Browsing by Author "Lin, SK"

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A flux estimation method for a permanent-magnet synchronous motor
(2004-11-01)
Wang, SH
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Fang, CH
;
Lin, SK
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電控工程研究所
;
Institute of Electrical and Control Engineering
This paper deals with the flux estimation of a permanent-magnet synchronous motor (PMSM). Contrary to the conventional no-load test, the proposed method needs no extra servomotor. It is simply to drive the PMSM in a single-phase mode with the currents large enough to make the PMSM rotate in the same direction. Under such a condition, the flux of the PMSM can be easily estimated. (C) 2004 Elsevier B.V. All rights reserved.
A performance criterion for the depth estimation of a robot visual control system
(2001)
Fang, CJ
;
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.
A study on information security management system evaluation - assets, threat and vulnerability
(2004-10-01)
Farn, KJ
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Lin, SK
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Fung, ARW
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資訊管理與財務金融系註：原資管所+財金所
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Department of Information Management and Finance
The security of information system is like a chain. Its strength is affected by the weakest knot. Since we can achieve 100% Information Security Management System (ISMS) security, we must cautiously fulfill the certification and accreditation of information security. In this paper, we analyzed, studied the evaluation knowledge and skills required for auditing the certification procedures for the three aspects of ISMS-asset, threat, and vulnerability. (C) 2004 Elsevier B.V. All rights reserved.
Adaptive backstepping motion control of induction motor drives
(2004-05-01)
Lin, SK
;
Fang, CH
;
電控工程研究所
;
Institute of Electrical and Control Engineering
In this paper, an adaptive backstepping controller is proposed for position tracking of a mechanical system driven by an induction motor. The mechanical system is a single link fixed on the shaft of the induction motor such as a single-link robot. The backstepping methodology provides a simpler design procedure for an adaptive control scheme and provides a method to define the sliding surface if the robust sliding-mode control is applied. Thus, the backstepping control can be easily extended to work as an adaptive sliding-mode controller. The presented position control system is shown to be stable and robust to parameter variations and external disturbances. The effectiveness of the proposed controllers is demonstrated in experiments.
Adaptive sliding-mode torque control of a PM synchronous motor
(2002-05-01)
Fang, CH
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Huang, CM
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Lin, SK
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電控工程研究所
;
Institute of Electrical and Control Engineering
An adaptive sliding-mode torque control system, which incorporates the merits of both the sliding-mode control and the adaptive algorithm, is proposed. The sliding-mode controller is constructed by two integral surface functions. The uncertainty is formulated as a random variable around a constant mean, so that an adaptive mechanism is used to estimate the constant mean and the bound of the random variable. Moreover, an application of the proposed torque control to the position control of a motor is also presented. Some experiments verify the control theory and demonstrate the usefulness of the proposed control scheme.
An automatic pin identification method for a three-phase DC brushless motor
(2005-10-01)
Wang, SJ
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Cheng, CC
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Lin, SK
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Ju, JJ
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Huang, DR
The pin identification is to find the definition of each connecting pin of a three-phase brushless motor. The 11 pins of the motor can be distinguished into three groups by a simple resistance measurement method. An automatic method has two steps. In the first step, the motor is in an open-circuited mode; and the individual pins of the windings are identified by comparing back electromotive forces. A special integral is defined and used to match Hall signal pins with the Hall sensors. The polarity of each pair of the Hall signal pins is determined by the second step of a standstill method. The proposed method is illustrated and verified by an experiment.
Analytical prediction of the cogging torque and torque constant of a hybrid stepping motor
(2002-02-01)
Wang, SJ
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Lin, SK
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電控工程研究所
;
Institute of Electrical and Control Engineering
We present an analytic method to efficiently calculate the torque constant and cogging torque of a hybrid stepping motor. The feature of the proposed method is its computational efficiency in that it is a useful tool for the motor design which is aimed at reducing the level of cogging torque or increasing the torque constant. This method is verified by comparing with the 3D finite element method and some experiments. (C) 2002 Elsevier Science B.V. All rights reserved.
Analytical prediction of the incremental inductance of the permanent magnet synchronous motors
(2004-07-01)
Wang, SJ
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Lin, SK
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電控工程研究所
;
Institute of Electrical and Control Engineering
An analytical method for calculating the incremental line inductance of a permanent-magnet synchronous motor is proposed in this paper. First, the incremental inductance is simplified as a linear combination of the slot inductance and the air-gap inductance, which are both estimated by the equivalent magnetic circuits. The reluctance of the rotor back irons and the stator back irons are ignored when the slot inductance is calculated. However, for the calculation of the air-gap inductance, the iron saturations and the perturbations of the permanent magnet are considered. The proposed method is verified by a finite-element method.
Autoadjusting the photodetector in an optical head system for optimum focus
(2004-07-01)
Wang, SJ
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Lin, SK
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電控工程研究所
;
Institute of Electrical and Control Engineering
In the assembly of an optical head system, it is required to mount the photodetector integrated chip (PDIC) in the correct position so that the astigmatism phenomenon can be achieved. The conventional means of adjustment requires an experienced engineer to shift the PDIC in the three dimension (3D) space until the S-word profile is obtained. This paper proposes an automatic method for replacing an experienced engineer, which can be formulated as an optimization problem with parameters trained by a neural network method. During the training process, a convex cost function of the 3D position is established and the minimum of this function indicates the correct position of the PDIC. In the mounting stage, the steepest descent method is then applied to search for the optimum of the trained function, so that the PDIC is automatically mounted at the optimal position.
Design a linear motor absorber
(2006-04-15)
Chang, CS
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Liu, TS
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Lin, SK
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機械工程學系
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電控工程研究所
This paper raises a valid method to design a linear motor which serves as active dynamic vibration absorber to reduce disk drives vibration at multiple speeds. A better linear motor performance, such as lower consumption energy and higher electrical efficiency, can be achieved by tuning the diameter of a winding coil, the thickness of the magnet, and the winding spaces in a linear motor absorber. (C) 2006 American Institute of Physics.
Design of a voice coil motor used in the focusing system of a digital video camera
(2005-10-01)
Yu, HC
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Lee, TY
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Wang, SJ
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Lai, ML
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Ju, JJ
This paper raises a valid method to design a voice coil motor (VCM) used in the focusing system of a digital video camera (DVC). A better VCM performance, such as lower battery consumption, higher efficiency, and shorter focusing time, can be achieved by turning the diameter of a winding coil, the thickness of the magnet, and the winding spaces in a VCM.
Efficient formulations for the manipulator inertia matrix in terms of minimal linear combinations of inertia parameters
(1999-12-01)
Lin, SK
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Fang, CJ
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電控工程研究所
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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.
Hybrid-damped resolved-acceleration control for manipulators
(1997-08-01)
Wu, SL
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Lin, SK
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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
The singularity problem of the resolved-acceleration control scheme can be solved by the damped least-squares method. This approach, however, does suffer from one serious drawback: oscillations of the end-effector when the target is outside the workspace and self-motion of the manipulator when it is at the orientation degeneracy. In this paper, we present a hybrid-damped resolved-acceleration control scheme (HDRAC), which is capable of damping both the accelerations and the velocities to overcome this drawback. The main advantage of the present approach is that the control system need not plan the path to avoid the infeasible region of the manipulator, since the controller will automatically command the end-effector to move along the boundary of the workspace with a minimum trajectory error. Thus this approach renders the resolved-acceleration control scheme a much more practical control for the industry. The stability of the proposed control scheme is also proved in this paper. Incorporated with the concept of the degenerated-direction damped least-squares method (DDDLSM), this new control scheme can also apply only to the degenerated directions, which scheme is simulated on the PUMA 560 manipulator to verify its usefulness. (C) 1997 John Wiley & Sons, Inc.
Hybrid-damped resolved-acceleration control for manipulators
(1997-08-01)
Wu, SL
;
Lin, SK
;
電控工程研究所
;
Institute of Electrical and Control Engineering
The singularity problem of the resolved-acceleration control scheme can be solved by the damped least-squares method. This approach, however, does suffer from one serious drawback: oscillations of the end-effector when the target is outside the workspace and self-motion of the manipulator when it is at the orientation degeneracy. In this paper, we present a hybrid-damped resolved-acceleration control scheme (HDRAC), which is capable of damping both the accelerations and the velocities to overcome this drawback. The main advantage of the present approach is that the control system need not plan the path to avoid the infeasible region of the manipulator, since the controller will automatically command the end-effector to move along the boundary of the workspace with a minimum trajectory error. Thus this approach renders the resolved-acceleration control scheme a much more practical control for the industry. The stability of the proposed control scheme is also proved in this paper. Incorporated with the concept of the degenerated-direction damped least-squares method (DDDLSM), this new control scheme can also apply only to the degenerated directions, which scheme is simulated on the PUMA 560 manipulator to verify its usefulness. (C) 1997 John Wiley & Sons, Inc.
Implementation of damped-rate resolved-acceleration robot control
(1997-06-01)
Wu, SL
;
Lin, SK
;
交大名義發表
;
電控工程研究所
;
National Chiao Tung University
The damped least-squares method has frequently been used to solve the singularity problem of resolved-acceleration control schemes. It works by damping only the joint accelerations, so that the joint accelerations in the degenerated directions (the end-effector cannot move along these directions) are zero at a singular point. However, the joint velocities in the degenerated directions may be nonzero in some situations, in which case they will create fluctuations around the singular point. In this paper, a damped-rate resolved-acceleration control scheme (DRRAC) is proposed to overcome this drawback. The paper also shows that the DRRAC is asymptotically stable, and its convergent property is discussed. Experiments were undertaken to verify the proposed control scheme. Copyright (C) 1997 Elsevier Science Ltd.
Low power consumption focusing actuator for a mini video camera
(2006-04-15)
Yu, HC
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Lee, TY
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Lin, SK
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Kuo, LT
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Wang, SJ
A novel low power consumption autofocusing actuator in a mini video camera is constructed in accordance with the result of a systematic design procedure of voice coil motors (VCM). This paper emphasizes the position control of such a VCM. The position feedback signals are provided by a magnetoresistive (MR) encoder. The position estimation algorithm (PEA) is developed to precisely decode the MR signals for the position of the moving part of the VCM. Different postures change the loading of the moving part of the VCM, so that an adaptive model-following control system based on the PEA is proposed to compensate for the loading variation. The experiments verify the fast dynamic performance and high power efficiency of the VCM. (C) 2006 American Institute of Physics.
Nonovershooting and monotone nondecreasing step responses of a third-order SISO linear system
(1997-09-01)
Lin, SK
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Fang, CJ
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交大名義發表
;
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.
On the stability of the hybrid-damped resolved-acceleration control
(1998-09-01)
Lin, SK
;
Wu, SL
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電控工程研究所
;
Institute of Electrical and Control Engineering
This paper points out that the stability analysis of the hybrid-damped resolved-acceleration control in our earlier work is incomplete, since the stability was concluded directly from the fact that the joint velocities come to rest as time approaches infinity. A similar incomplete technique was also used in the work of Wampler and Leifer to prove the stability of a damped least-squares resolved-acceleration control scheme. In this paper, we use LaSalle's invariance principle rigorously to show that the solution trajectory of the hybrid-damped resolved-acceleration control will eventually come to the target without steady-state error or will stay at a kinematic singular point with some steady-state error. Discussions on the case of staying at a singular point are also given. (C) 1998 John Wiley & Sons, Inc.
On-line parameter estimator of an induction motor at standstill
(2005-05-01)
Fang, CH
;
Lin, SK
;
Wang, SJ
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電控工程研究所
;
Institute of Electrical and Control Engineering
This paper describes an automatic identification procedure for an induction motor. The transfer function of the motor at standstill is used to obtain a linear parametric model. An on-line parameter estimator is then derived from this model. In the implementation of the proposed estimator, a PI current controller is constructed to stabilize the current signal and to prevent the flux from saturation. An experiment with an input that is persistently exciting verifies the theory of the proposed estimator and demonstrates its usefulness in industry applications. (C) 2004 Elsevier Ltd. All rights reserved.