Research on the Calculation Method of Torque Fluctuation Coefficient for Industrial Robot Servo Motors Based on Stator Current

As one of the core components of industrial robots, the output of servo motors directly affects the overall accuracy of industrial robots. This paper selects the torque fluctuation coefficient of the servo motor as the main parameter to evaluate the health condition of the motor. By analyzing the impact of the fundamental wave current and harmonic currents on torque, a model linking the stator current signal to the torque fluctuation coefficient is constructed. During the current analysis process, the variational mode decomposition method (VMD) is used to decompose and reconstruct the current signal, reducing the impact of noise on the model's accuracy. In the laboratory, the model is verified using servo motors with different health conditions. The experimental results show that this method can be used to calculate the torque fluctuation coefficient of the servo motor in real-time under actual working conditions.