Critical Design Review Carnegie Mellon Rocket Command Jan 16, 2018 - PowerPoint PPT Presentation

Project SCOTTIE: Critical Design Review Carnegie Mellon Rocket Command Jan 16, 2018 1

Table of Contents 1. Vehicle Overview …………………………………………………………………………………………. TBD 2. Subscale Launch ………………………………………………………………………………………..... TBD 3. Apogee Targeting System …………………………………………………………………………….. TBD 4. Recovery Subsystem ……………………………………………………………………………………. TBD 5. Mission Performance Predictions ……………........................................................... TBD 6. Payload Overview ……………………………………........................................................... TBD 7. Requirements Compliance Plan ………………........................................................... TBD 8. Logistics ……………………………………………………………………………………………………….. TBD 2

Table of Contents 1. Vehicle Overview …………………………………………………………………………………………. TBD 2. Subscale Launch ………………………………………………………………………………………..... TBD 3. Apogee Targeting System …………………………………………………………………………….. TBD 4. Recovery Subsystem ……………………………………………………………………………………. TBD 5. Mission Performance Predictions ……………........................................................... TBD 6. Payload Overview ……………………………………........................................................... TBD 7. Requirements Compliance Plan ………………........................................................... TBD 8. Logistics ……………………………………………………………………………………………………….. TBD 3

Vehicle Overview Motor Cap, Base, and Plate UAV Nosecone UAV Electronics 3 Tapered GPS Shoulder Sub- Fins Compartment Drogue Chute Main Chute 75 mm Ballast Recovery ATS Bay UAV Bay Motor Containe Bay Tube r 3:1 Ogive Nosecone Upper Lower Middle Nosecone Airframe Airframe Airframe Airframe =Switchbands 4

Summary of Vehicle Specifications Vehicle Section Dimensions Mass (lb) Ogive Nosecone 18” Length x 6.17” Base Di. X 2.44 4” Shoulder Nosecone Airframe 8” L x 6.17” OD 0.927 Upper Airframe 28” L x 6.17” OD 3.5 Middle Airframe 20” L x 6.17” OD 2.5 Lower Airframe 24” L x 6.17” OD 3 UAV Bay 15” L x 6” OD 5.41 Recovery Bay 10” L x 6” OD 3.53 ATS Bay 10” L x 6” OD 3.99 Fins [Next Section] 2.75 Motor Retention [Next Section] 3.17 Switchbands (x3) 2” L x 6.17” OD 0.25 Total 6.17” D x 105” L 36.75 (Dry), 46.81 (Wet) *All airframe components, couplers, and bulkheads are G10 fiberglass. 5

Fin Design 3 Fins • Trapezoidal planform • 7 degree bevel cross • section G10 Fiberglass • 3/16” Thick • Fin flutter calcs.: •  Flutter Velocity- 2909 ft/s  Max rocket velocity- 650 ft/s 6

Motor Retention System 7

Table of Contents 1. Vehicle Overview …………………………………………………………………………………………. TBD 2. Subscale Launch ………………………………………………………………………………………..... TBD 3. Apogee Targeting System …………………………………………………………………………….. TBD 4. Recovery Subsystem ……………………………………………………………………………………. TBD 5. Mission Performance Predictions ……………........................................................... TBD 6. Payload Overview ……………………………………........................................................... TBD 7. Requirements Compliance Plan ………………........................................................... TBD 8. Logistics ……………………………………………………………………………………………………….. TBD 8

Primary Subscale Model Parameter Value Length 57.5 in Schematic Diameter 3.125 in Dry Mass 93 oz (5.8125 lb) Wet Mass (CTI I212) 110 oz (6.875 lb) Wet Mass (CTI I236) 107 oz (6.6875 lb) Airframe material G12 Fiberglass As-built Airframe thickness 0.0625 in 9

Ejection Charge Testing Drogue Charge 1.0 g: Unsuccessful • 1.2 g: Successful • Main Charge 1.0 g: Successful • Conclusion 1.2 g black powder for drogue charge • 1.0 g black powder for main charge • 10

Launch 1 – Dec 9th Good liftoff and ascent • Drogue chute deployed at apogee • Main ejection charge failed to separate • airframe at 700 ft No visible damage on landing • Liftoff Success Sensor data up until apogee still relevant • Result: Unsuccessful • Drogue Chute Success Main Chute Failure 11

Launch 2 – Dec 9th Unstable liftoff – insufficient rail exit velocity • Resulted in steep liftoff angle • Drogue ejection charge failed to deploy • Main chute successfully deployed at 700 ft Liftoff Instability • Zippered airframe and damaged fin • Cause by chute deployment or impact • with tree Sensor data not valid for duration of flight • Result: Unsuccessful • Damaged Fin Zippered Airframe 12

Secondary Subscale Model Parameter Value Length 30.5 in Schematic Diameter 1.63 in Dry Mass 7.56 oz Wet Mass (Estes D12-5) 9.07 oz Airframe material Kraft Paper Airframe thickness 0.079 in As-built 13

Launch 3 – Jan 4 Good liftoff • Main parachute successfully deployed 5 • seconds after burnout Successful recovery • Sensor data valid throughout flight • Result: Successful • Liftoff Success Recovery Success 14

Sensors Primary Subscale Secondary Subscale Stratologger CF Altimeter Stratologger CF Altimeter (Recovery) • • Control recovery ejection charges Record altitude data for launch • • verification Record altitude data for launch • verification MPL3115A2 Altimeter • Record altitude data for ATS • system testing BNO055 IMU • Record IMU data for ATS system • testing 15

Post-Launch Analysis OpenRocket simulations accurately model the in flight altimeter data recorded 16

Coefficient of Drag Estimation The ATS altimeter altitude data was • differentiated to get velocity and acceleration (less noise than Stratologger data) • Acceleration was converted into drag • force based on mass of the subscale Coefficient of drag was calculated based • on the recorded velocity of the subscale Average value of 0.39 • High variability • 17

Table of Contents 1. Vehicle Overview …………………………………………………………………………………………. TBD 2. Subscale Launch ………………………………………………………………………………………..... TBD 3. Apogee Targeting System …………………………………………………………………………….. TBD 4. Recovery Subsystem ……………………………………………………………………………………. TBD 5. Mission Performance Predictions ……………........................................................... TBD 6. Payload Overview ……………………………………........................................................... TBD 7. Requirements Compliance Plan ………………........................................................... TBD 8. Logistics ……………………………………………………………………………………………………….. TBD 18

ATS Overview Active prediction and control • system predicts apogee and enacts the appropriate control Electronically controlled drag • inducing flaps respond by extending and retracting to control speed 19

ATS Timeline 20

Flap Deployment System Features central hub • controlling flap extension through rotation Couples to • electronics bay using threaded rods and servo connection 21

Air Brake Flap Design 22

Air Brake Flap Performance Flap CD evaluated at • key positions to provide prediction model a precise measurement of CD at different flap positions Rectangular flap design • produces a predictable, interpolable CD curve 23

Electronics Bay Sensor system 4x MPL3115A2 • altimeters BNO055 IMU • Computational system Raspberry Pi 3 • Deployment system SB2282SG servo • 24

Flap Deployment System and Electronics Bay Connection 25

Prediction and Control Overview 26

Apogee Prediction Model Design Given a state X t including an altitude h t , vertical velocity s t and attitude h t 1. While ( s t > 0) Set X t to the prediction of X t+dt 2. Take h t to be the vehicle’s apogee. Repeatedly predicting vehicle state one time step into the future using • known launch vehicle physics and flap position based drag model Once vertical speed has reached 0, we take the current altitude to be • apogee 27