Differences

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--- marvin:lab9 [2008/11/14 11:50] – rieper
+++ marvin:lab9 [2008/11/21 06:46] – rieper
@@ Line 33: / Line 33: @@
 ====Test Drive====
+If both calibrations were precise the robot should be able to navigate precisely around in a cartesian coordinate system. The testrun is shown on the figure below together with a video of the performance. There seems to be a weakness in the rotations, but the distance is very accurate. One way to improve the precision during rotations could be to add a compass.
 {{marvin:lab9-3.gif?300}}
 [[http://www.youtube.com/v/kQWv8H6lPtM|{{marvin:lab9-1.jpg}}]]
+====Adding the Compas====
+We do not know much about the compass as to how it measures and whether the readings from 0 to 360 degrees are truly linear. But we assume the compass has a higher precision than the tachometer readings and we also assume the output readings from the compass to be a linear function of the sensor input.
+There were magnetic disturbances at the test area, which of course made the compass inaccurate.
+The precision of the compass was tested by placing a marker on the robot. In this way we can simply measure the deviation by letting the robot turn on a whiteboard and measuring the angle. A little noise was added to these measurements as the slippery surface of the whiteboard caused the wheels to spin a little. The acceleration was too high for this surface and one could have reduced the motor power.
+{{marvin:lab9-4.jpg?300}}
+The final code: {{:marvin:navigatingcar.tar.gz}}