1. IAT 800 Braitenberg Vehicles

2. Oct 31, Fall 2006IAT 8002 Outline  Braitenberg vehicles –Concept behind vehicles –Introduce several vehicles –Look through major code sections –Talk about possible project ideas

3. Oct 31, Fall 2006IAT 8003 Braitenberg Vehicles  Valentino Braitenberg –Vehicles: Experiments in Synthetic Psychology –Neuro-psychologist interested in how primitive neural structures can give rise to complex behavior –He developed a simple model of robots with sensors and motors to show how complex behavior can arise from simple mechanisms  We're interested in his vehicles as a simple autonomous agent framework we can play with –Build ecosystems of interacting agents and sensory sources Dr. B’s homepage: http://www.kyb.mpg.de/~braitenb

4. Oct 31, Fall 2006IAT 8004 Vehicle Sensors Wheel and motor Wires Sensory source

5. Oct 31, Fall 2006IAT 8005 Vehicle 1 Sensors (light sensors) connected directly to motor on same side What will happen when light is to side? Directly in front?

6. Oct 31, Fall 2006IAT 8006 Vehicle 1: Coward Steers away from source Charges source directly in front Rests in darkness

7. Oct 31, Fall 2006IAT 8007 Vehicle 2 Sensors connected directly to motor on opposite side What will happen when light is to side? Directly in front?

8. Oct 31, Fall 2006IAT 8008 Vehicle 2: Aggressive Sensors connected directly to motor on opposite side Turns towards source and charges Charges source directly in front Rests in darkness

9. Oct 31, Fall 2006IAT 8009 Vehicle 3 Sensors connected through inverter to same side What will happen when light is to side? Directly in front? - - - -

10. Oct 31, Fall 2006IAT 80010 Vehicle 3: Love Sensors connected through inverter to same side - - - - Turns towards source and rests Move toward source and rest Moves in darkness - -

11. Oct 31, Fall 2006IAT 80011 Vehicle 4 Sensors connected through inverter to opposite side What will happen when light is to side? Directly in front? - - - -

12. Oct 31, Fall 2006IAT 80012 Vehicle 4: Explorer Sensors connected through inverter to opposite side - - - - - - Turns away from source Rotates away (unless exactly on target) Moves in darkness

13. Oct 31, Fall 2006IAT 80013 Classes in code  Classes –Vehicle (1) Includes logic for movement –Wheel (2) The flapping things on the vehicle –Sensor (3) The “eyes” on the vehicle – how much they glow indicates activation (+ inverter) –Source (4) The light sources  Vehicle draws itself, plus wheel and sensor (1) (2)(3) (4)

14. Oct 31, Fall 2006IAT 80014 Vehicles  All vehicles are currently vehicles of the same type –Initialized in setup() Up/down arrow displays/hides vehicles –To create multiple types of vehicles, subclass Vehicle instead of commenting in and out different doSenseLogic() methods  Draw() repeatedly calls move() and drawMe() methods on vehicle –To change the way the vehicle looks, change the drawMe() methods –move() contains call to doSenseLogic(), which contains the relationship between sensors and wheels

15. Oct 31, Fall 2006IAT 80015 Ground  The ground (background) is a PImage - different sources change the pixels of the ground  This is the mechanism for summing different sources together –updateGround() sums light sources to produce background pixels  Sensing takes place by asking the ground what the summed sense value is (rather than by directly asking the sources)  Ground will need to be modified to handle multiple source types –Separate by color (r, g, b), but then can only have three –Better – lay multiple sensory grounds on top of each other Transparency will make them all visible Different sensor types will look at different grounds (sound, light sources, etc.)  Instead of PImage, we will make a 2D array for ground instead (drawing optional => MUCH FASTER on slower machines!)

16. Oct 31, Fall 2006IAT 80016 Sources  The only source currently implemented is light sources –Strength determines brightness –Max_radius determines how far out influence extends  Sources only draw the little circle in the middle –The light gradient around them is actually in the ground  getReading() is used by ground to sample a light source (to determine how much a light source effects a given pixel)

17. Oct 31, Fall 2006IAT 80017 Extensions  Make vehicles also be sources (vehicles start following each other, are repelled by each other, etc.)  Implement other sources (e.g. sound, smell…), other objects in the world  Add more complex sensor response curves (everything we’ve looked at so far is linear)  Add more interactions between different types of vehicles

18. Oct 31, Fall 2006IAT 80018 Project ideas  Braitenberg vehicles provide a simple framework for exploring autonomous behavior in computational ecosystems  Text machines – autonomous words and letters  Drawing machines – brush interacts with vehicles, spawns vehicles, vehicles interact with each other  Ecosystem responds to data (sources represent web data, vehicles spawned in response to data, etc.)  Miniature worlds – alien, aesthetically interesting worlds