance criterion for the depth estimation of an active vision system. It is well-known. that the linear velocity of the. camera. must satisfy sonic constraints for a success of the depth, estimation, However, thr-se constraints cannot ensure a good convergence performance of the depth estimation. Our Criterion is an extension from an estimation result of a linear system. Furthermore, we use it to develop a new visual servo control scheme that has good performance in both the depth estimation and the visual control. Finally, experiments and simulation results of a visual application verify our proposition.
A performance criterion for the depth estimation with application to robot visual servo control
(2001-10-01)
Fang, CJ
;
Lin, SK
;
電控工程研究所
;
Institute of Electrical and Control Engineering
This article deals with the depth observability problem of a robot visual system with a moving camera. In the visual system, the unknown depth of a feature point is estimated from the input of the camera velocity and the output of the image of the feature point. Although it is well known that the linear velocity of the camera must satisfy some constraints for successful depth estimation, this proposes a criterion to measure the performance of the depth estimation, which is a heuristic extension from an estimation result of a linear system. This performance criterion depends on both the image position and the linear velocity of the camera. Some simulation and experiment examples demonstrate and verify the proposed performance criterion. Furthermore, this criterion is used to develop a new visual servo control scheme that has good performance in both the depth estimation and the visual control. This control scheme is also verified by a simulation example. (C) 2001 John Wiley & Sons, Inc.
Efficient formulations for the manipulator inertia matrix in terms of minimal linear combinations of inertia parameters
(1999-12-01)
Lin, SK
;
Fang, CJ
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電控工程研究所
;
Institute of Electrical and Control Engineering
This article summarizes four formulations of the composite body method for the inertia matrix of a manipulator in the earlier works and presents a new formulation. These five formulations all use the first moments and the inertia tensors of composite bodies about the origin of the local frame. This paper also presents an algorithm for computing these first moments and inertia tensors. This algorithm utilizes a set of minimal linear combinations of inertia parameters instead of the natural inertia parameters, so that a number of redundant computations are saved. It is found that the new algorithm for the first moments and the inertia tensors of composite bodies is computationally superior to the others in the literature. On the other hand, two among the five formulations for the inertia matrix are more efficient than the other three as well as the others in the literature. The new formulation is one of these two most efficient formulations, and is specially adequate to a manipulator with some translational joints. (C) 1999 John Wiley & Sons, Inc.
Nonovershooting and monotone nondecreasing step responses of a third-order SISO linear system
(1997-09-01)
Lin, SK
;
Fang, CJ
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交大名義發表
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電控工程研究所
;
National Chiao Tung University
This paper presents the necessary and sufficient conditions for a third-order single-input/single-output linear system to have a nonovershooting (or monotone nondecreasing) step response. If the transfer function of an overall system has real poles, a necessary and sufficient condition is found for the nonovershooting (or monotone nondecreasing) step response. In the case of complex poles, one sufficient condition and two necessary conditions are obtained. The resulting conditions are all in terms of the coefficients of the numerator of the transfer function. Simple calculations can be used to check a system for the nonovershooting (or monotone nondecreasing) step response. Another feature is that the conditions in terms of pole-zero configurations can be easily derived from the present results.