Preliminary Design
Version 2 (Jeremy Wright, 01/31/2013 02:27 pm)
1 | 1 | Jeremy Wright | h1. Shepard Test Stand Preliminary Design |
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2 | 1 | Jeremy Wright | |
3 | 1 | Jeremy Wright | {{toc}} |
4 | 1 | Jeremy Wright | |
5 | 1 | Jeremy Wright | This is a newer document based on "this one":https://opendesignengine.net/projects/shepard-ts/wiki/Preliminary_Design_v1_0 , and you should refer to that original version if you want to see the revision history. |
6 | 1 | Jeremy Wright | |
7 | 1 | Jeremy Wright | h3. Introduction |
8 | 1 | Jeremy Wright | |
9 | 1 | Jeremy Wright | The preliminary design discussion is broken down into two parts in the forums. |
10 | 1 | Jeremy Wright | |
11 | 1 | Jeremy Wright | # "Mechanical systems":https://opendesignengine.net/boards/4/topics/158 |
12 | 1 | Jeremy Wright | # "Data Acquisition (DAQ) Systems":https://opendesignengine.net/boards/4/topics/159 |
13 | 1 | Jeremy Wright | |
14 | 1 | Jeremy Wright | Most of this preliminary design work was done via Google+ Hangout. The meeting minutes from those hangouts will be distilled down into a form suitable for this document, but in the meantime you can find links to the raw meeting minutes below. You will most likely need to request permission to view the document. |
15 | 1 | Jeremy Wright | |
16 | 1 | Jeremy Wright | # "Mechanical Hangout Minutes":https://docs.google.com/document/d/1M5qMFE-SNDYR_yHCI5XGnKLK1Xq17f7NVWNOhb3XkyU/edit |
17 | 1 | Jeremy Wright | # "Data Acquisition Hangout Minutes":https://docs.google.com/document/d/1c4HOtpcp2yDxln5aTmMffk5PxDC5d3YM5UA53KJLoi0/edit |
18 | 1 | Jeremy Wright | |
19 | 1 | Jeremy Wright | _Note: Need to get all of the minutes linked here_ |
20 | 1 | Jeremy Wright | |
21 | 1 | Jeremy Wright | h3. Preliminary Mechanical Design |
22 | 1 | Jeremy Wright | |
23 | 2 | Jeremy Wright | * *STSPM 1.1* We're going to use "FreeCAD":http://sourceforge.net/apps/mediawiki/free-cad/index.php?title=Main_Page as the base CAD program for this project. |
24 | 2 | Jeremy Wright | ** *STSPM 1.1.1* Files will be stored on "Open Design Engine":https://opendesignengine.net in the default FreeCAD file format. |
25 | 2 | Jeremy Wright | ** *STSPM 1.1.2* For milestone versions, STEP files will also be provided for models, and PDF formats will be provided for draft files. |
26 | 2 | Jeremy Wright | * *STSPM 2.1* The overall design will be composed of three principle components. |
27 | 2 | Jeremy Wright | ** *STSPM 2.1.1* The body will hold the other system elements (both mechanical and DAQ related) with sufficient weight to prevent movement. |
28 | 2 | Jeremy Wright | ** *STSPM 2.1.2* The rail system will limit the motor's movement to the x-axis. |
29 | 2 | Jeremy Wright | ** *STSPM 2.1.3* The motor mount will connect the motor under test to the rail system. |
30 | 2 | Jeremy Wright | * *STSPM 2.2* Concepts considered for the body design. |
31 | 1 | Jeremy Wright | ** *STSPM 2.2.1* "Integrated body/rail system":https://lh5.googleusercontent.com/-7g_Oh9iY94E/T_KiaNjAzXI/AAAAAAAABp8/8_6TBhH77Og/s721/12+-+1 similar to "RepRap 3D Printer":http://reprap.org/wiki/File:Plumb-1.jpg |
32 | 1 | Jeremy Wright | ** *STSPM 2.2.2* "Open Box":https://lh6.googleusercontent.com/-EL0FCBNC7TU/T_KiaPZghdI/AAAAAAAABqA/IPtEM64lX5E/s801/12+-+2 design |
33 | 1 | Jeremy Wright | ** *STSPM 2.2.3* Back plate and beam(s) |
34 | 1 | Jeremy Wright | * *STSPM 2.3* Concepts considered for the rail system design |
35 | 1 | Jeremy Wright | ** *STSPM 2.3.1* Smooth rods and linear bearings (number of rods depends on the body design) |
36 | 1 | Jeremy Wright | ** *STSPM 2.3.2* Ball bearing drawer guide |
37 | 1 | Jeremy Wright | * *STSPM 2.4* Concepts considered for the motor mount design |
38 | 1 | Jeremy Wright | ** *STSPM 2.4.1* Estes motor mount placed in a rocket body tube |
39 | 1 | Jeremy Wright | ** *STSPM 2.4.2* An aluminum tube |
40 | 1 | Jeremy Wright | ** *STSPM 2.4.3* Estes motor mount with a plumbing t-connector on the back to route the ejection charge away from the force sensor |
41 | 1 | Jeremy Wright | * *STSPM 2.4* Some sort of shielding such as chicken wire or plexi-glass may be used to protect observers from runaway rockets. |
42 | 1 | Jeremy Wright | * *STSPM 2.5* The thermocouple will be attached to the motor casing with Kapton tape. |
43 | 1 | Jeremy Wright | ** *STSPM 2.5.1* The thermocouple leads will be routed away from the motor exhaust and in such a way that it won't interfere with the movement of the motor mount carriage. |
44 | 1 | Jeremy Wright | * *STSPM 2.6* A Mount will be created for to attach the selected force sensor to the body such that it will interface with the motor mount |
45 | 1 | Jeremy Wright | * *STSPM 2.7* Selected design concept: back plate and beam body (covering a concrete block for added weight), ball bearing drawer guide rail system, and Estes motor mount with a plumbing t-connector |
46 | 1 | Jeremy Wright | |
47 | 1 | Jeremy Wright | *Preliminary Mechanical Cost Estimates (For One-Off Quantities)* |
48 | 1 | Jeremy Wright | |_.Item |_.Cost (Shipping to Midwest U.S.)|_.Approx Total |_.Link | |
49 | 1 | Jeremy Wright | | 8' 2x10 pine board | $7.75 | $7.75 | | |
50 | 1 | Jeremy Wright | | 8' 2x4 pine board | $2.50 | $2.50 | | |
51 | 1 | Jeremy Wright | | 4"x8"x16" solid concrete block | $1.50 | $1.50 | | |
52 | 1 | Jeremy Wright | | Small Ball Bearing Drawer Guide | $6.00 | $6.00 | | |
53 | 1 | Jeremy Wright | | Pulley | $3.00 | $3.00 | | |
54 | 1 | Jeremy Wright | | Estes D/E Motor Mount | $9.00 | $9.00 | http://bit.ly/Rrn330 | |
55 | 1 | Jeremy Wright | | Estes Motor Adapters | $6.00 | $6.00 | http://bit.ly/MYMnNg | |
56 | 1 | Jeremy Wright | | Copper T-Fitting | $3.00 | $3.00 | | |
57 | 1 | Jeremy Wright | | High Heat Spray Primer | $8.00 | $8.00 | | |
58 | 1 | Jeremy Wright | | High Heat Spray Paint | $5.00 | $5.00 | | |
59 | 1 | Jeremy Wright | | Misc Hardware | $5.00 | $5.00 | | |
60 | 1 | Jeremy Wright | | *Total*| | $56.75 | | |
61 | 1 | Jeremy Wright | |
62 | 1 | Jeremy Wright | _Note: Need to address shielding in the cost table above._ |
63 | 1 | Jeremy Wright | |
64 | 1 | Jeremy Wright | h3. Preliminary Data Acquisition Design |
65 | 1 | Jeremy Wright | |
66 | 1 | Jeremy Wright | * *STSPD 1.1* An "Arduino Uno":http://www.arduino.cc/ will be used as the data collection platform which includes the ADC interface with the load cell and thermocouple(s). |
67 | 1 | Jeremy Wright | * *STSPD 1.2* A "Force Sensing Resistor":http://www.trossenrobotics.com/c/robot-force-sensor-fsr.aspx (FSR) will be used for the load cell. We will need to watch for hysteresis issues with this type of load sensor. |
68 | 1 | Jeremy Wright | ** *STSPD 1.2.1* A "unity gain amplifier":http://banananan.wordpress.com/2012/01/12/pressure-sensor-arduino-processing-signal-analysis/ will be used to obtain measurable output from this sensor. |
69 | 1 | Jeremy Wright | * *STSPD 1.3* A "type K glass braid insulated thermocouple":http://adafruit.com/products/270 will be used to measure the casing temperature of the motor. |
70 | 1 | Jeremy Wright | ** *STSPD 1.3.1* An Adafruit "thermocouple amplifier":http://adafruit.com/products/269 will be used to condition the thermocouple signal for the Arduino's analog inputs. This requires SPI communication with the Arduino. |
71 | 1 | Jeremy Wright | * *STSPD 1.4* The data will that is recorded by the Arduino will be streamed over the USB connection unless it is found that is not fast enough. |
72 | 1 | Jeremy Wright | ** *STSPD 1.4.1* The data format will consist of a data point coupled with a simple time stamp. |
73 | 1 | Jeremy Wright | ** *STSPD 1.4.2* Data processing will be handled by the computer. This will include the conversion from voltage to force due to the logarithmic nature of the force sensing resistor. |
74 | 1 | Jeremy Wright | * *STSPD 1.5* The Wiring programming language will be used to program the Arduino, and Processing will be used for any computer-side code. |
75 | 1 | Jeremy Wright | |
76 | 1 | Jeremy Wright | *Preliminary DAQ Cost Estimates (For One-Off Quantities)* |
77 | 1 | Jeremy Wright | |_.Item |_.Cost (Shipping to Midwest U.S.)|_.Approx Total |_.Link | |
78 | 1 | Jeremy Wright | | Arduino Uno R3 | $29.95 + shipping | $35 | http://bit.ly/N5kizl | |
79 | 1 | Jeremy Wright | | 1.5 Inch Square FSR | $7.95 + shipping | $16 | http://bit.ly/Pd3ztz | |
80 | 1 | Jeremy Wright | | TLV2374 Op Amp | $1.71 + shipping | $8 | http://bit.ly/OcVA12 | |
81 | 1 | Jeremy Wright | | 560 Ohm Resistor x 2 | $0.20 (combined w/ shipping above) | $0.20 | http://bit.ly/M3duBJ | |
82 | 1 | Jeremy Wright | | Type-K Glass Braid Insulated Thermocouple | $10.00 + shipping | $13.87 | http://bit.ly/NPRosE | |
83 | 1 | Jeremy Wright | | Adafruit Thermocouple Amplifier | $17.50 + shipping | $21.50 | http://bit.ly/OqVc2A | |
84 | 1 | Jeremy Wright | | Misc (Wire, etc) | | $5.00 | | |
85 | 1 | Jeremy Wright | | *Total*| | $99.57 | | |