This time I though I'd try and make a robotic Forklift truck. It's mainly made of parts from the Robotics Invention Sytem 2.0 (3804) and the Ultimate Builder Set (3800) but there may also be some parts from the Ultimate Accessory Set, Exploration Mars and Vision Command. Also, two of the old double lights are used on the roof.
It has a front wheels differential powered by a central, forward facing motor geared down 1:3. On top of the forklift, a pair of lights are connected to the same output port as the drive motor. The steering is a simple rear wheel rack and pinion, driven by another motor running through a pulley connected to a gearbox containing a worm gear and 24 tooth. This is on the same axle as a 16 tooth gear, meshing with another below it, which is on the same axle as the 8 tooth that moves the steering rack.
At the back of the forklift, the upper steering axle is connected to a cam, which will engage a touch sensor when the steering is centered, allowing the RCX to keep the forklift moving straight.
The most complex part is the pneumatic system that raises and lowers the forks. Another motor, connected to an axle joiner, drives a 16 tooth bevel gear and a medium pulley, which is on the outside left of the forklift. This pulley moves a small pneumatic pump which provides the pressure for the pneumatic system. The previously mentioned bevel gear conects to another one on a forward pointing axle, which drives a worm gear/24 tooth gear box. The 24 tooth is on the same axle as an 8 tooth, which is meshed with a 24 tooth clutch gear. The axle this is on comes out of the right side of the forklift and is connected to a pair of liftarms that are in parallel with the pneumatic switch below them and the two are connected by another liftarm.
When the motor for the pneumatics turns in one direction, the switch is lifted and the forks raise through a cylinder mounted on them, and when run in the other direction, they will lower. The clutch gear will slip when they reach maximum travel position in either direction, while still allowing the pneumatic pump to run and the motor to spin to prevent a stall.
The forks, as well as being joined to the vehicle at the base, are also connected by a pair of liftarms at about 2/3 the height of the raising part. The whole lifting assembly pivots at the base, so these liftarms cause it to tilt backwards when the forks are raised.
On top of the forks, there are a pair of touch sensors, which register the presence of an object and cause the forklift to perform a manoeuvre to raise and move the load, lower it, reverse and return to it's previous path. A light sensor is also mounted between the forks, pointing downwards to allow line following. All programming was done in NQC, though an RCX code program probably would have worked just as well.
Quoting MR. LEGO
nice job on this man! I really want one of those pnuematic lifts! uum, I just got the NXT 1.0 and got my refund for the RCX.
Thanks for the comments!
I hope you get on well with the NXT, The bluetooth capabilities and extra sensors available for it are something I'd love to have a go with. The Pneumatic elements are quite fun. I put together the Pneumatic set 5218 a little while ago as well so I've added that to my collection, plus I've got a few odd extra pumps and cylinders laying around.