Semi-empirical model for elastic tyre trafficability and methods for the rapid determination of its related parameters

To build an accurate and practical model for trafficability, experiments were conducted in a soil bin on elastic-tyre interaction. Wheel-soil interaction used a semi-empirical model and compared parameter identification methods based on improved an simulated annealing (SA) algorithm, an improved artificial fish swarm algorithm (AFSA), and an improved particle swarm optimisation algorithm (PSO) to calculate the maximum stress angle and the departure angle of the elastic tyre. The trafficability experiment included the acquisition of stress distribution, sinkage, and properties of soil of the contact length between elastic tyre and soil with different slip rates. The study proposed an improved semi-empirical model for the calculation of maximum stress angle, an improved slip sinkage semi-empirical model, and a method of determining the departure angle and tyre-soil contact length according to parameter identification research. The results indicated that the improved SA was most efficient algorithm to obtain the maximum stress angle and the departure angle, with the average number of iterations equal to 3.94 and the average time consumption of computer equal to 15.41 s. The method proposed can closely estimate the tyre-soil contact length and the elastic tyre sinkage, requiring only the slip rate and the vertical load on tyre. In addition, the method can provide the maximum stress angle for calculation, approach angle, and departure angle necessary for a wheel-soil interaction semi-empirical model.