I’m working on a robot chassis in SketchUp this week (even though we’re closed). Over the last several of months I’ve been working on consulting designs and product development, and got behind on one of the research projects I wanted to spend time on. This week I’ve had a chance to catch up a little.
A few months back I built a prototype of a four wheel robot (photo above, video here). I wasn’t able to get the functionality I wanted using an Arduino as the controller. I ended up slapping together a BASIC Stamp 2, Arduino Uno, and one of our Motor Mind C motor controllers to get close to my desired goals. At that point I set aside the design and started working on a custom controller that an Arduino (or any other microcontroller) could interface to. It needed to read servo pulses, control motors, and output servo pulses. Here’s a blog post on that design concept.
I’ve reached the the point where the motor/servo controller design is close to being finished, and I can order the prototype PCB. That puts me back in a position to work on the hardware again. Yesterday I downloaded the newest version of SketchUp and got to work. I had to create 7 different parts for the robot to get to the point where I could fit together something that resembles a chassis. Last time I did this I built the hardware from brass pieces soldered together. This time I’m going to try to use Ponoko a 2D/3D laser cutting service.
Here’s the model of the end-plates which also mount 2 servos. I’m going to try to make them out of 5.6mm blue acrylic.
With the pieces I designed I was able to do a rough fit as well as test for clearance for the joints associated with the wheel arms. I still have a lot of work to do. I need to decide if I’m going to fit electronics on the inside or outside of the chassis and place mounting holes. I’ve also been limited to the length of the acrylic by Ponoko, so the battery I’ve been using will not fit inside the chassis. I’ll have to select a new battery and come up with charging and power switch scheme. But all-in-all, this was a good start.