| Precision agriculture is a high-yield,high-quality agricultural production method,and intelligent agricultural machinery and its automatic control are one of the contents of precision agriculture.Tractors are important equipment for agricultural mechanization and modernization,and the control of tractors determines whether they can operate efficiently and at a low cost.Based on the current research status at home and abroad,this article focuses on the collaborative and efficient work of tractor units and agricultural tools under plowing conditions,and the collaborative control of the engine and plow depth.The paper firstly analyzes the methods and research status of tillage depth control for tractor-plow units in domestic and foreign research,and proposes a comprehensive control method for the engine operating conditions of the tractor and the working parameters of the plow unit to address the shortcomings.A research plan is formulated accordingly.Secondly,a mathematical model for the working load characteristics of the tractor-plow unit is established.The traction characteristics of the ploughing unit were analyzed,and the matching requirements of the tractor-plow units were analyzed.The composition of the collaborative control hitch system is designed,and the communication mode among the component elements is determined.Combining with the load characteristics and fuel consumption characteristics of the engine,a coordinated control strategy for tillage depth,throttle position,and gear position is designed.The change in tillage depth can adjust the size of the traction resistance,while the throttle position and gear position can adjust the operating point position of the engine.Therefore,the tillage depth,throttle position,and gear position can be controlled to make the engine run in a high-power and low-fuel-consumption zone.A fuzzy controller based on engine speed and tillage depth is designed to control the tillage depth and engine speed.The fuzzy control strategies of the high-speed part and the low-speed part are designed by using the method of sub-speed interval.An accelerator control system is designed with the vehicle speed and engine speed as targets.In addition,a gear shift control strategy is formulated under the light-load plowing mode with fuel economy as the target and heavy-load plowing mode with power as the target.Ultimately,the efficient operation of the tractor-plow unit is achieved.To achieve the research objectives,a dynamic model of the tractor plowing unit and a hydraulic hitch system were established using AMESim dynamic simulation software.A fuzzy controller for the plowing depth of the throttle controller and hydraulic hitch system was built in Simulink environment,and the effectiveness of the shift strategy and plowing depth control method was co-simulated and verified.A comparative simulation analysis was conducted using different soil parameters as variables to compare the mix control and the collaborative control method proposed in this paper.The results show that the control method proposed in this paper makes the engine speed fluctuation rate smaller under small soil parameter fluctuations and always runs in the high power and low fuel consumption range.The method got more balanced results in tillage depth and speed fluctuations under large soil parameter fluctuations.A testing system for plowing depth control based on engine load characteristics was built.The tillage and sensor data were calibrated.The plowing depth controller and a data acquisition system based on Lab VIEW were produced.A control panel was made using a touch screen,and the effectiveness of sending and receiving messages from nodes on the bus was verified using a CAN analyzer.The bench test results show that the proposed plowing depth control method based on engine load characteristics can achieve efficient and stable operation of the engine by controlling the plowing depth. |
