Soft robots offer an alternative approach to manipulate within a constrained space while maintaining a safe interaction with the external environment. Owing to its adaptable compliance characteristic, external contact force can easily deform the robot shapes and lead to undesired robot kinematic and dynamic properties. Accurate contact detection and contact location estimation are of critical importance for soft robot modeling, control, trajectory planning, and eventually affect the success of task completion. In this article, we focus on the investigation of a one degree of freedom (1-DoF) soft pneumatic bending robot, which is regarded as one of the fundamental components to construct complex, multi-DoFs soft robots. This 1-DoF soft robot is modeled through the integral representation of the spatial curve, where direct and instantaneous kinematics are calculated explicitly through a modal method. The fixed centrode deviation method is used to detect the external contact and estimate the contact location. Simulation results and experimental studies indicate that the contact location can be accurately estimated by solving a nonlinear least-square optimization problem. Experimental validation shows that the proposed algorithm is able to successfully estimate the contact location with the estimation error of 1.46 mm.

中文翻译：

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基于模态的软机器人运动学和接触检测

软机器人提供了一种替代方法，可以在受限空间内进行操作，同时保持与外部环境的安全交互。由于其适应性强的特性，外部接触力很容易使机器人形状变形并导致不希望的机器人运动学和动力学特性。准确的接触检测和接触位置估计对于软机器人建模、控制、轨迹规划至关重要，最终影响任务完成的成功与否。在本文中，我们重点研究单自由度（1-DoF）软气动弯曲机器人，它被认为是构建复杂的多自由度软机器人的基本组件之一。这个 1-DoF 软机器人是通过空间曲线的积分表示来建模的，其中直接和瞬时运动学通过模态方法显式计算。固定重心偏差法用于检测外部接触并估计接触位置。仿真结果和实验研究表明，通过求解非线性最小二乘优化问题，可以准确估计接触位置。实验验证表明，该算法能够成功估计接触位置，估计误差为1.46 mm。