Dynamic parameters identification of an omni-directional mobile robot

Dynamic modelling of mobile robots is very important to design of controllers, mainly when the robots need to travel at higher velocity and perform heavy works. For example, in (Liu et al., 2003) and (Watanabe, 1998), control strategies for omnidirectional robots using the dynamic model are discussed. However, non-linearities, like motor dynamic constraints can greatly affect the robot behaviour, especially when the robot is accelerated and decelerated. This paper presents a robot model identification that could find the non-linear saturation elements. Three methods are described to identification of the model’s parameters. We focus attention on a omni-directional mobile robot with four motors, as shown in Fig.1(a), built for the 5dpo Robotic Soccer team from the Department of Electrical and Computer Engineering at the University of Porto at Porto, Portugal. For this application (Robotic Soccer) the mobile robot needs to execute trajectories quickly and with a perfect position to the objective, for example, positioning to the ball, or to the goal, or to avoid dynamic obstacles. So, the dynamic characteristics of the motion are essential to follows the path correctly. In section 2, the omni-directional mobile robot model is developed. The experimental methods of identification to model’s parameters is presented in section 3. In section 4, simulation environment, simulation and real results of the identified model are presented. Finally, the conclusion and future works are drawn in section 5.