| The automobile industry has reached a critical stage,which is not only the necessities of life but also promotes the economic development.Intelligence is the way of the future and main scientific question at this stage,which is driven by electrification.Electric vehicles which have independent drive,brake and compound energy system are useful platforms for studying vehicle intelligence.The electrification powertrain of electric vehicle is the promotion of traditional vehicle with electronic and hydraulic chassis.The electronization and electrification of vehicle establishes the foundation for intelligence,especially it is contributed to the development of autonomous driving.Integrated vehicle control is a key technology for distributed electric vehicles which are over-actuation systems.The electric vehicles integrate environment perception,planning decision,dynamic control and energy management.It should satisfy the requirements of longitudinal and lateral direction control,autonomous driving and energy management.Because of the subsystems are coupled and have nonlinear characteristic,it brings challenges to integrated vehicle control.The non-linear constrains reflect tire-road adhesion constraints,motor constraints,energy system constraints.Energy management is involved in integrated vehicle control,and it constraints on control systems by force or torque transformed power.The integrated vehicle control including powertrain control,energy management and chassis control have been a focused issue,due to its more degrees of freedom on the integrated vehicle control.The regenerative braking is a key function of electric vehicles,and it has integrated energy management with integrated vehicle control.It is necessary to study the dynamic characteristics and energy exchange mechanism for improving the rate of energy recovery.To address the key issues on energy dynamic exchange mechanism and integrated vehicle controls for multiple systems coupling electric vehicles,the modeling and control methods on electric vehicles based on energy exchange,network scheduling for distributed controls of electric vehicles considering actuator dynamic characteristics and torque control allocation based on optimization with the constraint for electric vehicles are investigated.An integrated vehicle control methods and architectures are to be proposed with the aim to satisfy energy efficiency performance and vehicle dynamic performance as a whole.Energy dynamic exchange mechanism for multiple systems coupling electric vehicles is to be studied and proposed.The energy management system covering between electric motor and battery and between regenerative braking and electric hydraulic braking is to be established under energy exchange law and with minimum energy consumption to be the objective.The method for the estimation of both vehicle and energy states is to be studied.An integrated control method under a proposed control framework is to be established based on the energy flow with the aim to achieve the objectives of handling,stability and energy efficiency.An integrated modeling and simulation environment is to be established along with hardware-in-the-loop simulation and an experimental vehicle to support the proposed research with testing and verification.Firstly,the nonlinear model of vehicles and tires has be established,and the coupling mechanism between vehicle longitudinal,lateral dynamic and road and energy constrains are to be studied.The modeling methods for energy dynamic exchange is to be sdudied,and the efficiency of different electric architectures is investigated.The energy dynamic function of battery and powertrain and energy efficiency model are established.This paper proposes a bus voltage control method that actively and dynamically controls the bus voltage applied to the inverter through a DC/DC converter.The constraints of force or power of energy management strategy on integrated vehicle control are to be studied,and the influence of electrical parameters on vehicle performance is to be analyzed.An integrated vehicle control method based on multi-objective optimization under energy constraints has been proposed.Some simulation and in-vehicle experiment under a driving cycle has been conducted that demonstrate the effectiveness of the proposed method on the improvement of energy efficiency of the inverter,and the system as a whole.Secondly,to address distributed electric vehicles with distributed drive systems,compound energy systems and composite braking systems,the problem of performance of the control system is degraded has been solved by the scheduling optimization.The dynamic characteristics of each actuator are considered on the control allocation with higher-bandwidth actuators being used for faster control commands.A network control system model is first established with a continuous-time based plant model,a discrete controller and a Flex Ray communication model,in addition to the electric vehicle model with tire model and driving/braking actuator models.It is also considered for the scheduling optimization of Flex Ray which minimizes a cost function and subject to a set of constraints.Finding optimal sequences of the vehicle plant and controller is a problem that is solved by the PSO algorithm.The optimized results have been simulated by a vehicle control system implemented in a Flex Ray bus.From the results it is shown that the proposed optimization sequences can guarantee the performance and reduce the bus occupancy.Thirdly,the different dynamic characteristics between regenerative braking and hydraulic braking for integrated vehicle control is to be studied.A constrained optimization-based torque control allocation method aimed to improve energy efficiency is proposed.The optimal regenerative braking is derived to minimize power losses for energy efficiency,and the coordination mechanism of composite braking is proposed.The cost function is defined not only to achieve desired yaw moment for vehicle handling and stability,but also to minimize power losses for energy efficiency.The power losses at different deceleration are analyzed.The road adhesion and energy constraints are also set based on thorough investigation on various extreme condition,the methods of integrated vehicle control is proposed in order to minimize power losses for energy efficiency.The proposed control allocation method has been tested and verified to be effective on energy efficiency improvement through both simulation and experiment under various driving maneuvers.Finally,a testing platform,including compound energy systems,powertrain systems,composite braking systems and in-vehicle network systems,has been established to verify the proposed subsystem methods.The distributed electric vehicle is established to be tested on NEDC and FMVSS126 test.The results show that the method can effectively improve the vehicle stability and minimize power losses.The main innovations of this paper are:(1)A unified modeling method with multi-domain energy is to be studied and studied in order to understand the coupling mechanism through dynamic energy exchange.The constraints of force or power of energy management strategy on integrated vehicle control are to be studied,and the influence of electrical parameters on vehicle performance is to be analyzed.(2)To address network optimization of distributed electric vehicles with distributed drive systems,compound energy systems and composite braking systems,the dynamic characteristics of each actuator are considered on the control allocation with higher-bandwidth actuators being used for faster control commands.(3)The different dynamic characteristics and energy dynamic exchange mechanism between regenerative braking and hydraulic braking for integrated vehicle control is to be studied.The cost function is defined not only to achieve desired yaw moment for vehicle handling and stability,but also to minimize power losses for energy efficiency.The road adhesion and energy constraints are also set based on thorough investigation on various extreme condition,the methods of integrated vehicle control is proposed in order to minimize power losses for energy efficiency.The coordination mechanism between regenerative braking and ABS is proposed. |
