We present a robot base placement and control method that enables a mobile manipulator to gracefully recover from manipulation failures while performing tasks on-the-move. A mobile manipulator in motion has a limited window to complete a task, unlike when stationary where it can make repeated attempts until successful. Existing approaches to manipulation on-the-move are typically based on open-loop execution of planned trajectories which does not allow the base controller to react to manipulation failures, slowing down or stopping as required. To overcome this limitation, we present a reactive base control method that repeatedly evaluates the best base placement given the robot's current state, the immediate manipulation task, as well as the next part of a multi-step task. The result is a system that retains the reliability of traditional mobile manipulation approaches where the base comes to a stop, but leverages the performance gains available by performing manipulation on-the-move. The controller keeps the base in range of the target for as long as required to recover from manipulation failures while making as much progress as possible toward the next objective. See https://benburgesslimerick.github.io/MotM-FailureRecovery for videos of experiments.

翻译：我们提出了一种机器人基座定位与控制方法，使移动机械臂在执行动态操作时能够优雅地从操作故障中恢复。与静止状态下可反复尝试直至成功的场景不同，运动中的移动机械臂完成任务的时限窗口有限。现有动态操作方案通常依赖规划轨迹的开环执行，无法使基座控制器根据操作故障进行响应（例如按需减速或停止）。为克服这一局限，我们提出一种响应式基座控制方法，该方法根据机器人当前状态、当前操作任务及多步骤任务的后续环节，反复评估最优基座定位。最终实现的系统既保留了传统移动机械臂方法（基座停止运行）的可靠性，又充分利用了动态操作带来的性能提升。该控制器可在操作故障恢复期间持续保持基座处于目标工作范围内，同时尽可能推进下一目标的进度。实验视频详见https://benburgesslimerick.github.io/MotM-FailureRecovery。