View Full Version : Crab Drive
nukelear1991
19-12-2007, 18:23
Well over here in Wyoming,Michigan things are beginning to get cold and thus... I AM CRZY ABOUT BUILD SEASON....my question is about programming the crab drive...particularly I want to do what I like to call "Doom Style" controls (Left Stick: Forward and Back and Strafe Right Stick: Turn) but am at a loss for how to program it. Please help
tank you,
Geeky Demon - Nukelear1991
we had a swerve drive last year and for are prototype it had "doom mode"this was very hard to control. We later went to a one joy stick drive. (wherever you point the joy the robot will go in the direction) However the 2 joystick drive would be far easier to program the one joystick drive is nicer for the drivers. I have yet to learn all the tricks for the swerve program. I know right know though are code did include a huge arc tan table that was a pain to get. :ahh:
Dave Flowerday
20-12-2007, 16:22
We have a lot of experience with crab drive and we've always set it up the same way: We use 2 joysticks. The right stick is used for normal tank-style controls, while the left stick can be moved left and right of center to cause the crab wheels to turn in that direction. We've found this quite effective.
Probably the most important piece of advice I can give for any teams considering using crab for the first time is this: you need practice. I don't care how good your drivers are at playing video games that are similar, it's different on the robot. You won't be able to take advantage of the capabilities of crab unless you practice, simple as that. So, get a prototype base up and running early in the build season for your drivers to practice with!
need[/b] practice. I don't care how good your drivers are at playing video games that are similar, it's different on the robot. You won't be able to take advantage of the capabilities of crab unless you practice, simple as that. So, get a prototype base up and running early in the build season for your drivers to practice with!
I could NOT AGREE MORE!! We went into St. Louis with no practice assuming it would not be very hard to learn in minimal time. Are driver went out there with no practice and it was terrible! GET PRACTICE!
Practice is key, but I would agree, two joysticks is probably easier in the long run!
Practice is key, but I would agree, two joysticks is probably easier in the long run!
From a programing look at it i would agree two joysticks is easier to program
[QUOTE=Dave Flowerday;662035]Probably the most important piece of advice I can give for any teams considering using crab for the first time is this: you need practice.[QUOTE]
I couldn't agree more. True, this is espeically necessary for crab drivetrains, but it is in some degree true for ALL holonomic drive trains.
Believe me, I know Master Chief wishes he was holonomic but he isn't, so video gamers won't have much of an advantage over anyone else learning how to drive a holonomic vehicle, especially since you can't feel the G forces or even keep your frame of reference locked to the vehicle's like you can in a car.
It takes some getting used to, even for the Legendary players among us.
-q (who played too much Halo this weekend) :rolleyes:
I know Master Chief wishes he was holonomic but he isn't,
Technically speaking..... He does have three axis of movement (Foreward-backwards, straft Left-right, turning) therefore really he is....
Although I would agree it would be completely different with the robot (especially if it isn't field centric driving)
Could you imagine try to running around as master chief with the camera turning around him all the time, and foreward, isn't the way the camera faces but whatever direction he is facing :p it would take a bit of getting use to it lol
nukelear1991
20-12-2007, 21:01
well we are hoping to have the drive built by end of second build week....which will give us time to practice.... I am going to go with the two joys and I think the controls will still be Doom Style
Aren_Hill
21-12-2007, 00:26
I could NOT AGREE MORE!! We went into St. Louis with no practice assuming it would not be very hard to learn in minimal time. Are driver went out there with no practice and it was terrible! GET PRACTICE!
Pshh i think i did pretty good for no practice. What would have really helped was a robot that wasn't completely symmetrical so i could tell which way was forward:D
colour codes help tell which way is foreword ( make the front and back a different colour than the rest of the bot.)
Thats what we did but we colored one side with a jumbo sharpie and the other side was Al. It still was very hard though since you cant always see the bot with the rack in the way!
lol true enough, best bet is a rectangular bot lol (but you guys didn't do that so.... lol)
lol true enough, best bet is a rectangular bot lol (but you guys didn't do that so.... lol)
well when we put are arm on there it was mounted on the back run up and down with a lead screw thru a 64:1 bane bots and that made it easy because the arm was always aimed at the from so we knew what way we were going however are other arm was in the middle on a turn table so that didnt work for that one...
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