Design Of Brake By Wire System And Research On Longitudinal Collision Avoidance By Man-machine Cooperation

In recent years,the global automotive industry is undergoing tremendous changes.The development mode of "Internet plus" has penetrated into all industries,bringing great subversion to life.Automobile is no longer a cold means of transportation,but gradually becomes the emotional terminal of human-computer interaction.The "new four modernizations" strategic layout of intelligence,networking,electrification and sharing has been put on the agenda,and the cutting-edge technologies such as driverless,intelligent cockpit and vehicle networking are gradually becoming reality.With the continuous development of "intelligent" technology,the vehicle needs a more intelligent driving assistance system to assist the driver to take over the vehicle.Through the intelligent control algorithm,the chassis can be controlled more accurately,so that the vehicle can accurately complete the driver's intention to operate.Under this background,the brake by wire system emerges as the times require.It is a key technology to develop a reasonable control strategy,reduce the response time,improve the response accuracy,ensure redundancy and safety,and seek a new breakthrough in braking performance.Based on the National Natural Science Foundation of China and the major science and technology projects of Anhui Province,this paper independently designed the hardware in the loop test platform of the integrated by wire booster and HCU,and based on this platform,carried out the research on the cooperative control strategy between the driver and the active braking system.Its main contents include:(1)Set up the hardware in the ring platform of hydraulic brake by wire.According to the specific implementation process of the line control technology,hardware equipment,controller,sensor are selected,software program is compiled,and finally the basic power control of the line control booster and the active brake control based on HCU are realized.(2)Based on the modeling of brake by wire system.Considering the motion track and friction relationship of the process,the system dynamics models such as DC motor model,by-line booster model and hydraulic system model are constructed in order to provide the basis for verifying the human-machine cooperation strategy in the following paper.(3)In the research of human-computer cooperative collision avoidance based on line control,in view of the fact that most of the existing researches do not consider the braking stability,this paper proposes a safe distance model considering the stability by integrating the factors such as two vehicle speed and road adhesion coefficient.By dividing the dynamic warning boundary and the critical braking boundary,the vehicle can keep a proper distance under different working conditions,improve the acceptance of drivers and passengers,and effectively improve the vehicle stability under the premise of ensuring safety.(4)The upper control strategy based on extension decision theory and the lower controller based on radial basis function neural network are designed respectively.Combined with the proposed safety distance model,the classical domain,extension domain and non domain are divided based on the actual distance between two vehicles and collision time.Through the smooth distribution of human-computer driving weights in different domains,the flexible scheduling of intelligent driving control is realized,and a human-computer interaction idea applied to the line control of moving direction is provided.