On Adaptive Control of Robotic Manipulators with Actuator Deficiencies

Abstract

In this work, we tackle the tracking problem of robotic manipulators with uncertain dynamical parameters and actuator deficiencies in the form of an uncertain control effectiveness matrix. Specifically, two different novel adaptive controller formulations are presented. Aside from the uncertainties of the dynamical system, both adaptive controller formulations proposed can also deal with the so-called control effectiveness matrix that pre-multiplies the control input. The uncertainty compensation of the dynamical parameters is achieved via the use of desired model compensation-based adaptation, while the uncertainties related to the control effectiveness matrix are dealt with via two fundamentally different novel adaptation methods. The global stability of the system states and convergence of the error terms to the origin are proven via Lyapunov-based arguments. Extensive numerical studies performed on a two-link planar robotic device, are also presented in order to illustrate the effectiveness of both adaptation controllers.