The Bowmar Builders are an FLL team associated with Bowmar Elementary School. The purpose of this blog is to help other students interested in robotics to learn from what we have learned. As an FLL Robotics team we use the Lego EV3 robotics system and the Mindstorms graphical programming language.

Sunday, October 17, 2021

Using Rack and Pinion for Steering a Robot

 Using Rack and Pinion Gears for Steering a Robot

By Julia Byrd
October 17th, 2021

After my last experiment in using rack and pinion gears, I was googling and noticed a picture of a rack and pinion gear for a car. So I wanted to use one to steer some wheels.

I used the blue wheels and the large rack gear. It took some trial and error to figure out how to connect the rack to the wheel.

Connecting both wheels, I noticed that it would wiggle a lot and I needed a) something to push against, and b) hold the rack up in place.

I added a regular beam to the other side. I should be able to use the blue regular beam to connect the wheels to the robot frame. By holding one part of the steering mechanism in place I can use that to push against and hold the pinion gear.

I'm also experimenting with which way the rack gear works better - rack up, pointing out or rack down, pointing in. This picture shows rack up, pointing out. Now I need to create a frame that holds the wheels, rack and pinion, and a motor.

This setup seemed to work okay. I reused my motor turning code to check it.

It worked. I did notice that because the way the rack is attached to the wheels that it moves back and forth as it turns.

I also noticed the hub doesn't fit too well on top. There is also a lot of space. Time for a re-do.

This looks like it will work okay. The wheels tilt side to side by two holes. The L piece helps push the rack against the pinion. The challenge now is mounting it onto a frame. And figuring out how to make it drive.


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