The book "Vehicles" by Valentino Braitenberg is short by academic standards. Only 152 pages including the references, and of this total 10 pages are covered by Maciek Albrecht's illustrations. Yet this book has influenced the thought of a number of researchers in the fields of Artificial Intelligence, Artificial Life, Cognitive Psychology and Neuroanatomy. The book conveys it's initially simple message in a short and efficient manner. The ideas in the book are equally simple when first encountered, but their beauty is that they demonstrate what complex behaviour can result from an apparently simple structure. The book is subtitled "Experiments in synthetic Psychology" and represents a series of increasingly complex thought experiments based on the simple rewiring of small vehicles. For an interesting review follow this link.
According to Michael Arbib's foreword to the book Valentino Braitenberg is:
"...a cybernetician, a neuroanatomist, and a musician" (Braitenberg, 1986, p.ix)
In fact Braitenberg is still working and publishing. He is based at the Max Planck Institute of Biological Cybernetics, Tubingen, Germany
The vehicles were simply wired between sensors (e.g. to detect light), and effectors (e.g. the wheels). This simple wiring could result in apparently complex behaviour. For example the vehicle below would move towards the light because the sensor on the front corner of the vehicle is wired to the effector on the diagonally opposite corner. The more the sensor is stimulated by light the more the effector it is wired to will be stimulated.
A more in depth discussion of each chapter of the book, and the vehicles described in each chapter can be found here (Univ. of Alberta).
Why did he conceive the idea of these Vehicles?
Braitenberg used the vehicles to demonstrate ideas from neuroanatomy. To show that complex, apparently purposive behaviour did not need to depend on complex representations of the environment inside a creature or agents brain. In fact simply by reacting to the environment in a consistent manner was more than enough to explain the low level reactive behaviours exhibited by many animals. The biological nature of the Vehicles is discussed in the second half of the book. And also here (Univ. of Alberta, again).
What were they used for at the time?
Braitenberg wanted to use the Vehicles as a thought experiment to illustrate the simplicity of structure that could result in complex behaviour. He was working in neuroanatomy and perhaps could see well that at least in some areas there is no need for there to be conscious control of actions at all times. By using his Vehicles as thought experiments he could investigate the ways in which brains and nervous systems might work, rather than being constrained by the ways in which they did work.
What have they been used for since, and what are they used for now?
The ideas from Braitenberg's vehicles have been used as an inspiration by many researchers. Particularly the subsumption architecture put forward by Rodney Brooks at MIT, and further work at MIT has benefited from Braitenberg's ideas. To the extent that from the work at MIT a series of "smart" bricks have been developed. The idea of these smart bricks has been provided to Lego, who produced their "Mindstorm" programmable robot using the technology from MIT. Also see Luc Steels article on the same topic and the programmable brick page at MIT. It is almost certainly the case that the autonomous features of the Mars Pathfinder mission Sojourner/Rover robot also benefited from Braitenberg's original ideas. Also see MIT's version of a Mars Rover. Other robot builders have been similarly inspired. The Solaroller Background section of the BEAM robotics page is just one example. The simple wiring of the vehicles once there are many links begins to resemble a neural network of connections. Some have even argued that there will be a robotic version of the Cambrian explosion.
Did anyone else have similar ideas before Braitenberg?
Braitenberg was working on ideas that had first been put forward by cybernetics groups. Cybernetics was a discipline conceived during and immediately after the Second World War, including such visionary researchers in the realm of Computers as John von Neumann and Alan Turing. The important character for Braitenberg vehicles is W. Grey Walter. W. Grey Walter invented a series of turtles or tortoises that have only recently come to light. These valve driven creatures seem to include many of the ideas that Braitenberg uses in his vehicles.
One aspect of Braitenberg's vehicles that seems to inspire many people is the relative ease with which they can be modelled in simulation. These models can then be used to explore different types of autonomous behaviour. Some examples of this software are:
The simulations are normally used to investigate ideas of communication or group behaviour that can result from assigning different roles to the vehicles. Some vehicles may be made aggressive, or wired in such a way as they will act together in groups to collect balls of different colours. The form of communication can be very simple. For example turning on a red light on the back of the vehicle if a red light detecting front sensor is triggered. Thus signalling to others of the same type that danger is near perhaps.
Braitenberg, Valentino, "Vehicles: Experiments in Synthetic Psychology", 1986, MIT Press, MIT.