Dynamics analysis of bionic parallel joint mechanism for the snake robot

Abstract

Joint mechanism is a key factor for a snake robot adjusting its postures adapted to clutter environments in search and rescue tasks. Most joint mechanisms in prior research simply consist of serially connected revolute joints, which are lack of great load carrying ability. Imitating nature snake structure, a modular bionic parallel joint mechanism (BPJM) is proposed for the rescue snake robot. Dynamics analysis of the BPJM is necessary for its optimal design and control, providing the force and constraint that must be resisted by joints, links and actuators. To reduce the dynamics computation load, Newton equation and Euler equation are combined by synchronizing the inertial force and inertial moment with the aid of screw theory. Therefore, the dynamics equations for moving platform and links are formulated in a simplified form. Viscous friction at the joints and external force acting on BPJM, which actually affect the motion, are both considered in the formulation. Finally, the virtual prototype is provided in order to visualize the joint mechanism and the numerical results from the dynamics analysis are given.