Subsumption architecture is a reactive robot architecture heavily associated with behavior-based robotics

Behavior-based robotics

Behavior-based robotics or behavioral robotics is the branch of robotics that incorporates modular or behavior based AI .- How they work :...

. The term was introduced by Rodney Brooks

Rodney Brooks

Rodney Allen Brooks is the former Panasonic professor of robotics at the Massachusetts Institute of Technology. Since 1986 he has authored a series of highly influential papers which have inaugurated a fundamental shift in artificial intelligence research...

 and colleagues in 1986. Subsumption has been widely influential in autonomous robotics and elsewhere in real-time

Real-time computing

In computer science, real-time computing , or reactive computing, is the study of hardware and software systems that are subject to a "real-time constraint"— e.g. operational deadlines from event to system response. Real-time programs must guarantee response within strict time constraints...

 AI

Artificial intelligence

Artificial intelligence is the intelligence of machines and the branch of computer science that aims to create it. AI textbooks define the field as "the study and design of intelligent agents" where an intelligent agent is a system that perceives its environment and takes actions that maximize its...

.

Description

A subsumption architecture is a way of decomposing complicated intelligent behaviour into many "simple" behaviour modules, which are in turn organized into layers. Each layer implements a particular goal of the agent, and higher layers are increasingly abstract. Each layer's goal subsumes that of the underlying layers, e.g. the decision to move forward by the eat-food layer takes into account the decision of the lowest obstacle-avoidance layer. As opposed to more traditional AI approaches subsumption architecture uses a bottom-up

Top-down and bottom-up design

Top–down and bottom–up are strategies of information processing and knowledge ordering, mostly involving software, but also other humanistic and scientific theories . In practice, they can be seen as a style of thinking and teaching...

 design.

For example, a robot's lowest layer could be "avoid an object", on top of it would be the layer "wander around", which in turn lies under "explore the world". Each of these horizontal layers access all of the sensor data and generate actions for the actuators — the main caveat is that separate tasks can suppress (or overrule) inputs or inhibit outputs. This way, the lowest layers can work like fast-adapting mechanisms (e.g. reflex

Reflex

A reflex action, also known as a reflex, is an involuntary and nearly instantaneous movement in response to a stimulus. A true reflex is a behavior which is mediated via the reflex arc; this does not apply to casual uses of the term 'reflex'.-See also:...

es), while the higher layers work to achieve the overall goal. Feedback is given mainly through the environment.

Attributes of the architecture

The main advantages of the methodology are:

• the modularity
  Modularity
  Modularity is a general systems concept, typically defined as a continuum describing the degree to which a system’s components may be separated and recombined. It refers to both the tightness of coupling between components, and the degree to which the “rules” of the system architecture enable the...
  
  ,
• the emphasis on iterative development & testing of real-time systems in their target domain, and
• the emphasis on connecting limited, task-specific perception directly to the expressed actions that require it.

These innovations allowed the development of the first robots capable of animal-like speeds.

The main disadvantages of this model are:

• the inability to have many layers, since the goals begin interfering with each other,
• the difficulty of designing action selection
  Action selection
  Action selection is a way of characterizing the most basic problem of intelligent systems: what to do next. In artificial intelligence and computational cognitive science, "the action selection problem" is typically associated with intelligent agents and animats—artificial systems that exhibit...
  
   through highly distributed system of inhibition and suppression, and
• the consequent rather low flexibility at runtime.

See also

• Robotic paradigms
  Robotic paradigms
  A robotic paradigm can be described by the relationship between the three primitives of robotics: Sense, Plan, and Act. It can also be described by how sensory data is processed and distributed through the system, and where decisions are made....
  
  
• Agent architecture
  Agent architecture
  Agent architecture in computer science is a blueprint for software agents and intelligent control systems, depicting the arrangement of components...
  
  
• Behavior based AI
• Behavior-based robotics
  Behavior-based robotics
  Behavior-based robotics or behavioral robotics is the branch of robotics that incorporates modular or behavior based AI .- How they work :...
  
  
• Cognitive architecture
  Cognitive architecture
  A cognitive architecture is a blueprint for intelligent agents. It proposes computational processes that act like certain cognitive systems, most often, like a person, or acts intelligent under some definition. Cognitive architectures form a subset of general agent architectures...
  
  
• Mibe architecture
  Mibe architecture
  MIBE architecture is a behavior-based robot architecture developed at of Politecnico di Milano by Fabio La Daga and in 1998...
  
  
• Emergent behavior
• Scruffies
• Situated
  Situated
  In artificial intelligence and cognitive science, the term situated refers to an agent which is embedded in an environment. The term situated is commonly used to refer to robots, but some researchers argue that software agents can also be situated if:...
  
  
• Hierarchical control system
  Hierarchical control system
  A Hierarchical control system is a form of Control System in which a set of devices and governing software is arranged in a hierarchical tree. When the links in the tree are implemented by a computer network, then that hierarchical control system is also a form of Networked control system.-...
  
  

External links

• Subsumption Behaviors used for a Variety of Real World Tasks
• SB-MASE is a subsumption-based multi-agent simulator.
• Subsumption for the SR04 and jBot Robots , DPRG website
• Develop LeJOS programs step by step , Juan Antonio Breña Moral website