Journal of Terramechanics最新文献

{"title":"Terrain mobility performance optimization: Fundamentals for autonomous vehicle applications. Part I. New mobility indices: Optimization and analysis","authors":"Vladimir V. Vantsevich ,&nbsp;David J. Gorsich ,&nbsp;Jesse R. Paldan ,&nbsp;Masood Ghasemi ,&nbsp;Lee Moradi","doi":"10.1016/j.jterra.2022.09.001","DOIUrl":"10.1016/j.jterra.2022.09.001","url":null,"abstract":"<div><p>Based on an analysis of vehicle mobility performance indices in use, it is shown that an index for the optimization of autonomous vehicle mobility performance should be constituted as a set of technical parameters that result directly from the interactive dynamics of tires and terrain and should be measurable and controllable in real-time. In addition, the combination of the parameters should characterize the vehicle’s technical productivity/efficiency (not energy efficiency), and thus, enable the estimation and control of vehicle mobility performance. If such requirements are satisfied, the index can be optimized and optimization results can facilitate autonomous control design. This article provides results of a study to address the above-formulated requirements in the proposed mobility performance index.</p><p>In <strong>Part I</strong><span><span> of this article, wheel mobility performance is characterized first by the wheel circumferential force and the actual </span>linear velocity. The proposed </span><em>wheel mobility performance</em> (<em>WMP</em><span>) index mathematically relates the wheel circumferential force and velocity to the theoretical maximum performance. Thus, the actual performance can be evaluated in terms of the theoretical maximum performance in a similar manner that the actual energy efficiency is compared to its theoretical maximum, i.e., to unity. The </span><em>WMP</em>-index is then extended to multi-wheel vehicles. The proposed <em>vehicle mobility performance</em> (<em>VMP</em>) <em>index</em><span> relates the traction and velocity characteristics of all wheels to a theoretical maximum performance.</span></p><p>Founded on the circumferential force and velocity characteristics of the wheels, the <em>VMP</em>-index mathematically reflects the influence of the power distribution among the wheels on the vehicle mobility performance. Hence, the <em>VMP</em><span><span>-optimization is formulated as an examination for the optimal tire slippages. Essentially, their combination characterizes the optimal wheel power split, and consequently, the best set of the wheel circumferential forces and the vehicle actual velocity for the maximum mobility performance in a given terrain condition. The tire slippages are subject to lower and upper bound constraints. The lower bound ensures positive tire slippages, and thus, positive traction of the wheels. The upper bound is imposed in the form of characteristic slippages such that exceeding them drives the wheels into an extremely nonlinear zone of the traction characteristic. In this zone, the wheel mobility margins drop significantly and some or all wheels can easily be immobilized. Further, the optimization is subject to the vehicle </span>longitudinal dynamics, which sets the summation of the wheel circumferential forces equal to the motion resistance forces.</span></p><p>By applying Lagrange Multipliers (LMs) to the objective function, a system of equations is arranged ","PeriodicalId":50023,"journal":{"name":"Journal of Terramechanics","volume":null,"pages":null},"PeriodicalIF":2.4,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43506130","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}