They are calling it Snowpocalypse. It’s not really that bad for Colorado, a steady 24 hour snowstorm that will pile up 18 to 24 inches of snow. O.K., it is a little more than normal for Denver in February. Since the storm is a long one, we can look forward to shovelling the sidewalk two or three times today. Did the first one just now, and thought about the snow shovelling robot.
At first glance, how hard can it be to move snow from one place to another? Just need some device to transport snow. So let’s get started. First we’ll grab a snow blower, that solves the transport snow issue. We’ll need to make sure it is one of those self-propelled ones. Then all we need to do it provide sensors and steering, and we are done. This is easy, should have done this years ago.
What? You have a question? How does it know where to take the snow from? Um, okay, we want the sidewalk cleared, so it just has to know where the sidewalk is. Well, we could use a vision system, but the sidewalk is buried under a foot of snow, so that’s out. Heck, I sometimes find myself missing the walk if the snow is deep enough. Okay, let’s add a marker of some sort – perhaps one of those ‘invisible fence’ wires down each side of the walk, then the robot just has to stay between the lines. Oh, yeah, and a marker for the property lines, so that we know when to stop. Sure, sure, we’ll go a little over so the neighbors know that we care. Now that we know where we are, we will need to steer. Where is the steering control? What? WHAT? You have to man-handle this thing around by jerking on the handles? That means applying force from an external anchor point, like the person standing securely on the cleared sidewalk. The whole point was that we don’t have a person standing behind the snowblower. Well, maybe we can just use dead reckoning, and blindly go down the middle of the sidewalk. Oooops, that won’t work, we still need a person to line the snowblower up, and turn it around at the other end. Besides, I’m pretty sure my home-owner’s insurance would have something to say about a blind, robotic snowblower charging down the sidewalk chopping up everything in its path. Oh, well, back to the drawing board.
Let’s go out to the garage and grab that squat little tank-treaded prototype that was designed to weed the garden. Shoot, that means I need to shovel the 13″ of snow off of the path out to the garage. I really need a snow shovelling robot.
The tank chassis steers itself around, so that is covered. It is pretty heavy so it can transport even heavy wet snow. It knows (roughly) where it is using GPS. And it has mounting points for manipulators. Let’s start by adding a simple plow blade on the front, and we’ll use the guide wires from version one, so that it can follow the walk. Piece of cake! Okay, let’s run it over the sidewalk between the house and the garage. The storm has only put down another 2″ while I was working, so let’s hit the on switch.
Sweet! Works like a charm, it is pushing the snow to either side of the walk, and left a beautiful clear path between the garage and the house. Now out to the front of the house to clear the walk.
We’ll wrestle the robot through the house, out onto the porch, and place it on the walk. The robot drops through the snow and settles in. Hit the on switch and watch those treads spin. And spin, and spin. The treads can’t get any purchase on the snow. Shoot. Pick the robot up, and put it back on the porch, track snow back through the house to grab the shovel, and clear just a small space on the walk to let the treads hit concrete. Pick the robot off the porch (I need a robot to haul robots) and put it on the walk, and hit the go button. The robot takes off and slams into the (now 14″) wall of snow. It struggles on for about a foot, and then stops. It can’t push the snow out of the way, even when it has good traction. I guess that is why we humans use shovels to lift the snow out of the way, rather than just trying to push it aside. Back inside, pour some more tea, and back to the drawing board.