Biorobotics Laboratory BioRob

Stéphane Mojon (Semester project 2003)

Realization of a Physic Simulation for a Biped Robot

The goal of this project was to implement a simulation of a biped robot. This simulation is going to be used to study and to get a better understanding of biped locomotion and its control. The main challenge of this project was to make the robot's model as close as possible to reality. Otherwise, the observations made in simulation would be irrelevant once applied to a real robot. Therefore we used a library called Open Dynamics Engine (ODE) to simulate rigid body dynamics.

In the very first step of the project, we directly used ODE to simulate the biped robot. But we quickly noticed some limitations of this approach in terms of flexibility and reusability. It's why we decided to transfer our model to Webots. Webots is a 3D mobile robotics simulation software that uses ODE and that provides a fast and convenient way of modeling, programming and simulating mobile robots.

The current simulated robot has a structure that is inspired by SONY's SDR 4X humanoid robot.

Our simulated robot into Webots.

The development of the simulation was greatly facilitated by the use of ODE and Webots. So the development was quick, and at the end of the project we had time to make our robot walk by using a genetic algorithm. The results obtained with this technique can be viewed in the videos below. The walk is controlled by very simple open-loop controllers and is far from being perfect, but it demonstrates that our simulation works and behave correctly.

Project report:

Project Report (in pdf format): report.pdf

Sample movies:

Walk obtained by artificial evolution (front view) : walk_front.mpeg (4.0MB) walk_front_divx.avi (1.2MB),
Walk obtained by artificial evolution (side view) : walk_side.mpeg (3.7MB) walk_side_divx.avi (1.2MB),
The main steps of the evolution (speed accelerated 6x) : evolution.mpeg (5.8MB) evolution_divx.avi (1.8MB)