The research interest in mobile robots with independent steering wheels has been increasing over recent years due to their high mobility and better payload capacity over the systems using omnidirectional wheels. However, with more controllable degrees of freedom, almost all of the platforms include redundancy which is modeled using the instantaneous center of rotation (ICR). This paper deals with a Tetris inspired floor cleaning robot hTetro which consists of four interconnected differential-drive units, i.e., each module has a differential drive unit, which can steer individually. Differing from most other steerable wheeled mobile robots, the wheel arrangement of this robot changes because of its self-reconfigurability. In this paper, we proposed a robust path tracking controller that can handle discontinuous trajectories and sudden orientation changes. Singularity problems are resolved on both the mechanical aspect and control aspect. The controller is tested experimentally with the self-reconfigurable robotic platform hero, and results are discussed.

中文翻译：

---

具有四个差分驱动单元的自重构机器人hTetro的路径跟踪控制

近年来，由于与使用全向轮的系统相比，具有高机动性和更好的有效载荷能力，具有独立方向盘的移动机器人的研究兴趣不断增加。然而，由于具有更多可控的自由度，几乎所有平台都包含使用瞬时旋转中心 (ICR) 建模的冗余。本文介绍了一个受俄罗斯方块启发的地板清洁机器人 hTetro，它由四个相互连接的差动驱动单元组成，即每个模块都有一个差动驱动单元，可以单独转向。与大多数其他可转向轮式移动机器人不同，该机器人的轮子排列由于其自重构性而发生变化。在本文中，我们提出了一种鲁棒的路径跟踪控制器，可以处理不连续的轨迹和突然的方向变化。奇点问题在机械方面和控制方面都得到解决。控制器与自重构机器人平台英雄进行了实验测试，并讨论了结果。