Quote:
Originally Posted by dmitch
"For example, the gyroscope is very good at finding rate of angular change, but poor at finding absolute angle. The accelerometer can determine absolute angle when the robot is stable, but is easily confused when the robot moves." I understood this to mean that "absolute angle" is the actual angle that one piece is at relative to another, not the rate at which an object is turning. For example, I thought that "absolute angle" would mean the angle of the robot heading in relation to the field. |
In this case, "absolute angle" means the
tilt of the robot in relation to the floor. It can tell you when you've fallen over, or how steep a sloping ramp is. It can't tell you which compass direction you are facing.
To keep track of the direction of the robot, use a yaw rate sensor (i.e. "gyro"). It'll tell you how quickly you're turning, and the software can integrate that information to tell you what direction you've turned to. The accuracy will get worse over time as the integration bias "drifts", and you will lose accuracy if you ever turn faster than the sensor is capable of tracking. For the first fifteen seconds of a match, that should not be a great problem.
To measure the angle of a robot component, use an absolute sensor such as a potentiometer (easy, inexpensive, but prone to becoming electrically "noisy" as it wears out) or a magnetic angular sensor (easy, more expensive, durable, but possible to damage with static electricity if mishandled).