Research On Vehicle Sideslip Angle Acquisition Based On Switch Strategy

Currently,vehicle safety can be greatly enhanced by the application of active safety systems.However,the performance of these systems is tightly bounded with accurate vehicle motion state information.Among which,vehicle sideslip angle(VSA)information is particularly vital.The soft measurement-based VSA acquisition has the merits of low cost and easy transplantation,and has become an important research direction.It should be noticed that the problem of modeling accuracy,especially the accurate representation of tire force,is unavoidable for the acquisition effectiveness of the VSA using dynamic model.While for the VSA acquisition utilizing kinematic model,it is limited by the measurement signal quality of low-cost onboard sensors.In the meanwhile,unmatched inertia measurement unit(VSA)measurements will inevitably undermine the performance of ensuring calculation blocks.In addition,the existing VSA acquisition scheme based on kinematic-dynamic fusion faces the challenge of complicated structure and low efficiency.Addressing these issues,this dissertation conducts a study to seek high-performance method for the VSA acquisition,where the calculation of tire forces and the scheme design for the VSA acquisition are involved,as well as the analysis and evaluation of its applicability.The contents of this dissertation are as follows:(1)Simulation platform is constructed to make comparison and analysis between the frequently-used tire models and the tire force calculation approaches employing observer/filter.On this basis,comprehensive evaluation is carried out to determine their merits and demerits based on accuracy and complexity.Take the accuracy and Implementation difficulty into account,linear tire model with time-variant tire cornering stiffness for lateral tire force acquisition technical route is determined.(2)The kinematic and dynamic models are established for the VSA acquisition,and the merits and demerits of these two schemes are analyzed.For the error accumulation problem in the kinematic scheme,a pre-process way for the measurement biases in inertial sensors is presented to suppress the accumulated errors from the perspective of signal process.Furthermore,for the scheme adopting the dynamic model,a linear tire model is proposed based on time-variant tire cornering stiffness.Utilizing this model,the calculation accuracy of the tire force can be effectively guaranteed with low computation and easy implementation.Besides,the Bessel filter is employed to preprocess the noise of the measurement signals and alleviate its influence on the VSA acquisition.In addition,take the latent mutations of IMU measurements into consideration,a strategy for measurements reliability judgement is designed to enhance the robustness of estimation system.Simulation results testify the effectiveness of the proposed strategy.(3)On the Consideration that the VSA acquisition schemes utilizting the kinematic or dynamic models have theri own good points,a fuzzy logic-based kinematic-dynamic fusion scheme for the VSA acquisition is devised to draw on each other’s strengths.Moreover,a switch strategy-based scheme for the VSA acquisition is proposed to tackle with the deficiency of the fusion one in structure and efficiency.By means of this scheme,the system complexity can be decreased and the utilizing efficiency of information can be improved.The test results of simulation and hardware-in-the-loop platform prove the performance of the switch scheme in different scenarios.