Suppression of mechanical resonance in digital servo system considering oscillation frequency deviation

High-stiffness servo system is easy to cause mechanical resonance in elastic coupling servo system. Although on-line adaptive notch filter is effective in most cases, it will lead to a severer resonance when resonance frequency deviated from the natural torsional frequency. To explain this phenomenon, an improved discrete system model is proposed. This paper quantitatively analyzes the influence of damping, discretization and current loop time constant on mechanical oscillation frequency. A conclusion is drawn that the most effective notch frequency is the natural torsional frequency when resonant frequency is deviate. Simulation and experimental results verify the accuracy and effectiveness of the theoretical analysis.