RockSat-C 2012

PDR

Minnesota Sound WreckersPreliminary Design Review

University of MinnesotaAlexander Richman

Jacob Schultz Justine Topel Will Thorson

10/26/11

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RockSat-C 2012

PDR

Mission OverviewJustine Topel

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RockSat-C 2012

PDR

Mission Overview

• Our mission is to design a system that actively removes noise in a test chamber during a rocket launch

• We require at least some reduction in intensity of noise in the test chamber compared to the control chamber as well as the safe operation of the entire payload.

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RockSat-C 2012

PDR

Mission Overview cont.

• We expect to show that this technique is a viable solution to noise sensitive testing onboard rockets.

• This would benefit any sound sensitive experiment onboard a rocket including any testing in which live subjects are used and it is desired to lower their stress levels.

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RockSat-C 2012

PDR

Theory and Concepts

• The theory of active noise cancellation is that when one sound wave meets another wave which is an inverse of itself the two waves cancel out and overall noise is reduced

• While no research has been done onboard rockets to our knowledge, active noise cancellation has successfully been used in many other aplications.

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RockSat-C 2012

PDR

Concept of Operations

• Data collection will begin upon the signal line going hot.

• We expect to see limited noise reduction during initial burns and maximum reduction after the completion of both burns and through reentry.

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RockSat-C 2012

PDR

Example ConOps

t ≈ 15 min

Splash Down

-All systems on

-Data collection running

t = 0 min

Apogee

t ≈ 2.8 min

Altitude: ≈115 km

End of Orion Burn

t ≈ 0.6 min

Altitude: 52 km

Altitude

t ≈ 5.5 min

Chute Deploys

RockSat-C 2012

PDR

Expected Results

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• We expect to be successful in reducing the overall power of the wavelength spectra between about 50 Hz and 20kHz

• This means a reduction in amplitude at most of the frequencies within this range.– We are planning to use a middle range

speaker, and thus will maybe see more response from 1kHz to 10kHz

RockSat-C 2012

PDR

System OverviewAlex Richman

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RockSat-C 2012

PDR

Subsystem Design – Physical Model

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Power Supply Data LoggerANC System

RockSat-C 2012

PDR

Design in Canister

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RockSat-C 2012

PDR

Critical Interfaces

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• At the PDR level you should at minimum identify these interfaces

Interface Name Brief Description Potential Solution

ANC/STRThe electrical power system and boards will need to mount to the canister plate to fix them rigidly to the launch vehicle. The connection should be sufficient to survive 50Gs in the thrust axis and 10 Gs in the lateral axes.

We will screw the power supply and electronics for the ANC system directly into the Makrolon plate.

DL/STRThe data logger will need to mount to the canister plate rigidly. The connection should be sufficient to survive 50Gs in the thrust axis and 10 Gs in the lateral axes.

In the same fashion as the ANC system the data logger will mount directly to the plate.

CHM/STRThe chambers must affix rigidly to the mid plate so that they survive 50Gs in the thrust axis and 10 Gs in the lateral axis.

The base of the chambers will be welded to the mid plate ensuring a strong rigid connection.

SPK/CHMThe speakers must be placed inside the chambers so that they stay affixed and do not move in flight.

Possible solutions include making a bracket that attaches to the base of the cylinder or some other kind of mount.

MIC/CHMThe microphones must attach to the top of the chamber so that they do not move during flight.

A mount could be quickly designed to attach the microphones to the top of the chamber.

RockSat-C 2012

PDR

System Level Block Diagram

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DSP System

speaker microphone

Data Logger

microphone

Power Supply

Wallops activation signal

RockSat-C 2012

PDR

Requirement Verification

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Requirement Verification Method DescriptionThe ANC system should cancel noise in a cylindrical chamber

Test Mock up chamber with a speaker and microphone will be made and tested for noise reduction.

The power supply should have enough power to drive the speaker

Analysis The speaker’s power requirements will be researched and the amount of power we can supply will be calculated.

All components must fit within the canister Inspection Visual inspection of the SolidWorks drawing will fulfill this requirement

RockSat-C 2012

PDR

RockSat-C 2012 User’s Guide Compliance

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• Our estimated structure weight including canisters is 9.4 lbs. which is under the maximum weight we expected.

• Our predicted CG is .05 in above the geometric center. This does not account for the electrical components.

RockSat-C 2012

PDR

Subsystem DesignActive Noise Cancellation

SubsystemAlex Richman and Will Thorson

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RockSat-C 2012

PDR

ANC: Block Diagram

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ExperimentalChamber

Dummy Chamber

Control Systems

PowerSupply

MicPreamps

Power amplifier

Mic

Mic

Speaker

Speaker

Data Logger

DSP

In

Out

RockSat-C 2012

PDR

ANC: Trade Studies

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• The following trade study shows the differences between the Pyle Pro PMHMS20 Omni-Directional Microphone and the Dayton Audio EMM-6 Electret Measurement Microphone. As of now, we will go with the EMM-6, subject to further testing.

Microphone EMM-6 PMHMS20

Cost 8 9Availability 10 10Frequency Response

10 9

Size 7 9Sensitivity 10 7Average: 9 8.8

RockSat-C 2012

PDR

ANC: Trade Studies

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• The following trade study shows the differences between the Dayton ND90-8 3-1/2" Aluminum Cone Full-Range Driver 8 Ohm and the Tang Band W3-881SJ 3" Cast Frame Neodymium Driver. Currently, the W3-881SJ looks to be a better choice, but we are interested in the aluminum cone of the ND90-8.

Speaker ND90-8 W3-881SJ

Cost 10 9Availability 10 10Frequency Response

8 10

Diameter 9 9Depth 7 10

Average: 8.8 9.6

RockSat-C 2012

PDR

ANC: Trade Studies

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• This trade study shows the overview of DSP versus a prebuilt IC designed to cancel noise. As we are in the preliminary stages of the ANC design, we are not sure which solution will be more robust at the time being. We hope to discover quickly when prototyping gets underway.DSP vs ANC DSP ANC IC

Cost 10 10Availability 10 10

Ease of Implementation

4 7

Risk of Complications

6 4

Customizability 9 6Average: 7.8 7.4

RockSat-C 2012

PDR

ANC: Risk Matrix

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ANC.RSK.1: microphone fails in flight causing the amplifier to stop sending cancellation soundANC.RSK.2: the speaker creates a positive feedback and breaks itself, causing a mission failureANC.RSK.3: the launch is delayed and our data requires more memory than initially predicted, much more memory availableANC.RSK.4: The launch is delayed by an hour putting a strain on the power budget

RockSat-C 2012

PDR

Prototyping PlanWill Thorson

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RockSat-C 2012

PDR

Prototyping Plan

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Concern about the efficiency and ability to

cancel noise in the chamberDSP

Test our hypothesized noise cancellation in

mock ups.

Risk/Concern Action

• What will you build/test between now and CDR to mitigate risk?

RockSat-C 2012

PDR

Project Management PlanJacob Schultz

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RockSat-C 2012

PDR

Organizational Chart

• Our sponsor is the Minnesota Space Grant Consortium

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Project ManagerJacob Schultz

System EngineerWill Thorson

Faculty AdvisorTed Higman

SponsorMSGC

Faculty AdvisoryWilliam Garrard

Safety EngineerJustine Topel

Testing Lead Alexander Richman

Structure Jacob SchultzJustine Topel

ANC/ ElectricalWill Thorson

Alexander Richman

RockSat-C 2012

PDR

Schedule

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ID Task Mode

Task Name Duration Start Finish

1 research requirements 27 days Fri 9/9/11 Sat 10/15/112 prototype testing 15 days Wed 10/26/11Tue 11/15/113 structure design 34 days Fri 9/23/11 Wed 11/9/114 structure testing 15 days Wed 10/26/11Tue 11/15/115 CDR preperation 11 days Tue 11/15/11Tue 11/29/116 order materials 5 days Mon 12/12/11Fri 12/16/117 test systems before

integration15 days Mon 1/23/12Fri 2/10/12

8 integration and testing 36 days Mon 2/13/12Mon 4/2/129 mission simulation

testing6 days Mon 4/16/12Mon 4/23/12

10 prepare for LRR 26 days Mon 4/23/12Mon 5/28/1211 wallops testing 2 days Fri 6/15/12 Mon 6/18/1212 launch 1 day Wed 6/20/12Wed 6/20/12

T W T F S S M T W T F S S M T W T F S S MAug 7, '11 Sep 11, '11 Oct 16, '11 Nov 20, '11 Dec 25, '11 Jan 29, '12 Mar 4, '12 Apr 8, '12 May 13, '12 Jun 17, '12

RockSat-C 2012

PDR

Budget

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Item Supplier Estimated, Specific Cost Number Required Total Cost Notes

Microphone Parts Express $48.26 3 $144.78 Including one back up for testing.

Speaker Parts Express $26.80 3 $80.40 Including one back up for testing.

DSP TI $13.35 2 $26.70Not commited to a DSP solution or a noise cancelling IC solution as of yet.

ANC IC Austria Micro Systems $3.80 2 $7.60 Including back up chip.

Data Logger DATAQ $599 1 $599.00May be able to use last years data logger.

Misc. Electronics Digi-Key $100.00 N/A $100.00Various Resistors, Inductors, Caps, etc.

High Fidelity Audio Amplifiers Digi-Key $19.36 4 $77.44 Including back up chips in case of soldering failures.

Mic Preamps Digi-Key $5.00 4 $20.00Back up chips included.

Testing Materials ??????? $200.00 1 $200.00

Machine Time University of Minnesota $400.00 N/A $400.00 for chambers and structural materials

Total (No Margin): $1,655.92

Total (Margin): $2,069.90

RockSat-C 2012

PDR

WBS

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Structure Electrical

•Obtain electronics dimensions from electrical team•Perform test calculations on the structure design•Make any alterations necessary to keep design safe

• Prototype and test ANC system

• Finalize list of required electronics

• Finalize Power supply system

RockSat-C 2012

PDR

• Before CDR we plan to– Prototype the ANC system– Finalized CAD drawings and build details– Contact machine shop about

construction of parts– Perform calculations testing the

structure under G loads.

Conclusion

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