1).Servo motor detection -- cogging torque:

Cogging torque is an inherent phenomenon of permanent magnet motor, which can make the motor torque fluctuate and produce vibration and noise. We measure the change of motor torque in a rotation cycle on a special test bench and analyze the distribution of cogging torque.


2).Servo motor detection - torque ripple:

Under the condition of given speed and torque, the servo system measures and records the output torque of the motor in one circle, finds out the maximum torque and minimum torque, and calculates the torque fluctuation coefficient.


3).Servo motor detection--response time of torque / speed change



The speed response time is one of the key indexes to evaluate the servo driver. Under the condition of no-load, the servo system inputs the step signal to the speed command, and obtains the time response curve of the step input.



The torque response time is one of the key indexes to evaluate the servo driver. When the servo system is in normal operation, the sudden loading or unloading of the motor can affect the time response of sudden loading.



5).Servo motor detection--position tracking error

The position tracking error of servo system includes steady position tracking error and dynamic position tracking error. The driver works in position control mode and measures the margin between position command value and position feedback value.


6).Servo motor detection--bandwidth:

Bandwidth is an important index of servo system, which reflects the response speed and anti-interference ability of servo system.

When the driver works in the speed mode and the sine wave speed command is input, it will measures the 90 °phase shift bandwidth or - 3dB bandwidth of the servo system.