Rocket Flight Dynamics Section 1, Team 4 Student 1, Student 2, Student 3 May 5, 2008

Rockets Analyzed Large IMU rocket Large vibration rocket Small vibration rocket All launches at Lucerne Valley dry lake bed Altitude: 2848 feet

How the RDAS functions 6 channels of data Onboard accelerometer Onboard pressure sensor Samples at 200 Hz Runs on 9V battery supply

IMU and Vibration Sensors IMU 3 MEMS Accelerometers 3 MEMS Gyroscopes Vibration Piezoelectric strain gauges X axis Y axis Z axis

Modal Shapes Model rocket as a uniform beam At natural frequencies, distinct modal shapes Values of natural frequencies depend on beam dimensions and material properties Mode 1: Mode 2: Mode 3:.

Large IMU Rocket Launched April 26, 2008 with G339N motor RockSim used to model launch Estimated Apogee of ft

Large IMU Rocket Approximations Any point before time=0 needs to be set to zero Account for calibration drift Over thrust curve, all other sensors should be zero Noisy x and z gyroscopes have negligible effect Integration error doesn’t affect apogee

Large IMU Rocket Apogee at 5.45 seconds Made several approximations to eliminate noise Model only works until apogee

Large Vibration Rocket Launched April 19, 2008 with G69N motor Severe weathercock RockSim trajectory portrays weathercock

Large Vibration Rocket Six vibration sensors connected to RDAS Sensor 10 assumed as input 72.39cm 60.64cm 46.67cm 31.75cm cm 0 cm ADC0 ADC1 ADC2 ADC3 ADC4 ADC

Large Vibration Rocket Applied Fourier transform Treating sensor 10 as input, plotted FRF

Large Vibration Rocket Identified three resonant peaks Mode 1 assumed to be at Hz

Large Vibration Rocket Mode 2 assumed to be at Hz

Large Vibration Rocket Higher Mode at Hz

Small Vibration Rocket Launched April 19, 2008 with G104T motor Camera drew power from battery Parachute did not deploy

Small Vibration Rocket Five vibration sensors connected to RDAS Sensor 10 chosen as input 37 in 28 in 22 in 8 in 1 in ADC0 ADC1 ADC2 ADC4 ADC

Small Vibration Rocket Applied Fourier transform and 50 Hz filter Treating sensor 10 as input, plotted FRF

Small Vibration Rocket Identified two resonant frequency peaks Mode 1 assumed to be at Hz

Small Vibration Rocket Mode 2 assumed to be at Hz

Summary Large IMU Apogee at 5.45 seconds Modeled altitude at apogee of 3382 feet Large Vibration Three natural frequencies: Hz, Hz, Hz Small Vibration Two natural frequencies: Hz, Hz

Acknowledgements E80 lab professors Mary Cardenas, Reza Miraghaie, Erik Spjut, Ruye Wang, and Qimin Yang Lab proctors and Rocket Development Team Reference 1 Reference 2 Reference 3

References Miraghaie, Reza, Modal Vibration, ationLecture.pdf Remote Data Acquisition System, Spjut, Erik, Wang, Ruye, Inertial Navigation,