Stepper Motor is also known as pulse motor, based on the most basic electromagnet principle, it is a kind of free rotating electromagnet, its action principle is dependent on the change of air gap permeability to produce electromagnetic torque. The original model is from year to year. An attempt was made to control the electrode transfer mechanism of hydrogen arc lamp. This is considered the original stepper motor. At the beginning of the 20th century, stepper motors were widely used in automatic telephone exchanges. As western capitalist powers fought for colonies, stepper motors were widely used in independent systems such as ships and aircraft that lacked ac power. The invention of the transistor in the late 1950s was also gradually applied to stepper motors, making digital control easier. Since the 1980s, the stepper motor has been controlled in a more flexible and versatile way, thanks to the advent of cheap microcomputers.
The biggest difference between stepper motor and other control motors is that it receives the electrical pulse signal of digital control signal and converts it into the corresponding angular or linear displacement. And it can open loop position control, input a pulse signal to get a specified position increment, such a so-called incremental position control system compared with the traditional dc control system, its cost significantly reduced, almost need not carry out system adjustment. The angular displacement of the stepper motor is strictly proportional to the number of pulses input and synchronizes with the pulse in time. Therefore, as long as the number of pulses, frequency and motor winding phase sequence are controlled, the required Angle, speed and direction can be obtained.
Stepper motor in China started in the early 1970s, the mid-seventys to mid-eightys for finished product development phase, constantly develop new varieties and high performance motor, at present, with the development of science and technology, especially the permanent magnetic material and the development of semiconductor technology, computer technology, make the stepping motor has been widely applied in many fields.
As a special motor for control, the stepper motor cannot be directly connected to the dc or ac power supply, so it must be driven by a special power supply stepper motor driver. Used in microelectronics technology, especially computer technology development, the controller pulse signal generator by the hardware implementation, separate components or integrated circuit is adopted in the system control circuit, debugging installation is complex, not only consumes a large number of components, and once after finalize the design, to change the control plan have to redesign circuit. This makes it necessary to develop different drivers for different motors, which is difficult to develop and expensive to develop, and difficult to control, which limits the promotion of stepper motors.
Due to the stepper motor is a device that converts electrical pulses into discrete mechanical movement, has the very good control characteristic data, therefore, the computer become the ideal of stepper motor driver source, with the development of microelectronics and computer technology, software and hardware combination control mode has become the mainstream, is produced by the program control pulse, the hardware circuit. Microcontroller through the software to control the stepper motor, better tap the potential of the motor. Therefore, it has become an inevitable trend to control stepper motor with single chip microcomputer, which also conforms to the trend of digital times.