Gyroscopic Rocket Stabilization
FInal Project for Experimental Engineering, HMC
Jan - May 2016
Experimental Engineering is a core sophomore level engineering course where, as my professor explained, “engineers learn what to do with their hands.”
For the final project, my three team members and I investigated the effects of gyroscopic rocket stabilization induced by a high roll rate. Meaning we added canted fins to make the rocket spin and compared its stability to a non-spinning flight.
The actual spin of the rocket is hard to see, but the spiraling smoke helps illustrate the spinning. This video is great because the rocket starts veering off slightly, but as the roll rate increases the rocket actually straightens out.
Auxiliary fiberglass fins secured via custom clamp for easy attachment. The primary fins (at the very bottom) were required to stay in place due to safety concerns.
To analyze the stability of the rocket, the orientation of the rocket was determined from the gyroscope readings. The plots track the position of the tip of the rocket such that (0,0) indicates the rocket is upright. Additionally, the periodic “centers” of the paths are plotted as points to illustrate the relative stability. The plot axis are equal scale for fair comparison.
Ultimately, the spinning rocket registered a staggering 1500 RPM. In fact this registered voltage was outside of the documented linear region of the sensor, thus to verify the accuracy of the reading, the team stuck the IMU in a lathe to create a calibration curve up to 2000 RPM (rocket payloads fit nicely in lathes).
Looking at the normal flight (left) there is clearly more chaos compared to the spinning flight (right). Specifically, the “centers” are more erratic in the normal flight. The wide circular path of the spinning flight is likely due to the imbalance of moment of inertia of the rocket.
Overall, the high roll rate clearly had a significant effect on the stability of the rocket, though further investigation would be required to make a definitive conclusion. Some further steps could include using the canted fins alone without the primary fins, comparing the max altitude to estimates of energy dissipation, and properly balancing the rocket to avoid spiraling instability.