Unified Behavior Framework for Reactive Robot Control

Abstract

Behavior-based systems form the basis of autonomous control for many robots. In this article, we demonstrate that a single software framework can be used to represent many existing behavior based approaches. The unified behavior framework presented, incorporates the critical ideas and concepts of the existing reactive controllers. Additionally, the modular design of the behavior framework: 1) simplifies development and testing; 2) promotes the reuse of code; 3) supports designs that scale easily into large hierarchies while restricting code complexity; and 4) allows the behavior based system developer the freedom to use the behavior system they feel will function the best. When a hybrid or three layer control architecture includes the unified behavior framework, a common interface is shared by all behaviors, leaving the higher order planning and sequencing elements free to interchange behaviors during execution to achieve high level goals and plans. The framework's ability to compose structures from independent elements encourages experimentation and reuse while isolating the scope of troubleshooting to the behavior composition. The ability to use elemental components to build and evaluate behavior structures is demonstrated using the Robocode simulation environment. Additionally, the ability of a reactive controller to change its active behavior during execution is shown in a goal seeking robot implementation. Categories KeywordsBehavior-based robotics, reactive control architecture, software design patterns, software frameworks.

Genetic evolution of hierarchical behavior structures

“…At is core the UBF uses an abstract behavior interface to define a family of behavioral algorithms that can be used interchangeably regardless of the underlying behavior architecture. Using the UBF, the developer (and in this case, the evolutionary algorithm) is not restricted to using any single behavior architecture [23].…”

“…The composite pattern allows new control structures to be formed as arbitrated hierarchies of existing behaviors, with the resulting structure acting as a single behavior unit [23].…”

“…This isolates code complexity to the atomic (or leaf) behaviors. The freedom to join existing behaviors as compositions encourages experimentation with various structural arrangements of elemental behaviors, arbitration components and existing behavior structures [23].…”

“…This work demonstrates the ability of evolution to develop and tune individual architectures to a given domain. This paper uses the common interface of the unified behavior framework [23] to expand the scope of the evolutionary search, allowing the fitness of several behavior-based architectures to be evaluated concurrently for a particular domain.…”

“…By using the unified behavior framework (UBF) [23] to provide behavioral logic to robots operating in the Robocode domain, various behavior structures are possible based on a pool of simple elemental behaviors and interchangeable arbiter components. While many formations are poor choices, some unexpected combinations may be quite good.…”