Elasticity in Humanoid Robotics

 

Mirjana Filipović,

Veljko Potkonjak,

Miomir Vukobratović

 

This paper gives a new approach to modeling of the kinematics and dynamics of a complex humanoid robotic system with elastic and stiff elements of joint. Each biped joint is defined with the states of motor (active or locked) and gear type (rigid or elastic). In this way, the new Denavit-Hartenberg parameters, transformation matrix and Jacobi matrix are defined. Mathematical model defines the dynamics of the locomotion robotic system with elasticity elements walking on an immobile platform. Furthermore, it is written in a general, universal, form, describing the motion dynamics of any robotic system that contains elastic elements. Reference trajectory of each joint is defined so as to encompass or not encompass elastic deformations. The synthesized new software FLEXI makes it possible to choose robotic configuration. The user can form very diverse biped configurations and the FLEXI software will define an appropriate mathematical model. The analysis of the simulation results of the humanoid robot motion on an immobile platform gives evidence for all the complexity of this system and shows how much system parameters (choice of trajectory, configuration, geometry, elasticity characteristics, motor, etc.) influence stabilization of its humanoid motion. All research in humanoid robotics aims at creating a robot similar to a human that would be his servant, worker or soldier and that would replace him in all dangerous situations.

 

Key words: robotics, humanoid robot, modeling, locomotive systems, joints, joint elasticity, programmed trajectory, software.