The "Spring Break" robot (so deemed due to the fact I had to work on it over spring break, oy...) in its final state. The robot focused on completing two of the tasks on the competition board (modeled off the Operation board game): "wrenched ankle", where students had to pick up a wrench from the ankle without hitting the metallic sides, and "hip replacement" where students had to pull up to 6 rubber bands between two posts...The unique aspect of this robot's design was that it did both tasks simultaneously using a single wench mechanism. Two strings were connected and wound in opposite fashion onto a metal axle which was spun by a motor. On the backside of the wench, a metallic gripper picked up the wrench, while on the front side, a rubber band holder extended the rubber bands while being pulled back. While the robot did not always work as expected, there was a 30% success rate when it actually could perform both tasks at once!
QUICK N' DIRTY PROTOTYPING
On the onset of the class, the students were assigned to fabricate a robot in one day using only 5 unique items, excluding fasteners. This is the result of that: a battery, two sets of wheels, a motor, and a bent piece of plastic was the result!
In prototyping the gripper for pulling up the wrench, I tried many foam-based prototypes with different gripping mechanisms, but found that the magnetic approach was the simplest. In doing these prototypes I also learned that I needed a rigid arm extending down that would not sway back and forth as the string-based prototype did.
NEXT STOP: CAD MODEL
The 3D exploration was very helpful in identifying potential problems & highlighting manufacturing complications that could result. In this case, I realized that I would need to have two dowels connected to the slider so that I would lose an unwanted rotational degree of freedom.
MAPPING OUT STEP BY STEP
For my most critical module, I chose the rubber arm extender. I tried to break down the action into its most basic constituent steps, so I could better understand potential hurdles to overcome during the full action.
KILLING TWO BIRDS WITH ONE WENCH
The robot during practice rounds, attempting to do both the hip replacement and ankle operation activities. When the robot did perform, it achieved 32 points, a score that would have placed it second in the class!