Adaptive Robust Motion Control of Direct-Drive DC Motors with Continuous Friction Compensation

Jianyong Yao,Guichao Yang,Dawei Ma,Zongxia Jiao

doi:10.1155/2013/837548

Abstract

Uncertainties including the structured and unstructured, especially the nonlinear frictions, always exist in physical servo systems and degrade their tracking accuracy. In this paper, a practical method named adaptive robust controller (ARC) is synthesized with a continuous differentiable friction model for high accuracy motion control of a direct-drive dc motor, which results in a continuous control input and thus is more suitable for application. To further reduce the noise sensitivity and improve the tracking accuracy, a desired compensation version of the proposed adaptive robust controller is also developed and its stability is guaranteed by a proper robust law. The proposed controllers not only account for the structured uncertainties (e.g., parametric uncertainties) but also for the unstructured uncertainties (e.g., unconsidered nonlinear frictions). Furthermore, the controllers theoretically guarantee a prescribed output tracking transient performance and final tracking accuracy in both structured and unstructured uncertainties while achieving asymptotic output tracking in the absence of unstructured uncertainties, which is very important for high accuracy control of motion systems. Extensive comparative experimental results are obtained to verify the high-performance nature of the proposed control strategies.

Highlights

There are many requirements for high-performance tracking control in industries [1,2,3], like robots [4], gantry systems [5], active suspension systems [6], micromechanisms [7], motion platforms [8], and so on
A new continuously differentiable friction model proposed in [13] is utilized in this paper to develop a continuous friction compensation law that cancels the majority of friction in the systems in conjunction with adaptive robust control [29] to handle other structured uncertainties and unstructured uncertainties for a motion system directly driven by a dc motor
The detail description of the hardware components used in the platform can be found in [8] and the measurement and control system consists of monitoring software and real time control software

Summary

Introduction

There are many requirements for high-performance tracking control in industries [1,2,3], like robots [4], gantry systems [5], active suspension systems [6], micromechanisms [7], motion platforms [8], and so on. Based on the limitation analysis of LuGre-model-based friction compensation and note the fact that it is more popular when the controller is continuous, simple, less noise-sensitive, and can achieve high precise performance With these concerns, a new continuously differentiable friction model proposed in [13] is utilized in this paper to develop a continuous friction compensation law that cancels the majority of friction in the systems in conjunction with adaptive robust control [29] to handle other structured uncertainties and unstructured uncertainties for a motion system directly driven by a dc motor.

Problem Formulation and System Models

Controller Design

Comparative Experimental Results

Conclusion

Proof of Theorem 4

Proof of Theorem 6