Browsing by Author "Horng, Rong-Hwang"

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Advanced parameter identification for a linear-motor-driven motion system using disturbance observer
(2009-10-01)
Pan, Yi-Ren
;
Shih, Yi-Ti
;
Horng, Rong-Hwang
;
Lee, An-Chen
;
機械工程學系
Disturbance observer (DOB) is generally introduced into motion control systems to eliminate undesired disturbances and plant uncertainty. The DOB is also used for system identification. This work presents a novel experimental identification algorithm using disturbance observer to identify inertia, viscous coefficient, and friction of linear-motor-driven motion system. A conventionally adopted algorithm for determining the inertia of the motion system based on orthogonal relations among system responses is modified and extended to estimate the viscous coefficient and the magnitude of Coulomb friction of the underlying system. The advantages of the proposed method are high convergence rate and only one experiment needed to evaluate the system parameters. The proposed algorithm is demonstrated to be workable by both simulation and experiment.
Rejection of limit cycles induced from disturbance observers in motion control
(2006-12-01)
Horng, Rong-Hwang
;
Chou, Heng-Lung
;
Lee, An-Chen
;
機械工程學系
;
Department of Mechanical Engineering
A disturbance observer (DOB) is generally introduced into motion control systems to eliminate the unwanted disturbance and plant uncertainty. Due to the quantization error from the sensors and D/A converter, DOB-based controller might generate limit cycles which severely decreases positioning accuracy as the system reaches steady-state positioning. This paper presents a sufficient condition for removing limit cycles and explores the condition to design controller parameters. In addition, since the parameters based on the condition make the system sluggish, an adaptive mechanism is introduced not only to maintain the system performance but also to eliminate limit cycles. The experimental results validate the analytical results and also illustrate the effectiveness of the proposed method.
Sliding Observer for Friction Compensation in a Linear-Motor-Driven Motion System
(2011-02-01)
Horng, Rong-Hwang
;
Lee, An-Chen
;
機械工程學系
;
Department of Mechanical Engineering
In this work, a sliding-mode observer is developed for estimating unavoidable frictions and undesired disturbance in motion systems. The estimated parameters are then feedback for compensation to achieve precise control. With proper observability analysis performed by using Lie derivative method, the design of observer is based on the underlying nonlinear system with LuGre friction Model. While maintaining the stability of the observer, we choose the observer gains to make the system a dissipative one. As a conclusion in the last section, the proposed method is applied to a linear-motor-driven motion system. The experimental results show that the tracking and positioning performance with the proposed friction compensation method are smaller than those of the disturbance observer (DOB) compensation or without friction compensation.