SketchUp is great for robot designs. It’s also a free and easy to use tool. SketchUp was Google’s drawing software, but was recently purchased by Trimble. You can learn more about this software product at this web site. Last weekend I downloaded the free version and watched about an hour’s worth of YouTube videos detailing the basic tools the software provides. It didn’t take long to figure out the basics, but I’m still just scratching the surface of this useful tool.
In the past I’ve used some mechanical CAD programs, but my skill set is really centered on electronic design. Having some free and easy to use mechanical design software fit a goal I set for myself. I really want to spend more time interfacing our products to mechanical systems that I’ve designed. I think this will give me better insight into what I should be designing, and what kind of problems robot builders regularly face.
A couple of weeks back I designed, without any software, a simple servo driven wheel deployment. One goal I set was to move the wheel while relying only on a simple mechanical hinge system. All of the gearing would be integral to the servo (you can see this design here). While I achieved that goal it was also obvious that the entire system was too “long”. In wanted it to be more compact, as I need to fit 4 robot wheels into the design I’m putting together.
Through trial and error I came up with a slightly different system. Using some scrap brass I cut out a simple prototype and put it together. Then I went through a series of iterations where I would grind, cut, or add pieces until I had something close to what I was looking for. In the end I want a 4-wheel system that can deploy and retract. The image below shows one side of the system. A mirror image would sit behind this, and the wheels pull up into the notches cut on the left and right side of the assembly.
After some testing I took measurements off of the prototype and entered a further modified design into SketchUp. Now I’ve got some firm dimensions to work with and can proceed to work on the third revision, which will hopefully be a little cleaner. I’ll probably build another two wheel assembly to see if all of the dimensions are correct. Then I would like to put together all of the pieces together in SketchUp to document the entire system. Ideally I would even send the pieces off for laser cutting.
In this instance I kind of worked backwards, first building, then using CAD on the system. This worked for me since I wanted to start out being “hands on”. As I learn to use SketchUp’s tools I expect it to be faster and more efficient to run through a design in software and then start cutting metal. Anyway, Sketchup was a great experience, and I look forward to using it often.