Dynamics modeling of fully-actuated humanoids with general robot-environment interaction

In this article, a general method for dynamics modeling of a humanoid robot which interacts with its environment is presented. This general method is based on developing equations assuming no interaction with its environment. Then, consistent constraints in different phases of motion are taken into account. In this method, each holonomic interaction constraint is considered as an unknown force/ moment which are then mapped into joint space of the robot, using transpose of jacobian matrices of interaction points. To this end, constrained dynamics model for the robot with broad-spectrum interaction with its environment in different phases of motion is encapsulated. In order to validate the proposed method, a dynamics model for a 21 DOF humanoid robot during different phases of walking is obtained and the results are verified and discussed.

I. Introduction

Due to complex structure of humanoid robots and their variable dynamics behavior during different phases of motion, a general approach in dynamics modeling which is valid for all phases and include any interaction with environment is of significant value. This dynamics model may be exploited during design procedure, simulation and analysis of the robot and model-based controller design in joint or task space.