Optimal Number and Positioning of Inertial Measurement Units in Spherical Robots

Spherical robots are a rather niche part of robotics. Often IMUs are used for orientation determination of those robots. These IMUs are mostly placed in the center of the spherical shape, but for different subtypes of spherical robots, this is not possible due to different drive mechanism. This paper evaluates Inertial Measurement Unit (IMU) configurations for different spherical robot types in terms of orientation determination accuracy in a series of four experiments. We establish the relationship between the accuracy of orientation determination and the following aspects of IMU configurations: (A) the number of IMUs, (B) the distance of an IMU from the center of the sphere, (C) symmetrical placement of IMUs around the sphere’s center, and (D) axial placement. Based on the findings of these experiments, we set up the optimal configurations for the different types of spherical robots.