NEX ROBOTICS FIREBIRD V ATMEGA 2560 Hardware Manual page 38

Calculation of position encoder resolution:
Case 1: Robot is moving forward or backward (encoder resolution is in mm)
Wheel diameter: 5.1cm
Wheel circumference: 5.1cm * 3.14 = 16.014cm = 160.14mm
Number slots on the encoder disc: 30
Position encoder resolution: 163.2 mm / 30 = 5.44mm / pulse.
Case 2: Robot is turning with one wheel rotating clockwise while other wheel is rotating
anti clockwise. Center of rotation is in the center of line passing through wheel axel and
both wheels are rotating in opposite direction (encoder resolution is in degrees)
Distance between Wheels = 15cm
Radius of Circle formed in 360
Distance Covered by Robot in 360
Number of wheel rotations of in 360
Total pulses in 360 0 Rotation of Robot
= Number of slots on the encoder disc / Number of wheel rotations of in 360
= 30 x 2.941
= 88.23 (approximately 88)
Position Encoder Resolution in Degrees = 360 / 88
© NEX Robotics Pvt. Ltd. and ERTS Lab, CSE, IIT Bombay, INDIA
0
rotation of Robot = Distance between Wheels / 2
= 7.5 cm
0 Rotation = Circumference of Circle traced
= 2 x 7.5 x 3.14
= 47.1 cm or 471mm
0 rotation of robot
= Circumference of Traced Circle / Circumference of Wheel
= 471 / 160.14
= 2.941
= 4.090 degrees per count
Fire Bird V ATMEGA2560 Hardware Manual
0 rotation of robot
38