2.007 - Design and Manufacturing 1

2.007 is one of MIT's capstone Mechanical Engineering classes, one that every freshman looks forward to. It's essentially a semester-long robotics competition during class time! It doesn't get much better than that.

The theme my year was "May the Torque be With You" AKA STAR WARS! I could not have been happier.

The shop staff for the class built this fantastic arena which had an array of challenges for us to attempt. The competition (created by Woodie Flowers initially and is the basis for FIRST), involves a short autonomous period, followed by 90 seconds of operator controlled competition.

Tasks included pushing Stormtroopers into the trash compactor below the X-Wing, freeing the staff from carbonite by lifting them out, and most importantly SPINNING THE THRUSTERS. Spinning the thrusters was without a doubt the best strategy. All the other tasks had fixed point totals, but the thrusters were scored as:(thruster speed (in rad/s)) ^2 / 2 or (thruster speed (in rad/s)) ^2 / 3depending on whether we spun the top or bottom. Unfortunately, they did set a max speed for safety concerns, so a little more strategy was required than simply spinning up the thrusters as fast as possible.

A big limiting factor in the class is the actuator limit. We're only allowed to use 8 motors total, but can have as many robots as we like. Also, we were given NO BEARINGS. Only very inconsistent bushings.

With most of the class knowing about my previous robotics experience, there was a lot of pressure for me to do well, but I decided it'd be more fun if I focused on building interesting and exciting robots.

My initial strategy involved building two robots, one to spin the lower thruster to full speed, and another to spin the top thruster, and then tip the lightsaber located on top of the X-wing which would give me up to a 2x multiplier depending on how far I tipped it.

To keep to my competition goals, I decided to use a grappling hook for the lightsaber multiplier. My robot would fire a completely mechanically actuated (no motors) grappling hook and latch onto the lightsaber and then drive off the arena, using the weight of my robot to tip the lightsaber.

The entire grappling assembly is powered by springs, rubber bands, and latches in order to avoid wasting actuators.

An early grappling hook assembly

The robot would drive up to the lightsaber holder which would push on the bar on the left, releasing the swinging arm

The swing arm would then slam the scorpion tail into the lightsaber, firing the hook into the lightsaber. The grappling hook was spring loaded shut, and was held open by a "knock out bar", which would be knocked out by the force of the assembly slamming into the saber.

This robot worked fantastically and was a great source of excitement, but unfortunately the professors didn't like the idea of my robot exiting the arena (even thought the rules don't prohibit it!) and so the idea was scrapped.

Lower thruster spinner prototype

My final design still involved two robots, Skywalker and Frank. Frank was an extremely last minute addition after the grappling hook was scrapped.

Skywalker used a 4 bar linkage to be able to spin the top and bottom thrusters from the floor, while still fitting in our volume limit. By itself, Skywalker could score ~525 points (for reference, the winner scored 625 points every match).

Frank

was

a

piece

of crap.

Mainly just due to its last minute creation, Frank did not work at the competiton. It did work in lab though!

Frank would drive into the lightsaber base (which has ~1.5" gap) and the aluminum arms would flex in, at the end, they would spring back out and catch on the side of the base. This would allow me to exert as much linear force as I wanted without relying on traction. I then used the world's worst cantilevered lead screw to tip the lightsaber. Ironically, the part of the robot that failed at the competition was the electronics, but regardless, Frank will not be missed.

I ended up placing 5th at the competition (it was single elimination and Frank let us down) but received an award for having innovative designs. Overall 2.007 did not disappoint!