Some Aspects of Modeling and Robust Control of a Robotic Manipulator

The problem of exact linearization via feedback consists in transforming a nonlinear system into a linear one using a state feedback. In the multivariable case, the nonlinear control law achieves also decoupling. The use of feedback linearization requires the complete knowledge of the nonlinear system. In practice, there are many processes whose dynamics is very complex, highly nonlinear and usually incompletely known. It is possible that the controlled system become unstable in the presence of significant model uncertainties. To improve robustness, it may be necessary to modify the exact linearization controller. In this paper, some robustification techniques for the exact linearization method are presented and applied for some multivariable models of a robotic manipulator. Numerical simulations are included to demonstrate the behavior and the performances of these controllers. Key-Words: Robotic arm, Modelling, Nonlinear control, Linearizing control, Robust control