Hi, this was my master thesis.Evolution of Morphology and Behavior of Virtual Creatures: A model based on Swarm Intelligence and Artificial Neural Networks.
In this paper, simultaneous evolution of morphology and behavior of virtual creatures takes place in a virtual world physically realistic governed by Newtonian physics.
The creature's morphology is built with rigid bodies shaped as capsules, cones, cylinders, parallelepipeds, and spheres, which mass and size may change. The rigid bodies are joined by spherical joints with customizable restrictions on angular limits within a given range in each degree of freedom, so to model any type of rotational joint. Each rigid body has a proprioceptive sensor which measures orientation using quaternions, and also an effector that exerts moments of force on its center of mass. The maximum moment of force that each effector may exert is calculated using the equations for static equilibrium of rigid bodies so to avoid abnormal motion caused by the excess of forces.
Regarding behavior, it is modeled by an Artificial Neural Network (ANN) which receives data from all sensors and transmits the amount of moment of force that must be exerted by each effector so to induce motion to the creature. The architecture of the ANN emulates the biological central nervous system by linking the orientation of each rigid body before orchestrating motion.
Finally, evolution of morphology and behavior is carried out using Particle Swarm Optimization (PSO), where each particle encodes the morphology and behavior of one creature.
Conducted experiments revealed characteristics that improve performance of virtual creatures, such as: shape, size, and mass of rigid bodies; angular limits of joints; morphological structure; and architecture of the ANN.
Furthermore, experiments revealed that evolved virtual creatures outperform those by Miconi and Channon (2005) up to four times in average speed. Keywords:
Artificial Life, Virtual Creatures, Particle Swarm Optimization, Artificial Neural Networks, Static Equilibrium of Rigid BodiesDownloadable PDFs:https://sites.google.com/site/jcrada/publications/2009mscthesis.pdf
(english, short version)https://sites.google.com/site/jcrada/publications/2009msctesis.pdf
(spanish, long version)Video:http://www.youtube.com/watch?v=2UqHgZRV9w43D Pole Balancing using Fuzzy LogicFuzzy Logic Library: fuzzy-litehttp://code.google.com/p/fuzzy-lite/Video:http://www.youtube.com/watch?v=YOKk8G_5aRA
Thanks to the Bullet Physics Developers these works were possible. Amazingly great platform you have and infinite thanks for keeping it free and open-sourced