California State University, Long Beach USLIJanuary 22, 2018

Critical Design Review

System Overview Nose Cone

RDM and Rover

Drogue Deployment

Avionics Main Deployment

Propulsion

Launch Vehicle Dimensions

24’’ 16’’ 8’’ 13’’ 15’’ 27’’

• Total Length: 103 inches

• Airframe OD: 6.17’’ ID: 6.00’’• Coupler OD: 5.99’’ ID: 5.78’’• Motor OD: 2.97’’ ID: 2.77’’• Centering Rings .25’’ thickness

Mass Statement

Section Mass (lb)

Nose cone/Payload 14.82

AV Bay 4.77

Propulsion 19.17

Total 38.7

● Mass Margin○ Maximum Mass: 51.47 lb, 33% difference

Fin AnalysisAeroFinSim - By AeroRocket/John Cipolla

• Analysis performed on all four carbon fiber fins

• Program uses Pine’s Approximation Method to calculate Divergence and Flutter Velocity

• AeroFinSim was also used to perform stress analysis

Fin AnalysisDivergence and Flutter Velocity

*Maximum Velocity: 645 ft/s

• Divergence Velocity is the critical speed at which the elastic stiffness becomes insufficient to hold the fin in position

• Flutter Velocity is the lowest speed at which an elastic body flying at given conditions will exhibit sustained harmonic oscillation

Fin AnalysisStress Analysis

• AeroFinSim calculated fin stress as a function of velocity up until the flutter velocity

• The stress experienced at the flutter velocity is still less than the maximum allowable fin stress

Stress Analysis - Centering Ring

Stress analysis results using SolidWorks Simulation

• Orange arrows represent fixed geometry where centering ring is screwed into airframe

• Purple arrows represent force of motor equal to 371 lbf

Stress Analysis - Thruster Plate

• Green arrows represent fixed geometry where thruster plate is screwed into thruster mount

• Purple arrows represent force of motor equal to 371 lbf

Stress analysis results using SolidWorks Simulation

Stress Analysis - Fin

• Green arrows represent fixed geometry where fin is epoxied into the airframe

• Purple arrows represent a force of 97.5 lbf representing impact if fin were to land on that edge

Stress analysis results using SolidWorks Simulation

Motor Selection

• AeroTech L1390G

• Provides sufficient thrust to reach apogee of 5280 ft.

Motor Thrust Curve from OpenRocket Simulation

Stability

• Measured from tip of nose cone:

• Center of Gravity 65.258 inches

• Center of Pressure 80.675 inches

• Stability Margin = 2.5 cal80.675 - 65.2586.17

Flight Simulations

• Total Mass: 38.7 lbs

• Projected Apogee: 5295 ft

• Thrust to Weight Ratio: 7.984

• Velocity Off Rod: 75.9 ft/s

Recovery Subsystem

Changes Made Since PDR● Main and Drogue Parachute location

○ Main Parachute inside Propulsion Bay○ Drogue Parachute inside Payload Bay○ Main priority was to protect the

Payload Bay ● Follow NASA’s suggestion

○ Switch the location of Main and Drogue parachutes

○ Main Parachute inside Payload Bay○ Drogue Parachute inside Propulsion

Bay○ Better parachute spacing, higher LV

spacing, kinetic energy upon landing of each component will still be under 75 ft-lbs

Main and Drogue Parachute

Approx. Full-Scale

Launch Vehicle Weight

= 32.1-lbs

Type Size/Type Drag Coefficient

Descent Velocity (fps)

Drogue

20" FC TARC Parachute 1.50 90.67

Main 84" FC Iris Ultra Parachute

2.20 17.86

● Maximum allotted kinetic energy upon each section is 75 ft-lbs.

Recovery ComponentsComponents

3/8” Flat Nylon Webbing (34' and 28')

5/16" Galvanized Steel U-Bolt (600 lb Capacity)

3/8" Zinc-Plated Steel Quick Links (2,200 lb Capacity)

6061 Aluminum Bulkheads (1/4" Thickness)

Terminal Blocks

PVC Ejection Charge Holders

Shock Cord Protector Sleeves

Nomex Kevlar Protective Blankets

Deployment Bag

4-40 Nylon Shear Pins

Drift Calculations● Assumptions

○ Launch vehicle will be above launch point at apogee

○ Drift speed is equal to wind speed● Drogue parachute deployed at apogee● Main parachute (500 feet)

Wind Speed (mph)

Wind Speed (fps)

Drogue Drift (ft)

Main Drift (ft)

Total Drift (ft)

0 0 0 0 0

5 7.33 385.84 205.30 591.14

10 14.67 771.68 410.60 1182.28

15 22 1157.51 615.90 1773.42

20 29.33 1543.35 821.20 2364.56

Drogue Deployment Altitude (ft)

5280

Primary Deployment Altitude (ft)

500

Landing (ft) 0

Drogue Descent Time (s)

52.61419923

Main Descent Time (s) 27.99552072

Kinetic Energy

Kinetic Energy for Each Independent Upon Landing

Section Weight (lb) Mass (slugs) Descent Velocity (ft/s) Kinetic Energy (ft-lb)

Payload Bay (Top Section)

14.30 0.44 17.86 70.83

Avionics Bay (Middle Section)

4.77 0.15 17.86 23.63

Propulsion Bay (Bottom Section)

13.05 0.41 17.86 64.64

● Maximum allotted kinetic energy upon each section is 75 ft-lbs.

Tests of Staged Recovery System

● Drogue Pop Test● Successful● Using 3.41 g of

Black Powder

Tests of Staged Recovery System (Cont.)

● Main Pop Test● Semi-Successful● Using 3.08 g of

Black Powder● Mainly due to

packaging of main parachute

● Fixed via better packaging (more condensed in the airframe)

Subscale Test Flight

• Subscale: 66.7% of the Full-Scale• Total Length: 70 in.• Diameter: 4.024 in.• Motor: AeroTech K805• Static Stability: 2.68 lb

Subscale Result

• Apogee: 4111 ft• Max Acceleration: 9.5 G• Max Velocity: 534 ft/s• Experimental Drag: 0.58

Subscale Recovery● Main and drogue parachutes

successfully deployed● Slight tangle on drogue shock cords;

due to tight packaging of the drogue causing a higher probability for the shock cords to tangle.

● Shock cord layout on drogue compartment was overlooked (longer cord and shorter cord locations switched during launch)

● Ground testing proved it would still deploy - believe this might cause a higher probability for tangling

● Fixes include better spacing and packaging of the parachutes to decrease any risk for tangling during descent.

Launch Vehicle Testing Plan

• Full-Scale Ground Test• Objective: Validate black powder charges are sufficient to break all shear pins and

separate all 3 sections of the launch vehicle

• Success Criteria: All sections successfully separate and all parachutes deploy• Procedure: Ejection charges are loaded into the AV. All sections are assembled and

secured with shear pins. LBR will manually eject the charges

Launch Vehicle Testing Plan

• Full-Scale Flight Test• Objective: Validate the flight characteristics, recovery and structural integrity of the

full-scale LV and demonstrate a working payload system

• Success Criteria: The LV is stable during flight and is fully recoverable.• Procedure: The LV is manufactured based on the design planned in the CDR

report. The performance of the flight is analyzed for competition launch.

Launch Vehicle Testing Plan

• AV Bay Switch Test• Shock Cord and Bulkhead Strength Test• Airframe Test• Vibration Test

Design Experiment - Rover Deployment Mechanism

RDM Design OverviewObjective: Separate nose cone from the airframe to enable rover deployment from internal compartment

RDM uses a system of:● Three rods

○ One threaded (14”)○ Two unthreaded (14.5”)

● Two Bulkheads ○ Motor bulkhead with electronics bay○ Nose cone bulkhead with entrapped nut

● One rover pushing-plate with entrapped nut● Motor and electronics

Motor Bulkhead

Electronics Bay

Nose Cone Bulkhead

Rover-pushing-plate (0.5” thick)

Rover

Mechanical Hardware

14” Medium Strength Grade B7 Threaded

Rod

14.5” 6061 Aluminum

Un-threaded rods

Electronics Bay● Electronics Bay Assembly (5.25”)

Components:○ Electronics Bay

■ 6” diameter, 4.42” long○ Detachable Motor Bracket○ Motor Bracket Cover ○ Motor Bulkhead Cover with rod

couplers■ 0.827”

● Houses RDM Electronics

● Constructed from 3D printed ABS material

Motor and Electronics System Activation

○ Limit switch○ 2.4GHz Digital Transmitter/Receiver

Motor and Electronics○ 118 RPM HD Premium Planetary Gear

Motor w/Encoder■ Stall Torque: 958.2 oz-in■ rotary encoder for motor feedback

○ Arduino Nano Microcontroller○ L298N H-Bridge○ 11.1 V LiPo Battery

■ 1800mAh

System Integration and Interfaces

● The base of the electronics bay is 17” from the top of the 36” airframe.

● The rods stick 4” into the nose cone.

● The nose cone coupler attach the nose cone to the airframe

● Secured together using 4-40 Nylon Shear Pins

Testing Plan

● Communication Range Test

● Full Rover Deployment Test

● Rover Deployment Drop Test

● Rotary Encoder Test

● Radio Transceiver-Receiver Channel Value Test

● Maximum Load Test

● Shear Pin Breakage Test

Design Experiment - Deployable Rover

Rover Design Overview● Objective: Autonomous deployable

rover capable of traveling 5 feet from rocket and deploying solar panels

● Triangular rover chosen

● Light yet robust for impact, can traverse rough terrain, and efficiently stored and deployed from RDM

● Capable of deploying in any orientation

● Components will be both purchased and manufactured by the team

Rover Drivetrain● Motor mount allows for simple internal assembly and a means to secure components.

● One motor to drive each side using gearbox system.

● Center driveshaft simultaneously rotates all three wheels.

● Rover will change heading using differential drive.

● Rubber tires used over 3D printed wheels for additional traction.

Bogie System● Bogie system acts as suspension. All 4 wheels make contact with the ground.

● Titanium rod-high strength and low weight

● Ball joint is needed as the connection cannot be fixed and needs movement

● 3D printed ABS parts specific to LBR rover design

● M3 screw and locking nut for fastening

Solar Panel Deployment

• Servo is attached to 3D printed motor mount.

• Motor mount is designed to house all electronics and to fully utilize the space inside the rover

shell.

• Solar panels deployed using a servo and connecting rods.

• The solar panels designed to orient rover so that the solar panels are facing the sun.

Rover Electronics

● 2X 116 RPM HD Premium Planetary Gear Motor

○ Stall Torque: 159.7 oz-in○ 0.2A no load current at 12V

● Hitec HS-7950TH Servo○ 403 oz-in torque at 6V

● Arduino Nano Microcontroller

● MPU 6050 IMU

● L298N H-Bridge Motor Driver

● 11.1 V LiPo Battery○ 1800mAh

Rover ControlChallenge Approach

Landing Orientation Natural shape of rover allows landing any orientation. Rover will proceed in direction with no obstacles.

Traversing in a straight line PID is used for response to change in orientation and systems response to create yaw suppression

Obstacle Detection Rover detecting lack of movement and attempt to circumvent object until successful.

Solar panel deployment timing Discrete-Closed Loop ResponseControl choice of discrete closed loop response because it allows the continuous loop to be exited.

Rover flipping If the rover is flipped, it will land on another set of wheels and change its heading to a different direction to avoid flipping over again

Rover Testing PlanRequirement Verification Plan

Impact Testing Rover will be subjected to indirect impact of up to 30 ft/s to simulate rocket landing and remain operable

During launch the rover will be subject to vibrations which it must withstand.

The team will create a testing apparatus that will vibrate the rover for an hour of which after the rover must remain operable

Rover must traverse a variety of environmental conditions.

Rover will be tested in a variety of ground conditions including large obstacles to test object avoidance system.

Rover must be able to transverse up an incline of up to 45°.

Rover will be tested on rough terrain with 45° slope. If this angle is exceeded it must use obstacle avoidance to find an alternate route.

Significant Failure Mode - Launch Vehicle

● Tail Fins shear off or deform during flight due to fin flutter○ Fin analysis was performed and it can be seen that the stress experienced at

the flutter velocity is still less than the maximum allowable fin stress● Proper fin alignment during assemble

○ As seen in the CDR report a 3D printed jig has been created to align the fins when epoxy is being applied

○ This method was tested during the subscale launch and proved to be successful

● Centering rings or thruster plate failure○ Stress analysis was performed on the centering rings and thruster plate to

ensure no deformation or fractures occur during launch

Significant Failure Mode - Recovery

● Parachute does not deploy○ Parachute will be properly integrated as by the procedures listed the Launch

Operation Procedures of the report○ Primary and backup ejection charges will be used as discussed in the recover

and avionics section of the paper to ensure that the parachutes will deploy even if one of the main ejection charge fails

● Parachute has a rip or tear○ Parachute will be inspected before it is integrated into the launch vehicle as

stated in the Launch Operation Procedures● Electronics failure of avionics system

○ Design of avionics bay is discussed in the recovery and avionics section and goes over ways to avoid electronics failure such as securing the batteries in place by fixing the avionics tray between two wooden boards so that the batteries do not disconnect during flight

Significant Failure Mode - Rover

● Rover damaged from forces subjected to during flight○ Sub-scale launch verified that the rover material was capable of handling all

forces that the rover would be subjected to during flight● Rover getting stuck on terrain

○ Wheel design is discussed in the rover section of the paper with the plans on how to design and test the rover wheels so that it is capable of handling the terrain at the launch site

● Rover veering off course○ IMU sensor will be used on the rover to detect gyroscopic and acceleration

data so that the rover can analyze its motion and correct itself as discussed in the rover section of the report

Significant Failure Mode - RDM

● RDM deploys during flight○ Subscale launch proved the electronics system function as desired and the

RDM system did not deploy during flight● RDM becomes damaged from the forces of flight

○ The RDM section of the report goes over the materials that are going to be used for the RDM system and what was successful for the subscale launch

● RDM does not deploy when activated○ Subscale launch verified that the RDM system was capable of being

deployed when desired

Project Plan

Status of Requirements Verification

• Launch Vehicle Requirements Verification• 25/46 requirements verified• Remaining requirements will be verified in February• All requirements shall be verified by FRR

• Payload Requirements Verification• 2/4 requirements verified• Remaining requirements will be verified during the full-scale flight test

in February and March• All requirements shall be verified by FRR

• Safety Requirements Verification• 18/18 requirements verified

Timeline

• Full-Scale test launch on February 24, 2018

Educational Engagement

Event Date Estimated Attendees

Girls Day at the Beach (1) 3/2017 50

Girls Day at the Beach (2) 9/2017 200

Introduction to Engineering Presentations

2/2018 100

MAES Latinos in Engineering Bottle

Rocketry

3/2018 60

High School Engineering Presentation

4/2018 500

TOTAL 1160

Budget-ExpensesSubteam Projected Expenses

RDM $178.84

Rover $553.58

Avionics $538.63

Recovery $517.10

Launch Vehicle $2,295

Business $8,670

Total $13,870.91

Budget-Income

Source Income

College of Engineering $4,200

AIAA - CSULB $1,500

Fundraisers $1,500

ASI Travel Grant $7,000

Sponsorships $600

Total $14,800

Thank You!