P19127: XHab Deployable Crew Lock Structure
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Subsystem Build & Test

Table of Contents

Team Vision for Subsystem Level Build & Test Phase

During this phase, the team wanted to complete individual subsystem development. The electrical engineering team will complete PCB design in order to complete a review from professors and to request a quote from board manufacturing companies. The bulkhead team will complete CNC preparation and possibly CNC the bulkheads by the next review. At the very least the bulkheads will have a CAM program approved by the Construct director. The vacuum barrier team will be completing heat sealing, adhesive sealing, and load testing on the vacuum barrier material and ergonomic devices. The testing rig team will begin preliminary plans to build the testing rig for the final crew-lock. The team expects to further investigation of the components bought for their subsystems and complete preliminary testing on the components as necessary.
Full-size Concept Model from Subsystem Build

Full-size Concept Model from Subsystem Build



































Problem Tracking

The Problem Tracking sheet can be downloaded in the Design Review Materials Section at the bottom of this page.
Problem Tracking - Phase 6

Problem Tracking - Phase 6

Change Management

The Change Management workbook can be downloaded in the Design Review Materials Section at the bottom of this page.

The changes detailed below were driven by the problems listed in the Problem Tracking document above.

IV Bulkhead (Front) CAM Program Output

IV Bulkhead (Front) CAM Program Output

The major design update which was made during this phase was the change from solid bulkheads to machined bulkheads with vinyl film sandwiched in between. An airtight zipper is also added to the EV bulkhead for PCB maintenance and for a simulated EVA hatch. This was done to accomplish the following:

Below is an image of an exploded view of the EVA Bulkhead side. The layers are named from bottom left to top right: EVA Outer Bulkhead, Vinyl Layer, EVA Inner Bulkhead.

Exploded View of EVA Bulkhead

Exploded View of EVA Bulkhead

Below is an image showing the vinyl wrapping into the EVA bulkhead sandwich towards the IVA bulkhead sandwich.

Vinyl Sandwich Illustration

Vinyl Sandwich Illustration

Testing Flow Chart

Due to the interdependence of the Subsystems, the team created a flow hart to illustrate the roadblocks the team has come to for this phase. Most of the testing and building will come together in the next phase.
Testing and Component Build Flow Chart

Testing and Component Build Flow Chart

Test Results Summary

The Test Results Summary and all the tests in the following section can be downloaded in the Design Review Materials Section at the bottom of this page.
Test Results Summary - Phase 7

Test Results Summary - Phase 7

Vacuum Barrier Testing

Vacuum Barrier Material testing was one of the most important parts of this phase. The ability of the material to heat seal to itself and the vinyl parts of the bulkheads, the material's ability to work with the glue which the team has on hand, and the vacuum barrier material's strength are all important factors for the Crew-Lock's successful delivery and function.

Below are the results for the 3 sets of tests done on the Vacuum barrier Material.

Results of Glue Testing on Vacuum Barrier Material

Results of Glue Testing on Vacuum Barrier Material

Results of Heat Seal Testing on Vacuum Barrier Material

Results of Heat Seal Testing on Vacuum Barrier Material

Results of Vacuum Barrier Material Testing

Results of Vacuum Barrier Material Testing

The Handles Test was meant to look at the strength of the bond between the handle and the vacuum barrier material, as well as the strength of the handle itself. Matty performed a stitch and glue pattern that created a handle acceptable for the theoretical 1/4th scale astronaut who will be using them as navigational aids on the Crew-Lock.
 Handle Strength of Material and Design Testing

Handle Strength of Material and Design Testing

Electrical Components Testing

This phase mainly focused on the design and confirmation of the PCB, thus the testing done on the electrical side was limited to individual components that could be supplied with power.

LED Lighting Test

The Crew-Lock LEDs were tested to confirm the pins (12V and ground) and to confirm that they can be lit. The test went through several iterations where voltage was varied to see the LED response to the changes. The results can be seen below.
Test Setup for LED Strip

Test Setup for LED Strip

Results of Current-Voltage Test on LED Strip

Results of Current-Voltage Test on LED Strip

Pump Testing

The Crew-Lock pump was tested to confirm that it was indeed functional. The pump was hooked up to a car's 12V port and turned on. The video can be seen by following the link seen here: 12V Pump Test Video

Risk Management Changes

The full Risk Management workbook and the Problem Tracking sheet can be downloaded the Design Review Materials Section at the bottom of this page.

Risk Management Changes

Risk Management Updates

Risk Management Updates

Fabrication Updates

Bulkheads

During this phase, the bulkhead team consulted multiple sources for better clarification on what material and fabrication method should be used to complete the bulkheads. After this consultation, the team ultimately decided to stick with Temple-Inland UltraStock Select Medium Density Fiberboard (MDF) due to:

In addition, the design changes no longer requires the MDF to have an air-tight, wood-epoxy finish. The vinyl and vacuum barrier material will be the air-tight interfaces, thus freeing the design restraint placed on the wood material.

The main work on the bulkhead during this phase consisted of modifying the drawings for the bulkheads to conform to the new design changes. These drawings were then brought to the RIT Construct where the director of the area, Michael Buffalin IV, provided machining advice to the team. The Construct also provides a Drawing to Vector Profile to CAM g-code program. This program is attached to the ShopSabre CNC Router 4860. The CAM program outputs a simulation to confirm cutting as well as tool-path G-code and operations orders delineations to the CNC router. The tooling to be used during the machining include:

The Operations Orders were decided based on the inside-to-outside principle of CNC machining and feature importance. The safety tabs were decided based on consultation with the Construct. The securing of the bulkhead material will be accomplished through wood-screwing and double-sided tape based on consultation from the Construct. Peck depth, cut depth, feed, speed, and spindle RPM were/will be decided based on consultation with the Construct.

CAM Program Outputs

All G-code tool-paths and vectoring program files can be downloaded the Design Review Materials Section at the bottom of this page.
IV Bulkhead (Front) CAM Program Output

IV Bulkhead (Front) CAM Program Output

IV Bulkhead (Back) CAM Program Output

IV Bulkhead (Back) CAM Program Output

EV Bulkhead (Front) CAM Program Output

EV Bulkhead (Front) CAM Program Output

EV Bulkhead (Back) CAM Program Output

EV Bulkhead (Back) CAM Program Output

Deployment Systems

For the deployment systems design, a CAD drawing was made of the motor bearing support for the purpose of fabrication in the RIT Machine shop. In order to set the job up in the shop, model and drawing files were required. In addition to this, the pair of two threaded metal rods for the motor were cut in half manually to ensure that enough pieces were made to accommodate the amount of motors (three).
Drawing of Motor Bearing Support

Drawing of Motor Bearing Support

Deployment System Components

Deployment System Components

Electrical Systems

The PCB design was completed by the electrical team and approved by the professors from the RIT EE department. Quotes for the boards are as follows:

The following are views of the PCB associated with the Sensors suite.This includes the proximity sensor and pressure sensor.

PCB CAD Sensors Board pt.1

PCB CAD Sensors Board pt.1

PCB CAD Sensors Board pt.2

PCB CAD Sensors Board pt.2

The following are views of the PCB associated with deployment control (motors and threaded rods system).

PCB CAD Motor Controller Board pt.1

PCB CAD Motor Controller Board pt.1

PCB CAD Motor Controller Board pt.2

PCB CAD Motor Controller Board pt.2

Testing Rig

The bulkhead clamp sub-assembly of the testing was modeled and drawn, as seen below. The purpose of the bulkhead clamp is to ensure a secure connection between each bulkhead and the mount and translational systems of the testing rig. Each of the pieces of the bulkhead clamp will be created out of wood, which was picked up as scrap during the previous phase.

Once the bulkhead machining is complete in the early part of the next phase, the bulkhead clamp can be accurately traced and machined. The scooter will be measured and the clamp will be attached. The scooter's height will be taken into consideration as the clamp for the IVA side is built, so that both bulkheads sit on the same horizontal plane.

Testing Rig Clamp Assembly

Testing Rig Clamp Assembly

BOM and Finance Tracking

During this phase, components, expenses, and confirmation were tracked on a workbook. The main problem the team had in this area was the lack of funds due to an administrative error. The team was mistakenly allotted $1,000 when we had requested and planned for $1,500.

The BOM workbook and Expense Tracking can be downloaded the Design Review Materials Section at the bottom of this page.

Crew-Lock Final BOM - Phase 7

Crew-Lock Final BOM - Phase 7

Conclusions for this Phase

This phase brought about many problems that the team had to face. First, we ran into design and testing problems early on which forced the team to re-think the way the vacuum barrier should be attached to the bulkhead. Second, the team had trouble contacting the right suppliers and fabrication specialists to complete purchasing and fabricating on schedule. Third, the team faced financial woes, as the MSD program mistakenly allotted $1,000 to the team, instead of the $1,500 budget we had requested. These problems led to the lack of deliverables during the Subsystem Build & Test phase review and demos. This puts the team slightly behind schedule and thus more hard work must be done in the coming phase.

Despite the negatives this phase brought, the team has been able to solve two of the three problems mentioned above in time for this phase review. Substantial design changes, for both functionality and aesthetic reasons, were made and approved by the entire team. These design changes made the envisioned final product more acceptable to the team, and more easily manufacturer. The suppliers and fabrication experts were contacted, and all issues were addressed. The finance problem was solved a few days before the Subsystem Build & Test review, allowing the team to turn its focus away from financial woes and back towards fabrication and testing.

Plans for next phase

In the next phase, Integrated System Build & Test, the team will be focusing mainly on the fabrication and integration of all subsystems. The team anticipates that all subsystems will be complete, and testing can be done to confirm functionality. The schedule shows that the team is not exactly where it wants to be as it heads into this phase; however, with a month's more time, the team should be able to get back on schedule.

For the next phase, the team will complete the following: complete the PCB, complete the bulkheads, complete the vacuum barrier attachment, complete the motor and threaded rod system integration, complete the ergonomics attachments to the entire crew-lock, finish wiring to all components, complete the testing rig, complete testing of the full system, and start on the Technical Paper and Imagine RIT Poster.

The Detailed Gantt Chart and Schedule can be downloaded the Design Review Materials Section at the bottom of this page.

Condensed Gantt Chart - Phase 7

Condensed Gantt Chart - Phase 7

Subsystem Build & Test Phase Review Notes

Starting Date Ending Date Meeting Notes
January 2019 February 2019 Design Review Notes - Subsystem Build and Test

Design Review Materials


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