Modeling of Visco-Elastic Environments for Humanoid Robot Motion Control

Abstract

This manuscript presents a model of compliant contacts for time-critical humanoid robot motion control. The proposed model considers the environment as a continuum of spring-damper systems, which allows us to compute the equivalent contact force and torque that the environment exerts on the contact surface. We show that the proposed model extends the linear and rotational springs and dampers -classically used to characterize soft terrains -to the case of large contact surface orientations. The contact model is then used for the real-time whole-body control of humanoid robots walking on visco-elastic environments. The overall approach is validated by simulating walking motions of the iCub humanoid robot. Furthermore, the paper compares the proposed whole-body control strategy and state of the art approaches. In this respect, we investigate the terrain compliance that makes the classical approaches assuming rigid contacts fail. We finally analyze the robustness of the presented control design with respect to non-parametric uncertainty in the contact-model.

Online Non-linear Centroidal MPC for Humanoid Robot Locomotion with Step Adjustment

“…Here the performances of the low-level torque control along with the base estimation capabilities become crucial to obtain successful results. A possible future research direction is to embed the controller in an architecture that considers the interaction with a compliant environment [45]. In this context, it is pivotal to ensure the tracking of the desired contact forces.…”

Dynamic Complementarity Conditions and Whole-Body Trajectory Optimization for Humanoid Robot Locomotion

“…This has been tested on a quadruped robot adopting a tailored soft contact model. Nevertheless, the use of soft contact models presents some limitations when applied to robots with finite size feet [45].…”