Instantaneous centre of rotation estimation of an omnidirectional mobile robot

Redundantly actuated mobile robots using conventional wheels need a precise coordination of their actuators in order to guarantee a safe and precise motion without generating high internal forces and slippage. Using the instantaneous centre of rotation (ICR) of the chassis to describe this motion is a well established method. But the ICR is a mathematical concept which is hardly achieved on a real robot. This paper addresses the problem of ICR estimation of a non-holonomic omnidirectional mobile robot using conventional wheels. Instead of estimating the ICR in the working space, our approach estimates it in the actuators´ space. The algorithm is presented in its general form and then adapted for a particular robot. The use of the algorithm with other omnidirectional robots is also discussed. Results from extensive testing done in simulation as well as with a real robot are presented, demonstrating the effectiveness of the proposed method.