1. Initialization parameters
Initialize parameters before wiring. On the control card: select the control mode; Clear PID parameters to zero; When the control card is powered on, the enable signal is turned off by default; Save this state to ensure that the control card is in this state when it is powered on again.
On the servo motor: set the control mode; Set enabling to be controlled externally; Gear ratio of encoder signal output; Set the proportional relationship between the control signal and the motor speed. Generally speaking, it is recommended to make the maximum design speed in servo operation correspond to the control voltage of 9V.
2. Wiring
Power off the control card and connect the signal line between the control card and the servo. The following lines must be connected: analog output line of control card, enable signal line, encoder signal line of servo output. After checking that there is no error in the wiring, the servo motor and control card (as well as PC) are powered on. At this time, the motor should not move and can easily rotate with external force. If not, check the setting and wiring of enabling signal. Rotate the motor with external force and check whether the control card can correctly detect the change of motor position, otherwise check the wiring and setting of encoder signal.
3. Test direction
For a closed-loop control system, if the direction of the feedback signal is not correct, the consequences will be disastrous. Turn on the enable signal of the servo through the control card. This is that the servo should rotate at a lower speed, which is the legendary "zero drift". Generally, the control card will have instructions or parameters to suppress zero drift.
Use this command or parameter to see if the speed and direction of the motor can be controlled by this command (parameter). If it cannot be controlled, check the parameter settings of analog quantity wiring and control mode. Confirm that the positive number is given, the motor rotates forward, and the encoder count increases; Given a negative number, the motor rotates in reverse direction and the encoder count decreases. If the motor is loaded and the travel is limited, do not use this method. Do not apply excessive voltage to the test. It is recommended that it be less than 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 it is better to suppress it. Use the parameters on the control card or servo to suppress zero drift and carefully adjust them to make the motor speed close to zero. Due to the randomness of the zero drift itself, it is not necessary to require the motor speed to be absolutely zero.
5. Establish closed-loop control
Once again, release the servo enable signal through the control card, and input a small proportional gain on the control card. As for how large it is, it is only a matter of feeling. If you are really not sure, enter the minimum value allowed by the control card. Turn on the enable signal of the control card and servo. At this time, the motor should have been able to act roughly according to the motion command.
6. Adjust closed-loop parameters
It is necessary to carefully adjust the control parameters to ensure that the motor moves according to the instructions of the control card. This part of work is more experience, which can only be omitted here.
Source: Industrial robots
