Question

What is the difference between acceleration and deceleration in position control mode?

Answer 1

In the position control mode, acceleration and deceleration are two crucial stages in the motor movement process, which have an important impact on the position control accuracy of the motor and the stability of the system. The following is the difference between acceleration and deceleration in the position control mode:

Definition and purpose

1. Acceleration phase:

- Definition: The acceleration phase refers to the process in which the motor starts from a stationary state or a low-speed state and gradually increases the speed to reach the target speed or position.

- Purpose: To enable the motor to reach the required movement speed in a short time and improve production efficiency.

2. Deceleration phase:

- Definition: The deceleration phase refers to the process in which the motor gradually reduces the speed when approaching the target position to ensure that it can stop accurately at the target position.

- Purpose: To reduce the impact and vibration when the motor stops and improve the accuracy and stability of position control.

Control strategy

1. Acceleration control:

- During the acceleration process, the control system will gradually increase the driving torque of the motor according to the preset acceleration curve (such as linear acceleration, S-shaped acceleration, etc.), so that the motor speed gradually increases.

- The acceleration process needs to balance the relationship between acceleration time and system stability, ensuring that the motor can quickly reach the target speed and avoiding excessive acceleration from causing impact on the system.

2. Deceleration control:

- The deceleration process is usually more complicated than the acceleration process because the position of the motor needs to be controlled more accurately. During the deceleration stage, the control system gradually reduces the driving torque of the motor according to the distance between the current position of the motor and the target position and the preset deceleration curve.

- The deceleration process needs to ensure that the motor can stop quickly and smoothly when it reaches the target position to avoid overshoot or undershoot.

Influencing factors

1. Acceleration/deceleration size: The size of acceleration and deceleration directly affects the motion characteristics and position control accuracy of the motor. Excessive acceleration may cause system vibration and shock, while too little deceleration may cause the motor to overshoot or undershoot.

2. Control algorithm: Different control algorithms have different control effects on the acceleration and deceleration process. Advanced control algorithms can more accurately control the motion trajectory and speed changes of the motor, and improve the accuracy and stability of position control.

3. System load: Changes in system load will also affect the control effect of the acceleration and deceleration process. Under heavy load conditions, the motor requires a larger driving torque to accelerate or decelerate; under light load conditions, a smaller driving torque may be required.

Summary

In the position control mode, acceleration and deceleration are two indispensable stages in the motor movement process. They use different control strategies and algorithms to achieve rapid start and smooth stop of the motor, thereby improving the accuracy and stability of position control.

In practical applications, it is necessary to select appropriate acceleration and deceleration strategies and control algorithms according to specific application scenarios and requirements.

Answer 2

In position control mode, in position control mode, acceleration can be expressed as the rate of change in the amount of position per unit time, that is, the speed of position change. In position control mode, deceleration can be expressed as the rate of reduction of the amount of position per unit time, that is, the speed at which the position decreases.

The difference is that acceleration describes the rate at which position changes, while deceleration describes the rate at which position decreases. In position control systems, acceleration and deceleration are important parameters that can affect the dynamic performance and stability of the system.

Answer 3

The functions of the position control mode in the servo system include the following:

1. Generate pulses to control the rotation of the servo motor, the number of pulses determines the rotation angle of the servo motor or the moving distance of the table, and the frequency of the pulse determines the speed of the motor.

2. It can receive up to 500KHz pulse (differential input) or 200KHz collector input.

3. The output torque of the motor is determined by the load, the larger the load, the greater the torque output by the motor, but it cannot exceed the rated load of the motor.

4. When the load is sharply accelerated or decelerated or overloaded, the main circuit overcurrent will affect the power device, so the servo amplifier sets the embedded circuit to limit the output torque, and the torque limit can be adjusted by analog or parameter settings.

5. The speed control mode can be adjusted by analog (0~±10VDC) or parameters, and up to 7 speeds can be set.

6. The control mode is similar to that of the frequency converter.

7. It can support direct load outer loop detection position signal, at this time the encoder at the motor shaft end only detects the motor speed, and the position signal is provided by the detection device at the final load end, which can reduce the error in the intermediate transmission process and increase the positioning accuracy of the entire system.