P18221: RIT Baja Driveshaft Efficiency Tester
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Detailed Design

Table of Contents

Team Vision for Detailed Design Phase

Prototyping, Engineering Analysis, Simulation

Controls & Data Acquisition

The ADS1115 ADC that was proposed earlier, in conjunction with a Raspberry Pi, were tested. This is shown in the set up below.
Board Setup for Test

Board Setup for Test

The test bench used the following

Supplies Setup for Test

Supplies Setup for Test

Below is a screenshot of the code used to test the performance of the system.

Program Code

Program Code

The results of the code's performance is shown in the screenshot below, outputting each message as quickly as possible.

Program Output

Program Output

This test confirms the ability of the Raspberry Pi to log the pulse rate of the rotary encoders while also logging the analog voltage that will be output by the load gauges and the Tecat sensor.

Mechanical Analysis

Modal Analysis of Chassis

Modal Analysis of Chassis

Modal analysis of the chassis was calculated using the SolidWorks Simulation package, this is showing a resultant amplitude of 0.0005.

FEA of Chassis Under Load from Motor

FEA of Chassis Under Load from Motor

The chassis was loaded with the weight of the motor on the motor supports in this simulation. FEA simulated with Solidworks Simulation.

FEA of Motor Mount Bracket

FEA of Motor Mount Bracket

SolidWorks Simulation FEA of the motor bracket. Bracket loaded with the weight of the motor and fixed on the mounting locations. Max Stress 5ksi.

Drawings, Schematics, Flow Charts, Simulations

Example representation of vehicle Camber and Toe.
Vehicle Toe and Camber

Vehicle Toe and Camber

Updated System Architecture

Updated System Architecture

Below is revision 2 of the Electrical Block Diagram, updated to include the change from the Futek sensors proposed in the Preliminary Design Review. The system now includes the load gauge and Tecat strain-gauge based sensor, and two rotary encoders that will simply pulse once per revolution.

Revision 2 of the Electrical Block Diagram

Revision 2 of the Electrical Block Diagram

The control and data acquisition flow has not changed since the Preliminary Design Review. It is shown here again for convenience.

Electrical Control Flowchart

Electrical Control Flowchart

CAD

Outboard Angle Adjustment Fixture

Outboard Angle Adjustment Fixture

Outboard Shaft Top View

Outboard Shaft Top View

Outboard Isometric View

Outboard Isometric View

Outboard Side View

Outboard Side View

Outboard Top View

Outboard Top View

Torque Measurement

Strain Gage Shaft FEA, 45 ft-lbs

Strain Gage Shaft FEA, 45 ft-lbs

Prints

Adjustable Bracket Spacer

Adjustment Inner Bracket 2

Adjustment Inner Bracket 1

Adjustment Middle Bracket

Adjustment Outer Bracket

Bottom Angle Bracket

Bottom Bracket

Caliper Spacer

Load Cell Spacer

Outboard Shaft

Upper Angle Bracket

Upper Bracket

R16 Outboard Adapter Shaft

R17 Outboard Adapter Shaft

R18 Outboard Adapter Shaft

Inboard Adapter Shaft

Motor Mount

Frame Member List

Bill of Material (BOM)

Bill Of Materials

Test Plans

Risk Assessment

While some of the risks involving funding have been taken care of, the main concerns with the project are still budget related.

Risks the team has begun to address:

  1. Not having enough funds to complete the project
    1. Many sponsors have been contacted
    2. In house Tecat sensor and load cell to be used for torque measurement
    3. In house drive motor will be used
    4. Friction brake system using in house parts will suffice for load
    5. Misumi will sponsor a portion of the project
    6. Alternative designs have been developed to use cheaper items
  2. Timeline risks
    1. Lack of sensor and motor sponsorships inherently reduces lead time risks
    2. Knowing what resources are available without sponsorships lead to design decisions made that have reduced the risk of re-design
    3. Team member class scheduling has allowed for time during each week to work on the project
  3. Incompatibility with existing Baja designs
    1. CAD of current designs is being utilized in development of test rig

The lack of sponsorships attained had both positive and negative effects on the project. The conclusions drawn as a result of the efforts allowed progression on the more detailed design aspects of the project in both the electrical and mechanical systems. However, there are new concerns with the quality of the system, specifically in torque measurement accuracy and resolution. Overall, during this phase the risk to the project has been reduced, but the priorities of mitigation efforts have been shifted from cost savings to technical quality.

Current Risk Assessment.

Plans for next phase

Preparing for Gate Review

Preparing for MSDII


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