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Research On Fault-tolerant Control Method Of Yaw Stability Of Distributed Electric Vehicle

Posted on:2020-11-18Degree:MasterType:Thesis
Country:ChinaCandidate:Z K XiaFull Text:PDF
GTID:2392330572484610Subject:Master of Engineering
Abstract/Summary:PDF Full Text Request
In the face of the severe challenge of energy conservation and emission reduction and the demand of industrial upgrading,the development of electric vehicles has become a major science and technology strategy in China.Distributed electric vehicle is independently driven by four hub motors.By controlling the drive,steering and braking of each wheel,vehicle performance optimization is realized and the stability of the vehicle is improved.At the same time,considering the actuator redundancy in the driving system,fault-tolerant control is carried out for the purpose of improving the vehicle's yaw stability,and the control allocation rate is reconstructed for different failure types of the driving motor to ensure the safe and stable running of the vehicle after failure.For the fault-tolerant control of distributed electric vehicle,the following research was conducted in this paper:Firstly,the vehicle dynamics model including tire model,wheel rotation dynamics model and hub motor model is established based on the three-dof vehicle planar motion model with the idea of block modeling.Compared with the same parameter model in Carsim software,the simulation experiment verifies that the established model can accurately represent the vehicle dynamic response.Secondly,in order to improve the vehicle yaw stability,a hierarchical fault-tolerant control method is adopted.The upper layer is the motion tracker,which tracks the transverse motion of the vehicle based on the model predictive control principle.The state of the vehicle at the next moment is predicted from the input of the vehicle at the current moment.Within the finite step size,the total yaw moment and the front wheel rotation Angle are obtained from the expected value of the predicted state tracking.The longitudinal motion is tracked based on the PI control principle,and the total longitudinal force is obtained by tracking the target vehicle speed based on the actual vehicle speed.The lower layer is the reconfiguration control distributor.When the vehicle is running normally,the total force and torque obtained by the upper controller are nominally controlled and distributed,and the tire force is optimally distributed with the objective of minimizing the tire load rate.When the vehicle fails,the actuator failure mode is determined by the fault information,and the control allocation rate is reconstructed according to different failure modes,so as to ensure the stability and safety of the vehicle.Finally,the distributed electric vehicle model and fault-tolerant control algorithm jointly established were used to build the open-loop control system in matlab/simulink software.Under different working conditions,the fault-tolerant control algorithm was verified to be effective according to fault information and steering wheel Angle input.At the same time,based on the NI hardware-in-loop test platform,the hardware-in-loop test verifies the real-time performance and reliability of the fault-tolerant control algorithm.
Keywords/Search Tags:Electric Vehicle, Fault Tolerant Control, Yaw Stability, Refactoring Control Allocation, Model Predictive Control
PDF Full Text Request
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