SGER: Dynamics of Wheeled Mobile Robots for Control: A Case Study of Advanced Nonlinear Control of Complex, Interconnected Mechanical Systems

轮式移动机器人属于一类复杂的互联机械系统，包括现有的和新兴的空中、地面和水下自主系统应用。随着对这些控制系统的性能要求越来越严格，现有的非线性控制理论大多是针对一般非线性系统发展起来的，发现它们的不足之处。一个可能的解决方案是通过充分利用系统固有的动力学特性，为一类特殊的系统开发新的控制理论，这类系统已经足够广泛，可以涵盖广泛的实际工程系统。一类复杂的互联机械系统就是这样一类特殊的系统。为了深入了解系统动力学及其内在结构，本SGER项目拟以轮式移动机器人动力学为例进行研究。研究了以下问题：(a)考虑不同机动化和不同配置下地形-轮胎相互作用非线性特性的移动机器人动力学建模；(b)利用机械部件互连的固有几何结构和移动机器人与环境相互作用的性质对移动机器人进行动力学分析。该研究的成功完成将(a)为发展一类复杂互联机械系统的先进非线性控制理论奠定坚实的基础，从而促进航天器、飞机、水下航行器和陆基航行器高性能控制的最新技术的进步；(b)为非线性系统动力学分析增加新的工具和技术；(c)为开发基于传感器的导航路径规划算法提供新的途径，从而促进自主移动机器人从研究实验室过渡到国家利益和商业化重要领域的实际应用；(d)为改进或设计移动机器人的新机械平台提供系统的指导。

Wheeled mobile robots belong to a class of complex interconnected mechanical systems, which includes existing and emerging new applications in autonomous systems in the air, on the ground, and under the water. As the performance requirements on these control systems get more stringent, the existing nonlinear control theories, mostly developed for general nonlinear systems, are found to be inadequate. A possible solution would be to develop new control theories for a special class of systems, which is yet broad enough to encompass wide range of practical engineering systems, by fully exploiting the system inherent dynamical characteristics. A class of complex interconnected mechanical systems is such a special class of system. To gain insight into the underlining system dynamics and its inherent structures, it is proposed in this SGER project to study the dynamics of wheeled mobile robots as an example. The following problems are addressed: (a) dynamical modeling of mobile robots considering the nonlinear characteristics of the terrain-tire interactions for different motorization and different configuration, and (b) dynamical analysis of mobile robots by exploiting the inherent geometric structure of the interconnection of the mechanical components and the nature of the interaction of the mobile robot with the environment.The successful completion of the proposed research will (a) lay a firm foundation for developing advanced nonlinear control theories for a class of complex interconnected mechanical systems, therefore contributing to the advancement of state-of-the-art technology in high performance control of spacecraft, aircraft, underwater vehicles and land-based vehicle; (b) add new tools and techniques to the repertoire of analysis of nonlinear system dynamics; (c) provide new avenues for developing path planning algorithms for sensor based navigation, thus facilitating the transition of autonomous mobile robots from research laboratory to practical applications in important areas of national interest and commercialization; and (d) provide systematic guidelines in improving or designing new mechanical platforms for mobile robots.