Qu-Bot, A Quickly Programmable Robot User’s Manual
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8.4. Distance measurement
This sample code shows how to move robot for specific distance using encoder
sensors mounted near wheels. This code is made to move robot forward for
approximately 1 meter.
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The diameter of the Qu-Bot wheel measures 66.3 mm. So the periphery of the
wheel becomes 208.182 mm (πD = 66.3 x 3.14 ).
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The wheel has 8 holes in it so it gives 16 counts (8 on + 8 off) when it rotates 1
revolution. In one revolution it moves forward to 208.182 mm distance (periphery
of wheel). So at each count we get distance of 208.182 / 16 = 13 mm. This is also
the accuracy which we get when the robot moves on motor count.
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If we want robot to move forward to 1 meter robot has to go forward until it gets
77(1000/13) motor counts on motor counter.
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So this is how it works. When switch1 is pressed robot starts moving forward. The
right motor counter is already initialized at code start.
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The while condition checks until the motor count reaches 76. We need 77 counts
but there is some inertia when the motors are stopped, so the robot moves a little
forward when motors stop, and we get approximately 1 meter move.
