| In recent years,the scale of pond aquaculture in China has been developing rapidly,and pond culture mode is gradually developing towards intelligence and unmanned.The realization of intelligent bait transportation is an important task to establish an unmanned pond aquaculture base.As the key technology of unmanned transportation,path planning and motion tracking control technology directly affect the safety and stability of unmanned feeder truck.In addition,in order to reproduce the replenishment work of the replenishment vehicle in the virtual simulation environment,it is also necessary to study the planning and control of the replenishment vehicle.Therefore,this paper mainly focuses on the local path planning,path tracking control and virtual simulation technology of unmanned replenishment vehicle in the replenishment process.This paper summarizes the research status of key technologies of unmanned driving at home and abroad,the existing local path planning algorithm and lateral trajectory tracking control algorithm are theoretically simulated and analyzed,which provides a theoretical basis for the local path planning algorithm and horizontal and vertical control technology studied in this paper.In order to solve the local path planning problem of unmanned vehicle,an improved DWA local path planning algorithm based on fuzzy logic was studied and designed on the basis of the kinematics model of unmanned vehicle.On the basis of considering the pond breeding environment and the demand to meet the expected direction of reaching the target point when the replenishment vehicle picks up and feeds,the constraints in the replenishment process of the replenishment vehicle are analyzed.By designing and improving the cost function,the problem of feeding demand and planning is transformed into a cost function optimization problem.The simulation results show that the improved DWA local path planning algorithm based on fuzzy logic can plan the local path meeting the demand of feeding,and has certain feasibility and stability.Aiming at the problem of trajectory tracking motion control of unmanned replenishment vehicle,it solves the problem of large computation and high tracking precision in vehicle motion tracking control,this paper establishes Frenet coordinate system on the planned path to decouple the horizontal and vertical control of motion control.Based on the two degree of freedom vehicle dynamics model,The lateral tracking controller based on LQR and a PID based longitudinal tracking controller are proposed for vehicle dynamic constraints and the lateral and longitudinal position and speed errors.In order to further verify the accuracy and feasibility of path planning and motion control algorithm,this paper simulates and analyzes it on the virtual simulation platform.Firstly,the pond map environment and replenishment chassis vehicle are accurately modeled,and then a Car Sim Simulink joint simulation platform based on vehicle dynamics is built to jointly simulate and analyze the local path planning and horizontal and vertical control algorithms studied in this paper,The rationality and correctness of the designed motion controller under the conditions of feed and recovery are verified and analyzed respectively.Finally,the vehicle automatic driving virtual simulation platform carla-ue4 is built,the pond map and the feeding chassis vehicle are introduced into the virtual simulation platform,and use the Car Sim Simulink co-simulation platform as the control center,Reproduce the real driving condition of the replenishing truck when replenishing.This paper aims to achieve the safe and accurate completion of reclaiming and feeding work of unmanned feeding vehicle in pond aquaculture,an improved local path planning algorithm based on fuzzy logic and a path tracking motion controller based on horizontal LQR control and vertical PID control are proposed.It provides a reference for the research on the intelligent transportation technology of feed truck in pond aquaculture. |
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