Back in May of 2005 I received a phone call from colleague at Colpitts Design. He was approached to build a puppet for feature film. They were looking for someone to make remote controlled robot character to play a part in an upcoming movie.
It was described as a walking biped robot about 3 feet tall and they wanted to start shooting in about 4 weeks. I would have loved to make a biped walker but we all thought it might be a bit ambitious given the time, budget and resources, so Peter and I agreed to pitch a two legged rolling robot.
After I hung up the phone I put together a lego prototype to propose a simple method of locomotion. We shot a video and sent it to the art department. The next morning we were given the go ahead to start building.
Step 1: Full Scale Prototype
We started by drawing up some parts on the computer and cutting them out, while at the same time looking at various motors, gears, servos available to make this thing move. To have the tork we wanted to drive the hips and wheels we decided to use windshield wiper motors that we drove with custom made control boards and a potentiometer connected to the drive shaft to turn it into a big servo. We took off the cast gear box and machined our own to allow us to design our own mounting face as well.
For our first test we wired everything into a plugged in power supply, later that would need to be changed for something self contained.
Step 2: Concept Art
Notice here the robot was named Steve Maqueen at this point of the project
Step 3: 3D CAD Modeling and Renderings
I have made the drawing available to download so you can view it as an edrawing. If you don’t have an edrawing viewer, get one here for free.
The CAD data served us in many ways. First off screen shots and renderings could be sent to the art department for approval, but more importantly for us it allowed us to build accurate parts that looked almost exactly like the drawing and rendering we were sending to the client.
Once we had a few key components modeled up and approved we started making them. A 3 axis CNC mill did a lot of the work for us. Some of the frame work for the body required only 2D cutting so for those aluminum plate was cut using a CNC water jet cutter.
Step 4: Making Parts
For other more detailed part that we did not want to machine we rapid prototyped using SLA back in 2005 this was a little more exotic then it is these days.
Step 5: Kit Bashing
I like mixing real manufactured parts with the ones we make, not only does it save time and money, it complements the other parts to make them look that much more real. It really helps to know of places where you can go to find this kind of stuff in the quantity and variety to make the trip worth while. I am careful to avoid single items unless I am positive I can get away with only having one of them. It is always good to have extras around or know that you can get more if you need it.
Step 6: Bringing It All Together
Step 7: On Set
So that's that. Make a robot puppet in under 4 weeks.
It was fun to make, don't remember seeing the movie though.