Servo Motor System Test Solution

With the rapid development of servo motor technology, CNC machine tools, industrial robots, and automated production equipment have begun to widely use servo motors as key components for motion control. Naturally, the performance requirements for servo motors are becoming higher and higher, especially their dynamic characteristics. At this time, traditional dynamometers can no longer perform related tests. Therefore, the industry urgently needs a complete solution that can provide high-performance servo motor dynamic characteristics and controller control performance testing.

 

With the rapid development of servo motor technology, CNC machine tools, industrial robots, and automated production equipment have begun to widely use servo motors as key components of motion control. Naturally, the performance requirements for servo motors are becoming higher and higher, especially their dynamic characteristics. At this time, traditional dynamometers can no longer perform related tests. Therefore, the industry urgently needs a complete solution that can provide high-performance servo motor dynamic characteristics and controller control performance testing.

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At present, the main equipment for measuring and evaluating the performance of motors is still the dynamometer. Initially, the dynamometer only measured the input voltage, current, output speed, and torque of the motor, and calculated the input and output power and efficiency of the motor. However, with the rapid development of the motor industry, there are more and more motor testing items, and the functions of the dynamometer have also been enriched. Even so, the dynamic test of the motor is still a technical problem in the industry.

First of all, the dynamic test includes a step response test to analyze the speed/torque control response time. When the motor load undergoes a step change and changes the motor's output speed/torque, the motor driver takes a certain amount of time to adjust the motor back to normal working conditions. Usually, the speed step response time of imported high-performance servo motors must be able to reach the us level, and the torque step response adjustment time must also be able to reach the ms level. For the Yaskawa servo motor SGM7A-10AFA6C model, its speed step response time can reach 790ms, and the torque step response adjustment time can reach 28ms (the above data is provided based on the test results of Zhiyuan Electronics' MPT1000-F motor transient control and test system).

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Secondly, the speed fluctuation test examines the fluctuation of the motor speed when the torque changes suddenly under the speed control mode; and the overspeed test checks the installation quality of the motor, the mechanical strength of each part of the test rotor to withstand the release force, and the mechanical strength of the bearing at overspeed.

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Dynamic testing difficulty 1: Slow PID adjustment

Traditional dynamometers generally use PID adjustment to change the load size during the test and loading process, and use industrial computers for feedback control judgment and display. Due to the delay of the communication bus, the PID adjustment speed is slow, and the loading mode can only realize loading point by point, as shown in the following figure:

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This results in the inability to increase the loading speed and even more so the inability to load any load. At the same time, the low sampling rate of the instrument itself and the low speed and torque sampling rate greatly limit the traditional dynamometer from being able to test the dynamic characteristics of the servo system.

Dynamic testing difficulty 2:

Traditional integrated manufacturers use a simple combination of instruments to build test platforms. Due to the lack of in-depth understanding of measurement principles and R&D experience, it is difficult to provide comprehensive functional customization services according to customer needs. The problems revealed by this are becoming increasingly serious, such as slow loading and test response, which can only be applied to steady-state test needs; supporting three-channel electrical parameter measurement and analysis, but unable to achieve systematic joint debugging and testing of motor drivers and motors.

Relying on its in-depth understanding and long-term accumulation in the fields of power analysis and motor measurement, ZHIYUAN Electronics has broken through the bottleneck of motor dynamic testing. It adopts an original free loading engine and integrates the design concept of the instrument. It uses a separate hardware PID controller to make negative feedback control judgments, greatly improving the PID adjustment speed and launching the epoch-making MPT hybrid motor test system. At the same time, it meets the industry's needs for steady-state and dynamic measurement of motors and their control systems, leading motor experiments into the field of dynamic measurement.

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