Slip Ratio Control Of Distributed Drive Electric Vehicle Based On Multiple Models Predictive Control

As an effective way to solve the problem of vehicle exhaust emissions,electric vehicles have attracted more and more attention from all over the world.Compared with traditional electric vehicles,distributed drive electric vehicles(DDEV)not only have the advantages of precise torque control and quick response,but also has more degrees of freedom,which makes the control of electric vehicles more flexible.Based on these characteristics of DDEV,dynamic control of DDEV has become the research focus of researchers in these years.In this paper,the longitudinal operation of DDEV is taken as the research target,and the following research is carried out for the problem of working condition switching unstable and difficult to achieve optimal slip rate control in its longitudinal operation.1?According to the longitudinal physical and dynamic characteristics of DDEV,two-degree-of-freedom vehicle dynamics model,eight-degree-of-freedom vehicle dynamics model,tire model,wheel dynamics model and judging conditions of DDEV longitudinal stability operation are established respectively.2?In order to solve the unstable operation problem caused by the switching of the working condition in the longitudinal operation of the DDEV,a soft-switching control method based on multi-model predictive control is proposed in this paper.Firstly,the DDEV longitudinal operation conditions are divided into three typical operating modes,and the corresponding dynamic model and reference model are established respectively.The sub-model predictive controller is designed for each working condition.Then the weight of each sub-model controller is calculated by improved recursive Bayesian method.Finally,the output of the multi-model predictive controller is obtained by weighting the output of the sub-model predictive controller and the weights of each sub-model,thus the smooth switching of the DDEV longitudinal operation conditions is realized.The effectiveness of the proposed control strategy is verified by comparison with the simulation results of traditional multi-model hard switching.3?In order to solve the problem that it is difficult to achieve optimal slip rate control under longitudinal multi-operating conditions of DDEV.An optimal slip rate control strategy based on multi-model predictive control for DDEV is proposed in this paper.Firstly,the DDEV longitudinal operation conditions are divided into 15 typical operating modes,and sub-models were established for each typical operating condition.An optimal slip rate controller based on model predictive control is designed for each typical sub-model.Then,the matching coefficient between the current operating condition of DDEV and 15 typical working conditions is calculated by the condition identifier.Finally,the output of the multi-model predictive controller is obtained by weighted summation of the output of each sub-model predictive controller and the output of the identifier.Thus,the optimal slip rate control of DDEV under multi-operating conditions is realized.