Automatic Control System Of Walking Velocity On Combine

The combine is playing the more and more important role in agriculture. However, the combine in our country have many problems. It has low efficiency and easy to fail. The developing direction is intelligence. The control of walking velocity for traditional combine is realized by gear and hydraulic speed variator. It is difficult to operate, and the control is not exact. So, an automatic control system of walking velocity is designed in this paper according to its requests. The control techniques of MCU and automatic control theory are used in the design course. This control system can change the walking velocity timely according to feed quantity and keep it in high efficiency.The paper analyzes the scheme of the control system firstly, and proposes that the combine is driving by electric motor. For this, the speed is easy to control and the system is simpler than hydraulic system.The hardware of the control system is designed according the requests of the automatic control. The paper analyzes the applying status and developing tendency of feed quantity sensors, and expands the MCU. The circuits are designed separately, which is the signal input circuit of feed quantity, the measure circuits of walking velocity, the display circuit of speed and the output circuit of control signal.The programs are designed with C51 in separate programmer modules. To solve the problem of the change of mathematics unit and the interfering, this paper propose the algorithms of the data demarcation and digital filtering, and design the program of digital filtering. Due to the hardware functions, the system can be divided into 4 function models. That is the model of feed quantity signal acquisition, the model of walking velocity acquisition, the model of speed display and the model of control signal output. The program of every model is designed separately. Finally, the anti-interfering methods are pointed out from hardware and software to the usual interfering resource.The result of simulant debugging to every program and the whole system show that, the control system is steady and simple to operate. It satisfies the anticipative request.