| A sine or cosine cure is the ideal driving current waveform for two -phase hybrid stepping motors, but general driver with ordinary control technology can not guarantee such idea phase current waveform, which lead to motor's precision lowing. Therefore, it is necessary to study the control technology for the stepping motor in depth.In this paper, two phase hybrid stepping motor was investigated. Based on the analysis of subdivision principles, a new kind of subdivision control system was proposed, and the feasibility and validity were verified with experiments.1. On the basis of analyzing various subdivision control technology, a new subdivision control system was developed. Frequency fixing PWM current tracking method was adopted in the control system. In such control system, the chop frequency is fixed, and the motor phase current is controlled with small closed loop, which can lead the motor phase current to approach given cosine current waveform. To obtain more selective subdivision points so as to satisfy user's demand of high subdivision points with a wider range,8 kinds of selections were designed, up to 128 subdivision points, in the main control circuit of microcontroller. Besides this, variety options of phase current amplitudes were also provided, which broadened the scope of application of the motor greatly. With opoto-isolation, PCB layout and other method used in the system, electromagnetic interference was suppressed effectively and the anti-interference of system was improved.2. The controller software system was developed. The software can realize following several functions. With the prompting on the LCD1602 screen, running steps and speed can be input with keyboard; the system's run is controlled by functional keys; stepping motor will run to the given steps if the "start" key is pressed and stepping motor will stop if the "stop" key is pressed during its running.3. The feasibility and validity of developed control system were verified with experiments. Experimental results show that the working precision can be greatly improved with this control system. |
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