Balancing
Most self balancing robots try to put all of the weight they can between the two wheels and as evenly distributed from front to back as possible. This ensures that the motors have to do as little work as possible in keeping the robot upright because an even weight distribution makes the robot more stable. The DuelBot is obviously not balanced that way. There’s a 9 inch lance coming out of the front and a 3 inch battleaxe sticking out the other side.
However, the weight distribution may not be as bad as it first seems. For starters, the battleaxe will have a negligible effect on the left and right or forward and back balance of the robot simply because it is on the same axis as the wheels (while it is stationary). This means that all is required for correct balance is that more weight is on the left side of the robot than the right. The lance virtually guarantees that this is the case, and even if it didn’t the battery, arduino, receiver would.
When it swings might be a different story. During melee competition the lance will be removed and the battleaxe will be moving very quickly from front to back as it is swung. This will definitely throw the robot off balance front-to-back and the electronics will have to be up to the task of keeping the bot upright. This is a pretty big engineering problem that can only be answered once all of the systems are built and the bot is coded.
The lance is also going to cause problems. It is a relatively large weight and it is very far away from where the axle of the robot is which magnifies the problem. Thankfully I took a few steps to mitigate this issue. For one, the battleaxe can be moved backwards, opposing the weight of the lance. Also, all of the electronics (besides the servo) are on the back of the robot which helps balance the lance. And as a last resort the battery, probably the heaviest component of the bot, can be moved backwards if necessary.
I do think that the robot will have to have a slightly backwards leaning stance, even with the weight balancing effort I’ve put into the design. Not the end of the world, of course, but might require building a lance that is slanted slightly down so that it will end up level when the bot balances itself. Again this is something that can only be determined once the bot is built.
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