Mibe architecture
Encyclopedia
MIBE architecture is a behavior-based
robot architecture developed at Artificial Intelligence and Robotics Lab of Politecnico di Milano by Fabio La Daga and Andrea Bonarini in 1998. MIBE architecture is based on the idea of animat
and derived from subsumption architecture
, formerly developed by Rodney Brooks
and colleagues at MIT
in 1986.
and autonomy should arise from superimposition of synergetic activities in response to multiple drives
. An autonomous agent is developed to achieve several goals (primary goals), but secondary goals also originate as a consequence of environmental or functional constraints. In MIBE architecture both primary and secondary goals are handled in the same way and defined as needs. A specific drive originates from each need.
MIBE architecture generates and weights all these drives in an explicit motivational state. The higher the urgency to satisfy a specific need, the higher its weight in the motivational state and the higher the drive to perform a behavior that satisfies the given need.
While subsumption architecture is built on a predetermined hierarchy of behavioral modules, MIBE architecture consists of a more complex structure, where several behaviors (that always compete for taking control of the robot via the motivational state) can activate and control dynamically an adaptive set of underlying modules, called abilities. Each behavior performs its task by activating and tuning the abilities it needs.
Abilities supply the functional modules for performing specific activities and may activate each other in a hierarchical structure in the same way behaviors use abilities.
Both behaviors and abilities are implemented by the same kind of functional modules, but a fundamental difference exists: behaviors are self-activating modules in response to a robot+environment state, whilst abilities are just functional blocks activated and controlled by behaviors for accomplishing their tasks (or by higher-level abilities that have been already activated by a behavior).
Behaviors exist for satisfying specific needs, whilst abilities are not related to any need, cause they are used by behaviors for accomplishing their tasks, but have no meaning alone.
The list of abilities needed by each module (behavior or ability) is represented by its activation tree; the complete set of activation trees can be represented by a system-wide acyclic activation graph.
Behaviors are activated on the basis of their specific drive pressure in the motivational state at run time: the most motivated behavior (i.e., the most urgent or convenient) is always activated. Nevertheless, less motivated behaviors could even be activated at the same time, with the constraint they cannot use any of the abilities already collected by a more motivated behavior which is already acting. The BCR subsystem (Behavior Conflict Resolver) ensures no conflicting behaviors (i.e., sharing one or more abilities in their activation trees) can be active at the same time.
The main advantage of MIBE architecture consists in its high modularity: new abilities and behaviors can be added easily without changing the existing modular structure. Similarly, a behavior can be modified or removed with no functional effects on other modules.
Even drives can be added to/removed from the motivational structure or modified with no need to change the previous system structure, except rebalancing the drive-generation functions.
The main issue of MIBE architecture consists in defining the boundaries of the state-space by shaping the motivational structure (i.e.: tuning the drive-generation functions and/or their learning algorithms) so that the autonomous agent performs the right behavior for each robot+environment state.
Behavior-based robotics
Behavior-based robotics or behavioral robotics is the branch of robotics that incorporates modular or behavior based AI .- How they work :...
robot architecture developed at Artificial Intelligence and Robotics Lab of Politecnico di Milano by Fabio La Daga and Andrea Bonarini in 1998. MIBE architecture is based on the idea of animat
Animat
Animats are artificial animals, a contraction of anima-materials. The term includes physical robots and virtual simulations. Animat research, a subset of Artificial Life studies, has become rather popular since Rodney Brooks' seminal paper "Intelligence without representation". The word was coined...
and derived from subsumption architecture
Subsumption architecture
Subsumption architecture is a reactive robot architecture heavily associated with behavior-based robotics. The term was introduced by Rodney Brooks and colleagues in 1986...
, formerly developed 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 at MIT
Massachusetts Institute of Technology
The Massachusetts Institute of Technology is a private research university located in Cambridge, Massachusetts. MIT has five schools and one college, containing a total of 32 academic departments, with a strong emphasis on scientific and technological education and research.Founded in 1861 in...
in 1986.
Description
MIBE architecture is based on the belief that autonomy is grounded on motivationMotivation
Motivation is the driving force by which humans achieve their goals. Motivation is said to be intrinsic or extrinsic. The term is generally used for humans but it can also be used to describe the causes for animal behavior as well. This article refers to human motivation...
and autonomy should arise from superimposition of synergetic activities in response to multiple drives
Drive theory
The terms drive theory and drive reduction theory refer to a diverse set of motivational theories in psychology. Drive theory is based on the principle that organisms are born with certain physiological needs and that a negative state of tension is created when these needs are not satisfied...
. An autonomous agent is developed to achieve several goals (primary goals), but secondary goals also originate as a consequence of environmental or functional constraints. In MIBE architecture both primary and secondary goals are handled in the same way and defined as needs. A specific drive originates from each need.
MIBE architecture generates and weights all these drives in an explicit motivational state. The higher the urgency to satisfy a specific need, the higher its weight in the motivational state and the higher the drive to perform a behavior that satisfies the given need.
Differences between MIBE and subsumption architecture
MIBE architecture mainly departs from subsumption architecture due to the introduction of a top level motivational structure which determines behavior priorities at run time. That is, there are not layers and static hierarchical dependencies between behavioral modules, but each behavior constantly competes with others for taking control of the agent through the top level motivational state from which specific drives originate (via predetermined or reinforcement-learned functions).While subsumption architecture is built on a predetermined hierarchy of behavioral modules, MIBE architecture consists of a more complex structure, where several behaviors (that always compete for taking control of the robot via the motivational state) can activate and control dynamically an adaptive set of underlying modules, called abilities. Each behavior performs its task by activating and tuning the abilities it needs.
Abilities supply the functional modules for performing specific activities and may activate each other in a hierarchical structure in the same way behaviors use abilities.
Both behaviors and abilities are implemented by the same kind of functional modules, but a fundamental difference exists: behaviors are self-activating modules in response to a robot+environment state, whilst abilities are just functional blocks activated and controlled by behaviors for accomplishing their tasks (or by higher-level abilities that have been already activated by a behavior).
Behaviors exist for satisfying specific needs, whilst abilities are not related to any need, cause they are used by behaviors for accomplishing their tasks, but have no meaning alone.
The list of abilities needed by each module (behavior or ability) is represented by its activation tree; the complete set of activation trees can be represented by a system-wide acyclic activation graph.
Behaviors are activated on the basis of their specific drive pressure in the motivational state at run time: the most motivated behavior (i.e., the most urgent or convenient) is always activated. Nevertheless, less motivated behaviors could even be activated at the same time, with the constraint they cannot use any of the abilities already collected by a more motivated behavior which is already acting. The BCR subsystem (Behavior Conflict Resolver) ensures no conflicting behaviors (i.e., sharing one or more abilities in their activation trees) can be active at the same time.
The main advantage of MIBE architecture consists in its high modularity: new abilities and behaviors can be added easily without changing the existing modular structure. Similarly, a behavior can be modified or removed with no functional effects on other modules.
Even drives can be added to/removed from the motivational structure or modified with no need to change the previous system structure, except rebalancing the drive-generation functions.
The main issue of MIBE architecture consists in defining the boundaries of the state-space by shaping the motivational structure (i.e.: tuning the drive-generation functions and/or their learning algorithms) so that the autonomous agent performs the right behavior for each robot+environment state.
See also
- Subsumption architectureSubsumption architectureSubsumption architecture is a reactive robot architecture heavily associated with behavior-based robotics. The term was introduced by Rodney Brooks and colleagues in 1986...
- Robotic paradigmsRobotic paradigmsA 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 architectureAgent architectureAgent architecture in computer science is a blueprint for software agents and intelligent control systems, depicting the arrangement of components...
- Behavior based AI
- Behavior-based roboticsBehavior-based roboticsBehavior-based robotics or behavioral robotics is the branch of robotics that incorporates modular or behavior based AI .- How they work :...
- Cognitive architectureCognitive architectureA 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...
- Emergent behavior
- Scruffies
- SituatedSituatedIn 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 systemHierarchical control systemA 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.-...