What are the advantages and disadvantages of driving mode, current and torque?
Two, low frequency characteristicsThe phenomenon of the stepper motor speed is seen in low frequency vibration, vibration frequency and load condition and drive performance, generally considered the vibration frequency of half no-load take-off frequency, determined by the working principle of the stepper motor from the low frequency vibration phenomenon for the machine's normal operation is very unfavorable. When the stepper motor working at low speed, should generally be used to overcome the phenomenon of low frequency vibration damping technology, such as adding dampers in the motor, or by subdivision technology step selection of high cost in the drive to ease. AC servo motor running smoothly, even in low speed does not appear when the phenomenon of vibration. The AC servo system with absolute value encoder has the function of resonance suppression, and the system has frequency analysis function (FFT), which can detect the resonance point of the machine so that the system can be adjusted.
The control accuracy of the AC servo motor is guaranteed by the rotary encoder at the back of the motor shaft. Full digital AC servo motor to the north of micro production as an example, the motor with the standard 2500 line encoder, the driver uses four internal frequency doubling technology, its pulse equivalent to 360 /10000=0.036 degrees, 1.8 degrees is the step angle of stepping motor pulse equivalent to 1/50; with 17 bit encoder motor for each driver received 17 times of 2 (=131072) of a pulse motor rotates a circle, namely the pulse equivalent to 360 degrees /131072=0.0027466 degrees, 1.8 degrees is the step angle of stepping motor pulse equivalent to 1/655. Therefore, the control accuracy of AC servo motor is much higher than that of stepping motor drive system.
First, the control accuracy is differentTwo phase hybrid stepping motor step angle is 3.6 degrees and 1.8 degrees; step angle of five phase hybrid stepping motor is generally 0.72 degrees and 0.36 degrees; step angle stepper motor and high performance of the hybrid stepping motor can be smaller. For the WEDM machine stepper motor for example produced by Beijing Stone Company, the only step angle is 0.09 degrees; Germany bergerlahr company (BERGER LAHR) three-phase hybrid step motor production by the step angle dial switch is set to 1.8 degrees, 0.9 degrees, 0.72 degrees, 0.36 degrees and 0.18 degrees 0.09 degrees and 0.072 degrees, 0.036 degrees, compatible with the step angle two-phase and five phase hybrid stepping motor.
Stepper motor is a kind of discrete motion device, which is widely used in domestic digital control system. With the development of full digital AC servo system, AC servo motor is more and more used in digital control system. In the general trend of digital control system development, stepper motor or full digital AC servo motor is adopted as the executive motor in motion control. Although the two are similar in control mode (pulse train and directional signal), there are great differences in performance and application, and the difference between performance and application of the two is compared.
Three, the torque frequency characteristics are differentThe stepper motor output torque increases with the speed decreases, and when the speed is high will be a sharp decline, the maximum operating speed of 300 600RPM in general; and the AC servo motor for constant torque output, which is at its rated speed (usually 1000RPM-3000RPM), can output the rated torque at rated speed is more than constant power output.
