Research On Key Techniques Of Vehicle Trafficability Based On Wheel Force Test

This paper focuses on the three key technologies of the evaluation system of vehicle trafficability on soft terrain, which are the test method, theoretical model and evaluation methodology. It aims to effectively evaluate and improve military vehicles’trafficability on soft terrain. To solve the involved key problems, firstly a research is done on the real vehicle test method, and a real vehicle test system is proposed and constructed to effectively measure the key parameters of wheel-soil interactions. On the basis of real vehicle tests, the theoretical models are deeply studied, especially the typical semi-empirical model. The problems of the slip-sinkage effect and the real-time acquisition of terrain parameters are focused on to improve the model precision and practicability.Then the improved semi-empirical model can be used to predict the evaluation indexes of vehicle trafficability. With the introduction of statistical learning methods, a statistical prediction model is developed, and it provides another practicable insight for the accurate prediction of evaluation indexes of vehicle trafficability. Finally, an in-depth discussion is done on the evaluation methodology of vehicle trafficability, and a multi-index evaluation method is proposed. Meanwhile, an evaluation system is set up to realize the effective evaluaton of vehicle trafficability, which is also helpful for the actual evaluation work. The main research work and achievements are summaried as follows:(1) For the test methods of vehicle trafficability on soft terrain are mainly limited to model tests, and for the lack of real vehicle tests, a real vehicle test system is proposed and constructed, which takes the wheel force transducer as the core and is supplemented by wheel speed sensor and GPS. Considering the actual application requirements, the hardware and software of the system are specifically designed. On this basis, field tests on rigid and soft pavements are designed and conducted. The effectiveness and reliability of the system is fully validated by the test results. A large number of real vehicle test data gained lays a solid foundation for the theoretical model study of vehicle traficability.(2) For the applicability of the existing silp-sinakge models in the semi-empirical model is not clear, typical silp-sinakge models’applicability in military vehicle applications is deeply analyzed based on real vehicle test data. An estimation model of the slip-sinkage model parameters is proposed with the combination of gauss-newton method and genetic algorithm. From the results, the model parameters are accurately estimated. On this basis, the applicability of slip-sinkage models is analyzed. Finally, an optimal model suitable for practical applications is confirmed, which helps to improve the prediciton accuracy of the semi-empirical model and lay the foundation for the accurate prediction of evaluation indexes of vehicle traficability.(3) To realize the real-time acquisition of terrain parameters, a research work is done on the online estimation methods. In this paper, an online estimation model is proposed based on terrain classification. It is indicated by the test results that the accuracy and instantaneity of the proposed model are both guaranteed. Cooperating with the real vehicle test system, the terrain parameters can be gained real-timely, which effectively improves the practicability of the semi-empirical model and provides accurate input data sources for the evaluation work of vehicle traficability.(4) For the limitations of the exsiting theoretical models of vehicle traficability, with the introduction of statistical learning methods, a prediction model of drawbar pull is proposed based on an improved relevance vector machine and real vehicle test data. Test results indicate that the statistical prediction model is feasible and effective. Compared with the simi-empirical model, the model complexity is reduced and the prediction accuracy is improved, which provides another practicable insight for the accurate prediction of evaluation indexes of vehicle trafficability.(5) For the imperfection of the evaluaton methodology and system of vehicle traficability, a series of practical evaluation indexes are confirmed after analysis; a multi-index evaluation method is proposed based on fuzzy inference theory to make a comprehensive evaluation of vehicle traficability. Moreover, on the basis of a summary and combination of the overall research contents, a relatively thorough evaluation system of vehicle traficability is proposed. It helps to realize the effective evaluation and it is of important guiding significance for the evaluation work.