Both servo motor speed control and torque control are controlled by analog, and position control is controlled by sending pulses. The specific control method to be selected depends on the customer's requirements and the motion function to be satisfied. Next, the editor of Dalan Motor will compare the three control methods.
1. Talk about the comparison of three control methods: torque control, position control and speed control.
If you have no requirements on the speed and position of the motor, as long as a constant torque is output, of course the torque mode is used.
If there is a certain accuracy requirement for position and speed, but not very concerned about real-time torque, it is better to use speed or position mode.
If the host controller has a better closed-loop control function, the speed control effect will be better. If the requirements are not very high, or there is basically no real-time requirements, there is no high requirement for the host controller in the position control mode.
From the perspective of the response speed of the servo drive: the torque mode has the smallest calculation amount and the drive responds fastest to the control signal; the position mode has the largest calculation amount and the drive responds to the control signal the slowest.
When there are relatively high requirements for the dynamic performance in motion, the motor needs to be adjusted in real time.
If the operation speed of the controller itself is very slow (such as PLC, or low-end motion controller), then use the position mode to control.
Second, talk about the third ring
The servo motor is generally controlled by three loops. The so-called three loops are three closed-loop negative feedback PID adjustment systems.
The innermost PID loop is the current loop. This loop is completely carried out inside the servo driver. The Hall device detects the output current of the driver to each phase of the motor. The negative feedback is used to set the current to adjust the PID to achieve the output current as close as possible Equal to the set current.
The second loop is the speed loop. The negative feedback PID adjustment is performed by the signal of the motor encoder detected. Its PID output in the loop is directly the setting of the current loop. Therefore, the speed loop and the current loop are included in the speed loop control.
The third ring is the position ring, which is the outermost ring. It can be built between the drive and the motor encoder or between the external controller and the motor encoder or the final load, depending on the actual situation.
Because the internal output of the position control loop is the setting of the speed loop, the system performs all three loop calculations in the position control mode. At this time, the system has the largest calculation amount and the slowest dynamic response speed.
----- Responsible Editor: Dalan Oil Pump Motor 02-Procurement Consultant
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