CRT PDR 2017 - Cornell Rocketry...

Cornell Rocketry Team

Preliminary Design Review

CRT PDR 2017



AIRFRAME



LAUNCH VEHICLE DIMENSIONS

Total Length: 104”

Airframe Tubing Outer Diameter: 5.15” Inner Diameter: 5.00”

Coupler Outer Diameter:4.998” Inner Diameter: 4.185”

Motor Mount Tube Outer Diameter:3.141” Inner Diameter: 2.995”

Fin/Centering Ring/Bulkhead Thickness: 3/32”



LAUNCH VEHICLE COMPONENTS

Rivet

Shear Pin

Nose Cone

and Comms

Bay

Forward

Airframe

Main and

Drogue

DRS

AV

BayBooster

Main and

Drogue

L1150-P

Tail

Cone

Retainer

Blast Charge



MATERIAL SELECTION

G12 Fiberglass (Filament Wound)- Airframe, Coupler, Motor Mount, Nose Cone

Provides necessary strength to resist compressive forces experienced by LV during

launch

Chose standard fiberglass over thin-walled tubing for strength and countersinking

G10 Fiberglass (Laminate) - Bulkheads and Fins

Provide higher strength to thickness ratio compared to plywood

3D Printed ABS Plastic - Avionics Sled

Easily prototyped and manufactured in Cornell Rapid Prototyping Lab



MATERIAL SELECTION CONT.

Kevlar - Shock Cord

Stronger than nylon and more fire resistant

▪ Multipurpose 6061 Aluminum - Motor retention

▪ Provides Strength and heat resistance to retain motor

▪ ES6209 Aeropoxy - Fin fillets

▪ Creates stronger bonds than faster drying epoxy



MOTOR SELECTION

75mm AeroTech L1150-P

▪ Provides sufficient thrust for LV to

reach apogee

▪ Max acceleration of 7.56 G is low

enough for DRS to remain secured

and undamaged during takeoff



STABILITY

▪ From tip of nose cone:

▪ Center of Gravity (CG) = 60.83”

▪ Center of Pressure (CP) = 76.811”

▪ Stability margin = 76.811" − 60.83"

5.15"=3.11 cal

Center of Gravity

Center of Pressure



SIMULATION DATA

Total mass - 35.4 lb

Projected Apogee - 5235 ft

Thrust-to-weight ratio – 7.71

Velocity off rod - 74.4 ft/s



RECOVERY SYSTEM



RECOVERY SYSTEM CONT.

Launch Vehicle Component Drogue Parachute Size (in.) Main Parachute Size (in.)

Forward Airframe 15” 70”

Booster Section 14” 60”




Wind Speed (mph) Forward Section (ft) Booster Section (ft)

0 0 0

5 657.10 640.68

10 1314.20 1281.37

15 1971.31 1922.05

20 2628.42 2562.74




LaunchVehicle

Component

Drogue

Descent

Velocity

(ft/s)

Drogue Kinetic

Energy (ft-lb)

Main and Drogue

Descent Velocity

(ft/s)

Landing

Kinetic Energy

(ft-lb)

Forward Section 85 1638.167 14.920 50.892

Booster Section 85 1382.168 16.059 49.337




Parachute Deployment Method

Forward Airframe Drogue Nose Cone ejection at Apogee

Forward Airframe Main Jolly Logic Chute Release at 500 ft

Booster Section Drogue AV Bay ejection at Apogee + 2 s

Booster Section Main Jolly Logic Chute Release at 500 ft



NASA SL REQUIREMENTS

The vehicle will deliver the payload to an apogee altitude of 5,280 feet above

ground level

The selected motor causes the planned launch vehicle to reach the target apogee.

Ballast can be added or removed to adjust predicted apogee

The launch vehicle will be designed to be recoverable and reusable. Reusable is

defined as being able to launch again on the same day without repairs or

modifications

Durable materials are used to construct the launch vehicle. Additionally, each

component on the launch vehicle will be analyzed and tested prior to launch

All other NASA launch vehicle requirements are covered in the PDR



TEAM DERIVED REQUIREMENTS

Wires connecting the altimeters to the forward airframe blast charges must

separate at apogee.

Ground testing is performed to verify the wires properly separate.

The Communications bay must be accessible for construction and repair.

The nose cone coupler will be removable and riveted.

The DRS deploys successfully after the launch vehicle lands.

Ground testing is performed to ensure the rover is deployed regardless of the angle at

which the launch vehicle lands.



SIGNIFICANT FAILURE MODES

▪ Large kinetic energy on drogue descent rate could lead to parachute tearing

when main parachutes deploy.

▪ Sub-scale and full-scale launches are used to test parachute strength.

▪ Jolly Logic Chute Releases do not release main parachutes.

▪ Jolly Logic Parachute Releases are put in series.

▪ Separable Wiring separates prematurely so forward airframe parachutes are not

deployed

▪ Sub-scale and full-scale launches will test reliability of recovery system



DEPLOYABLE ROVER SYSTEM (DRS)



SYSTEM SUMMARY

▪ Rover▪ Two primary wheels

▪ One small support wheel for stability

▪ Long, thin chassis

▪ Sensors for object avoidance

▪ Unfolding solar panels

▪ Lead Screw Mechanism (LSM)▪ Lead screw connected to a motor

▪ Deploys rover from bottom of section



ROVER

▪ Primary Wheels▪ 4.75” diameter, 1.25” thick

▪ Jagged, 0.07” tall treads

▪ Rubber for increased friction

▪ Holes for LSM shafts

▪ Attached to motor horns



ROVER

▪ Chassis▪ 6.5” x 2.5” x 1.5”

▪ Three interlocking sections

▪ Machined from aluminum

▪ Low center of mass



ROVER

▪ Support Wheel▪ Prevents rover from flipping

▪ Folds to fit inside LV

▪ Extends after deployment

Rover

Motion

Wheel

Rotation

Chassis

Rotation

Support

Wheel



LSM

▪ Lead Screw Mechanism▪ 10.5” long, 0.25” diameter lead screw

▪ DC motor turns lead screw to deploy rover

▪ Two 11” long, 0.25” diameter guide shafts

▪ LSM secures rover during flight




▪ The rover falls from the section before landing.▪ Upwards accelerations at launch and parachute deployment.

▪ Mitigated during launch by coupler inside AV bay section.

▪ Mitigated by high holding torque of motor.

▪ Evaluated through thorough testing.

▪ The LSM guide shafts or lead screw are damaged.▪ Results in misalignment, compromises deployment.

▪ Mitigated by additional guide shafts.

▪ Force of ejection charges are directed to coupler

▪ Evaluated through shock and ground testing.



ELECTRICAL AND SOFTWARE



SYSTEM SUMMARY

▪ Modular design approach

▪ Power Distribution

▪ Distributes power to modules

▪ Controls

▪ Determines each module's actions

▪ Wireless Communication

▪ Sends signal to start LSM

▪ Motors

▪ LSM as well as rover

▪ Object Avoidance

▪ Solar Panels



POWER

▪ Distributes and regulates power to all modules

▪ Provides overvoltage and

▪ Provides overcurrent and overvoltage protection to other modules

▪ Must supply 5V to both microcontrollers

▪ Must supply 6V to motors

▪ LiPo batteries

▪ High energy density

▪ Lightweight

▪ Rechargeable



CONTROLS

▪ Determines state of system

based on data inputs

▪ LSM:

▪ Transmitter

▪ Receiver

▪ Motor

▪ Rover:

▪ Sensors

▪ Motors/Wheels

▪ Solar Panels

▪ Display



WIRELESS COMMUNICATION

▪ Send signal to microcontroller in launch vehicle to start LSM motor

▪ Desired minimum range of 1 mile

▪ Receiver located in launch vehicle

▪ RFM98W LoRa module will be used

▪ 2.5 mile range



MOTORS

▪ LSM:

▪ DC Motor

▪ Electrically isolated from Controls Module

▪ Rotates in one direction

▪ Rover:

▪ Low torque requirement

▪ Continuous Rotation Servos

▪ Simple speed and directional control



OBJECT AVOIDANCE

▪ Object avoidance will be implemented using proximity sensors

▪ Time of Flight Distance Sensors

▪ Mounted on front of rover

▪ Used to detect objects in path

▪ Accurate

▪ Reliable



SOLAR PANELS

▪ Small servo motor will unfold panels on top of the

rover

▪ Two panel design

▪ 2.75” x 2.165”

▪ Voltage output from solar panels will be shown on a

display onboard the rover




▪ Damage to electronics during launch

▪ High acceleration could damage electronics or break connections

▪ System would become inoperable or damaged

▪ Mitigated by using printed circuit boards to eliminate physical

connections

▪ Wireless communication fails

▪ Launch Vehicle lands out of range

▪ LSM would fail to activate

▪ Mitigated by range testing the communication and ensuring at least 1

mile range



REQUIREMENTS COMPLIANCE

▪ The DRS shall deploy from the internal structure of the launch vehicle.

▪ The LSM secures the rover inside the LV during flight.

▪ The LSM deploys the rover from the end of the section after landing.

▪ After landing, the DRS deployment shall be triggered by a remote signal.

▪ After deployment, the rover shall autonomously move 5 ft from the LV.

▪ Primary wheels move the rover

▪ Stabilizing wheel to prevent flipping

▪ Obstacle detection and steering

▪ After the rover stops, it shall deploy foldable solar panels.

▪ Servo motor actuates panels



COMMUNICATIONS



SYSTEM REQUIREMENTS

NASA SL Requirements:

Determine launch vehicle position during the flight using GPS data

Incorporate GPS and other radio transmitters into the launch vehicle

Determine the location of the launch vehicle using the GRB, SRB, and the

TRACER after landing

Utilize backup systems in case a system fails to operate as expected



SYSTEM REQUIREMENTS

Team-derived Requirements:

Obtain video during flight of launch vehicle through onboard camera

Camera run by Raspberry Pi

Save and transmit all flight information for vehicle tracking and post-launch

analysis

Use TRACER to write sensor data to SD card



ELECTRICAL COMPONENTS



SIMPLE RADIO BEACON (SRB)

Morse Transmission of HAM Radio Operator callsign

Requires minimal power

Utilized for simple direction finding (using “fox hunting” technique)

Transmit power at 100 mW



GPS RADIO BEACON (GRB)

Transmits APRS packets to handheld radio

Enable CRT to find location of launch vehicle sections to within 10 meter range

Redundancy system for Simple Radio Beacon

Transmit power at 100 mW



TRACER MODULE ELECTRONICS

Arduino Uno

Raspberry Pi Zero W

GPS Module

Barometer

Accelerometer

Gyrometer

Camera

LoRa Radio

SD Card



GROUND STATION GUI

LoRa radio will be connected to high-gain Yagi directional antenna, which will be

connected to a custom board for data formatting and then streamed to the

Ground Station Laptop

CRT GUI will utilize information obtained from the connected board to plot

velocity and location information, as well as map the rocket to assist in quickly

finding the location of the launch vehicle after landing




Short-Circuit

Detached components could cause damage to tracking systems

Prior to launch all components will be checked and wires secured to rocket

All Communications equipment will also be subject to vibration testing

Battery Rupture

Improper charging/discharging of LiPo battery can increase explosion risks

Failure could cause damage to rocket or premature nosecone ejection

Risk mitigated using smart charger that prevents overcharging

Larger capacity batteries used to prevent over-discharging



INDEPENDENT TEST & VALIDATION

(INTEV)



MISSION REQUIREMENTS

Verify that all components on board the launch vehicle are capable of completing

the mission.

Develop appropriate testing procedures that produce valuable data through

reliable and repeatable testing of components.

Build long-term, general-use testing devices to validate models and predictions.



PLANNED TESTING

Specific subsystem tests

Parachute Test Rig (PTR)

General test rigs

Shock Test Rig (STR)

Centrifuge



PARACHUTE TEST RIG (PTR)

▪ Objective: To measure drag force of a parachute at airspeeds up to 90mph

▪ Verifies: Landing kinetic energy requirements are met

▪ System level design:

Wind Tunnel Air

Flow

Parachute

Attachment

Cable

Test Parachute

Tension Force

on Electronic

Scale

Attachment

Cable around

Pulley



SHOCK TEST RIG (STR)

Objective: To measure the shock response of tested components

Verifies: Flight hardware responds as expected to shock during various stages of

flight (liftoff, parachute ejection, landing impact)

System level design:

Test articleMounting

Platform

Give potential

energy to

platform

Release energy

through

acceleration

(shock)

Measure

Acceleration



CENTRIFUGE

Objective: To test components under launch condition g-forces

Verifies: Flight hardware and components respond as expected to high levels of

acceleration (8g’s)

Hardware Design: Controls Design:

MotorMotor

ControllerBatteries

Laptop



PROJECT PLAN



TIMELINE



EDUCATIONAL OUTREACH



BUDGET- EXPENSES



BUDGET- INCOME

Date post:	16-Oct-2020
Category:	Documents
Upload:	others
View:	1 times
Download:	0 times

CRT PDR 2017 - Cornell Rocketry...

Documents