Why Reinvent The Wheel?
I’ve noticed while doing research on various micromouse designs, that the designers (engineers?) often reference two sources of inspiration. One is an article written quite a while back by David Otten of MIT about how one of the early MITEE micromouse designs evolved. The second source of inspiration is RC model cars.
On most weekends, assuming the weather decides to cooperate, I like to go kickbiking. It’s great conditioning and exercise, and it gets me out of the house for a while. This morning (Sunday) it was extremely cold, but there was no wind, and no rain, so I put on a sweatshirt, muffler, jacket, and cap, and went out to exercise for a while. One of my favorite kickbiking routines is to kick through the local neighborhoods, through the bayside park, and then finally head up towards a major shopping center that has a Starbucks across the street. I buy a paper at the train station kiosk, then an iced cafe mocha grande, and spend the next hour or so relaxing, catching up on the news, and doing some people watching. This particular morning I also stopped by the bookstore and picked up a RC model magazine. I wanted to see what ideas I could find that might be adapted to robot design – especially to micromouse design.
It’s been years, perhaps decades, since I examined a RC model car in any detail. Apparently the technology and design has evolved quite a bit since I was very surprised at some of the models. It was definitely time well spent – a good investment. Here’s a short rundown of things that caught my attention:
Weight distribution – low center of gravity, batteries in the middle, motor to the rear giving more weight (traction) to the rear wheels. Servo controlling the steering is tilted at an angle (most robot designs tend to keep the servo mounting at right angles.)
Close-up view of the steering servo mounting and linkage.
Base plate is thin and low to the ground. In this case, it’s actually two separate plates. The base doesn’t have to be symmetrical – notice how the rear plate is offset to provide clearance for the motor gearing..
Different design but some of the same features.
Here’s an interesting diagram that explains how some of the steering mechanism works and how it’s controlled by the servo.
Here’s a very different design – this time with four wheel drive. The motor sits on one side of the chassis and its weight is counter balanced by the patterns on the opposite side. I was really impressed by the cut outs in the the chassis for the batteries and motor. They provide a lot of stability, and allow the center of gravity to be as low as possible. There were several other things about this design that stood out.
The effective use of cotter pins to secure some parts.
Here’s a closer look at the chassis cutouts I mentioned above.
The drive mechanism comes straight up the middle of the chassis.
This is a top view of the motor, gears, and toothed drive belt.
Side view of the motor, gears, and belt.
The drive belt runs almost the whole length of the vehicle.
It certainly seems possible, even probable, that I will be able to draw on some of these, and other RC model design concepts for my own robot projects.
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