Feedforward Model Predictive Control for Dual-Stage Fast Tool Servo With Realistic Constraints

This paper presents a model predictive control based optimal feedforward tracking integrated with a robust repetitive feedback control aimed for generating complex engine piston profiles in non-circular engine piston turning using dual-stage long stroke linear motor/high bandwidth piezoelectric actuators. By formulating and solving receding horizon optimization, which explicitly takes into account practical constraints and specific dynamic capabilities of the dual-stage actuators integrated with repetitive feedback control, the methodology is demonstrated in simulation to precisely track fast oscillating but non-periodic reference signals derived from an industrial engine piston profile. In comparison, linear repetitive feedback control alone would violate dual-stage actuator constraints and as a result generate tracking errors 50 times larger than the proposed approach.