Aasimon.org Wiki

User Tools

Site Tools

Trace:
marvin:ecp1

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revisionPrevious revision
Next revision		Previous revision
marvin:ecp1 [2009/01/29 08:37] – devamarvin:ecp1 [2009/01/29 11:03] (current) – rieper
Line 10: Line 10:
  
 =====Goal===== =====Goal=====
-Make robot able to communicate with gyroscope.+Make Marvin able to communicate with gyroscope.
  
 =====Plan===== =====Plan=====
Line 17: Line 17:
   * Find or create a class for the gyroscope communication.   * Find or create a class for the gyroscope communication.
  
-=====Analysis=====+=====Theory=====
  
  
-====Analogue to digital conversion and limitations====+====Analogue to Digital Conversion and Limitations====
 The main problem when dealing with sensors is that the real world is continuous and when we want to interpret these data it has to be digitized (discretized) in some way. This is done with an analogue to digital converter (A/D-converter or simply ADC). The opposite applies when we have a digital value, such as an integer and this is converted to an analogue value (D/A-converter or DAC).  This in itself is a huge area, and the conversion itself will not be covered further. The important thing to remember is that in order to get an appropriate estimate of the real world the samples that you take from your sensor has to be taken often enough so that you will not loose vital data. How often one should sample depends on the application, but as a rule of thumb one should sample minimum twice as fast as the highest rate of different that will occur.  As an example, if you want to reproduce a sinus with the frequency of 100 Hz, you will have to sample with 200 Hz. A higher sample rate will produce a more accurate output, but will also need more computational power.  The main problem when dealing with sensors is that the real world is continuous and when we want to interpret these data it has to be digitized (discretized) in some way. This is done with an analogue to digital converter (A/D-converter or simply ADC). The opposite applies when we have a digital value, such as an integer and this is converted to an analogue value (D/A-converter or DAC).  This in itself is a huge area, and the conversion itself will not be covered further. The important thing to remember is that in order to get an appropriate estimate of the real world the samples that you take from your sensor has to be taken often enough so that you will not loose vital data. How often one should sample depends on the application, but as a rule of thumb one should sample minimum twice as fast as the highest rate of different that will occur.  As an example, if you want to reproduce a sinus with the frequency of 100 Hz, you will have to sample with 200 Hz. A higher sample rate will produce a more accurate output, but will also need more computational power. 
 The gyroscope utilizes the ADC so that it is possible to get readings from the gyroscope. The gyroscope utilizes the ADC so that it is possible to get readings from the gyroscope.
Line 42: Line 42:
 The correct placement of the gyroscope can be seen in the [[#Building the robot|building instructions]] The correct placement of the gyroscope can be seen in the [[#Building the robot|building instructions]]
  
-=====Building the robot===== +====Building the Robot==== 
-====Preliminary considerations====+===Preliminary considerations===
 Our primary goal is to make a balancing robot, and therefore it would be nice to eliminate the possibility of failure due to a bad build. This is the reason why we chose to re-use the instructions provided as seen in the building manual(([[http://www.mathworks.com/matlabcentral/fileexchange/19147|Math Works]])). We know that this design is working. Another reason for choosing this design is that there exists extensive simulation material on this specific robot, which might make it easier to fine-tune the parameters later on. Our primary goal is to make a balancing robot, and therefore it would be nice to eliminate the possibility of failure due to a bad build. This is the reason why we chose to re-use the instructions provided as seen in the building manual(([[http://www.mathworks.com/matlabcentral/fileexchange/19147|Math Works]])). We know that this design is working. Another reason for choosing this design is that there exists extensive simulation material on this specific robot, which might make it easier to fine-tune the parameters later on.
  
-====The Build====+===The Build===
 The build is pretty straight forward, as the building instructions is well written and also accompanied by photos. One thing to note though, is that the robot is fairly symmetric, so building instructions is only provided for one side of the robot and it is up to the builder to mirror the other side. This is however no problem because of the good photos.\\ The build is pretty straight forward, as the building instructions is well written and also accompanied by photos. One thing to note though, is that the robot is fairly symmetric, so building instructions is only provided for one side of the robot and it is up to the builder to mirror the other side. This is however no problem because of the good photos.\\
 The finished robot can be seen in the picture below. The finished robot can be seen in the picture below.
Line 154: Line 154:
 </code> </code>
 The full source code for this class can be found in the file ''GyroscopeSensor.java'' in the Marvin code tarball (([[http://wiki.aasimon.org/lib/exe/fetch.php?media=marvin:marvin-1.0.tar.gz|marvin-1.0.tar.gz]])) The full source code for this class can be found in the file ''GyroscopeSensor.java'' in the Marvin code tarball (([[http://wiki.aasimon.org/lib/exe/fetch.php?media=marvin:marvin-1.0.tar.gz|marvin-1.0.tar.gz]]))
 +
marvin/ecp1.1233214640.txt.gz · Last modified: 2009/01/29 08:37 by deva