Cybernetics Wiki

public interface SimpleInterface

Defines the basic capabilites all robot classes should provide. A simple robot can detect obstacles, its position, and turn and move. The intention is for this interface to be implemented for several types of physical robots (e.g. Nomad 150s, Hummers, Dennings, etc.).

Frames of reference We use a standard cartesian coordinate system in meters and radians. Pretend you are looking down on the robot: +x goes out to your right (East), +y goes up (North). When the robot is initialized, it is facing the +x direction. Headings are given in radians, with East=0, North=PI/2 and so on CCW around to 2*PI. Some methods return "egocentric" vectors. An egocentric vector is given relative to the center of the robot in the same heading reference frame as global coordinates. An object one meter east of the robot is at (1,0) egocentrically.

Sensors The Simple robot can sense it's location and obstacles.

Timestamps Many of the sensor and motor command methods (e.g. get* and set*) require a timestamp as a parameter. This is to help reduce the amount of I/O to the physical robot. If the timestamp is less than or equal to the value sent on the last call to one of these methods, old data is returned. If the timestamp is -1 or greater than the last timestamp, the robot is queried, and new data is returned. The idea is that during each control cycle the higher level software will increment the timestamp and use it for all calls to these methods.