Skunkworks Drive Train??

[T3_1565]

Originally Posted by Alex Cormier

Omni wheels for President!!

w00000!!!

[JesseK]

2 Tips from my point of view of seeing alot of holonomic drives and researching to the extent of creating my own:

1.) Make it driver-centric holonomic. Figure out your driver's controls as well. I'd recommend having a circular nob for rotation as the Z axis and a joystick for all lateral movement. Then, when the joystick moves right, no matter what direction the robot is facing, it laterally moves right from the driver's point of view. If you push the joystick away, no matter what the robot moves down the field away from you. You'll need a gyro for this. Making a true-holonomic drive train is both hard & fun to learn, but it also can provide the agility you seek over a tank drive.

2.) Your manipulator/shooting mechanism/whatever else had better work. If your arm breaks in 2007 or doesn't work well you can't exactly go play effective defense. If your gathering or shooting mechanism in 2006 broke or didn't work you were in the same boat. Climbing ramps with omni drives this year was fairly easy *if* the ramp-bot had rails to guide you up -- otherwise you'd gun it too much and fall right off the side.

[Billfred]

Originally Posted by JesseK

2 Tips from my point of view of seeing alot of holonomic drives and researching to the extent of creating my own:

1.) Make it driver-centric holonomic. Figure out your driver's controls as well. I'd recommend having a circular nob for rotation as the Z axis and a joystick for all lateral movement. Then, when the joystick moves right, no matter what direction the robot is facing, it laterally moves right from the driver's point of view. If you push the joystick away, no matter what the robot moves down the field away from you. You'll need a gyro for this. Making a true-holonomic drive train is both hard & fun to learn, but it also can provide the agility you seek over a tank drive.

2.) Your manipulator/shooting mechanism/whatever else had better work. If your arm breaks in 2007 or doesn't work well you can't exactly go play effective defense. If your gathering or shooting mechanism in 2006 broke or didn't work you were in the same boat. Climbing ramps with omni drives this year was fairly easy *if* the ramp-bot had rails to guide you up -- otherwise you'd gun it too much and fall right off the side.

Fully agreed on the second part (boy, am I glad that Mike Walker talked me out of pressing for kiwi this year), though I still can't wrap my head around going driver-centric. Is it possible to do while allowing for different starting orientations? How does it work off the field?

[JesseK]

It works based upon the initial orientation of the gyro. If you orient the gyro 90 degrees offset from where the driver is facing, every movement you make will be 90 degrees off unless you somehow compensate.

It's the true-vs-relative crap I do all day while coding for submarines -- it's second nature to me now, and the hard part is encoding it in a language that has no built-in geometric calculator.

Without giving too much away too early, see if you can figure out how to control it. I'll give you some hints for the smoothest, most scalable (but not THE fastest) control: use unit vectors from the gyro.

[nsr]

nice

[Schnabel]

I think that it is really cool how you are using our drawings! I know we put the fact that we have them avalaible to the public in our chairman's entry every year, but this is actually the first time I have heard of it being used.

Originally Posted by Billfred

2) Why roll your own omnis over getting a set from AndyMark or elsewhere? (There are valid reasons for it, perhaps even answered by the first question, but it's nice to know.)

A lot of Andy Mark designs are based on a design that the TechnoKats have used and has been proven to work. This is one great example as the AM omni wheels for the most part are the same design. I think it is cool again that teams are taking the "old fashioned" approach to building their robot. Even though I love Andy and Mark, I praise teams that don't go out and buy the product that anyone can use. In stead they make their own modifications and they come up with something that hasn't been made ever before. Even if it uses a drawing that has been put into production, they can never make it the same as the mass produced product.
This is the whole way that many AM products are made, as I have said before. A great example of this is our robot from last year. We wanted to incorporate the two speed transmission into our robot's frame, so we designed our own shifter using the guts of a gen2 AM. We added a couple of extras to it like an encoder and wha-la the first working prototypes of the AM SuperShifter were born a year before even being put into production. That is why I feel that more teams should go out and try to make these things on their own because that will only inspire more people to make newer better products that other teams can use.

EDIT: Also, let me know what changes you make, I will be interested to know how these are improved upon!

[T3_1565]

Originally Posted by JesseK

1.) Make it driver-centric holonomic. Figure out your driver's controls as well. I'd recommend having a circular nob for rotation as the Z axis and a joystick for all lateral movement. Then, when the joystick moves right, no matter what direction the robot is facing, it laterally moves right from the driver's point of view. If you push the joystick away, no matter what the robot moves down the field away from you. You'll need a gyro for this. Making a true-holonomic drive train is both hard & fun to learn, but it also can provide the agility you seek over a tank drive.

This is another great idea that is being thrown around our team in the past few weeks! We have decided that if this were the route to go, the best way to control it is with an xbox 360 controller (as many of us on the team play video games ALOT. lol) this way it makes it seem like an FPS game, which gives a driving advantage to anyone who can play FPS games well as you already have practice in! (if only we could make our robot jump... )