Estimation method for lateral forces of front wheels of in-wheel motor driven electric vehicle

Abstract

The invention discloses an estimation method for lateral forces of front wheels of an in-wheel motor driven electric vehicle. The estimation method comprises the following main steps of firstly, designing a sliding-mode longitudinal force observer to estimate longitudinal forces of tires in real time based on vehicle dynamic equations according to vehicle state information acquired by various sensors; secondly, transmitting estimated longitudinal forces of all wheels, longitudinal acceleration signals, lateral acceleration signals, yaw angular velocity signals and the like to the sliding-mode longitudinal force observer, thus obtaining an estimation value of the lateral force of the right front wheel; and thirdly, performing further optimizing processing on the estimated lateral force by a filtering module, thereby solving the singular problem of the estimation value of the lateral force, and further outputting final estimation values of lateral forces of two front wheels. The estimation method disclosed by the invention has the advantages that by adopting a second-order sliding mode observer, on one hand, the real-time property of calculation is guaranteed; and on the other hand, good robustness for uncertain disturbance to an original system caused by different road surface conditions and tire characteristics is realized, so that a transverse control effect can be improved, and the stability of output is maintained.

Description

technical field [0001] The invention relates to a method for estimating tire lateral force during vehicle running, in particular to estimating the lateral force of a front steering wheel of a distributed drive electric vehicle. Background technique [0002] Against the background of environmental and energy issues, electric vehicles are increasingly becoming an important part of the automotive industry of the future. In recent years, distributed drive electric vehicles (In-wheelmotor Electric, IEV) have received widespread attention from researchers. It drives the wheels through the hub motor placed in the wheel hub or places two motors in the differential position to provide power to the vehicle. IEV has the advantages of fast corresponding speed, short transmission chain and high transmission efficiency, and is an important development direction in the field of electric vehicles. [0003] At present, the lateral stability control of IEV still needs to be improved, such a...

AI Technical Summary

Problems solved by technology

The tire model can estimate the tire force relatively accurately, but the tire lateral force in the tire model is directly related to factors such as tire slip angle, vertical load, longitudinal slip rate, and wheel speed, that is, many variables are involved, and a large number of calculations are required. The amount of calculation is large, and the algorithm of the tire model is complex, so it is difficult to meet the needs of rapid response in the application of real vehicle controllers.

In addition, for the lateral force estimation method based on the tire model, once the tire characteristics (tire pressure and wear degree, etc.) or the road surface conditions change rapidly, the fitting accuracy will drop rapidly, making the tire lateral force estimation inaccurate, resulting in lateral control The effect is affected

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