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Sensors and Actuators
SealedSphere robots can sense their position,
the locations of teammates, opponents, obstacles and attractors.
The robots can turn and drive.
Frames of reference
We use a standard cartesian coordinate system in
meters and radians. Pretend you are looking down
on a robot: +x goes out to your right (East), +y goes up (North).
The center of the world is (0,0).
When the robot is initialized, it is facing east.
Headings are given in radians, with East=0, North=PI/2 and so on
counter-clockwise 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.
Implementations
This class is extended by a simulation class (SealedSphereSim)
The subclass handles details of interaction with the simulated
world. Potentially, in the future, another implementation will
extend this class for actual physical spherical robots.
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 redundant
computations for the same movement step. When real robots are used,
this becomes especially important because I/O to sensors is expensive
in time.
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 greater than the last timestamp (or -1), the robot (simulated or real) 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.
Copyright (c)1997, 1998 Tucker Balch
public static final double MAX_TRANSLATION
public static final double MAX_STEER
public static final double RADIUS
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