Position control of induction and DC servomotors: a novel adaptive fuzzy PI sliding mode control

Abstract

The position control of a class of servomotors is addressed in this paper via a novel adaptive fuzzy PI sliding mode control. The premise and the consequence parts of the fuzzy rules are tuned with adaptive schemes. To attenuate chattering effectively the discontinuous control is approximated by an adaptive PI control structure. Moreover, the bound of the discontinuous control term is assumed unknown and an adaptive mechanism is used to estimate this bound. All adaptive laws are derived via Lyapunov synthesis method, thereby guaranteeing the closed-loop stability. The proposed approach has the added advantage that for external disturbances it only requires a bound to exist, without needing to know the magnitude of this bound. The proposed controller is applied to control a model of uncertain induction servomotor subject to significant disturbances and a model of DC servomotor with unknown parameters and uncertainty in load condition. Analysis of simulations reveals the effectiveness of the proposed method in controlling servomotors in terms of significant reduction in chattering while maintaining asymptotic convergence.

Passivity-based adaptive sliding-mode speed control for IPMSM drive systems

“…However, overly large values of the gains do lead to more chattering in the controls. To reduce the latter, a PI-saturation function is utilized to approximate the signum function [7] ( ) ( ) …”

“…Given this, we may therefore use an adaptive law to approximate the * 1 Γ value during a fixed sampling interval [5], [7]. Consider the following storage function and its time-derivative ( ) …”

“…Although good performance can be obtained, the systems may still suffer chattering due to switching. To overcome the chattering problem resulting from traditional sliding-mode control approach, several papers have addressed the issue [6], [7]. For example, Xu proposed a chattering free robust control for nonlinear systems [6].…”

“…The time-varying feedback gain, however, is very difficult to obtain in real-time implementation. Shahnazi et al proposed yet another novel adaptive fuzzy PI sliding-mode control for induction and DC servomotors in [7]. Through simulation results, their method showed good tracking performance without chattering.…”

Adaptive backstepping PI sliding-mode control for interior permanent magnet synchronous motor drive systems

“…In the above schemes, excellent dynamic and steady-state performances are shown; however, the systems may suffer chattering due to discontinuous switching functions. To overcome the chattering problem resulting from sliding-mode control, several papers have addressed such an issue [4], [5]. For example, Xu proposed chattering free robust control for nonlinear systems [4].…”