Unmanned Vehicle Following Control Based On Moving Block Leader-Follower Method

This paper studies following control of unmanned vehicle.A Moving Block Leader-Follower model is proposed to improve unmanned vehicle following safety and traffic efficiency of road.Based on nonlinear system model of unmanned vehicle following control,sliding mode control algorithm is applied,which shows advantages of simple in structure,strong robustness and high reliability.Then,quasi sliding mode is adopted to weaken the output chattering of controller.Taking account of time-varying information parameters uncertainty of authority point in the system model,which is caused by noise and disturbance case in practice.Adaptive control approach is utilized to deal with the time-varying parameters uncertainty.Adaptive sliding mode control law is designed.The research contents of this paper are summarized as follows:Firstly,applying the principle of Moving Block Signaling system in urban rail transit,this paper establishes Moving Block Leader-Follower model based on Leader-Follower model.An authority point is added to the Leader-Follower model,which separates the leader vehicle and the follower vehicle in different intervals.The following target of the follower is the authority point.The following distance between the authority point and the leader is time-varying."Block" can avoid the rear-end of the unmanned vehicle,so as to improve the following driving safety of the unmanned vehicle."Moving" makes the following distance change according to the leader’s linear velocity,which is conducive to improving the traffic efficiency of the unmanned vehicle on the road.Secondly,according to the established nonlinear system model,sliding mode control algorithm with simple physical implementation,fast response and insensitive to parameter changes and disturbances is used to control the unmanned vehicle following.However,sliding mode chattering is not conducive to the linear velocity and angular velocity control of unmanned vehicle.Quasi sliding mode is applied to weaken sliding mode chattering in this paper.Simulation results demonstrate that the sliding mode control law based on quasi sliding mode shows better control performance,better availability and effectiveness.Finally,considering time-varying information parameters uncertainty of the authority point in the system model caused by noise and disturbance,this paper adopts the adaptive control approach to deal with the uncertainty of the time-varying parameter.This paper utilizes smooth projection algorithm to ensure that estimated values of the parameter always fall within the prior interval.Combined with the advantages of sliding mode control,an adaptive sliding mode control law is designed to reduce the impact of time-varying parameter uncertainty,noise and disturbance on the following system performance of unmanned vehicle.The robustness of the system is enhanced.At the same time,by improving the sliding surface,the design of the control law is simplified and the convergence speed of the lateral error is improved.Hyperbolic tangent function with continuous switching characteristics is used to weaken the sliding mode chattering,and the theoretical proof of the system stability is shown.The effectiveness of the designed control law is verified by simulating the cases of ideal environment,noise interference and sudden change of leader’s linear velocity.The simulation results show excellent control performance.There are 35 figures and 72 references.