1. Joe Mozloom Eric Marz Linda McLaughlin Swati Maini Swapnil Mengawade Advisor: Jin Kang, PhD 1

2.  Drexel's RockSat payload will incorporate a platform rotating opposite the spin-stabilization of the Terrier- Orion sounding rocket during ascent, resulting in a rotationally static platform from an outside reference frame. 2

3.  Experimentally determine the feasibility of a despun platform under high acceleration and turbulence, driven by a low power system.  Provide a stable platform with respect to the exterior environment to accommodate experiments requiring constant frame of reference in an ascending object. 3

4.  Angular Velocity  ω = dθ / dt  At 5.6 Hz ω = 35.18 rad/sec  Radial Acceleration  a r = ω 2 r  At 35.18 rad/sec  With 0.0635 meter Radius a r = 78.62 m/s 2 = 8 g 4 ω arar atat

5. WORKBENCH  Meet all NASA / WFF requirements  Counter-rotating platform effective from 0.5 Hz - 10 Hz  Maximum platform spin-rate 10% of current canister spin- rate  Data is reliably collected and is usable FLIGHT  Meet all NASA / WFF requirements  Counter-rotating platform engaged when canister is spinning  Platform able to rotate under harsh flight conditions  Data is reliably collected and is usable 5

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7.  There are several flight points which are of interest to our experiment (Seen on next slide)  Rotation measurements of despun platform during following time periods:  Terrier Burnout  Orion Burnout  Remaining Ascent  Descent 7

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9. Despun Platform (DP) Motor Systems (MS) Data Systems (DS) Power Systems (PS)  Slip Ring  Despun Gear  DC Micro-motor  Pinion  Microcontroller  Memory  Accelerometers  Algorithms  Batteries  Voltage Regulators  G-Switch 9

11.  System Components  Through-Bore Slip Ring  Slip Ring Fastener  Undefined until Slip Ring is selected  May be unnecessary if mounting holes can be drilled into slip ring  Despun Plate/Cog  2-axis, High-G Accelerometer 11

12.  4:1 Gear Ratio between platform and motor pinion  Reduces torque needed by motor  Despun gear nominal dimension of 5” (127 mm)  Gear to be CNC cut from ¼” (6.35 mm) polycarbonate  Fabricated In-House 12

13. 1Platform shall be able to rotate at > 500 RPM 2 System shall be able to pass ≈ 2.2 mA from microcontroller to accelerometer 3 System shall be able to pass ≈ 5 V from microcontroller to accelerometer 4Slip ring shall include > 5 circuits for data and power transmission 5System shall perform throughout 25g acceleration 6System shall allow for center standoff 7Platform shall be < 7” 13

14. Slip Ring Jinpat LPT012 Aeroflex CAY-1847 Aeroflex CAY-1666 Max RPM6610 Max Voltage10 Max Amperage10 Through Bore989 Height777 Mass798 Cost1072 Availability399 Max Vertical Load688 Torque677 Totals758180

15.  Aeroflex Airflyte CAY 1847  Max RPM: 500  Through-Bore Diameter: 3/8” =9.525 mm  Length: 1.3” = 33.03 mm  Stator Diameter: 1.25” = 31.75 mm  # of Circuits: 18  Max Voltage: 210 V  Max Current: 2A/Circuit  Cost; $400 15

16.  DP.RSK.1  Sensor will not function  DP.RSK.2  Teeth on gear will break due to elevated torque levels from acceleration  DP.RSK.3  Vibrations will cause loss of contact in Slip Ring Terminals  DP.RSK.4  High Gs will cause slip ring bearings to seize  DP.RSK.5  High Load causes gear to distort, losing contact with pinion PROBABILITY CONSEQUENCES DP.RSK.3 DP.RSK.5 DP.RSK.4 DP.RSK.1DP.RSK.2 16

17. Power Supply Stationary Accelerometer Microcontroller Despun Accelerometer Slip Ring Digital to Analog Converter Motor 17

18. 18 AccelerometerGyroscope Range102 Resolution55 Ease of Calculations810 Maximum Shock108 Cost108 Availability33 Totals4636

19.  Microcontroller  ATMEL 8-bit AVR Microcontroller  Motorola M68HC12 Microcontroller  Accelerometer  Analog Devices ADXL278 MEMS Accelerometer  Colibrys MS8000.D MEMS Accelerometer  External Resistor Ladder for 8-bit/16-bit Digital to Analog Conversion 19

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21.  ADXL103/ADXL203  Size: 5mm x 5mm x 2mm  Resolution: 1mg at 60Hz  Bandwidth: 0.5 Hz – 2.5 kHz  Sensitivity: 960-1040 mV/g  Supply Voltage: 3.0-6.0 V  Supply Current: 1.1 mA  3500g Shock survival 21

22. Specification System Requirements ADXL203 ADXL278 Size5mm x 5mm x 2mm 5 mm × 5 mm × 2 mm, Resolution > 2 mg 60 Hz 1mg at 60Hz 2 mg 60 Hz Bandwidth 0.5 Hz – 2.5 kHz 0.5-400Hz Sensitivity Minimum 960-1040 mV/g 25.65-28.35mV/g Supply Voltage 3V 3.0-6.0 V 4.75-5.25v Supply Current 1.1-3.0mA 1.1 mA 2.9mA Full scale range x-y ± 50g ±1.7g ±35 g/±35 g, ±50 g/ ±50 g, or ±70 g/±35 g 22

23.  ADXL203 tested and specified at Vs = 5.0 V  Radiometric output  Vs = 3.0 V output sensitivity ≈ 560 mV/g  Noise density decreases as the supply voltage increases.  Vs = 3.0 V, Noise Density = 190 μg/√Hz  When ratiometricity of sensitivity is factored in with supply voltage, self test response is roughly proportional to the cube of power supply voltage.  Vs = 3.0 V, Self Response ≈ 150 mV 23

24.  Requirement for our electronic system: to convert signals from digital to analog forms  Analog to digital convertor (DAC)needed 24

25.  DS.RSK.1  Microcontroller Power Failure  DS.RSK.2  Motor Communication Failure  DS.RSK.3  Stationary Accelerometer Communication Failure  DS.RSK.4  Despun Accelerometer Communication Failure  DS.RSK.5  Microcontroller can’t survive launch conditions PROBABILITY CONSEQUENCES DS.RSK.1DS.RSK.2DS.RSK.5 DS.RSK.3 DS.RSK.4 25

27.  Required RPM: 600 (without gearing)  2400 RPM with 1:4 gear ratio  Amperage: < 300 mA  Torque: 80 mNm (without gearing)  20 mNm with 1:4 gear ratio  Max Length: 3” = 7.62 cm  Max Diameter: 2”= 5.08 cm  Max Mass: 250g  Pinion to be CNC cut from ½” (12.7 mm) polycarbonate  Fabricated In-House

28. Specificatio n System Requirements Re-16 Maxxon 3257 G MICROMO 3242 SCDC DC –Servo Motor RPM2400 RPM7130 RPM5700 RPM5300 RPM Voltage12 Volts Amperage< 300 mA6.05 mA258 mA199 mA Torque> 20 mNm5.47 mNm70 mNm50 mNm Length<762 mm61 mm790 mm720 mm Mass<250 grams38 grams242 grams189 grams Cost<300$$283.00 Brushed/Brus hless Brushed Brushless

29. SpecificationBrushedBrushless EfficiencyMediumHigh Speed/Torque Moderately flat (difficulty in switching speeds at very high rpm) Enables operation at all speeds Electrical NoiseHighLow CommunicationMechanicalElectronic MaintenanceHighLow LifeShorterLonger Motor Size Larger due to commutator and heat removal Smaller Speed RangesCommutator limits speedCan rotate at high speeds Drive ComplexitySimple and inexpensiveComplex and expensive

30.  3242 SCDC DC Servomotor from Faulhaber.  Selection Criteria  This brushless motor fit all of our design criteria- electronic communication, high speed, data transfer and reception and small size.  Gearing Requirement  Can be provided with the motor (3242 SCDC 012)  32A-available on request from the supplier. 30

31. 31 PROBABILITY CONSEQUENCES MS.RSK.1MS.RSK.4 MS.RSK.5MS.RSK.3MS.RSK.2  MS.RSK.1  Required Torque exceeds stall torque  MS.RSK.2  Motor-Battery Communication Failure  MS.RSK.3  Motor gear head and platform may lose contact under 25G  MS.RSK.4  Battery unable to sustain variable rpm requirements  MS.RSK.5  Motor may not respond to the micro-controller signals correctly.

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33.  Rechargeable Battery  9 V NiMH Powerizer Batteries  Amperage : 170mA  Amount needed : 4  Weight:125g  Voltage Regulator  ±3.3 V Linear regulator for flash memory and accelerometers  ± 5.0 V Linear regulator for microcontroller  Parallel and Series connection to achieve requirements of motor and electronic devices 33

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35. SpecificationSystem Requirements Energizer 175 mAh 9V NiMH NiMH Powerizer Batteries Nickel-metal Hydride Effective Voltage 16V9V 12V Number-442 TypeRechargeable Non - rechargeable Amperage 300mA175 mA per170 mA per2450 mA Mass (total) 32g125g255g Cost$32.0$27.0 $ 71.90 35

36. InterfaceDescriptionPotential Solution Despun Gear / Motor Pinion Motor will spin Despun Platform via spur gear. Number of teeth to be determined but GR set to 4:1 Optimal number of teeth to distribute stress for PC but sill give adequate response Despun Platform / Data System Connected via slip ring leads. Slip ring connection may be susceptible to vibrations Vibration test prior to launch. Slip ring connections can be adjusted to compensate for vibrations Despun Platform / Power System Connected via slip ring leads. Slip ring connection may be susceptible to vibrations Vibration test prior to launch. Slip ring connections can be adjusted to compensate for vibrations Motor / Data SystemConnections between motor and MC may not survive launch conditions Validate connections method is will survive vibrations of launch with vibrations testing Motor / Power SystemConnections between motor and MC may not survive launch conditions Validate connections method is will survive vibrations of launch with vibrations testing Data System / Power System Connections may not survive launch conditions Validate connections method is will survive vibrations of launch with vibrations testing 36

37.  TBD – Specified by WFF  Activate/deactivate at Wallops command  Light switch form  Current flow can be inhibited by Wallops via Relay  No latch activation  Able to allow Wallops to have full control of activation/deactivation 37

38.  Sharing ½ can with Temple University  Temple University will be measuring gamma and x- rays, up to 100keV, through the use of a scintillator and photomultiplier-tube. They will use visible solar light as a directional z-axis reference point to characterize the high energy particles as solar or cosmic rays.  No Ports needed for experiment  Drexel and Temple have been communicating regularly thus far  Close geographic proximity allows for the teams to meet face to face and will aid in future collaboration 38

39. ComponentsMass Lower Platform Weight268 grams Upper Disk105 grams Slip Ring250 grams Battery100 grams - 250 grams Motor189 grams - 242 grams Accelerometers25 grams Electronic Components100 grams Total1037 grams – 1240 grams 39 Design for 2 Kg, Leaving minimum margin of 760 grams

40.  The center of gravity for our Design will be confined within a 1inch cube from the center of the canister.  This will be obtained by placing the large components in such a way that their resulting moment will be within the center of gravity envelope. 40

41.  Gearing  Physical prototypes of gears to verify gear ration/ teeth size  Digital to Analog Converter  Created with resistor ladder and Op-Amp  Motor control algorithm  Slip Ring fastener  Interface stator section of slip ring to fixed platform

42. ItemPart NumberManufacturerVendorQuantityPrice (each)Total Dual Axis High-G Accelerometer AT26DF161AAnalog Devices 21224 MicrocontrollerATMega32-16PUAtmelDigi-key199 Slip RingCAY-1666Aeroflex1400 Pressure SensorASDX015A24RAtmelDigi-Key125 DC Micro-motor3242-SCDCMICROMOFaulhber1283 12”x24”x.25” PC Sheet 85805K43-McMaster-Carr120 12”x12” x 0.50” PC Sheet 8574K32-McMaster-Carr128 Flash MemoryAT26DF161AAtmelDigi-Key144 Battery9 V NiMH Powerizer PowerizerDigi-Key4728 Voltage Regulator/Misc Electronics --Drexel Provided --0 Total800 42

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44. 44 Advisor: Dr. Jin Kang, PhD. MEM Department, Drexel University Team Leader : Joe Mozloom Senior, Drexel University Subsystem Head: Despun Platform Team Members NameEric MarzLinda McLaughlinSwati MainiSwapnil Mengawade Year and Major Senior, Electrical and Computer Engineering Senior, Mechanical Engineering and Mechanics Subsystem Head Micro-controller, Storage and G- switch Sensors, DAC and Power Systems Motor System and Organization Modeling, System level requirements and Compliance to User guide

45.  Finalize design for slip ring holder  Choose number of teeth/ tooth design for gearing system  Determine interfacing between motor and fixed platform  Continue to become comfortable with Solidworks