Lesson10.markdown

@@ -18,18 +18,37 @@ The plan is to follow the plan described in [1].
 
 ## Odometry
 
+For this exercise the standard base vehicle from Lesson 6 is used together with the PilotSquare.java program provided in this lesson. 
+The parameters of the LEGO car in this program is defined as the following.
+
+| Parameter  				| Value		      | 
+| ------------------------- |:---------------:| 
+| Left wheel diameter       | 5.5 cm    	  | 
+| Right wheel diameter	    | 5.5 cm     	  |  
+| Track width		        | 16 cm           |
+
+The program makes the car drive 20 cm straight forward, turn 90 degrees to the left and repeat this 4 times in order to get back to the initial position. 
+A special piece of paper with multiple grids on it is used to measure the accuracy of the system. This is shown in the following image.   
+
 ![Measuring physical accuracy of the DifferentialPilot class](https://gitlab.au.dk/rene2014/lego/raw/master/Lesson10/Images/Odometry.JPG)
 
+Optimally, the LEGO car should end up in the exact same position as prior to the execution of the program. However this is not the case due to both **systematic** and **non-systematic** errors.
+The result of the 3 test runs are summarized in the following table. 
+
 | Attempt  | Measured x    | Measured y  | Calculated x | Calculated y |
 | -------- |:-------------:| -----------:| ------------:| ------------:|
 | 1        | -2.00 mm      | -2.00 mm    | 1.00 mm      | -1.60 mm     |
 | 2		   | -2.00 mm      |  2.00 mm    | 0.40 mm      | -0.60 mm     |
 | 3		   | -4.00 mm      |  3.50 mm    | 2.50 mm      | -1.90 mm     |
 
+"Measured" x and y is the physical error measured by a ruler and "Calculated" x and y is computed error displayed in the LCD on the NXT.
 
+The **Non-systematic** involves variations in the surface and the internal uncertainty of ~2% [2]. These errors are difficult to cope with. However the **systematic** errors involves incorrect definition of the LEGO car parameters and these can be corrected by calibration which is described in the following.
 
 ## Calibration of wheel diameter and the track width
 
+![Calibration of LEGO car paramters](https://gitlab.au.dk/rene2014/lego/raw/master/Lesson10/Images/Calibration.JPG)
+
 #### Initial square run with calibrated values
 
 | Parameter  				| Value		      | 
@@ -86,11 +105,23 @@ The plan is to follow the plan described in [1].
 | Track width		        | 16.27 cm        |  
 
 
-## Position tracking by means of particle filters
+
+Why this behavior?
+
+Quantization error in tacho counter in each step of the trip.
+Orientation of back wheel. 
 
 500 mm kørt distance. Afstand fra mål ~0.5 mm = dist_err 	= 0.001
 Rotation error ~0.5 degrees. 0.5/360 						= 0,00138
 
+## Position tracking by means of particle filters
+
+Hastighed ændret fra 5 til 15
+
+Distance noise factor = 0.005
+
+Angle noise factor = 2.5
+
 
 ## Conclusion
 
@@ -98,6 +129,7 @@ Rotation error ~0.5 degrees. 0.5/360 						= 0,00138
 ## References
 
 [1] http://legolab.cs.au.dk/DigitalControl.dir/NXT/Lesson10.dir/Lesson.html
+[2] http://lejos.sourceforge.net/nxt/nxj/tutorial/WheeledVehicles/WheeledVehicles.htm
 
 
 ### Code