Comparison of two motors of stone engraving machine:
At present, the power system of the stone engraving machine is nothing more than a stepper motor and a servo motor. The control methods of the two are very similar. They are both controlled by pulse trains and direction signals, but the performance of the two is quite different.
1. The accuracy of the two is different. The step angle of the two-phase hybrid stepping motor is generally 3.6° and 1.8°, and the step angle of the five-phase hybrid stepping motor is generally 0.72° and 0.36°; the control accuracy of the servo motor is guaranteed by the rotary encoder at the back end of the motor shaft. , For motors with standard 2500 line encoders, most of the drivers use quadruple frequency technology inside, and the pulse equivalent is 360°/10000=0.036°. For a motor with a 17-bit encoder, every time the driver receives 217=131072 pulses, the motor rotates one revolution, that is, its pulse equivalent is 360°/131072=9.89 seconds. It is 1/655 of the pulse equivalent of a stepper motor with a step angle of 1.8°. Simply put, the minimum control accuracy of the servo motor is more than 600 times that of the stepper motor.
2. The overload capacity is different. Stepper motors generally do not have overload capability. AC servo motor has strong overload capacity, it has speed overload and torque overload capacity. Its maximum torque is three times the rated torque, which can be used to overcome the inertial moment of inertial load at the moment of starting. Because the stepping motor does not have such overload capacity, it is often necessary to select a motor with a larger torque when selecting a model, and the machine does not need such a large torque during normal operation, so the phenomenon of torque waste occurs.
3. The running performance is different. The stepper motor is open-loop control. If the starting frequency is too high or the load is too large, it is easy to lose steps or stall. When the speed is too high, it is easy to cause overshoot. Therefore, in order to ensure its control accuracy, it should be handled well. Slow down problem. The AC servo drive system is closed-loop control, the drive can directly sample the feedback signal of the motor encoder, and the internal position loop and speed loop are formed. Generally, the phenomenon of step loss or overshoot of the stepping motor does not occur, and the control performance is more reliable.
The above is the comparison of the two motors of the stone engraving machine compiled by Xiaobian, I hope it will be helpful to everyone!
