... | ... | @@ -70,4 +70,32 @@ While fitting the caliper to the slim wheels, we noticed that the right wheel wa |
|
|
### Calculation of the true track width
|
|
|
Since the true track width is measured from the centre of one wheel to the centre of the other, we could not use the caliper to measure it directly and therefore had to do some calculations.
|
|
|
|
|
|
To calculate the true track width, we had to calculate the average wheel thickness. This was done by measuring the outer and inner track widths, subtracting them and dividing by two. |
|
|
\ No newline at end of file |
|
|
To calculate the true track width, we had to calculate the average wheel thickness. This was done by measuring the outer and inner track widths, subtracting them and dividing by two.
|
|
|
|
|
|
![outer track width](http://gitlab.au.dk/uploads/group-22/lego/8863569861/outer_track_width.jpg)
|
|
|
##### Fig. 7 - Outer track width.
|
|
|
|
|
|
Avg. wheel thickness:
|
|
|
![Skærmbillede 2015-06-01 kl. 09.42.53](http://gitlab.au.dk/uploads/group-22/lego/a94a8f240e/Sk%C3%A6rmbillede_2015-06-01_kl._09.42.53.png)
|
|
|
##### Fig. 8 - Average wheel thickness.
|
|
|
|
|
|
The point of the wheel where the diameter is largest would naturally be at the centre point, at 0,31cm/2 = 0,155 cm
|
|
|
|
|
|
The True Track Width with the slim wheels was therefore calculated as following:
|
|
|
|
|
|
![Skærmbillede 2015-06-01 kl. 09.45.12](http://gitlab.au.dk/uploads/group-22/lego/fe2c58f523/Sk%C3%A6rmbillede_2015-06-01_kl._09.45.12.png)
|
|
|
##### Fig. 9 - True Track Width calculation.
|
|
|
|
|
|
### Testing changes in orientation using extended pointer:
|
|
|
By attaching an extended pointer the change in orientation should be easier to detect. Initial result:
|
|
|
|
|
|
![Skærmbillede 2015-06-01 kl. 09.47.57](http://gitlab.au.dk/uploads/group-22/lego/2f8db38051/Sk%C3%A6rmbillede_2015-06-01_kl._09.47.57.png)
|
|
|
##### Fig. 10 - Screendump of the robot screen with values after extended version.
|
|
|
|
|
|
The extended arm with two pointers made it easier to align the robot to the line on the ground.
|
|
|
|
|
|
### Conclusion to first experiment
|
|
|
Play in the wheels is a non-systematic error, as it is determined by chance and not a consistent recurring inaccuracy. An example of a systematic error, would be if one wheel had a slightly larger diameter than the other, or that one of the electrical motors
|
|
|
|
|
|
## Calibrate the wheel diameter and the track width
|
|
|
To calibrate the robots travel distance according to the wheel diameter we modified the code from PilotSquare.java as follows: |
|
|
\ No newline at end of file |