Final Documentation

Our machine and team were depending on a very simple strategy needing only a simple design. The main components of our robot were the arm, funnel, and tube. Assuming that few teams were to attempt to score from the tower ledges, this team believed it had an advantage by planning to quickly score a single tower ledge ball at which the machine would continuously defend from then on. The arm would knock the ball off the tower ledge, which the funnel would guide towards an attached tube to secure the capture ball. The strategy was to be very simple and concise, giving the team plenty of time to defend.

The final design for the robot was quite similar to the CAD model in most respects. We used a mill to machine the base and brackets to length and to drill the holes in them. We used the mill for those parts because they connected the wheels, and any misalignment would have caused the robot to not drive correctly. The Arm did not need to be quite as precise, so the arm was cut to length with the band saw and filed, and the holes were drilled with a drill press and tapped by hand. The axles were cut roughly to length with the bandsaw and then finished on the lathe. The skirt was cut on the water-jet and then bent into shape using the break. We assembled the axle assembly by drilling a hole through the gear and axle and installing a spring-pin to fasten them together, and then the wheel was pressed onto the axle with the arbor press. We also added sandpaper to the wheels to increase the friction between the wheels and table. Our original design for the arm release was to use a torsional spring to force the upper arm back into place; this system was replaced by two extension springs inside the arm. We assembled most of the components with clearance holes and bolts, and only used screws where there was insufficient room for a nut. The chute was made from the 2 inch outer diameter corrugated tubing, and the funnel on top was constructed from rubber sheet. The Tube and funnel were attached together with tape and epoxy, and the tube was held in place with zipties, which allowed it to be adjusted slightly to remain just within the size constraint.

We had to change parts of the robot design when we manufactured it. In the CAD model we used two 1.5” gears for each wheel. In the robot, due to the placement of bolts, we had to use a 2” gear on the axle and a 1” pinion gear on the motor. This caused a different motor placement than the original design, so we had to drill a few new holes for it. The arm is also modified from the original CAD design. Our idea of using the 180 degree torsion spring was not working because we weren’t able to attach it on the arm very well. Instead we used two 3” extension springs that connected the two horizontal push rods in the arm. This worked very well for releasing the arm into the upright position. After we installed the skirt, it turns out to be very low to the ground and the front corners were getting stuck on the field. We decided to cut off the front corners on the skirt to give us better clearance.