A Braitenberg vehicle is a concept conceived in a thought experiment

Thought experiment

A thought experiment or Gedankenexperiment considers some hypothesis, theory, or principle for the purpose of thinking through its consequences...

 by the Italian

Italy

Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

-Austrian

Austria

Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...

 cyberneticist

Cybernetics

Cybernetics is the interdisciplinary study of the structure of regulatory systems. Cybernetics is closely related to information theory, control theory and systems theory, at least in its first-order form...

 Valentino Braitenberg

Valentino Braitenberg

Valentino Braitenberg is an Italian neuroscientist and cyberneticist...

 to illustrate in an evolutive

Evolution

Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

 way the abilities of simple agents

Intelligent agent

In artificial intelligence, an intelligent agent is an autonomous entity which observes through sensors and acts upon an environment using actuators and directs its activity towards achieving goals . Intelligent agents may also learn or use knowledge to achieve their goals...

. The vehicles represent the simplest form of behavior based artificial intelligence or embodied cognition

Embodied cognitive science

Embodied Cognitive Science is an interdisciplinary field of research, the aim of which is to explain the mechanisms underlying intelligent behavior...

, i.e. intelligent behavior that emerges from sensorimotor interaction between the agent and its environment, without any need for an internal memory, representation of the environment, or inference.

Mechanism

A Braitenberg vehicle is an agent that can autonomously move around. It has primitive sensors (measuring some stimulus at a point) and wheels (each driven by its own motor) that function as actuators or effectors. A sensor, in the simplest forms, is directly connected to an effector, so that a sensed signal immediately produces a movement of the wheel. Depending on how sensors and wheels are connected, the vehicle exhibits different behaviors (which can be goal-oriented). This means that it appears to strive to achieve certain situations and to avoid others, changing course when the situation changes.

Examples

The following examples are some of Braitenberg's simplest vehicles.

A first agent has one light-detecting sensor that directly stimulates its single wheel, implementing the following rules:

• More light produces faster movement.
• Less light produces slower movement.
• Darkness produces standstill.

This behavior can be interpreted as a creature that is afraid of the light and that moves fast to get away from it. Its goal is to find a dark spot to hide.

A slightly more complex agent has two light detectors (left and right) each stimulating a wheel on the same side of the body. It obeys the following rule:

• More light right → right wheel turns faster → turns towards the left, away from the light.

This is more efficient as a behavior to escape from the light source, since the creature can move in different directions, and tends to orient towards the direction from which least light comes.

In another variation, the connections are negative or inhibitory: more light → slower movement. In this case, the agents move away from the dark and towards the light.

Behavior

In a complex environment with several sources of stimulus, Braitenberg vehicles will exhibit a complex and dynamic behavior. Depending on the connections between sensors and actuators, a Braitenberg vehicle might move close to a source, but not touch it, or, the opposite, it could run away very fast, or describe circles around a point, or figures-of-eight. This behavior is undoubtedly goal-directed, flexible and adaptive, and might even appear to be intelligent, the way some minimal intelligence is attributed to a cockroach. Yet, the functioning of the agent is purely mechanical, without any information processing

Information processing

Information processing is the change of information in any manner detectable by an observer. As such, it is a process which describes everything which happens in the universe, from the falling of a rock to the printing of a text file from a digital computer system...

 or other apparently cognitive

Cognition

In science, cognition refers to mental processes. These processes include attention, remembering, producing and understanding language, solving problems, and making decisions. Cognition is studied in various disciplines such as psychology, philosophy, linguistics, and computer science...

 processes.

Often, BEAM robotics

BEAM robotics

The word "beam" in BEAM robotics is an acronym for Biology, Electronics, Aesthetics, and Mechanics. This is a term that refers to a style of robotics...

implements these sorts of behaviors.

External links

• Valentino Braitenberg's homepage
• A software Braitenberg vehicle simulator
• Another Braitenberg vehicle simulator, lets you play around with different settings, vehicles and sources