Braitenberg’s Vehicles Instructor: Erol Şahin

VEHICLES: Experiments in Synthetic Pscyhology 20/09/07 20/09/07 VEHICLES: Experiments in Synthetic Pscyhology A classic book by Valentino Braitenberg published in 1984. “Valentino Braitenberg is a cybernetician, and a neuroanatomist and a musician, seeking to understand how the beautiful structures of the brain constitute a machine that can enable us to exhibit such skilled behavior as that involved in playing music” Arbib’s foreword to the book. Braitenberg claims that “a way of thinking in which the hardware realization of an idea is much less important than the idea itself. Let’s design some simple robots and see what they do and how we interpret what they do! 2

Vehicle 1: Getting around 20/09/07 Vehicle 1: Getting around Simplest possible vehicle equipped with one sensor and one motor. The sensor is directly connected to the motor. The sensor’s output is higher as it gets closer to the light source. The vehicle will speed up where it’s warm, and slow down where it’s dark. With friction in the world, the vehicle will spend most of its time on dark areas, while escaping from light areas.

Vehicle 2a: Fear Two sensors and two motors. 20/09/07 Vehicle 2a: Fear Two sensors and two motors. Each sensor is connected to the motor on the same side. The vehicle turns away from light sources speeds up in light areas and slows down in dark areas spends more time in dark and less time in light. The vehicle “dislikes” light. The vehicle is a “coward”, it “fears” light!

Vehicle 2a: Trails http://kovan.ceng.metu.edu.tr/software/Braitenberg/ 20/09/07 Vehicle 2a: Trails http://kovan.ceng.metu.edu.tr/software/Braitenberg/

Vehicle 2b: Aggression Two sensors and two motors. 20/09/07 Vehicle 2b: Aggression Two sensors and two motors. Each sensor is connected to the motor on the other side. The vehicle heads towards light sources speeds up in light areas and slows down in dark areas spends more time in dark and less time in light. The vehicle “dislikes” light. The vehicle is “aggressive”, it “attacks” light!

20/09/07 Vehicle 2b: Trails

Vehicle 3a: Love By default, the motors turn! 20/09/07 Vehicle 3a: Love By default, the motors turn! Each sensor is connected to the motor on the same side inhibiting the motor. The vehicle Heads toward light sources speeds up in dark areas and slows down in light areas spends more time in light and less time in dark. The vehicle “loves” light.

20/09/07 Vehicle 3a: Trails

Vehicle 3b: Love By default, the motors turn! 20/09/07 Vehicle 3b: Love By default, the motors turn! Each sensor is connected to the motor on the other side inhibiting the motor. The vehicle Turns away from light sources slows down in light areas and speeds up dark areas spends more time in light and less time in light. The vehicle does not “love” light, but it explores light areas.

20/09/07 Vehicle 3b: Trails

20/09/07 Vehicle 3c: Values The vehicle has two types of sensors: one for red the other for green lights. How does the vehicle behave?

Vehicle 4: Values and Special Tastes 20/09/07 Vehicle 4: Values and Special Tastes What if the sensor has a nonlinear characteristic?

Vehicle 4a: Values What if the sensor has a nonlinear characteristic? 20/09/07 Vehicle 4a: Values What if the sensor has a nonlinear characteristic?

20/09/07 Vehicle 4a: Trails

20/09/07 20/09/07 Homework Modify Braitenberg’s vehicles 2a, 2b, 3a and 3b so that there are non-monotonic connections between the sensors and actuators. Try building vehicles that can Circle a single light source. Go back and forth between two light sources. Go in a figure 8 with a single light source in one of the lobes. Is this possible? Problem taken from Rodney Brooks. 16

20/09/07 20/09/07 Homework – cont’d Add a light source to the top of the Braitenberg vehicles so that others can sense their presence. Analyze the behavior of a pair of each of the same type vehicles 2a, 2b, 3a and 3b. Problem taken from Rodney Brooks. 17