Research On Cooperative Adaptive Cruise Control Of Connected Vehicles Under The Influence Of Communication

With the rapid development of auto-driving technology and wireless communication network technology,cruise control technology of vehicular platoon based on communication is becoming a research hotspot in the field of intelligent transportation.In this thesis,the problem of cooperative adaptive cruise control of connected vehicles under the influence of communication is investigated.Aiming at the situation of communication interruption under autonomous vehicles in a platoon,the switching control strategy of vehicular platooning cruise mode subject to communication interruption is designed.The main research contents in this thesis are as follows:To solve the problem of system instability caused by communication interruption in autonomous vehicle platoon,a switching method for autonomous vehicles in a platoon to switch from cooperative adaptive cruise control(CACC)mode to adaptive cruise control(ACC)mode under communication interruption is proposed.The cruise mode of vehicles subject to communication interruption is switched from CACC to ACC,but the time headway in CACC remains the same.Then,a time headway switching method based on minimum safe distance is proposed to ensure the safety of the platoon by combining collision avoidance theory.The mixed CACC-ACC controllers are designed to ensure the stability of the platoon(there are both CACC and ACC vehicles in it)after two switchings by combining final value theorem and frequency domain method.Finally,simulation results show the effectiveness and superiority of the proposed method by comparing with the existing method.The problems of onboard sensors have low measuring accuracy,delay of measuring information and limited sensing range are studied,a switched method to the cruise mode of the platooning based on finite-time stable control is presented.The mixed homogeneous CACC-ACC reference model is established.Then,CACC-ACC controllers are designed to ensure the stability of the system based on the Routh-Hurwitz stability criterion and frequency domain analysis method.The heterogeneous state tracking error system is constructed,combined with Lyapunov function and finite-time sliding-mode control theory,the finite-time sliding-mode controller is designed to make the error system states converge to zero in finite-time and the stability of heterogeneous platoon system after switching is guaranteed.Simulations have shown the effectiveness and superiority of the proposed method.The problem of the effect of matched and mismatched disturbance on vehicular platoons for actual driving is studied,a switched control method considering the influence of matched and mismatched disturbance is presented.The state tracking error system with matched and mismatched disturbances is established.A terminal sliding-mode control law(TSMC)based on finite-time disturbance observer(FTDO)is designed combined with Lyapunov stability theory,which enables heterogeneous error system states reach the sliding surface in finite-time,and they will be stabilized to the bounded neighborhood of the equilibrium point finally.Thus,the stability of the heterogeneous platoon system after switching is guaranteed.Simulation results show that the proposed method solves the problem of mode switching stability under the influence of matched and mismatched disturbances.Finally,the results of the thesis are summarized,and the future researches on the topic of switched control method to vehicular platoons are pointed out.