Multi-signal Processing Method Research Of Combine Harvester Load Feedback System

With the rapid development of microelectronics and computer technology, monitoring and automatic control technology has been widely used in modern agricultural machinery. Combine harvester, one of the main modern agricultural machineries, is used extensively in our agriculture production, and its role is becoming more and more important. Introducing automatic control technology into combine harvester realizes control of combine harvester's working condition, which can not only reduce operators'labor intensity, but also increase its production efficiency and working quality. It also has great significance to improve the agricultural mechanization, intelligence and automation for the entire agricultural production.Problems like low automation level, high fault failure frequency and poor reliability etc, exist in our country's combine harvester. By analyzing and studying combine harvester's working process, relationships among load changes of combine harvester, working quality and work efficiency has been obtained in this paper. And that is, state variables like feeding rate, threshing cylinder speed, crop screw conveyor speed, loss quantity etc, are the main parameters that reflect the load of combine harvester. Analyze the relationships between each state variable and load quantity. Introduce intelligent control algorithm. The method of load feedback control based on multi-signal fusion has been proposed. In this way, load feedback control system based on ARM is designed to make the unit work under full load by adjusting combine harvester's forward speed.In this thesis, the hardware of load feedback control system consists of six models:signal acquisition model, key control model, stepping motor speed control model, communication model, sound and light alarm model, and LCD display model. Each model's design principle and method is introduced in detail. Hardware platform for load feedback control system is built up. In the meantime, aiming at signals collected, to do intelligent algorithm. Introduce fuzzy control principle in view of multi-signal fusion to design a two-dimensional fuzzy controller for each signal. According to theoretical analysis and experiments, get each signal's importance in the whole control system. Set weight ratio of each signal rationally. Put up multi-dimensional fuzzy control system of the whole load feedback automatic control system. And describe each fuzzy controller's control principle and design process in detail.Finally, using Simulink software in Matlab, system simulation of load feedback control system for combine harvester is carried out to verify both hardware and software designs'rationality, and control algorithm's effectiveness. Meanwhile,4LZ-2.0 type combine harvester is used to verify the control system's feasibility and effectiveness during the experiments in the field. Combine harvester's load feedback control is realized that the system has certain stability and effects.