Day #44 – 2/15/15

Lab opening time: 1:05pm

List of Problems and Solutions.
List of Problems and Solutions.

The day started out with the weighting of the robot as the team wanted to see how much the robot weighted without the addition of the autocanners, elevator flaps, constant spring and its mount. By using Mr. Najarian’s scale the team came up with a weight of about 114 pounds. We then weighted the robot on the new scale that we had bought on Amazon which  stated that it was accurate to within 1/10th of a pound. When we weighted the robot on this scale, it read 109 pounds. We then spent some time trying to figure out which scale was accurate. We tried to see by having people who knew approximately how much they weighed stand on the new scale but their were still slight degrees of variance. We then placed 2014’s robot on the scales and found Mr. Najarian’s  scale to be more accurate. With the weight of the robot known, the team could get on with the rest of the day.

One of the first mechanical tasks was to replace the BaneBots RS550 motors on the elevator with RS775 motors.  After a bit of calculation, we determined that we’d like to stick with the 12:1 gear ratio.  After a bit of re-wiring and reconfiguration of the VersaPlanetary input side, the new motors were installed.  We’re happy to report they work great, and are able to lift 4 totes at a rather decent speed, and can also lift 6 totes and a can without issue.

Daniel working on programing.
Daniel working on programming.

The programming team worked on calibrating the swerve modules so that they would only need to be calibrated once and then not have to be re-calibrated every time. They also got last year’s driver station working on this years robot so that the drivers of the robot can get every second they can get with the robot, with a control board that will resemble the actual board.

While the programming team worked on the code, the rest of the mech team worked on fixing all of the problems with the robot. One of the problems that was found early on was that the ejector air cylinders were touching the ground and which could potentially damage the push-to-connect tube fittings. Another problem was the flaps we originally thought of using were not long enough so we had to redesign them. The new idea is to have flaps that fold out so that we have a larger area to pick up the totes.

Shay worked on getting the constant force spring mounted to the robot. Originally, we were going to have an aluminum casing but after weighting the robot, it did not seem practical so we decided to use laser cut delrin instead. After trying to mount the spring, it was realized that the small plate that we had manufactured to mount the spring to the chain was not long enough and would not hold the spring in place. After a redesign, the mount was put back on but was too short and we were worried that the spring would be pulled too far that it would slip off the mount. The mount was then redesigned again to be longer and, in keeping with the triangle theme, triangle pockets were added.

Mounting the constant force spring.
Mounting the constant force spring.

Sipan, Jack, and Joshua worked on the new design for the forks and how we could mount them without having to redo the whole fork system. It was decided that we could just add hinges and that would allow us to extend the length of our forks.

While the tote fits on the flaps we have now, the tote tends to want to fall off.
While the tote fits on the flaps we have now, the tote tends to want to fall off.

To solve the problem of the ejector piston going to low and not being able to push on the tote, pieces of polycarbonate were used to extend the width of the ejector and help to push the totes out. Additionally, we wanted to improve our intake design to be able to intake totes from a much wider angle.  To accomplish this, we are thinking about adding some sort of funnel that the tote would hit and then be sucked into the robot.

The business team worked on the sponsorship panels for the side of the robot and also spent some time repairing the printer, 3D scanner, and monitor that fell down when one of the business room tables came crashing down.   The expensive items took quite an impact after the fall, but it seems they fared well in the incident and still appear to be fully functional without any notable cosmetic damage.  Luckily no one was hurt and all items were repaired and are now back up and running.

DSC_0051
Our first major gouge in the robot happened when the carriage plates hit the side of the tote and then jumped out of the elevator frame. Oops.

Other details that were completed today included cutting and installation of the rear number plate and polycarbonate panels on the intake triangular frames.   Additionally, limit switches were installed to the top and bottom of the elevator to signal the roboRIO when the mechanism has reached the end of travel in either direction.  We intend to use the encoder as a primary means of software limiting, but we’ll add code for the limit switches to act as a failsafe if the encoder routine loses track of its counts.

By tomorrow, we will hopefully have almost all of the robot complete so that our drive team will have time to practice with the robot before bag day.  Tomorrow’s MAJOR mechanical objective includes extending the length of the forks, so the robot can actually pick up totes.  At this time, we anticipate we will not bag a working set of forks, and will need to completely redesign and remanufacture a new fork assembly and bring it as part of the 30lb withholding allowance.  But, we may be able to get something working for a few hours prior to bag time, just to try.

Lab closing time: 2:08am on 2/16/15