Study On Driving Force Control Strategy For Electric Car Driven By In-wheel Motors Independently

Relative to the Internal Combustion Drive System Electric Drive system has many advantages like quick response,high control precision,etc.Due to rapid and accurate response to control instructions four-wheel independent drive electric vehicle driven by in-wheel-motors has great advantage on the vehicle dynamics control,which will make great contribution to the development of intelligent chassis control.All-wheel-drive vehicles can make better use of the road adhesion compared to the two-wheel-drive vehicles.at the same time the intelligent chassis control system will dynamically distribute driving torque between four wheels which will reduce energy costing.Under the condition of the existing electrical transmission efficiency,reasonable driving control strategy is one of the key technologies for developing four-wheel independent drive electric vehicle driven by in-wheel-motors.At present,many scholars have done a lot of research on the layered driving force control,but mainly concentrated in simple function like anti-slip driving and direct yaw moment control by driving torque.It's necessary to put more energy on systematic driving control strategy which can be applied to different driving cycle and different vehicle state.This paper analyzed the layered driving force control strategy under no steering control condition of the four-wheel independent drive electric vehicle driven by inwheel-motors.The full text is composed of the following five chapters:First chapter is the introduction that introduced the development of the four-wheel independent drive electric vehicle driven by in-wheel-motors.Four key problems needed to be solved to develop the four-wheel independent drive electric vehicle driven by in-wheel-motors are concluded through the study of research status domestic and overseas.At the last,puts forward the main research content of this article and the overall mentality.The second chapter is the main part of the article that proposed the vehicle driving purpose according to the different running condition,also put forward the strategy to restrain the off-tracing caused by executing error of control instructions.When the purpose is safety,the driving system should reduce the yaw moment caused by wheel slip by adjusting the torque distribution rate between front and rear axle or deducing the expected driving torque.When the purpose is improving drive ability,the driving system will activate the anti-slip-drive system and the torque distribution function.To make the off-tracing under control,put forward the compensation control of single motor and direct yawing moment control to inhibit of vehicle running deviation phenomenon.Chapter iii introduced the offline simulation system structures,functional verification the control strategy.First built a simple driver model based on speed target.And then build the permanent magnet brushless dc motor Simulink model,and the motor torque control scheme and current regulation scheme for modeling research.Finally using the mature 8 degrees of freedom vehicle dynamics model built by our research group respectively verify vehicle straight driving force control strategy and the input simulation.The fourth chapter introduces the research of four-wheel independent driven by wire experiment platform vehicle.Platform based on the national instruments PXI platform as rapid control prototyping controller that as a virtual controller the compiled control strategy will be download to,to verify the realization of the control algorithm.The fifth chapter summarizes the content of the full text research,and put forward improvement plan for further future research.