Stepper motors, also known as steppers, which uses electromagnetic theory, convert electrical energy into mechanical energy, 
people began to use this machine in the early 1920s. As embedded systems (such as printers, disk drives, toys, wipers, pager vibration, mechanical arm and recorders, etc.) are increasingly popular, using a stepper motor began to surge. Whether in industrial, military, medical, automotive or the entertainment industry, as long as the need for a moving object from one location to another, the stepper motor will certainly come in handy. Stepper motor There are many shapes and sizes, but regardless of shape and size, they can be classified into two categories: variable reluctance stepper motors and permanent magnet stepper motors. 
Stepper motor is wound from a motor fixing member group - the stator teeth of the driving coil. Typically, a ring-shaped wound wire called a solenoid, whereas in the motor, the teeth around the winding wire, coil, or similar known. 
Stepper motor acceleration and deceleration process control technology 
being widely used because of stepper motor, stepper motor control study of more and more quickly if the step pulse change when starting or accelerating, the rotor due to inertia does not follow change in the electrical signal, generating stall or step-over-step may be generated for the same reason when stopping or decelerating. To prevent stall, and the step-over-step, increase the operating frequency, to be moved up and down the stepping motor speed control. 
Stepper motor speed depends on the pulse frequency, number of rotor teeth and the number of beats. The angular velocity directly proportional to pulse frequency, and pulse synchronization in time. Thus the number of rotor teeth and the number of beats in certain operating circumstances, as long as the frequency of the control pulses to obtain the desired speed. Stepper motors are synchronized by means of which the torque due to start, in order desynchronization does not occur, the start frequency is not high. Especially with the increase in power, rotor diameter increases, the inertia increases, starting frequency and maximum operating frequency can vary as much as ten times. 
Starting frequency characteristic of the stepping motor the stepping motor can not be reached directly operating frequency when starting, and a startup procedure must, i.e., from a low rotational speed to the operating speed rise gradually. Operating frequency reduced to zero not immediately stop, and to have a high-speed process of gradual deceleration to zero.
Output torque stepper motor with increasing pulse frequency decreases, the higher the starting frequency, the smaller the starting torque, the ability to drive the load worse, cause out of step when you start, but when you stop will overshoot. To achieve the desired rapid stepping motor speed or overshoot step yet, the key is to make the acceleration, the acceleration torque required full use of both the individual operating frequency of the torque provided by the stepper motor, and not exceed this torque. Thus, operation of the stepping motor is generally after acceleration, constant speed, deceleration three phases, the requirements during acceleration and deceleration time as short as possible, constant velocity time as long as possible. Especially in the work requires a quick response, from the beginning to the end of the time required to run a minimum, which must require acceleration, deceleration process shortest, and the highest speed at a constant speed. 
Domestic and foreign scientists to speed stepper motor control technology a lot of research, the establishment of a variety of acceleration and deceleration control mathematical model, such as the exponential model, linear models, and on this basis, developed a variety of control circuit design improved motion characteristics of stepper motor, stepper motor to promote the acceleration and deceleration of the scope of application index takes into account the inherent stepper motor torque frequency characteristics, can guarantee the stepper motor in motion without losing step, but also give full play to the motor the inherent characteristics of shortening acceleration and deceleration time, but changes in motor load, and difficult to achieve considering only the linear acceleration and deceleration pulse motor angular velocity proportional to the load capability of this relationship, the supply voltage does not fluctuate due to the load of the environment varying characteristic, an acceleration method which increases the speed is constant, the drawback is not fully consider the characteristics of the output torque of the stepping motor with speed variation, stepping motor step occurs at a high speed. 
Division drive stepper motor control 
stepping motor due to the limitations of the manufacturing process itself, such as the size of the step angle shot by the rotor teeth and the number of operating decisions, but the number of rotor teeth and the beat run is limited, and therefore the stepping motor step angle is generally large and is fixed, low resolution step, lack of flexibility, running at low frequency vibration, noise is higher than any other micro-motor, so that the physical fatigue or damage the device. These drawbacks can only be applied in the stepping motor of the lower case some of the requirements of demanding situations, closed loop control can be taken to increase the complexity of the system, these drawbacks severely limit the stepping motor as an excellent open-loop efficient use of the control assembly. Sub-drive technology to some extent, effectively overcome these shortcomings.
Stepper motor drive technology is a subdivision developed in the mid-years of drive technology can significantly improve the overall performance of the stepper motor. American scholar, first proposed in the United States stepper motor step incremental motion control systems and components annual meeting of the pitch angle control method subdivision. In the two decades thereafter, the stepper motor subdivision driver has been greatly developed. And gradually developed into full-blown nineties of last century. The research on the sub-drive technology, started almost the same time and abroad. 
In the mid-nineties to a larger development. Mainly used in industrial, aerospace, robotics, precision measurement and other fields, such as satellite tracking with a theodolite, military equipment, communications and radar equipment, widely used in sub-drive technology, making the number of phases of the motor step angle without restrictions for product design brings convenience. Subdivision technology currently driving the stepping motor, the chopper constant current drive, the pulse width modulation driving apparatus, a uniform constant amplitude current vector rotation driving control stop ,, several greatly improved precision stepping motor running operation, the stepping motor in the medium and small power applications to the development of high-speed and precision of direction. 
Initially, the control of the stepper motor phase current is realized by the hardware, generally two methods, multi-channel power switch current supply, a current superposed on the windings, this approach allows less consumption power tube, but due to the road number, therefore the device more bulky. 
First pulse signal is superimposed, and then enlarged the power line, to obtain a stepped current, with the advantage that fewer components, but the tube power consumption, low-power system, if the operation of the tube will cause distortion in the nonlinear region, because of their Bukekefu the drawback, so far has rarely used these two methods.