Wheeled mobile robots (WMRs) with variable wheelbases are capable of traveling on deformable terrains and handling complex detection tasks. While the variable wheelbase length of WMR allows it to interact with the terrains adaptively, enhancing its mobility, it brings a control challenge. Inspired by the worm's movement of stretching body at different lengths under different environmental resistance, a creeping gait (CG) strategy is proposed in this work to enable the WMR to be controlled in dual modes: wheeled following mode (WFM) and specified length mode (SLM). WFM adjusts the wheelbase's length by the wheels' movements freely to minimize the internal force and torque between wheels. SLM adjusts the wheelbase's length using a proposed fuzzy logic based algorithm to stabilize the body's posture on rough terrain and overcome specific motion challenges, such as escaping wheel sinking. A state-adaptive mode-switching controller is then developed using the dwell time approach to smooth the output velocities during the switching phase, and a Lyapunov analysis is performed to verify its stability. According to the results of physical experiments, three-wheeled mobile robot movements with CG enable more precise path following by 37% and faster response by 11% compared to fixed wheelbase movements, and the dwell time approach achieves smoother speed transitions between the modes than the direct switching method, especially when moving from flat to slope terrain.

中文翻译：

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采用受蠕虫启发的爬行步态策略对轮式移动机器人进行可变轴距控制


具有可变轴距的轮式移动机器人（WMR）能够在可变形地形上行驶并处理复杂的检测任务。虽然 WMR 的可变轴距长度使其能够自适应地与地形交互，增强其机动性，但它也带来了控制挑战。受蠕虫在不同环境阻力下不同长度拉伸身体运动的启发，本文提出了爬行步态（CG）策略，使WMR能够以双模式控制：轮式跟随模式（WFM）和指定长度模式（可持续土地管理）。 WFM通过车轮的运动自由调整轴距长度，以最大限度地减少车轮之间的内力和扭矩。 SLM 使用提出的基于模糊逻辑的算法来调整轴距的长度，以稳定车身在崎岖地形上的姿势并克服特定的运动挑战，例如避免车轮下沉。然后使用驻留时间方法开发状态自适应模式切换控制器，以平滑切换阶段的输出速度，并进行李雅普诺夫分析以验证其稳定性。根据物理实验结果，与固定轴距运动相比，带有CG的三轮移动机器人运动的路径跟随精度提高了37%，响应速度提高了11%，并且停留时间方法比传统方法实现了模式之间更平滑的速度转换。直接切换方法，尤其是从平坦地形移动到斜坡地形时。