Advantages of closed-loop stepping motor over servo motor
The advantage of closed-loop stepping motor over servo motor is that Servo motor is emphasized and enjoyed by current engineers. When it comes to motion control, it is almost impossible to imagine not to talk about servo motor, engineers are obsessed with the closed-loop control of servo motors and indulge in the advantages of high response, high speed and high precision. Truly'Three highs'.
However, as the saying goes, the ruler has its own advantages, and the servo motor also has the following shortcomings that it cannot avoid: 1.
Unable to stop: due to the selection of closed-loop control, the structure of the servo motor itself and the characteristics of the motor are determined, and the servo motor cannot be definitely stopped when it is stopped, under the condition that the load disturbance is small or the parameter debugging of the servo motor is outstanding, the servo motor has been shaken between plus or minus 1 pulse (
Can investigate the value of the encoder orientation on the servo driver, it has been shaken between plus or minus 1).
This is an element that affects accuracy in picture processing. 2.
Overshoot: when changing from high speed to low speed or stopping, it is unavoidable to overshoot a certain distance and then correct it back.
When the controller sends a pulse to the servo motor, the servo motor often does not take one pulse, but 3 pulses, and then rolls back 2 pulses.
This is definitely not allowed to die on occasions where one pulse and one pulse are needed. 3.
Debugging disorder: there are hundreds of parameters in the servo driver, and hundreds of pages of instructions are used, which really makes the novice feel embarrassed;
Replacing a brand of servo motor will also make the insider really headache.
This also brings a lot of work for after-sales service and repair. 4.
Low speed activity: at low speed, the operation of the servo motor will show activity, which may be called creeping.
The closed-loop stepping motor perfectly handles the above problems.
Since the closed-loop stepping motor is not simply equipped with an encoder for the stepping motor, it is planned and developed according to the operation principle of the servo motor system.
It uses 32-bit DSP as the main processor to ensure the high response and high speed of the whole system, and can adjust the current of the motor every 25 microseconds, an encoder with 10000 pulses/turns is standard, and it is an encoder with a metal code disc, which not only ensures accuracy, but also ensures high adaptability, stability and reliability to environment, temperature and oscillation, even better than the servo motor with glass encoder.
First of all, because the closed-loop stepping motor is the body of the motor, it will definitely stop when it stops.
Secondly, the closed-loop stepping motor will not overshoot (Because the stepping motor is characterized by no overshoot).
Third, the debugging and application are very simple. Only the orientation of the three potentiometers of the driver needs to be adjusted. Not only can the equipment manufacturer use them, but also the equipment operator can use them. The requirements for users are extremely low.
Fourth, the driver uses real sine wave, vector and filtering methods to control the current, and the minimum rotation speed can be controlled at 0.
2 rpm, and the closed-loop stepping motor runs very smoothly and stably, which even servo motors cannot do (
In general, servo motors can theoretically achieve 1 rpm, but in practice, they cannot achieve 1 rpm, which is roughly above 5 rpm)
Related reading: three classifications of stepping motors, development of closed-loop stepping motors in electromechanical industry TAG closed-loop stepping motors