Composable robot controllers

Software for controlling robots is often difficult to develop and maintain. Specialized robot programming languages make this task more manageable. These languages may be either created from scratch or incorporated within an existing language. In this paper, we demonstrate the latter technique: an embedded domain-specific language called Frob (for functional robotics) built within Haskell, a purely functional programming language. We use basic techniques of programming, transformation and composition, to create high-level controllers that are concise, understandable, and easily modifiable. Frob is constructed using functional reactive programming, a system that describes interactive computations using functions. In this paper, we demonstrate the use of Frob in the context of the Robocup robotic soccer competition. We develop a set of control systems for Robocup and show how these systems can be composed into complex soccer strategies.