Wednesday Wii – Train Your Brain 3

Training any neural system, natural or artificial, is hard. Think about how long it took you to learn to walk. Think about how long it took you to become confident behind the wheel of a car, or a truck, or a really big truck. Very often, the best way to learn something complex like this is to do what you did when you learned to walk, you took baby steps.

A classic problem in neural control systems is the truck backer upper problem. Yes, it’s a terrible name. I’m sure there’s something more formal out there in the literature. Ignoring that, the problem is, how do you train a neural net (NN) control system to back up a truck to a loading dock? The usual inputs to the system are the relative locations of the end of the truck and the dock, and the angle of the trailer to the cab. Did I mention that this was an 18-wheeler? Your controls are the brakes and accelerator, and the angle of the front wheels. The goal is to start anywhere in the yard, from any position, and end up with the back of the truck square against the dock. This is something that professional trucking schools spend a lot of time on. NN control trainers too.

Since we can’t explain things to the NN, the way you can to a trainee truck driver, we have to use a simpler, slower approach – baby steps. We start with the truck almost square to the dock, and a few feet away. Even so, we bang the back of the trailer quite a bit. Fortunately, it’s all electrons, so there’s no damage. As the NN learns to square up and move back, we start it from farther away, then from farther away, at a greater angle. By the time we are done, we can start with the truck facing the dock, with the cab cocked all the way around, and still have it smoothly maneuver into position. So, where does the Wii come into it?

Well, nobody’s used a Wii to back a truck, that I know of, but we do use the Wii Fit board as the training device when learning something like the Dance pose (in countries with longer vowels it’s called King of the Dance pose). This is where you balance on one leg, stick the other one out behind you, and grab that ankle, then lean forward and point your free hand at the screen, like you were practicing for a new career as a hood ornament. The way you do this is to take baby steps, to start with your back end up against the dock, as it were.

When I started, it didn’t matter which balancing pose I was involved in (Tree, Standing Knee), what I was really doing was just lifting one foot off the board and trying not to fall over. Later, I was able to lift it higher, then to (for example) cross my leg in a 4 position. In another six months, or year, or so, I’ll be able to stick my heel in my crotch and make it a true Tree pose. As for the Dance pose, I haven’t tried it yet, and don’t plan to until I can find two spotters who I don’t mind seeing me in my underwear. When I do try it, I’ll begin with baby steps.

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