Quasi-Static Simulation of a Wheeled Mobile Robot having a Passive Variable Camber

Vijay Eathakota∗    Gattupalli Aditya†    Madhava Krishna‡   

RRC, IIIT Hyderabad, India   

In this paper we present an algorithm for quasi-static motion of a wheeled mobile robot equipped with a passive variable camber on uneven terrain. The algorithm is based on Peshkin’s minimum energy principle which combines the force and kinematic relationship into a nonlinear optimization problem. The algorithm at each instant estimates the contact forces and velocity of the vehicle platform for a given set of joint velocities of the robot. This ensures that the vehicle satisfies not only kinematic no slip constraints but as well as no slip constraints that arise due to relations between traction and contact forces. In general a complete simulation of a WMR on a fully 3D terrain has been a difficult problem to solve. The best efforts so far have provided a simulation that incorporates the wheel ground contact constraints into a set of differential algebraic equations (DAEs) to estimate the full 6dof pose of the vehicle. This work integrates the quasi staic contraints within the DAE framework to provide a complete 6dof evolution of vehicle on 3D terrain that respects both kinematic and quasi static constraints. Simulations that depict variations in evolution of the vehicle with variation in friction coefficients ascertain the validity of the proposed algorithm.