Arm: Find encoder zero, minumum, and maximum values for each joint

[jetkov]

The absolute encoders on the arm need to be configured physically so that they emit a 50% duty cycle signal when the joint is positioned about in the middle of its rotational range.

Once this is done, the duty cycle needs to be recorded when each joint is at each end of its range as well as when it is at its specific zero location indicated below:

• Shoulder: 0 deg at horizontal, positive 90 deg at vertical
• Elbow and wrist pitch: 0 deg when fully extended, negative when rotating downwards (towards shoulder) and positive when rotating upwards (away from shoulder)
• Turntable: 0 deg when facing forwards, positive with counter clockwise rotation
• Claw: in cm, the distance between the fingers
• Wrist roll: 0 deg when claw motor facing down, positive with counter clockwise rotation
• Wrist pitch: Same as elbow