In order to synthesize controllers for wheeled mobile robots (WMRs), some design techniques are usually based on the assumption that the center of mass is at the center of the robot itself. Nevertheless, the exact position of the center of mass is not easy to measure, thus WMRs is a typical uncertain nonlinear system with unknown control direction. Based on the fast terminal sliding mode control, an adaptive fuzzy path tracking control scheme is proposed for mobile robots with unknown control direction. In this scheme, the fuzzy system is used to approximate unknown functions, and a robust controller is constructed to compensate for the approximation error. The Nussbaum-type functions are integrated into the robust controller to estimate the unknown control direction. It is proved that all the signals in the closed-loop system are bounded, and the tracking error converges to a small neighborhood of the origin in a limited time. The effectiveness of the proposed scheme is illustrated by a simulation example.

中文翻译：

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控制方向未知的移动机器人的自适应模糊路径跟踪控制

为了合成轮式移动机器人（WMR）的控制器，一些设计技术通常基于质量中心在机器人本身中心的假设。然而，质心的精确位置并不容易测量，因此WMRs是具有未知控制方向的典型不确定非线性系统。基于快速终端滑模控制，针对控制方向未知的移动机器人，提出了一种自适应模糊路径跟踪控制方案。在该方案中，模糊系统用于近似未知函数，并且构造了鲁棒控制器来补偿近似误差。Nussbaum类型的函数集成到鲁棒控​​制器中，以估计未知的控制方向。证明了闭环系统中的所有信号都是有界的，跟踪误差会在有限的时间内收敛到原点的一小部分。仿真实例说明了所提方案的有效性。