Study On The Dynamics Analysis And Path Tracking Control Method For Electric Articulated Tracked Vehicles

The articulated tracked vehicle(ATV)is hinged together by two double track units,and the steering is realized by the angle of the deflection track unit.It overcomes the lack of steering performance of double tracked vehicles,has high trafficability and mobility,can meet the driving needs of swamp,desert,snow and rough road.The traditional ATV is mostly powered by diesel engines,and it needs to control the emission of vehicles in order to avoid environmental pollution.In addition,the road conditions of the ATV are complex and the working environment is bad,so it has a certain threat to the personal safety of the operators.The research of path tracking control system for the ATV can improve the ability of travel intelligently in complex environment.Under the support of National Natural Science Foundation of China “Electromechanical coupling dynamics and adaptive control of multi-crawler travelling gears”(No.51775225),the electromechanical coupling performance of the electric ATV and the path tracking control system based on visual navigation are studied.The electromechanical coupling dynamics model is established,and the parameters changes law of the electrical part and the mechanical part under typical driving conditions are obtained.The control method of the ATV path tracking system based on fuzzy PID algorithm is proposed.Firstly,the research status of the dynamic analysis of the ATV,the electromechanical coupling research and the path tracking control is summarized.According to the structure and motion characteristics of the ATV,the dynamics equation of non-steady steering is established.Combining with the dynamic characteristics of the induction motor,the electromechanical coupling dynamic model of the ATV under the two typical conditions of straight and steering running is established.The change law of electrical and mechanical parameters under the typical conditions is obtained by numerical calculation.In order to verify the accuracy of the electromechanical coupling dynamics model of the ATV,a virtual prototype model of the ATV is established in RecurDyn and combined with the induction motor established in Matlab/Simulink,the co-simulation analysis is carried out.The physical prototype model of the ATV is designed and manufactured,and the correctness of the numerical calculation and the simulation results of the virtual prototype are verified.Taking the steering inaccuracy and slip rate as the evaluation index,through the virtual prototype simulation analysis,the relationship between the velocity difference of both sides of the tracks and the deflection angle of the hinge point,the steering accuracy and the steering stability of the vehicle is obtained.Aiming at the deviation between the actual path and the planned path as the goal,the overall scheme of the control system of the vehicle is controlled by changing the velocity of both sides tracks and the deflection angle of the hinge point.According to the fuzzy PID control theory,the fuzzy PID controller of the path tracking control system of the ATV is designed,and reasonable fuzzy rules are edited according to the corresponding control requirements.Taking the distance deviation and the course angle deviation between the actual path and the planned path as controller input variables,the position and posture of vehicle are controlled by changing the velocity of both sides tracks and the deflection angle of the hinge point.In order to verify the performance of the fuzzy PID controller,the path tracking of the ATV under the straight path and the curve path is simulated.The results show that the ATV can track the planned path quickly and accurately under the control of fuzzy PID controller,verifying that the parameters of the controller are reasonable.The ATV path tracking control experimental platform based on the visual navigation method is designed.In the path tracking control system,the image processed planned path is fitting as a navigation curve that can guide the ATV to travel.Through the coordinate system established in the image pixel matrix,the distance deviation and the course angle deviation are measured.The path tracking travelling of the planned straight path and the curve path are carried respectively.The changes of the distance deviation,the course angle deviation,the velocity of both sides tracks and the deflection angle of the hinge point are obtained.It is verified that the path tracking control system of the ATV has good control performance.In summary,the electromechanical coupling dynamic model of the ATV is established and verified by the experiments.The path tracking control of the ATV based on visual navigation is developed.The research work of this paper provides a reference for the development of the electric ATV and the improvement of the intelligent level of the vehicle.