I spent the last two weeks overhauling the entire physical design of the gantry. I replaced the aluminum angles with aluminum extrusions, and used brackets with t-nuts to provide an easily adjustable yet sturdy frame. I made it so that the supporting rod now goes through two wheel attachments which slide across the rails instead of having the rod sit on the edge of the frame. The z-axis rack has been changed from a 3d-printed part to a lazer cut one in order to make sure that it is rigid and straight. I also abandoned the bearing wheels on the z-axis in favor of a 3d-printed guide slot. I replaced some parts of the conveyor belt in order to add tension, and was able to pull the belt taught. I also made a mount for the conveyor belt stepper and added the stepper and the timing belt onto the conveyor, so that the conveyor now moves with the stepper motor. In short, the physical components of the gantry are essentially finished.
Next week, I plan to try to get the depth information from the stereo camera and help work on all of the steps necessary for integrating the work done by my teammates. I am behind schedule but I believe we should get everything done in time.
Verification
For our testing, we will test the gantry’s ability to move with a certain granularity. We’ll move it a certain number of steps and measure its movement in order to determine what the distance corresponding to a step is. We’ll also be doing rigorous testing with multiple common trash/recyclable items such as bottles, cans, cardboard, jars, chip bags, etc. to ensure that the end-effector is able to handle a wide variety of materials and surfaces. We will also make sure to test objects with different weights to determine if it is able to lift objects up to 1 lb. We’ll also be testing the overall accuracy of the depth information (z-coordinate of the object) calculated from the stereo camera.
