Answer:There are many reasons. What is more common is that the connection device between the servo motor and the load in the servo system is not ideally rigid, and elastic deformation will occur, resulting in vibration at the end of positioning. The residual vibration will not only aggravate the wear of the connecting device and affect the service life of the equipment, but also prolong the response time of the system, especially under the working conditions of frequent start and stop, high acceleration and high positioning accuracy. Therefore, it is of great engineering significance to suppress the residual vibration of the servo system.

In addition, the size of the load inertia and the setting of the controller bandwidth will have a certain impact on the vibration of the servo system.

Answer:Vibration is one of the important factors that affect the positioning accuracy of servo system. Therefore, vibration suppression for production, can achieve accurate point, improve production efficiency, reduce costs and other effects. For example:

When there is horizontal handling, through vibration suppression, reduce the time to wait for vibration elimination, improve production efficiency.

When filling the packaging machine, the liquid shaking can be suppressed to ensure the sealing quality.

The movement of the chip tray can prevent the workpiece from being damaged due to vibration during transportation.

When crane, suppress shaking during transportation.

Answer:In production practice, vibration suppression is generally achieved quickly through the three major tricks of elastic connection device optimization (optimization of transmission device), active suppression and passive suppression. among them,

• The elastic connection device is optimized to suppress vibration by adding or changing the mechanical structure;

• Active suppression is usually achieved by changing the structure and parameters of the controller;

• Passive suppression does not change the control structure and uses compensation or corrective measures to suppress the resonance frequency directly.

The ways to change the mechanical structure include: changing the rigidity, increasing or decreasing the mass, increasing the mechanism of vibration isolation, adding damping materials, installing tuned dampers (shock absorbers), and precise dynamic balance. These ways all require "surgery" on the equipment or its components, which has the disadvantages of low control efficiency, poor control flexibility and increasing the weight of the structure.

For the production of molding equipment, for servo-controlled actuators, the need for passive vibration suppression is particularly prominent.

Answer:The vibration of the servo drive system is mainly manifested in: mechanical vibration and electromagnetic vibration. Therefore, with regard to vibration suppression, researchers generally study these two manifestations.

Main control methods of mechanical vibration

1. Control method based on notch filter

   For example: a vibration suppression method by adding a notch filter and using the notch filter to compensate the vibration frequency of the system. -- Yang Ming, Xu Dianguo, etc.

2. observer-based control method

   Such as: a by adjusting a reasonable system inertia ratio, so that the resonant frequency and anti-resonant frequency offset each other, so as to achieve vibration suppression. -- Liangsong Huang et al

3. Control method based on H ∞ control theory

   For example, a model that introduces the integral into the controlled object, and transforms the torsional vibration suppression problem of the servo drive system into an H-control problem. -- Zhang Ruicheng et al

Main control methods of electromagnetic vibration

1. harmonic elimination method

   Such as: a three-phase modulation voltage waveform to add the corresponding harmonic components of the harmonic injection method to offset the control current in the harmonic components to achieve vibration suppression method. -- Liao Yong et al.

2. direct torque control

   Such as: a use of torque and magnetic chain slip controller to replace the traditional hysteresis controller control method. -- Yang Junhua

3. intelligent control

   Such as: the use of fuzzy control algorithm, do not need to know the model and parameters of the controlled system in advance, good anti-interference.

Answer:At present, in order to deal with mechanical vibration, the servo controller at home and abroad basically has the function of parameter self-tuning. This has also led many manufacturers to believe that having this feature can be done once and for all. In fact, the parameter self-tuning also has its specific nature. That is, parameter self-tuning is generally used to suppress vibration caused by improper parameter setting under rigid mechanical load. This method requires high accuracy and consistency of the load, and the tuning results cannot fully adapt to the change of the load or the change of the mechanical position, which leads to the change of the mechanical parameters. For non-rigid loads, it is difficult to achieve the ideal vibration suppression target by using the method of parameter self-tuning.

Answer:According to experienced engineers in the industry, the vibration caused by the servo system is summarized as follows:

● Servo wiring

1. Use standard power cable, encoder cable, control cable, whether the cable is damaged;

2. Check whether there is a source of interference near the control line, whether it is parallel to or too close to the nearby high-current power cable;

3. Check whether there is any change in the ground terminal potential to ensure good grounding;

4. Whether the jitter is caused by the interference of the analog input port, the magnetic ring is placed on the motor input line and the servo driver power input line to keep the signal line away from the power line.

5.  

● Servo parameters

1. The integral gain of speed loop, proportional gain of speed loop, acceleration feedback gain and other parameters are improper. Generally, the servo gain setting is too large, and it is recommended to readjust the servo parameters manually or automatically;

2. Confirm the setting of the time constant of the speed feedback filter, the initial value is 0, and try to increase the setting value;

3. The electronic gear ratio setting is too large, it is recommended to restore to the factory setting;

4. Servo system and mechanical system resonance, try to adjust the notch filter frequency and amplitude.

● Mechanical systems

1. The coupling connecting the motor shaft and the equipment system is offset, and the mounting screws are not tightened;

2. Poor engagement of pulleys or gears will also lead to changes in load torque. Try no-load operation. If it is normal during no-load operation, check whether the combined part of the mechanical system is abnormal;

3. Confirm whether the load inertia, torque and speed are too large, try no-load operation, if the no-load operation is normal, reduce the load or replace the drive and motor with a larger capacity;

4. Check whether the connection between the spindle and the spindle motor is faulty, and whether the spindle and the pulse generator installed at the tail of the AC spindle motor are damaged;

5. Check whether the fuse melt is blown, whether the switch contact is good, and measure whether there is electricity in each phase of the power grid;

6. Check whether the brake is open, by adding the encoder vector control zero servo function, the use of torque reduction way to output a certain torque to solve the jitter;

7. Check whether there is a fault on the printed circuit board, you need to check the circuit board or readjust it.