Control of backlash in electromechanical system-design and simulation based approach

Backlash is a dynamic non-linearity which is found in gear trains in an electromechanical actuator system. Backlash may give raise to undesirable inaccuracy, oscillations and instability in control system. In this work, we solved the problem of backlash using two approaches-simulation and design based approach. In simulation based approach, a novel PD controller tuned using signal constraint block of simulink design optimization toolbox is developed to restrain the overshoot, rise time and settling time in the system with backlash. The results show that PD and PID controllers tuned using Ziegler Nichols method show limit cycle oscillations in the systems with backlash. PD controller tuned using simulink design optimization toolbox show better steady state response as compared to PID controllers in the electromechanical system with backlash. In design based approach, friction in the electromechanical system is increased to compensate the backlash. Controller based compensation of backlash is less expensive as compared to design based compensation of backlash.