Interpretation of the difference between holding torque and positioning torque of stepping motor
Stepper motor, also known as pulse motor, is based on the most basic electromagnet principle. It is an electromagnet that can rotate freely. Its action principle is to generate electromagnetic torque by changing the air gap permeability. Its original model originated from year to year. At the beginning of the year, attempts to control were applied to the electrode transport mechanism of the hydrogen arc lamp. This is considered to be the original stepper motor. At the beginning of the twentieth century, stepper motors were widely used in telephone automatic switches. Because Western capitalist powers compete for colonies, stepper motors are widely used in independent systems such as ships and airplanes that lack AC power. The invention of transistors in the late 1950s was gradually applied to stepper motors, making it easier to control digital. After the 1980s, the control method of the stepping motor was more flexible due to the appearance of a cheap microcomputer in a multi-functional posture.
Analysis of the concept of stepping motor holding torque and positioning torque
The biggest difference between a stepper motor and other motors for control purposes is that it receives the digital control signal electrical pulse signal and converts it into an angular displacement or linear displacement corresponding to it. It is itself an actuator that performs digital mode conversion. Moreover, it can control the open loop position, and input a pulse signal to obtain a specified position increment. Compared with the conventional DC control system, the so-called incremental position control system has a significantly reduced cost, and almost no system adjustment is necessary. The angular displacement of the stepper motor is strictly proportional to the number of pulses input and is synchronized with the pulse in time. Thus, as long as the number of pulses, the frequency and the phase sequence of the motor windings are controlled, the desired angle, speed and direction can be obtained.
China's stepper motor started in the early 1970s. From the mid-1970s to the mid-eighties, it was the development stage of finished products. New varieties and high-performance motors were continuously developed. At present, with the development of science and technology, especially The development of permanent magnet materials, semiconductor technology and computer technology has made stepper motors widely used in many fields.
The basic principle of stepper motor
As a special motor for control, the stepper motor cannot be directly connected to the DC or AC power supply, and a dedicated drive power stepper motor driver must be used. Before the development of microelectronics technology and special computer technology, the controller pulse signal generator was completely realized by hardware. The control system used separate components or integrated circuits to form a control loop. Not only the debugging and installation were complicated, but also consumed a large number of components, and once the type was set, To change the control scheme, you must redesign the circuit. This makes it necessary to develop different drivers for different motors, which has high development difficulty and development cost, and is difficult to control, which limits the promotion of stepping motors.
Since the stepping motor is a device that converts electric pulses into discrete mechanical motions and has good data control characteristics, the computer becomes an ideal driving source for stepper motors. With the development of microelectronics and computer technology, hardware and software The combined control method has become the mainstream, that is, the control pulse is generated by the program to drive the hardware circuit. The single-chip microcomputer controls the stepping motor through software to better dig out the potential of the motor. Therefore, the use of single-chip microcomputer to control stepper motor has become an inevitable trend, and also in line with the digital age.