Debugging method of servo motor

There are some precautions for servo motor operation. As we introduced last time, the servo motor can control the speed, making the position accuracy quite accurate. It can convert the voltage signal into torque and rotational speed to drive the control object. However, the servo motor must be debugged before using it. The debugging method is as follows:

1. Initialization parameters

Before wiring, initialize the parameters.

On the control card: select the control method; clear the PID parameters; allow the enable signal to be turned off by default when the control card is powered on; save this status to ensure that it will be in this status when the control card is powered on again.

On the servo motor: set the control method; set the enable external control; the gear ratio of the encoder signal output; set the proportional relationship between the control signal and the motor speed. Generally speaking, it is recommended that the planned speed in servo operation corresponds to a control voltage of 9V. For example, Sanyo sets the rotation speed corresponding to 1V voltage, and the factory value is 500. If you only plan to have the motor operate below 1000 rpm, then set this parameter to 111.

2. Wiring

Power off the control card and connect the signal line between the control card and the servo. These lines must be connected: the analog output line of the control card, the enable signal line, and the encoder signal line of the servo output. After checking that there are no errors in the wiring, power on the motor and control card (and PC). The motor should be stationary at this point and can roll easily with external force. If not, you can check the settings and wiring of the enable signal. Use external force to roll the motor and check whether the control card can correctly detect the change in motor position. Otherwise, check the wiring and settings of the encoder signal.

3. Try the direction

Regarding a closed-loop control system, if the direction of the feedback signal is incorrect, the result will definitely be catastrophic. Turn on the servo enable signal through the control card. At this time, the servo should roll at a lower speed, which is the legendary "zero drift". Generally, there will be instructions or parameters to suppress zero drift on the control card. Use this command or parameter to see if the motor's speed and direction can be controlled by this command (parameter). If it cannot be controlled, check the parameter settings of the analog wiring and control method. If a positive number is given, the motor will rotate forward and the encoder count will increase; if a negative number is given, the motor will rotate reverse and the encoder count will decrease. If the motor is loaded and the stroke is limited, do not use this method. Do not give too much voltage during the test, it is recommended to be below 1V. If the directions are inconsistent, you can modify the parameters on the control card or motor to make them consistent.

4. Suppress zero drift

In the closed-loop control process, the existence of zero drift will have a certain impact on the control effect and should be suppressed. Use the parameters on the control card or servo to suppress zero drift and adjust carefully to make the motor's speed approach zero. Because the zero drift itself also has a certain degree of randomness, there is no need to require the motor speed to be zero.

5. Establish closed-loop control

Pass the servo enable signal through the control card again, and enter a smaller proportional gain on the control card. As for how large is considered small, you can only rely on your feeling. If you are really worried, enter the small amount that the control card can allow. value. Turn on the enable signals of the control card and servo. At this time, the motor should be able to roughly follow the motion instructions.

6. Adjust closed-loop parameters

Fine-tuning the control parameters to ensure that the servo motor moves according to the instructions of the control card is a necessary task, and this part of the task requires more experience accumulation.