Study On Controlling Stepper Motor With High Accuracy That Based On MCU

Rapid development of Hard Disk Drive industry in recent years has beenpushing HDD to advance on the trend of large capacity, small size and rapid access, which put great requirements on machining techniques of HDD.But, processing middle is to adopt step-by-step electric motor to be servo control systematically mainly.With its special features in the construction stepper motor is widely used in the system that without speed sensors and location sensors to achieve precise positioning of the non-feedback controlling central or synchronous operation. We adopted the regulation that we can conveniently achieve precise position by sending to the stepper motor a given number of electrical pulse and by adjusting the step pulse frequency to control its speed .These characters can be contribute to make the device or equipment miniaturization and low-cost, so they are widely spread in many areas.The stepper motor's micro-stepping driver is a kind of driving technology that can effectively improve the step precision and characteristic of low frequency. It is mostly used when the equipments require high-precision, low noise or low vibration system, and it is being a more and more popular driving technology.In this paper, the working principle and configuration of three-phase hybrid Stepper are introduced, then based on technologies such as stepper motor controller, PWM inverter and microcontroller. We analysis the using of micro-stepping driving technology to improve operational performance,discuss the principles of SPWM inverter for stepper motor with invariable torque micro-stepping driver, and propound sine wave current subdividing and current tracking PWM technology. Sine wave current subdividing technology not only overcomes the disadvantages of motor's vibration and noise at low speeds but also reduces probability of resonance. Current tracking PWM technology can maintain constant torque within wide speed range. It prevents the reactive voltage errors brought by other windings and the drift errors brought by current. It improves the precision of subdivision. In the thesis, we develop a single chip computer -based digital controlling system for a three-phase hybrid stepper motor that is mainly constructed from a AT89C51 single chip computer and 8279IC which is used as the core of control parts and a three full-bridge driver IR2130.The power stage of this driver uses IGBT IR2130 that provides high reliability.Based on the approach, the system's whole architecture, the design of hardware and software are introduced in detail.In finally, the reliability and stepper accuracy of this new control system are tested. The results show that the system can effectively satisfy the fixed position accuracy of customer request, represses movement noise and mechanical vibration. Meanwhile, the realization of the invariable torque micro-stepping technology of stepper motor can effectively reduce the cost ,improve the system's reliability and relevance.