the Rochester Institute of Technology microgravity drop tower

1. the Rochester Institute of Technology microgravity drop tower P14651 Customer & Sponsor: Dr. Satish Kandlikar Faculty Guide: Charlie Tabb Team Members: Dustin Bordonaro (ME) YoemClara (ME) Jacob Gray (ME) Adam Hertzlin (ME) Santiago Murcia (ME) Project Description Background: Microgravity is a condition in which objects experience the effect of ‘floating’ from a relative perspective. Microgravity can be simulated near Earth’s surface for brief periods of time by putting objects in a state of freefall and eliminating all forces, except gravity. One method of achieving this is with the use of a ‘drop tower’. Purpose / Goal: The team was given the task of designing and building a microgravity drop tower to be used for educational and research purposes at RIT. The drop tower design must drop two objects simultaneously within a vacuum environment, while tracking one objects descent to calculate standard gravity. The tower must be fun, educational, easy to operate and aesthetically pleasing. https://edge.rit.edu/edge/P14651/public/Home Release Mechanism Laser Tracking System • Laser Distance Sensor • MICRO-EPSILON ILR 1030-8, laser class 2 • Measuring range of up to 8 meter w/ 10 millisecond response time • Circuit w/ Resistor • Powers laser & converts signal from current to voltage • Data Acquisition Device (DAQ) • Takes laser analog voltage data and sends signal to computer via USB • Labview Program • Allows user to select chamber environment (Atmosphere – Vacuum) • Uses data signal to display graph of object’s position vs time • Allows user to save data for further analysis • Results • Able to capture entire object descent • Measures Standard Gravity (9.81 m/s2) within 1% Error • Requirements • Drop two objects simultaneously with zero lateral velocity • Center objects consistently under laser sensor • Support a maximum object weight of 0.23kg (~0.5lb) • Be removable and adaptable • Solution • Used an Arduino Uno microcontroller to actuate servo motors. • Connected the servos to doors via a 3:1 gear ratio. This ensured that the doors were quick enough to allow the objects to fall simultaneously, while strong enough to hold the max object weight. • Used sloped doors with custom geometry to center the object. • Made the mechanism adaptable and removable by using screws to hold all the parts together (no glue). • Results • Objects fell simultaneously with zero horizontal velocity. • The door geometry centered the objects consistently. • The doors were able to hold all tested objects. • The mechanism proved to be quite adaptable and easily removable. Pump Structural Frame • Pressure Conversions • 1 Atmosphere equivalent to: • 14.7 psi • 101.325 kPa • 760 Torr • 760,000 microns • VP6 CPS two stage Vacuum Pump • 6.25 CFM at 60 Hz • Ultimate vacuum pressure of 23 microns • Weldless Bulkhead • Connection allows for vacuum hose to be connected though the bottom polycarbonate cap • Seals against each side of plate via gasket • Digital Vacuum Gauge • Measures pressure from atmospheric to vacuum • Piping system • Minimizes pressure leak rate • Results • System reaches ultimate pressure in 10 – 12 minutes • Full integrated system reaches ultimate pressure of 150 microns • Full system leak rate of less than 150 microns per minute • Drop Tower Frame • Backbone of the microgravity drop tower • Supports vacuum chamber in a stable, upright position • Uses height adjusters at base to level the entire structure • Facilitates easy transportation via wheels, once tipped back • Swing out brackets at base of tower allow for added stability • Frame lays level when placed horizontally during transport and can be pushed flush against a wall during operation Vacuum Chamber & Energy Dissipation Design Achievements • Demonstrates standard local gravity • Drops two objects simultaneously • Allows for full drop visibility • Educational and inspiring • Mobile and stable structure • Aesthetically pleasing • Allows further static experiments • Vacuum Chamber • Schedule 40 clear PVC pipe • 0.15m (6in) diameter • 2.7m (9ft) tall • Catching Mechanism • Polystyrene bead filled sack • Absorbs energy dissipated by falling objects • Stand • Removable 0.20m (8in) tall stand • Supports any stationary vacuum experiments • Results • Allows full view of drop • Full absorption of energy from falling objects • Adaptable for non-falling experiments • Allows for adjustable pressure • Displays tower pressure • Appropriate tower height • Provides safe and intuitive operation • Drops objects with no horizontal motion • Allows objects to be changed out • Adaptable for a future continuous lift mechanism Dr. Satish Kandlikar Charlie Tabb Santiago Murcia, Yoem Clara, Dustin Bordonaro, Jacob Gray & Adam Hertzlin