These our working drawings. Due to miscommunication between myself and Chris there will be many changes made, mostly to due with the arm and claw.




The arm will be attached directly to the arm, instead of the mechanism with the wooden wheel/dowel and the string for lifting the arm as depicted above. (directly as in x radians of rotation in the servo wheel equals an equal angular displacement of the arm). We lose a significant amount of torque the other way because we're not applying the force perpendicular to the lever arm (remember you have to multiply F * d * sin theta). Again, this was just from poor communication, we need to work on that.

A lot of changes we are really only able to see the use of making once we are actually in the shop with the actual materials in hand. Like this styrofoam stuff we had no idea was back there. It's pretty strong, so we made the arm out of that instead and reinforced it with pine wood on the sides. This will reduce the weight significantly without affecting strength too much.

The claw mechanism, while we're not 100% sure on it, is probably going to end up looking how I described it before - rubber binder attached to a claw, and a string on a pulley to pull the claw back. The servo will have to be right on the arm or very close to it to avoid the string from moving, or we'll have to work something to let the string can give a little slack when necessary. Another change made after actually seeing what we're working with was the addition of a thin rubber material we found. We're going to wrap this around the claw to increase friction. We think we're going to  make the claw out of masonite, which is lightweight, and we can get it a lot thinner than the pine wood, so it's easier to build with. We're going to have 2 masonite fingers/claws, one on each side of the arm, and a masonite board at an angle to the end of the arm so that when the claw hits the bottom, the flat piece of masonite willl be perpendicular to the floor. We'll have to calculate this angle based on the length of the arm and the length of the masonite piece.

The drive mechanism remains unchanged. We went with thinner, larger wheels to get more speed. Measurements are in the drawing. We still need to do actual power and torque calculations, but we don't know the actual final weight of our vehicle, and the motors and servos are so overpowered we're not too concerned. This has been discussed with respect to the servos in an eariler post.

We will try and post a more detailed drawing of the claw design tonight, as well as a more detailed drawing of the exact design of the structure that connects the arm to to the servo.