智慧农业（中英文）2024，Vol.6Issue(3)：69-81,13.DOI:10.12133/j.smartag.SA202306013
基于MPC延时补偿器的农机多机器人编队行驶轨迹跟踪方法
Trajectory Tracking Method of Agricultural Machinery Multi-Robot Formation Operation Based on MPC Delay Compensator
摘要
Abstract
[Objective]The technology of multi-machine convoy driving has emerged as a focal point in the field of agricultural mechanization.By organizing multiple agricultural machinery units into convoys,unified control and collaborative operations can be achieved.This not only enhances operational efficiency and reduces costs,but also minimizes human labor input,thereby maximizing the operational potential of agricultural machinery.In order to solve the problem of communication delay in cooperative control of multi-vehicle for-mation and its compensation strategy,the trajectory control method of multi-vehicle formation was proposed based on model predic-tive control(MPC)delay compensator. [Methods]The multi-vehicle formation cooperative control strategy was designed,which introduced the four-vehicle formation coop-erative scenario in three lanes,and then introduced the design of the multi-vehicle formation cooperative control architecture,which was respectively enough to establish the kinematics and dynamics model and equations of the agricultural machine model,and laied down a sturdy foundation for solving the formation following problem later.The testing and optimization of automatic driving algo-rithms based on real vehicles need to invest too much time and economic costs,and were subject to the difficulties of laws and regula-tions,scene reproduction and safety,etc.Simulation platform testing could effectively solve the above question.For the agricultural automatic driving multi-machine formation scenarios,the joint simulation platform Carsim and Simulink were used to simulate and validate the formation driving control of agricultural machines.Based on the single-machine dynamics model of the agricultural ma-chine,a delay compensation controller based on MPC was designed.Feedback correction first detected the actual output of the object and then corrected the model-based predicted output with the actual output and performed a new optimization.Based on the above model,the nonlinear system of kinematics and dynamics was linearized and discretized in order to ensure the real-time solution.The objective function was designed so that the agricultural machine tracks on the desired trajectory as much as possible.And because the operation range of the actuator was limited,the control increment and control volume were designed with corresponding constraints.Finally,the control increment constraints were solved based on the front wheel angle constraints,front wheel angle increments,and control volume constraints of the agricultural machine. [Results and Discussions]Carsim and MATLAB/Simulink could be effectively compatible,enabling joint simulation of software with external solvers.When the delay step size d=5 was applied with delay compensation,the MPC response was faster and smoother;the speed error curve responded faster and gradually stabilized to zero error without oscillations.Vehicle 1 effectively changed lanes in a short time and maintains the same lane as the lead vehicle.In the case of a longer delay step size d=10,controllers without delay com-pensation showed more significant performance degradation.Even under higher delay conditions,MPC with delay compensation ap-plied could still quickly respond with speed error and longitudinal acceleration gradually stabilizing to zero error,avoiding oscilla-tions.The trajectory of Vehicle 1 indicated that the effectiveness of the delay compensation mechanism decreased under extreme delay conditions.The simulation results validated the effectiveness of the proposed formation control algorithm,ensuring that multiple vehi-cles could successfully change lanes to form queues while maintaining specific distances and speeds.Furthermore,the communication delay compensation control algorithm enables vehicles with added delay to effectively complete formation tasks,achieving stable lon-gitudinal and lateral control.This confirmed the feasibility of the model predictive controller with delay compensation proposed. [Conclusions]At present,most of the multi-machine formation coordination is based on simulation platform for verification,which has the advantages of safety,economy,speed and other aspects,however,there's still a certain gap between the idealized model in the sim-ulation platform and the real machine experiment.Therefore,multi-machine formation operation of agricultural equipment still needs to be tested on real machines under sound laws and regulations.关键词
车联网技术/智能农机/多机协同/编队行驶/轨迹跟踪Key words
vehicle to everything/intelligent agricultural machinery/multi-machine collaboration/traveling in formation/trajectory tracking分类
农业工程引用本文复制引用
栾世杰,孙叶丰,贡亮,张凯..基于MPC延时补偿器的农机多机器人编队行驶轨迹跟踪方法[J].智慧农业（中英文）,2024,6(3):69-81,13.基金项目
上海市科技兴农项目(沪农科推字[2022]第3-1号) （沪农科推字[2022]第3-1号）
国家重点研发计划项目(2022YFD2001201) Shanghai Science and Technology Agriculture Project(Shanghai Nongke Tuzi[2022]No.3-1) （2022YFD2001201）
Key R&D Project of Ministry of Science and Technology(2022YFD2001201) （2022YFD2001201）
