SUMMARY
In Sliding Modes control literature, a popular paradigm says that the so called “chattering-effect” (undesirable mechanical vibrations on the plant under control) can be reduced or even removed at all without affecting the control robustness. Nevertheless, results of practical implementations support that this is not necessarily true. In this work, the actual behaviour of a class of high order Sliding Modes used as the control law for a Multiple-Input Multiple-Output system is presented, where the real performance of system robustness is studied when the chattering-effect change in magnitude. In this study, to achieve the chattering reduction, the Super-Twisting algorithm is used, and the plant to control is a 3-DoF robot arm. The results of this work show that when techniques to reduce the chattering-effect are utilized, the corresponding reduction in system robustness should also be taken into account, and that achievements of theoretical concepts must be bounded when they are implemented in practical applications.