A Noniterative Controller Design Framework Addressing Torque Ripple, Mechanical Resonance, and Time Delay in High-Precision Motion Systems

This article proposes a noniterative controller design for high-precision motion systems that systematically addresses torque ripple, mechanical resonance, and time delay. The proposed method follows a sequential torque–resonance–delay decoupling strategy to enable the analytical controller synthesis without iterative tuning. The torque ripple is first identified using low-frequency excitation for the compensation via feedforward linearization. After that, the mechanical resonance is mitigated based on a model-based resonance compensation. It results in a double-integrator dynamics with a time delay. Finally, the residual phase characteristics are exploited to estimate the system delay. An extended Smith–Åström predictor (ESAP) is developed for delay-free trajectory tracking within a delay-aware P-PI architecture. All control parameters are derived in closed-form through measured frequency responses, resulting in a deterministic and straightforward design procedure. Experimental results on a dual-axis precision motion system are presented. It is concluded that fast transient response, accurate tracking, and consistent performance across axes are achieved with a 10-μs control cycle.