3. A rule-based visual language for LEGO robots

Altaira is specifically intended for use in mobile robots such as have been described above. Its execution cycle is based on the interaction of two data structures: a two-dimensional array of states called the map, and an ordered set of rules called the ruleset.

On each execution cycle, the following steps are performed:

• The robot's sensors are sampled.
• Based on the sensors, the state of the current map tile, and the robot's state, one or more rules are enabled for firing.
• The set of enabled rules are combined to produce new values for the robot's actuators, the current tile state, and the robot's state. The current tile may be changed as a result, as well.

Altaira's environment, rules, execution engine, and ruleset development tools will be described in more detail in the remainder of this section.