Study On Tire Force Estimation Method Of Intelligent Tires By Using Flexible Ring Model

Intelligent tire means that helps the driver improve the vehicle dynamics control by installing sensors on the tire to monitor the tire force and road conditions.In order to monitor the tire force in real time,the relationship between tire dynamics parameters and strain signals is built based on the tire theoretical model,the tire force information required by the vehicle is calculated based on the circumferential strain of the tire inner liner,and an intelligent tire vertical/longitudinal force estimation algorithm is developed.Based on the tire flexible ring model,this paper derives the circumferential strain formula of the inner surface of the ring,and aims to estimate the tire contact angle based on the characteristics of the circumferential strain.Taking the 205 / 55R16 tire as the research object,a finite element analysis model of the tire was established,and the simulation results of the finite element model were used to identify and verify the parameters of the flexible ring model.The results show that the load-contact angle relationship calculated by the flexible ring model is in good agreement with the finite element simulation results.In order to establish an algorithm for estimating the contact angle based on the circumferential strain,the tire flexible ring model was used to analyze the curve characteristics of the circumferential strain.The results show that using the average of CA2 and CA3 as the estimated value of the contact angle has higher accuracy.The tire contact angle increases with the increase of the vertical load and decreases with the increase of the inflation pressure.The effect of rolling angular velocity and longitudinal force of the contact angle is negligible.The vertical force estimation algorithm based on the tire flexible ring model with the contact angle as the intermediate variable is studied,and the reliability of the algorithm is proved by finite element simulation analysis.For longitudinal force estimation,on the basis of the previous flexible ring model,the tread is simplified into a brush model.Then combined with the mechanical properties of the brush model,a longitudinal dynamic model of the thin ring is established.Under pure longitudinal slip conditions,the circumferential strain formula of the inner surface of the thinness ring is derived.The longitudinal dynamics model was used to analyze the curve characteristics of the circumferential strain.The results show that the longitudinal force causes an asymmetric change in the strain curve,and the greater the longitudinal force,the more obvious the asymmetric phenomenon.Using the asymmetry of the circumferential strain curve,a physical quantity describing this asymmetry is proposed,and the relationship between the physical quantity and the longitudinal force is analyzed.Finite element simulation analysis proves the reliability of this method.