Optimal Parametric Design of Discrete-Time Robust Force Control System Based on Disturbance and Reaction Force Observers

This article introduces an advanced methodology for optimal parametric design based on discrete-time analysis findings of a robust force control structure, integrating both a disturbance observer and a reaction force observer. While conventional continuous-time analyses are commonly employed to enhance system performance, offering guidance for stability and robustness improvement, they often fall short in explaining practical implementation instabilities. A significant knowledge gap persists in the systematic design approach for tuning the control system to meet specific desired behaviors. To bridge this gap, this article thoroughly investigates the system's frequency response. Design constraints derived from this analysis process formulate the nominal parameter design as a minimization problem, subsequently solved using a genetic algorithm to determine optimal parameter values. Simulations illustrate the control system behavior, emphasizing the design constraints and optimal parameter design process. The proposed method is applied to a force-controlled spindle via calibrated experiments, providing robust validation. The results unequivocally confirm the effectiveness of the proposed design approach, achieving stability, and robustness concurrently.