Chameleobot the Quadruped is modeled after a chameleon. However, in reality, it could be a lizard or iguana or any other type of lizard you want. Chameleobot is a massive dual RCX robot that is over 4 feet long, uses 6 motors, 5 sensors, 5 gearboxes, a host of gears, and consists of nearly 10 different Mindstorms sets. It is separated into 11 different sub-assemblies including the 4 feet, tail-motor, head-motor, tail, head, and 3 different sub-assemblies for the chassis (the chassis is so large it had to be separated into 3 different parts!). Chameleobot has many cool features including the rotating head, fiber optics which are located on the head-motor sub-assembly, a turning tail, independently powered legs, and super large feet! Because of the size of this robot, I was able to give each leg its own motor.
To make sure everything is in sync, each leg is monitored with its own touch sensor using a crankshaft as the mechanism that actually presses the touch sensor. Chameleobot has a special sequence it follows to operate as both RCXs must communicate and deal with the resources together. Unlike the slave-master relationship 2 different RCXs sometimes hold in an invention, Chameleobot gives both microcomputers equal power. They both “own” 2 legs and either the head or the tail. The old program version had it operate by having 1 RCX move two legs and its other resource, then send an IR message to the other RCX which will take control and when that one finishes it will send another message to the opposite RCX thus continuing the process forever. The new version has both RCX's send messages to each other and each move a leg then one will execute another movement. After that the other legs will move after exchanging messages again and the whole process will go on forever.
In Chameleobot there is room for a few improvements. The tail could be a little more efficient as it droops some because of it length and size. Actually, the one in the picture has the tail just drooping on the ground and not working much! However, in a revised addition I added universal joints that connected to the tail and the chassis and then used tape to hold them together! I think a shorter, smaller tail might be better but I wanted a tail with a ratio to the rest of the robot. You kind of have to make a trade off! Also, the touch sensors actual pressing mechanism could be slowed down as it takes 75 clicks for one revolution! Of course, the feet are slow, but still the touch sensors amount of clicks could be smaller. I had a lot of fun making this robot look like a reptile but probably should have given it something besides a square head. Most chameleons don’t have square heads! |
