Below is a video of the initial (small scale) testing of the large scale delta robot movement in three dimensions. The controller is making a 10 x 10″ square then moving up 5″ as well on the last segment and then repeats.
Last weekend I built one rig for testing my calculations for the large scale delta project and to verify the concept. The goal was to be able to lift 22 lbs vertically using an 125 oz-in stepper motor and an AutoDriver stepper motor driver, both from SparkFun. All the mechanical bits, timing pulley, timing belt, pulley and axle, were from SPD/SI. While I was able to determine that the general concept will work it failed to lift the 22 lbs. This was due to the timing belt and pulleys not being a heavy duty enough and skipping when the load got around 8 lbs, so on the next version I will go for better a heavier duty timing pulley. See below for a video of it in action.
The first test of my robot platform using wheel encoders and a rough PID loop to perform a box routine. The overshoot and quick turn around are because I did not round off the corners of the box pattern so as the robot finishes one segment it realizes that is has gone to far and quickly turns to get back on course.