P18310: Tuned Vibration Absorber Demo System
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Preliminary Detailed Design

Table of Contents

Desired Review Outcomes

Team Vision for Preliminary Detailed Design Phase

Recap of Customer & Engineering Requirements

Customer Requirements

The customer requirements from the Problem Definition page are reproduced below for convenience in comparing with proof of concept tests and calculations.

Customer Needs List

Customer Needs List

Click here for a link to the live document.

Engineering Requirements

The engineering requirements from the Problem Definition page are reproduced below for convenience in comparing with engineering test plans.

Engineering Requirements

Engineering Requirements

Click here for a link to the live document.

Engineering requirements testing listed in the above document are high level summaries of the planned test. Detailed test plans specific to each engineering requirement are located in the Test Plans section near the bottom of this page.

Display Setup Drawing

Trade Show Display

Trade Show Display

Prototyping, Engineering Analysis, Simulation

System Model Proof of Concept

System Model Derivation

Click here for a .pdf of the system model derivations.

Proof of Concept

Piston

Based on the dimensions used on a typical small-displacement motor, we designed our components to either meet or exceed the dimensions used in order to ensure that our piston system will have a sufficient life cycle. For instance, our connecting rod uses slightly more material to secure the piston pin than even a regular gas engine that's exposed to gas and friction forces of a functional combustion engine. We feel that with such small forces in comparison to an actual engine, our engine components will be more than adequate to deal with their respective stresses and strains for the life of the system. Based on stress calculations done through the link below, our system is more than adequate to deal with the relatively small forces of the piston.

Click here for more information about the piston.

Click here for more information about stresses.

Micro-Controller

The Arduino Mega is chosen for carrying out control and data processing for the electrical system. This brand of hardware was chosen due to the large vast library of tutorials and code available due to the open source stance the company has. This will allow for LORD engineers to debug any issues via google. Multiple team members have experience programming in C/C++, and the language is very common among most engineers. The Mega was chosen over the Uno due to it's high number of analog/digital pins. This will ensure that any unforeseen additions to the electrical system will be covered. Comparing the two, Mega has 38 extra data pins and 10 extra analog pins.

A link to the Arduino website with all information regarding the Mega can be found here.

Motor Shield

The Cytron 3A Motor Driver Arduino Shield was chosen to drive the motors based on the high current ability and the stack-ability with the Arduino Mega. This means that the shield can be "plugged in" or "stacked" directly on top of the Mega. They will share all pins except the "extra" pins the Mega has compared to the Uno. This makes for easy circuit design because it removes the need for the 6 connections (EnA,In1,In2,In3,In4 and EnB) that would have to be made between the Mega and the shield, thus eliminating the possibility of an accidental disconnect or short. During the motor test, a single motor operating at no load only drew ~600 mA, and when loaded (with a hand squeezing the output shaft), only jumped up to ~800 mA. This ensures that the 3A output capacity of this motor shield will be sufficient enough to supply two motors during normal operation. The motor has a stall current of 20A, which exceeds the motor shields capacity greatly. The shield has a built in current limit protection circuit, but external fuses will be implemented to ensure that the shield will never be exposed to current in that magnitude.

Click here for the motor shield data sheet.

Motor

The motor chosen is brushed, requires 12 VDC with a premium planetary gear head that has a 13.734:1 ratio and supplies 612 rpm at no load. The motor has a stall torque 222.2 oz-in and comes with a rotary encoder built in to the drive shaft. This motor was mainly chosen for the convenience of having the rotary encoder built in along with the designed output rpm, which matches the needed frequency for the system. Because the motor is brushed, it was decided that a robust test should be done now in order to ensure longevity and consistency of the motors performance. Since the vibration system that the motor will be powering is so heavily dependent on a consistent output frequency, a motor that will lose its output angular velocity quickly after long term use should not be chosen. Unfortunately, this is not a part of the specs, and therefore a test is required to measure the wear of the motor. Due to the extremely reasonable price/unit (~$60), it was decided that if this motor can last for several weeks without showing signs of deterioration, then there is no need to go a more expensive route. This would involve a more expensive, larger motor with higher quality components, perhaps a brush-less synchronous DC.

The test is as follows: A script was written that will run the motor at full speed, while recording output frequency at a constant voltage. The motor is ran for 10 hours a day (the maximum time range that is required for trade shows, as requested in the prp) and the output frequency of the motor and the current drawn by the motor shield will be recorded at the beginning and end of each day. This will allow for the changes in the output of the motor to be analyzed. If at the end of the 2 week trial the motor doesn't show signs of significant wear or change in output frequency at the same constant applied voltage, the motor can be used in this application. If not, a more robust expensive motor will be chosen and some design specs will be changed.

Motor Test Drawing

Motor Test Drawing

Click here for the motor test schematic.

Drawings, Schematics, Flow Charts, Simulations

Mechanical Drawings

Top Level Assembly Demo

Top Level Assembly Demo

Click here for a link to the live document.

Electrical Drawings

Top Level Electric Drawing

Top Level Electric Drawing

Click here for a link to the live document.

Bill of Material (BOM)

Click on the document to enlarge.

Bill Of Materials

Bill Of Materials

Click here for the active BOM document.

Test Plans

Test Number Assignments

Each engineering requirement is assigned a specific test number per the table below.
Test Numbers

Test Numbers

Each Set of engineering requirements has had a specific test plan drafted for it, similar to the one pictured below. Each test plan includes detailed objectives target values and steps for completion.

Vibration Test Plan

Vibration Test Plan

The following link will open the full engineering testing document, which contains the detailed test plans for each engineering requirement.

Click here for the full engineering requirements test plans.

Risk Assessment

Connor: Safety Weight Hazard

Shayne: Safety Hazard Pinch Points

Ideal Dimensions: Top x1: 18”x18” Sides x4: 18”xh” h: 6”~18” Whatever will contain demo

Malik: Technical - Mismatch operating frequencies

Kyle: Safety - Shock hazard from circuitry

Nathan: Environmental - Rough Handling/Assembly Causes Damage

Risk Mitigation Timeline

Risk Mitigation Timeline

Click here for a link to the live document.

Phase I & II Review

Phase 1 Gantt

Phase 1 Gantt

Phase 2 Gantt

Phase 2 Gantt

Phase III Review

Phase III Summary:
Phase 3 Gantt Chart

Phase 3 Gantt Chart

Phase III Task Assignment Changes:

Phase Task Changes

Phase Task Changes

Phase IV Future Outlook

Phase IV Summary:
Phase Task Changes

Phase Task Changes

Task Assignments:
Phase Task Changes

Phase Task Changes

Peer Review Updates

Stephen: Refine Reverse Schedule Work with Gary and keep in contact with guide

Nathan: Help assign team members to tasks

Connor: Communication, Presentation role

Kyle: Work on assigned tasks at a more manageable pace

Malik: Help with hardware preference for later software development

Shayne: More Technical Tasks

Lessons Learned

Stephen:

Nathan:

Connor:

Kyle:

Malik:

Shayne:

Team Vision for Detailed Design Phase IV


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