Research On The Structure Layout And Control Strategy Of Electric Tractor For Protected Agriculture

Facility agriculture refers to the agricultural production mode conducted in greenhouses and other facilities through artificial means.Currently,there are problems in the development of facility agriculture in China,such as low levels of mechanization and automation,lack of dedicated pollution-free power machinery,and so on.Therefore,this article proposes a problem-solving method-developing electric tractors for facility agriculture to reduce noise and exhaust pollution,reduce energy replenishment and maintenance costs,and develop motion control strategies,overall communication strategies,and electricity warning strategies suitable for facility agriculture electric tractors to improve production efficiency and quality.This article conducts research on the structural layout and control strategy of electric tractors in facility agriculture.Combining the forward investigation of the requirements for facility agriculture and horticulture with the reverse analysis of the parameters of the mature greenhouse king model,it is preliminarily determined that the design parameters of the facility agriculture electric tractor prototype are 20 k W in power and less than 2m in width;By analyzing the advantages and disadvantages of different types of electric tractors,a dual motor centralized drive pure electric tractor was ultimately selected as the development type of the prototype,and the basic framework for designing and constructing pure electric tractors was designed and constructed.Dynamic analysis is conducted for different driving and walking modes of electric tractors,and corresponding mathematical models are established.Through the analysis of operational performance,a theoretical basis is provided for the structural selection and layout design of electric tractors.The 20 k W permanent magnet synchronous motor produced by Zhuhai Embraer Company is selected as the driving motor and power output motor of the prototype,and three 119 series of lithium iron phosphate power batteries are selected to form the energy system.This paper studies the supporting charging equipment in facility agriculture,proposes a charging mode that follows the operation of an electric tractor in real-time,and designs a charging robot control strategy based on a PID controller.The feasibility is verified through Simulink simulation.Complete the modeling and layout design of the prototype based on Alias software,while studying three unmanned concept models with different steering modes,complete the rendering of three-dimensional models,design two different shapes of the hood,and use EDEM software to conduct dust prevention simulation of the hood to verify its reliability.In terms of control strategy,design a complete machine control strategy based on CAN bus to achieve networked control of the entire machine;A low battery alarm based on a PIC microcontroller is designed to provide alarm prompts for low battery conditions caused by battery self-discharge when electric tractors are idle;Two tracking control strategies based on backstepping method and Lyapunov function are designed for wheeled electric tractors and tracked electric tractors,respectively.At the same time,path planning and simulation are conducted for the actual operation of tracked electric tractors in facility agriculture.The simulation results by Simulink prove that the algorithm has the advantages of faster convergence speed and strong robustness of the system.The production of trial prototype was completed,and prototype tests including traction power,endurance and CAN communication were completed,which verified the progressiveness and applicability of electric tractors in facility agriculture.