Computational advantages in robotics by evaluating Newton-Euler equations with respect to a moving reference point in a non-inertial frame

Abstract

Maintaining stability while walking on arbitrary surfaces or dealing with external perturbations is of great interest in humanoid robotics research. Increasing the system's autonomous robustness to variety of postural threats during locomotion is the key despite the need to evaluate noisy sensor signals. The equations of motion are the foundation of all published approaches. In contrast, we propose a more adequate evaluation of the equations of motion with respect to an arbitrary moving reference point in a non-inertial reference frame. We use simulation results to compare our algorithm with established approaches and test it with physical robot data. Conceptual advantages are, e.g., getting independent of global positions and velocity vectors estimated by sensor fusions or calculating the imaginary zero-moment point walking on different inclined ground surfaces. Further, we improve the calculation results by using specific characteristics of physical robots and reducing noise amplifying methods in our algorithm.