Task-space Control of Robots Using an Adaptive Taylor Series Uncertainty Estimator Revisited

Subject Areas :

Masoud Shahhosseini ¹ (Department of Electrical Engineering, Garmsar branch, Islamic Azad University, Garmsar, Iran)

Received: 2019-08-28 Accepted : 2019-11-17 Published : 2018-11-01

Keywords: Stability Analysis, Electrically Driven Robots, Actuator Saturation, Adaptive Uncertainty Estimation,

Abstract :

This paper presents an improved version of the article “task-space control of robots uses an adaptiveTaylor series uncertainty estimator” by designing a more general framework for dealing withactuator saturation. There are four important issues about the aforementioned article. Firstly, thesaturated and unsaturated regions have been discussed separately in that article, while this paperpresents a unified approach for stability analysis. Secondly, the linear parameterization of unknownmulti-variable vector-valued nonlinearities represented in the aforementioned article is not true.Consequently, it will affect the stability analysis significantly and the obtained results are doubtful.Thirdly, although the tracking error is bounded in the saturated area, it may be unacceptable due toundesirable performance. Thus, performance evaluation is needed to verify the satisfactoryoperation of the control system. However, in the aforementioned article, performance evaluationhas not been presented. Fourthly, the aforementioned paper applies the Taylor series as a universalapproximator without verifying the conditions of the universal approximation theorem. This paperproves that the Taylor series can satisfy the conditions of this theorem. All these four importantissues are addressed in this paper and a modified version of the aforementioned article is presented.