Torque Constraint Modeling and Reference Shaping for Servo Systems

Servo systems, one of the backbones of modern manufacturing, are supposed to move as fast as possible for high productivity. Due to the inaccurate information on torque capacity, conventional trajectory generation methods are either overly conservative, compromising yield, or violate dynamical feasibility, compromising quality. This letter proposes a method to address these shortcomings. Stable adaptive estimation of the servomotor model parameters is first performed, then torque capacity constraints are established as analytical functions of the motor speed based on parameter estimates, and finally, a computationally efficient algorithm is developed to reshape an aggressive (dynamically infeasible) trajectory into a feasible one. Theoretical analysis and numerical simulation validate the effectiveness of the proposed method.