Observability-based Placement of Inertial Sensors on Robotic Manipulators for Kinematic State Estimation

In recent years, the demand for accurate and delay-free kinematic state estimates, especially regarding acceleration, led to the adoption of inertial sensors placed along the kinematic chain of robotic manipulators. With state-of-the-art signal processing algorithms, arbitrary setups of accelerometers and gyroscopes can be deployed, raising the question of where and how many sensors should be placed for an optimal estimation quality. This paper presents a novel observability-based approach to answer this question independent of a specific estimator implementation. For this purpose, methods for calculating the required sensor measurement ranges and predicting the estimation quality regarding velocity and acceleration are introduced and discussed. The resulting procedure is validated successfully by comparing predicted and actual estimation quality for two example manipulators, indicating that it can provide meaningful aid to a design engineer.