This paper studies the dynamics and motion generation of a self-propelled robotic system with a visco-elastic joint. The system is underactuated, legless and wheelless, and has potential applications in environmental inspection and operation in restricted spaces which are inaccessible to human beings, such as pipeline inspection, medical assistance and disaster rescue. Locomotion of the system relies on the stick–slip effects, which interacts with the frictional force of the surface in contact. The nonlinear robotic model utilizes combined tangential-wise and normal-wise vibrations for underactuated locomotion, which features a generic significance for the studies on self-propelled systems. To identify the characteristics of the visco-elastic joint and shed light on the energy efficacy, parameter dependences on stiffness and damping coefficients are thoroughly analysed. Our studies demonstrate that the dynamic behaviour of the self-propelled system is mainly periodic and desirable forward motion is achieved via identification of the variation laws of the control parameters and elaborate selection of the stiffness and damping coefficients. A motion generation strategy is developed, and an analytical two-stage motion profile is proposed based on the system response and dynamic constraint analysis, followed by a parameterization procedure to optimally generate the trajectory. The proposed method provides a novel approach in generating self-propelled locomotion, and designing and computing the visco-elastic parameters for energy efficacy. Simulation results are presented to demonstrate the effectiveness and feasibility of the proposed model and motion generation approach.

中文翻译：

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具有粘弹性关节的自走式机器人系统：动力学和运动分析

本文研究了具有粘弹性关节的自走式机器人系统的动力学和运动生成。该系统为欠驱动、无腿、无轮系统，在管道检查、医疗救助、灾难救援等人类无法进入的受限空间环境检测和作业中具有潜在的应用价值。系统的运动依赖于粘滑效应，它与接触表面的摩擦力相互作用。非线性机器人模型利用切向振动和法向振动相结合进行欠驱动运动，这对自航系统的研究具有普遍意义。为了识别粘弹性接头的特性并阐明能量功效，对刚度和阻尼系数的参数依赖性进行了彻底分析。我们的研究表明，自航系统的动态行为主要是周期性的，通过识别控制参数的变化规律和精心选择刚度和阻尼系数来实现理想的向前运动。开发了运动生成策略，并基于系统响应和动态约束分析提出了解析两阶段运动轮廓，然后是参数化程序以优化生成轨迹。所提出的方法提供了一种产生自走运动的新方法，以及设计和计算能量效率的粘弹性参数。