Adaptive Backstepping Compensation of Drives with Sandwiched Deadzone Nonlinearity

Nizar Alkhateeb ,Bassam M Alrahsed,Hameed K Ebraheem,Ebraheem Sultan

doi:10.4236/ica.2021.123005

Abstract

In this paper, a nonlinear robust adaptive controller is proposed for gear transmission servo system (GTS) containing a sandwiched deadzone due to improper gear meshing. The controller is robust to dynamic uncertainties and can compensate the effect caused by the sandwiched nonlinearity which is separated from the control input through drive compliance. The proposed design methodology does not require an adaptive inverse deadzone function and does not require the knowledge of its parameter and only the knowledge of upper bounds is required.

Highlights

Deadzone is one of the most common nonlinearities that affect a typical gear transmission servo systems (GTS) where the spacing between meshing causes a temporary loss of contact resulting in an inevitable mismatch error between desired reference trajectory and the actual one
A nonlinear robust adaptive controller is proposed for gear transmission servo system (GTS) containing a sandwiched deadzone due to improper gear meshing
The controller is robust to dynamic uncertainties and can compensate the effect caused by the sandwiched nonlinearity which is separated from the control input through drive compliance

Summary

Introduction

Deadzone is one of the most common nonlinearities that affect a typical gear transmission servo systems (GTS) where the spacing between meshing causes a temporary loss of contact resulting in an inevitable mismatch error between desired reference trajectory and the actual one. To overcome the nondifferentiability of deadzone the authors developed a soft differentiable model of deadzone which allowed them to analytically prove the stability of the overall system [8] and simulations showed the elimination limit cycling problem and improved tracking performance. To address the tracking problem for sandwich-like systems, Taware et al [10] first proposed an inner-outer loop structured controller with a nonlinearity inverse. The proposed control scheme employs an inner-loop discrete-time feedback design and an outer-loop continuous-time feedback design, combined with an adaptive dead-zone inverse to reduce the dead-zone effect resulting in improved output tracking. A similar problem was proposed by [10] to control a sandwich non-smooth nonlinearities between linear dynamic blocks by employing an inner-loop discrete-time feedback design along with an outer-loop continuous-time feedback design, combined with a nonlinearity inverse, to cancel the nonlinearity effect, for improving output tracking. Simulation studies show a clear improvement in the tracking and step response of the overall system

Problem Statement

Applying Adaptive Backstepping Control Method

Simulation Studies

Findings

Conclusion