potential future white paper: swerve drive implementation

[Gdeaver]

Team 1640 did swerve for the first time this year. As part of our off season design project several papers were developed. Mostly the math. You may want to look at them.
This is the first paper after the summer work.
http://wiki.team1640.com/images/8/85...heel_Drive.pdf
This is a paper commenting on the summer project.
http://wiki.team1640.com/images/6/60...rive_Robot.pdf
This is the final paper commenting on crab with orientation control. Mode1 in the paper was implemented on the 2010 robot. Mode 2 is tough because it requires tracking states and would require some feed forward algorithms.
http://wiki.team1640.com/images/3/3a...Twist_edit.pdf
Browse our website for the mechanical implementation.
Comments and comparisons to your work are welcome.

[davidthefat]

Isnt it just simple as getting the angle of the joystick relative to the center of the joypad., which is using tangents. Then get the distance of the joypad from the center, which would be the speed.... Doesnt sound all that complicated as people make it out to be...

[PAR_WIG1350]

Originally Posted by davidthefat

Isnt it just simple as getting the angle of the joystick relative to the center of the joypad., which is using tangents. Then get the distance of the joypad from the center, which would be the speed.... Doesnt sound all that complicated as people make it out to be...

That would be CRAB drive, the simpler, less maneuverable cousin of swerve drive.

[JamesBrown]

Originally Posted by davidthefat

Isnt it just simple as getting the angle of the joystick relative to the center of the joypad., which is using tangents. Then get the distance of the joypad from the center, which would be the speed.... Doesnt sound all that complicated as people make it out to be...

http://www.firstwiki.net/index.php/D...n#Swerve_Drive

Briefly explains that Crab drive is a type of swerve drive where all wheels are turned to the same angle (either through hardware connections, or due to a simplified algorithm like the one you describe).

[PAR_WIG1350]

What math level should I write for? I was thinking Algebra II but I also thought it would be beneficial to open up access to teams without that level of experience. How much in depth should I go? Should I walk through the derivation of the method step by step, or should I just present the general formulas and algorithms and point out the various constants and variables and what they are in real life (as opposed to on paper or in code)?

-Alan

[JamesBrown]

I think that an Algebra 2 level should be fine (assuming you actually meant Algebra 2) I would imagine that all teams would have members who have taken math up to Algebra 2, all mentors should also have this level of understanding.

I personally thing that the Derivations would be useful as a learning tool for students, that being said I would not include any derivations that a HS student with knowledge of Algebra 2 and Geometry couldn't do (i.e. no Calc, and nothing other than sin/cos/tan as far as Trig)

[PAR_WIG1350]

Originally Posted by JamesBrown

I think that an Algebra 2 level should be fine (assuming you actually meant Algebra 2) I would imagine that all teams would have members who have taken math up to Algebra 2, all mentors should also have this level of understanding.

I personally thing that the Derivations would be useful as a learning tool for students, that being said I would not include any derivations that a HS student with knowledge of Algebra 2 and Geometry couldn't do (i.e. no Calc, and nothing other than sin/cos/tan as far as Trig)

OK, thanks for the feedback, sounds good to me.

[PAR_WIG1350]

Originally Posted by Gdeaver

Team 1640 did swerve for the first time this year. As part of our off season design project several papers were developed. Mostly the math. You may want to look at them.
This is the first paper after the summer work.
http://wiki.team1640.com/images/8/85...heel_Drive.pdf
This is a paper commenting on the summer project.
http://wiki.team1640.com/images/6/60...rive_Robot.pdf
This is the final paper commenting on crab with orientation control. Mode1 in the paper was implemented on the 2010 robot. Mode 2 is tough because it requires tracking states and would require some feed forward algorithms.
http://wiki.team1640.com/images/3/3a...Twist_edit.pdf
Browse our website for the mechanical implementation.
Comments and comparisons to your work are welcome.

The graphs in the second paper resemble graphs generated with by algorithms, which is comforting, but they are not the same algorithm. The technique you use focuses on achieving goals that with my technique are simply after thoughts that a good driver could still probably approximately mimic. My algorithms focus more on a maneuver that is not present in your calculations, but you do include a replacement for this maneuver.

I also was considering some form of drifting 'snake' maneuver, similar to our '09 bot, but I decided Against it for the experiment I'm running <although the Algorithm that the paper will describe can be used to figure out how to do this, and the calculations have been run, I just don't think that I will use them.>

One advantage I see with your algorithm is simpler math, that is, not necessarily lower level, just less of it.