P16105: RIT-SPEX ADCS
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Systems Design

Table of Contents

Our documents can be found in the Systems Level Design Documents directory.

Team Vision for System-Level Design Phase

From our standing after the Problem Definition Review, we were able to move forward and create a functional decomposition for our entire system. After reviewing current products, our competition, we managed to brainstorm our own ideas as to how some of these particular functions could be completed. We then created criteria by which to compare our new ideas and rated them appropriately. Once we produced the best design for functionality, we analyzed the feasibility of the design. With our design in place, we aim to make progress and keep driving towards our final goal.

Functional Decomposition

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Above is the functional decomposition for our project. The parts outlined in red went under further scrutiny as to how we wanted to accomplish these functions.

There are three main functions to an ADCS test is to obtain the CubeSat and customer requests, setup the apparatus accordingly, and to finally run the test and record the results.

The category with the most variability is the apparatus test setup. Within this category, functions such as collapsibilty, test bed, calibration, and test execution. The functions listed are further explored in the morphological chart.

Benchmarking

Most commercially available Helmholtz coils are single axis and cost from $400 to $700.

Some three axis versions are available but are mostly custom ordered. A refurbished Helmholtz coil cage was found as seen below, with a retail price of $21,900, and refurbished price of $1,950.

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This Helmholtz coil cage uses 3 Watts of power max and creates up to a 1 Gauss magnetic field. The dimensions of the Helmholtz coil cage is 82cm x 72cm x 64cm.

Source

Datasheet

Morphological Chart and Concept Selection

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Low friction sphere concept

Concept Development

Most Viable Options from Morphological Chart

Combinations Moving Forward in the Selection Process

From the Ideas presented above, all possible fusions of ideas are as follows:

Concept Selection

Criteria used in the concept selection process:

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Analysis

From the Pugh Chart above, we were able to determine the combination consisting of the disassembled structure, a low friction sphere, power supply calibration, and the MATLAB interface utilizing CSV files would be optimal.

Notes regarding the Pugh Chart:

Feasibility Analysis

The power requirements, magnetic field requirements, spatial requirements, and cost were analyzed for feasibility

Power

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Where B is the magnetic field, N is the number of wraps, I is the Amperage, and R is the radius

Spatial

Cost

This is well enough below our financial limits to be considered feasible, as well as hits our power limitations, spatial limitation, and magnetic field requirements

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This is a rough draft of what our bill of materials will look like.

Designs and Flowcharts

Calibration

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This is the ideal process when performing a calibration on the apparatus.

Test Execution

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This is the ideal process for producing the magnetic field in order to execute a ADCS test with the apparatus.

Risk Assessment

This is the updated Risks Chart, from the Problem Definition Review, along with the proper Risk Analysis public/Systems%20Level%20Design%20Documents/pictures/risk_chart.jpg?rev=0

Plans for next phase

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Team Goals

We hope to have a well developed BOM, completed the feasibility and risk analyses of the subsystems, and adequate schematics for the respective subsystems. In addition, we hope to produce a small prototype as a proof of concept to verify our calculations.

Individually


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