Application of robust chattering-reduction sliding mode control techniques for position control of a vector-controlled induction machine with non-linear friction dynamics

Sliding mode control (SMC) methods possess several advantageous properties such as robustness against parameter variation, disturbance rejection, straightforward design, and are simple to implement. In this paper, a sliding mode control algorithm (which considers the non-linear friction dynamics) based on an equivalent control technique is designed and implemented on a non-linear induction machine system with non-linear friction dynamics such as Coulomb, windage, Stribeck, and static friction. The chattering phenomenon, which is inherent in the standard sliding mode algorithm, is discussed, as well as the techniques to reduce the chattering effect. A sixth-order non-linear induction machine model is employed for simulation analysis. The developed control algorithms are then tested for position control of a practical vector-controlled induction machine, in three different operating conditions (nominal load, high inertial load, and rotor resistance mismatch). The controller performance results are compared practically with several different sliding mode control algorithms as well as with a fixed-gain controller test.