Evolving Neural Controllers

DEMO Home Gregory S. Hornby
hornby@cs.brandeis.edu
Dynamic & Evolutionary Machine Organization Lab

Overview

This project addresses the problem of creating controllers for robots, for which there are three sets of experiments:

Method

The system for evolving controllers consists of an evolutionary algorithm, neural network module and a simulator. Neural networks are used as the controllers of the robots and these are evolved by the evolutionary algorithm in simulation.

Results

Pole Balancing

The objective of this set of experiments is to evolve a controller for the slider to balance the pole(s) when random forces are applied to the pole. Two sets of controllers are evolved. The first set of controllers are evolved to balance one pole resting on a cart. Here the character being controlled is the cart and it must move to keep the pole upright. This is to show that one-pole balancing is readily solveable. The second set of controllers are evolved to balance two poles, one on top of the other. This is a highly chaotic problem. By starting with a stiff spring-joint connecting the two poles the problem is like one-pole balancing. As balancers are evolved the spring is relaxed.

1. An initial controller.
2. Partially evolved controller.
3. Final evolved controller.
1. An initial controller.
2. A controller that balances for 2.7 secs.
3. A controller that balances for 7.1 secs.

Co-evolution of Pursuers and Evaders

In some situations evolving against a static fitness function has its limitations: in general you can only evolve a solution as good as your fitness function. One way to achieve open-ended evolution is to evaluate individuals by comparing them against other individuals. In this way the system provides steadily increasing challenges to itself thereby enabling more open-ended evolution.

In this project two different types of co-evolutionary tournaments were compared. Here is a video presentation of this work:
2.2M MPEG
3.8M Quicktime
This research was conducted in collaboration with Brian Mirtich at
MERL, a Mitsubishi Electric Research Lab.


Transferring from Simulation to Reality

In this phase of our project we show that our controllers evolved in simulation will work on actual robots: we evolve ball-chasing with Sony's AIBO. Evolved controllers were downloaded onto AIBO and found to perform similarly in reality as they do in simulation.

In simulation.

On an actual AIBO.
Ball-chasing in simulation #1 (1.2M MPEG).
Ball-chasing in simulation #2 (2.0M MPEG).
Ball-chasing on AIBO (3.1M AVI).

The system (evolutionary algorithm, neural network module and simulator) used for this set of experiments is available under the Gnu Public License from this web page.


Publications

  • Hornby, G.S., Takamura, S., Yokono, J., Hanagata, O., Fujita, M. and Pollack, J. (2000). Evolution of Controllers from a High-Level Simulator to a High DOF Robot.
    Miller, J. (ed) Evolvable Systems: from biology to hardware; proceedings of the third international conference (ICES 2000). Springer (Lecture Notes in Computer Science; Vol. 1801). pp. 80-89.

  • Pollack, J. B., Lipson. H., , Ficici, S., Funes, P., Hornby, G. and Watson, R. (2000). Evolutionary Techniques in Physical Robotics.
    Miller, J. (ed) Evolvable Systems: from biology to hardware; proceedings of the third international conference (ICES 2000). Springer (Lecture Notes in Computer Science; Vol. 1801). pp. 175-186.

  • Hornby, G.S. and Mirtich, B. (1999). Diffuse versus True Coevolution in a Physics-based World.
    Proceedings of 1999 Genetic and Evolutionary Computation Conference (GECCO). B\anzhaf, Daida, Eiben, Garzon, Honavar, Jakiela, Smith, eds., Morgan Kauffmann, pp. 1305-1312.

  • Pollack, Jordan B., Lipson, Hod, Funes, Pablo, Ficici, Sevan G. and Hornby, Greg (1999). Coevolutionary Robotics.
    The First NASA/DoD Workshop on Evolvable Hardware (EH'99). John R. Koza, Adrian Stoica, Didier Keymeulen, Jason Lohn, eds., IEEE Press.


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    hornby@cs.brandeis.edu - Last modified: June 12, 2003
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