Paul Gelhaus

David Carratu

Astronaut Tools: Astro Tool Documentation

    For this project we were assigned to remove a nut from a bolt and reinsert the nut onto a different bolt with a device we created with Lego Mindstorms. The device had to be something that astronauts could use, so there were a number of criteria we had to meet. Our tool had to be able to be operated one-handed, in any direction, with either the left or right hand, and while wearing ski gloves to simulate the space suit.

    We began by building the nut holder and rotating assembly. For the nut holder, we used the 4 rubber pieces that are supplied in the kit to form a snug fit around the nut. Since the nut could be screwed far down on the bolt, we used two long beams for the rotating assembly, to straddle the bolt but still hold the nut. Next, we made the gear drive for the rotating assembly to attach to the motor. We also made a frame that holds the axle of the rotating assembly to the rest of the tool while letting it spin freely. The gear drive consists of a big bevel gear which holds the rotating assembly which is driven by a small bevel gear off the motor. We attached the motor straight to the brick with a sturdy bundle of reinforced beams. Next, we attached the buttons to control the direction of the motor’s rotation. We attached them in the front of the brick so the user put their hand over the brick and uses their index and middle finger to push the buttons. Next, we made a strap that goes over the wrist part of the hand that supports the weight of the brick and relieves stress on the hand. Finally, we made a little frame that goes over the fingers operating the tool to support them and protect them.

    Our tool uses two touch sensors and one motor. As you wear it, the left touch sensor makes the motor go clockwise, and the right touch sensor makes the motor go counter-clockwise. We used LabVIEW Block Diagrams to program the brick, as this gave us lots of control over the movements of the motor. We created two while loops (one for each touch sensor) so that when button1 is pressed the motor spins clockwise while when button2 is pressed the motor spins counter clockwise. The motor rotates in the corresponding directions for as long the touch sensor is held. The user can use the tool for as long as the program is running, and it loops infinitely so it can be used for as long as the battery lasts or as long as the user likes.