Study On Design Theory And Control Strategy Of Electric Tractor

As a new type of agricultural power machinery,electric tractor has the advantages of high efficiency,low pollution and low noise,so it is of great academic and engineering significance to carry out the research on electric tractor suitable for different uses and solve the theoretical methods and technical problems in the design of new products.In order to provide theoretical and technical support for the development of new products of electric tractors,this paper studies the structure scheme,drive system,power supply system design and control strategy of electric tractors.The main research contents of this paper are as follows:Through the function analysis of electric tractors,the performance requirements of electric tractors are determined,the traction power and economic evaluation methods of electric tractors are given,and the mathematical model of the performance evaluation index is established.The characteristics of the main components of electric tractors are analyzed and the selection research is carried out.The power system,drive system and overall structure scheme of electric tractors suitable for the characteristics of the tractor operation are designed,and the power system,drive system and working mode of the tractor are analyzed.Through the calculation process of the main parameters of the electric tractor,the mathematical models of design input,power supply system,electric motor,transmission system and overall parameters is given.The traction power and economy of the electric tractor are analyzed.The results show that the designed structure scheme of electric tractors and the parameter calculation method can ensure that the tractor has better working performance.In this paper,the performance optimization method for electric tractors with the goals of traction,economy and continuous operation performance is proposed,the design variables for electric tractor optimization are determined,and the objective function and the mathematical model of constraint conditions are established.The mathematical model of electric tractor optimization design is analyzed,and the optimization algorithm is designed based on the improved non-dominated genetic algorithm,and the optimization design process of electric tractors is formulated.The results of design verification examples show that the proposed optimal design method can better improve the traction,economy and continuous operation performance of electric tractorsAccording to the function,operation requirements and overall structure of electric tractors,a rule-based power management strategy is proposed.Using wavelet transform to analyze the method of constructing a two-channel orthogonal filter bank.Aiming at the problem of dynamic power distribution in power management strategies,a power distribution control algorithm is designed,and a supercapacitor state of charge(SOC)estimation algorithm is derived model According to the power and economic control requirements of the electric tractor driving system,the drive motor control strategy and the transmission shift strategy based on global optimization are designed,and the particle swarm algorithm and fuzzy logic threshold algorithm are used to design the torque inference for processing the drive control signal Algorithm,global optimization algorithm,speed control algorithm and initialization algorithm The overall control strategy of electric tractors meeting the overall control function requirements is designed,and communication protocol electric tractors based on J1939 is formulated.The hardware in the loop(HIL)test method of electric tractors is studied,the HIL platform of electric tractors is constructed,and the performance of the platform is analyzed.Based on AVL Cruise,a simulation model of electric tractor plowing and rotary plowing operations is established,and a complete machine controller is developed.Based on dSPACE Simulator platform,HIL system is established and HIL tests of electric tractor plowing and rotary plowing operations are carried out.The test results show that the proposed control strategy can optimize the working state of the power supply system in farmland operation,significantly improves the economy of traction operations such as plowing,increase the continuous operation time,realizes the switching of working speed in rotary power take-off(PTO)conditions such as rotary tillage,and achieves the expected control target.