P17665: Rotating Dynamometer for Cutting Tools

Customer Handoff & Final Project Documentation

Table of Contents

Team Vision for Final Demo and Handoff

The goal of this phase was to continue to narrow down the root cause of the issue with the Wheatstone Bridges. The team was able to successfully get about a 1.1mV signal from the bridges, allowing a demonstration to be performed at ImagineRIT.

What we planned on doing

What was accomplished

What's next?

Final Bill of Materials

Indented Bill of Materials

The Indented Bill of Materials provides documentation of all assemblies and sub-assemblies delivered for the project. Each sub-assembly and their components have links documenting either their purchase location or their design (CAD models, Engineering Drawings, etc.), as well as the quantity and materials they are composed of.

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Click to download the Indented Bill of Materials in Excel or PDF formats.

Purchasing Bill of Materials

Click to download the Purchasing Bill of Materials in Excel or PDF formats.

Test Results Summary

Bridge 2 Calibration

The functional Wheatstone Bridge, Bridge 2, was calibrated in order to determine the equivalent for a given output voltage. This was done in the same manner as the deflection verification test, with the device placed in a 7/8” collet in a mill, with a steel cable threaded through a test tip and a pulley system. Set weights of increasing weight were placed on a mass hanger attached to the end of the cable to apply a transverse load to the tip of the structure, replicating the transverse loading condition it would experience during a machining process. Plotting the applied load versus the differential output voltage of the Wheatstone bridge and fitting the curve with a 2nd-order polynomial function allowed the development of a calibration formula. With this, the user can interpret the voltage readings from the device to get the transverse load it is currently experiencing.

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Calibration Data

Full Summary of Testing

The Testing Summary document provides a detailed summary and analysis of all tests ran during this project's span. Links are provided to individual tests' sections on their respective EDGE pages, as well as the actual documentation of each test.

Full Test Summary

The link below shows the individual summaries of each of the tests ran during the Integrated System Build & Test phase.

Individual Test Summaries

Project Performance

This document outlines the successes and short comings of the final device compared to the engineering requirements.

Performance vs. Engineering Requirements

Risk and Problem Tracking

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Risk Graph

Risk Assessment

Problem Tracking

ImagineRIT Exhibit

public/ImagineRIT\imagineexhibit1.jpg public/ImagineRIT\imagineexhibit2.jpg

Final Project Documentation

Mechanical Assembly

The assembly of the mechanical structure is as follows:
  1. Acquire the tool being used for the task
  2. Find appropriate DA180 style collet size for the tool
  3. Insert tool into collet and insert collet+tool assembly into tool holder
  4. Place tool holder into a holding block and tighten with a 1.25" wrench
  5. Insert tool holder into adapter and align cutouts with two posts sticking out of the adapter
  6. Tighten tool holder in place with a 1/2-13 bolt
  7. Attach the lower assembly to the structure using the 4 1/4-20 bolts and threaded holes

Electrical Assembly

The assembly of the electronics of the system is as follows:
  1. On the measurement structure, connect the wires labeled 2/1 (white), 9/13 (yellow), and 17/21 (green) to 3.3 volts.
  2. On the measurement structure, connect the wires lableded 7/4 (white), 16/12 (yellow). and 20/24 (green) to ground.
  3. Connect the following differential pairs to individual amplifiers on amplifier boards:
    • 6/3 (white) to negative and 5/8 (white) to positive
    • 11/14 (yellow) to negative and 15/10 (yellow) to positive
    • 23/22 (green) to negative and 19/18 (green) to positive
  4. Connect positive power rail of amplifier to 3.3V and negative power rail of amplifier to ground.
  5. Connect VCC and GND pin of MSP430 to 3.3V and ground respectively.
  6. Connect TX pin of MSP430 to RX pin on bluetooth transmitter.
  7. Connect VCC and GND pin of bluetooth transmitter to 3.3V and ground respectively.
  8. The circuit should now be functioning. A serial port communication program such as RealTerm can now be used to obtain the data.

Circuitry Placement

The order of placement of the circuitry into the housing:
  1. Place MSP430 into the respective slot
  2. Place the MS430 bracket over the MSP430
  3. Use square nuts size 3M and corresponding screws and then do the same for PCB boards
  4. Slip square nut size ¼ in for battery lid and counter weight lid into the corresponding hole
    • This hole is harder to see clearly, the hole is square and is along the wall of the battery compartment and counter weight compartment
    • The hole intersects the screw hole of the battery compartment and counter weight compartment
  5. Once these screws are in place they shouldn’t be removed unless there is a serious problem with the circuit.
  6. Solder the wires to the MSP430, Bluetooth, battery, and amplifying circuit while they are setup in the 3D housing.
  7. The Bluetooth antenna can be glued to its slot to better secure it.
  8. The wires coming off the separate Wheatstone bridges plug into one of the PCB boards and then gets connected to the amplifying circuit.
    • The PCB board that the Wheatstone bridge connects to should be wired up before attaching to the 3D housing.
    • Carefully insert the wired components into the housing.

Electrical Housing

These documents provide the drawings and specs in order to recreate the 3D Printed electrical housing.

Part B Drawing

3D View of Part B

.stl file of Part B

.ipt file of the Electrical Housing part b

Part A Drawing - Back

3D View of Part A

Part A Drawing - Front

.stl file of Part A

.ipt file of the Main Electrical Housing

Lid part B Drawing

.stl file of the lid for part b

.ipt file of the part b lid

MSP430 bracket Drawing

.stl file of the MSP430 bracket

.ipt file of the MSP430 bracket

Academic Deliverables

Physical Deliverables

Box with all items.

Box with all items.

The team has compiled all items from both workspaces (EE Lab and Dr Liu's Lab) and has placed it in a single box in Dr. Liu's Lab. Major items in the box are:

Technical Deliverables

Recommendations for future work

The following are excerpts from the technical paper outlining recommendations for future teams that may try to tackle this project:

Data Analysis

The output voltage is too low for an analog low pass filter to safely handle thus a digital filter was required. LabVIEW was the ideal candidate because the team’s mechanical engineers were taught the program and had experience with it as well as working with digital filter through Matlab. LabVIEW shared the same type of filters with Matlab and in theory could record the data and process it at the same time due to its parallel processing capability. LabVIEW has compatible drivers for 3rd party ADC such as the MSP430G2553. However, issues with the program arose that proved that LabVIEW was not the best candidate. The two key issues are legal terms of use and cost. The cost for a basic license for LabVIEW is $999 which was not affordable at during MSD 2. And in addition to its cost was the risk that the base version might not have a high enough process speed to record and filter the data at 1667 Hz. In fact RIT’s SME John Wellin cautioned against using base LabVIEW to record and process our system fearing that the process speed will be so slow that some data packet will be skipped all together and the LabVIEW base will only process the data at 50 Hz. This very low frequency means the analysis that LabVIEW displays doesn’t represent that data. He recommended using post processing to analyze the data. To ensure the program captures all the data and filters it to display the forces the latency needs to be cut down and the best way to achieve that in LabVIEW is by using LabVIEW Real Time Operating System which makes this program more expensive. But the code could be repurposed for the hopper in future iterations of this project. The second major hang up with LabVIEW is its terms of use for its academic licenses. While Kate Gleason College of Engineering have academic licenses of the program for its classes they aren’t allowed to grant students licenses. Their license agreement prohibits students from using their free academic license for any courses outside of courses that teaches LabVIEW: “If you are a student, you may use the Software for your personal education purposes and not for any other purpose.” [1]. National Instruments clarifies what the above statement means with examples: “This software license is for students. By selecting "I Agree", you understand that you are receiving a Student Edition License; and you understand and agree that you can only use the software for your personal education purposes, and not for any commercial, instructional, for-credit coursework, or research purposes.” [2]. Without special permission from National Instruments to use their program and without proper funds LabVIEW is not viable for this project.

[1] “National Instruments Software License Agreement”, National Instruments Software License Agreement – National Instruments, Addendum E-Academic Licenses, May 2015. [Online] Available: http://www.ni.com/pdf/legal/us/software_license_agreement.pdf [Accessed: 10-May-2017].

[2] "Free 6-Month Evaluation of LabVIEW Student Edition for At-home Learning." Free 6-Month Evaluation of LabVIEW Student Edition for At-home Learning - Discussion Forums - National Instruments. National Instruments, 20 Mar. 2017. Web. 11 May 2017.




Wheatstone Bridge

Other Recommendations

Functional Demo Materials

Plans for Wrap-up

Project Overview

Post Mortem

This document highlights the objective analyses throughout the year of MSD I and II, as well as the assessment of the team vs. the norms and values.

Post Mortem Analyses

Project Validation/Analysis Mechanical Design Electrical Design Academic

Project Overview

Requirements Flow

Customer Requirements Validation

Engineering Requirements Validation

Performance vs. Engineering Requirements

MSD I Project Plan

MSD II Project Plan

Bill of Materials

Purchasing Bill of Materials


Risk Graph

Test Plans

Full Summary of Testing

Calibration Data

ANSYS Simulations

Initial Feasibility Analysis

Mechanical Analysis:

Force Equations

Deflection Analysis

Electrical Analysis:

Wheatstone Bridge Circuit

Amplifier Circuit

Power Consumption

Toolholder Adapter & Toolholder Acceptor CAD/Drawings

Measurement Structure CAD/Drawings

Housing Drawings

Full Assembly CAD/Drawings

Deflection Analysis (.xlsx)

Force Calculation Values

Force Calculation Spreadsheet (.xlsx)

Mechanical Assembly

Circuitry Placement

High Level Overview

Wheatstone Bridge Circuit

Amplifier Circuit

Program Flow

Wiring Diagram

Power Calculations

Bluetooth Transmission: Sitting Voltage Values

Bluetooth Transmission: Packet Loss Test

Electrical Assembly

Electrical Housing

Mid-Phase Report

Updated Mid-Phase Report

ImagineRIT Poster

Technical Paper

Post Mortem Analyses

Lessons Learned

Feedback and Self Critique

Recommendations for Future Work

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