Sabelhaus Andrew P, Patterson Zach J, Wertz Anthony T, Majidi Carmel
Department of Mechanical Engineering, Boston University, Boston, Massachusetts, USA.
Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA.
Soft Robot. 2024 Aug;11(4):561-572. doi: 10.1089/soro.2022.0131. Epub 2024 Feb 6.
Although soft robots show safer interactions with their environment than traditional robots, soft mechanisms and actuators still have significant potential for damage or degradation particularly during unmodeled contact. This article introduces a feedback strategy for safe soft actuator operation during control of a soft robot. To do so, a supervisory controller monitors actuator state and dynamically saturates control inputs to avoid conditions that could lead to physical damage. We prove that, under certain conditions, the supervisory controller is stable and verifiably safe. We then demonstrate completely onboard operation of the supervisory controller using a soft thermally actuated robot limb with embedded shape memory alloy actuators and sensing. Tests performed with the supervisor verify its theoretical properties and show stabilization of the robot limb's pose in free space. Finally, experiments show that our approach prevents overheating during contact, including environmental constraints and human touch, or when infeasible motions are commanded. This supervisory controller, and its ability to be executed with completely onboard sensing, has the potential to make soft robot actuators reliable enough for practical use.
尽管与传统机器人相比，软体机器人在与环境的交互中表现得更安全，但软机制和致动器仍有很大的损坏或退化风险，尤其是在未建模接触期间。本文介绍了一种在软体机器人控制过程中实现软致动器安全运行的反馈策略。为此，一个监督控制器监测致动器状态，并动态饱和控制输入，以避免可能导致物理损坏的情况。我们证明，在某些条件下，监督控制器是稳定且可验证安全的。然后，我们使用一个带有嵌入式形状记忆合金致动器和传感装置的软热驱动机器人肢体，展示了监督控制器的完全机载操作。使用该监督器进行的测试验证了其理论特性，并显示了机器人肢体在自由空间中的姿态稳定。最后，实验表明，我们的方法可防止在接触过程中过热，包括环境约束和人体触摸，或在命令执行不可行运动时。这种监督控制器及其完全机载传感执行能力，有可能使软体机器人致动器足够可靠以用于实际应用。
