Optimal placement of optical mice for accurate mobile robot velocity estimation

There can be some restrictions during the installation of optical mice at the bottom of a mobile robot, owing to the non-circular base or other existing structures of the robot. This paper presents the optimal placement of optical mice under positional restriction during installation for the velocity estimation of a mobile robot. First, the velocity kinematics between a mobile robot and an array of two or more optical mice is derived, mapping the velocity of a mobile robot in the world coordinate frame to the velocities of optical mice in their local frames. Second, the error characteristics of the velocity estimation of a mobile robot are represented by the uncertainty ellipsoid, and the performance index is then defined as the inverse of the volume of the ellipsoid, which should be minimized for the optimal placement of optical mice. Third, the global optimization strategy is stated in terms of the distances to each optical mouse and the geometrical center of all optical mice, and the local optimization strategy is described as the positional change of each optical mouse, leading to optimal optical mouse placement. Fourth, simulation results for three optical mice within a given elliptical region are given to show how the positional restriction during installation affects the resulting optimal optical mouse placement.