Self - Propelled Robotic System with a Visco - Elastic Joint: Dynamics and Motion Analysis

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 space which are inaccessible to human beings, such as pipeline inspection, medical assistance and disaster rescues. Locomotion of the system relie s on the stick - slip effects, which interacts with the frictional force at the surface in contact. The nonlinear robotic model utilizes combined tangential - wise and normal - wise vibrations for underactuated locomotion, which features a generic significance f or 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 dy namic 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 generati on 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 nov el 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.