Kinematics Analysis and Simulation of a Rocker Bogie Mobile Robot

Abstract

-For a wheeled mobile robot in rough terrain, one of the known suspension systems is the rocker-bogie mechanism. The high mobility of the robot, moving in 3 dimensions with 6 degrees of freedom makes the kinematics modelling as a challenging task. In this paper, a full 6-DOF kinematic model of a rocker-bogie mobile robot is presented. The A matrices has been derived based on Denavit-Hartenberg coordinate transformation approach. The kinematic equations and Jacobian matrices for the wheels are derived which relates the rover velocity vector with wheel angular velocities and joint angular rates. Furthermore, a rover-terrain model is developed to obtain the necessary joint angles and some attitude angles by solving nonlinear optimization equations. Finally, the robot model is also constructed in MD Adams and simulations are carried out to verify the kinematics model. The results show very close match of kinematic model and simulation in rough terrain trajectory.