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--- marvin:lab4 [2008/10/03 10:39] – rieper
+++ marvin:lab4 [2008/10/03 11:39] (current) – rieper
@@ Line 41: / Line 41: @@
 {{:marvin:lab4-kd.png}}
 {{:marvin:lab4-ki.png}}
+\\
+The above pictures are from http://en.wikipedia.org/wiki/PID_controller \\
 By inspection we summarize the following. An increase in the proportional gain will create a larger overshoot, but reduce the steady state error and rise time. An increase in the integral controller also increase the overshoot, while eliminating the steady state error. (This is actually depending in how many poles we have in the system). If we increase the differential controller, we decrease the overshoot with no affect on the steady state error, but the bandwith of the system will be reduced.
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 </code>
+====Conclusion====
+The main problem in balancing the robot seemed to be the fluctuations of the light sensor. We used three approaches to limit the fluctuations by changing the environment, the robotdesign and the software. The environment was changed by using clean white paper, which made the readings more reliable. Next, a tube was mounted around the sensor to make the sensor less susceptible to surrounding light fluctuations. Lastly we decided that an error of +/-3 would not would be overwrited to zero error. Some finetuning on these approaches may still be lacking.
+Another problem was the oscillations, which caused the robot wheels to turn too far in proportion to the error signal. We tried reducing this by increasing the proportional gain and reducing the overall gain. All in all the result is far better than the default program and the robot can actually balance for some time.
+====Future Improvements====
+In order to further reduce the oscillations we may read the tachometers on the motor. In this way we might be able to add these readings to the control loop and improve the control of the oscillaitons. There was one bug in the program we could not fix. Every ten seconds or so, the program got stuck for a second, which of course tripped the robot. We were unable to resolve this problem.
 [[http://www.youtube.com/v/5_XGJUgSKIQ|{{:marvin:Lab4_movie_1.jpg}}]]
-Movie with a boom mounted in the Marvin
+Movie with a boom mounted on Marvin
 [[http://www.youtube.com/v/kXf08CPnus8|{{:marvin:Lab4_movie_2.jpg}}]]
-Movie of Marvin
+Movie of Marvin in the final version