On Tuesday, March 7th, members of our rockets Intercollegiate Rocket Engineering Competition (IREC) team visited Quanta Labs to perform a vibration test of our avionics system. Our unit passed the test. No major problems were detected, but we did gain insight into how to make our avionics system even more vibration and shock tolerant.
The Avionics System:
The avionics system in our rocket for IREC has been designed for high-reliability using redundant commercial altimeters and a custom student researched and developed flight computer. Its main function is to trigger deployment of the payload and recovery parachutes. In addition, the unit provides an RF beacon for locating the rocket after landing and a telemetry stream of live flight data using an RF link. Thanks to our recent sponsorship from Harwin, our avionics system features high-reliability connectors in important, safety critical connections.
The unit that we tested included the parachute deployment assembly and avionics. This full assembly sat inside a sample section of our in-house custom fiberglass and carbon fiber airframe. To fixture our airframe section to the shake table, a CNC’ed delrin clamp was bolted into the shake table.
Integration of the system on the shake table
Using a shaker table at Quanta Labs, we performed the following tests of the system
- 30G 6ms positive direction per axis, 3 axes
- 30G 6ms negative direction per axis, 3 axes
- 10Grms thrust axis 20Hz - 2kHz 20 seconds
- 7.6Grms lateral axes 20Hz - 2kHz 20 seconds each
The test specifications came from two sources. For shock, we used real values that we had recorded on previous flights. For vibration, we used the specs from the NASA Sounding Rockets User Handbook - Vehicle Level 1. These vibration specs are used to qualify payloads for going to space on NASA sounding rockets.
Here is a plot of the spectral content of the vibration applied for one of the tests:
To measure the continuity of the ignition lines from the avionics bay during the vibration and shock tests, we used one of our Keysight oscilloscopes, and recorded a 30 second session of the voltage across all of the lines.Our Keysight Oscilloscope used for recording ignition line continuity during the test
Here are some other pictures from our testing:Overhead view of the shake table
Connections for the test
We owe a huge thanks to Quanta Labs for providing their facilities and time to allow us to perform this test. Vibration and shock testing is critical for safety and reliability, and would not be possible without our sponsors.