Key components in the creatures system

Genetic Algorithms (GA) has 3 phases

Varied population with heredity
Some sort of test (selection)
Variations of the winners/survivors (breeding)

The most creative and challenging parts of programming a GA are usually the problem specific aspects - Hervey, Inman (2009)

We will roughly follow Sims, but with simplifications

We'll use the URDF format

We don't have a CM-5 handy, or access to the original Sims code, we'll use an alternative physics engine.

Genotype

We'll follow Sims somewhat, but with simplifications.

Fitness function

How far does it move? But... they are going to cheat!

Population model

Roulette wheel selection etc.

Compute in parallel

We can gain a lot of speed by computing in parallel

Technology stack

Python
Pybullet
URDF format

Introduction to pybullet

What is bullet

It's a rigid and soft body physics engine originally developed by Erwin Coumans.

Demo

It's written in C and C++. It's been translated to JS in ammo.js http://kripken.github.io/ammo.js/

Install pybullet

Create the virtual env and install pybullet

The URDR file format

Stands for Unified Robot Description Format

It's an XML-based file format for building robot models, including their motors and other dynamics.

To generate a model programmatically is too complex when the problem has a currently viable solution.

Using URDF makes it easier to share the models.

Links are the parts, joints are the points where the parts meet and interact.

Moving a URDF robot

There are 3 types of joints available in pybullet, though the URDF standard supports more. These are:

JOINT_REVOLUTE: rotate
JOINT_PRISMATIC: move along an axis
JOINT_FIXED: does not move

Mving a preset robot

Joint info

getNumJoints
getJointInfo

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