Control arm for mobile pickle bucket

Community General Discussions
1

I had this 3D printed for my robot, before I realized it didn't include the arm itself:
http://www.thingiverse.com/thing:652366

Does anyone have an idea or source for creating something I can tie this into to control my robot? The body for the bot is 26cm in diameter and the part that attatches to the arm has a little screw hole for where it connects, though I obviously don't have to use that piece. The motors/wheels I'm using are those yellow motors, with the thick yellow wheels and black tires you can get cheap, so they have to obviously clear to move.

I'm willing to use a control axle (or whatever you call it) off of an existing car model, make something new, or make the control arm out of K'Nex and use this if anyone has an idea how. The 3D printer is at a library out of town and has a queue, so it's not like I can just print and try random ideas.

2

I would just use
I would just use differential steering for the robot. It’s the easiest way of steering.

You can use this with multiple motors, but the easiest way of visualizing this is with two motors and a single caster.

The motors go side by side near the front, and the caster is in the rear. To go forward, move both motors in the forward direction. To go backwards move both motor in reverse. To spin in place, give both motors the same power but in opposite directions. To go forward curving left, let both motors go forward, but the right motor has to move faster than the left.

If you have a four wheel drive, you dI the same things, except you treat all the left motors as a single motor and all the right motors as a single motor.

Happy building!

3

Thanks, I’m already using

Thanks, I’m already using steering like this, though:
1) With the side, I’d need them further apart for balance.
2) Due to the weight of the project compared to the torgue of the motors, I would want the control arm to reduce resistance from traction when turning. I’m already using swivel wheels in the back, but the front wheels have trouble turning, hence why I’m looking for a swivel bar.

4

I’m just not a big fan of
I’m just not a big fan of Ackerman steering (steering like a car). I like the elegance of differential steering and I’ve never found the friction to be a problem. I might suggest that since your robot is around 20 lbs, you might need stronger motors.

5

Thanks for the input. It’s

Thanks for the input. It’s actually around 5-10lbs, but I’m rounding up to 10 for once I add the final casings. :slight_smile: