GMDH-based modeling and feedforward compensation for nonlinear friction in table drive systems

This paper presents a novel mathematical model-based feedforward compensator design for the nonlinear friction in table drive systems using the Group Method of Data Handling (GMDH). In the proposed approach, the nonlinear friction can be autonomously modeled as a polynomial expression for appropriate control state variables according to the process of GMDH and, as a result, the complicated structural modeling and its parameterization, indispensable to conventional model-based strategies, can be completely eliminated. In addition, since the proposed GMDH-based model can achieve the generalization ability for table drive conditions, the robust compensation for friction can be attained against the change of drive conditions. Experimental verifications using a table drive system of actual machine tools show the significant performance improvement of the proposed algorithm in the trajectory control with velocity reversal motion.