Nonlinear speed control of elastic systems with backlash

Backlash in elastic systems is one of the most important nonlinearities that limits the performance of speed control in industrial drives. In this work a new robust nonlinear speed controller for such system is proposed. Two linear controllers are designed, one globally stable with reduced performance, and one with high performance exhibiting limit cycles around the backlash. The two controllers are combined into one high performance, stable nonlinear controller with soft switching. The advantage of the new controller is shown with simulations and measurements on a large real life drive system