Please comment on my design

[cparker71]

I'm looking for any and all feedback on this design idea for a robot. This isn't meant to be a 'battle' robot of any kind. I want to experiment with steering and suspension a bit on this project. I've build robots before with tank-style steering, and also using omni wheels on the front. Something about depending on specialty parts like omni wheels just doesn't appeal to me.

I'm wondering how important different steering angles on the front wheels are (so called 'Ackerman' steering)?

The suspension is an attempt to cut down on vibration a little.

The forks are much taller than needed in order to accommodate larger wheels as the budget allows. I'm starting with rollerblade wheels that happen to have on hand.

The material is mostly 5/8" steel square tube which I found on ebay for a good price.

I have to admit it's pretty fun learning and using google sketchup.

Please let me know what you think. Too complicated? Too fragile? Too heavy?

Thanks!

Pic (http://the-parkers.net/local--files/start/roverbot-big.jpg)
Video tour of model (http://youtube.com/watch?v=t8cbtQgrHRw)

[wrighthobbies]

Hello cparker71,

Neat 3D model! A lot of us don't take the time for virtual design but it can pay off in the long run.

I would say ackerman steering would be important for your design, depending somewhat on the surface you will be navigating. Your design has a wide wheel base, which is where ackerman becomes more important. The turning radius of the inside and outside steering wheels are different, forcing one or both wheels to slide. If both wheels slide, you may lose some steering efficiency.

The back wheels also have the same issue. If you use 2 motors and direct drive them at the same speed during a turn, they will fight against the steering. A differential driven by a single motor (like those used by RC cars) will alleviate this.

Homemade suspension can be difficult to build. You may want to look at standard suspension types you can find on the internet.

Another option would be use the 2 drive motors to steer and replace the front steering wheels with casters - differential steering. This is easier to build and easier for the controller to steer.

How heavy do you estimate your robot to be? Have you thought about the type of battery you will use?