P19231: Training Wheels
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Systems Design

Table of Contents

Team Vision for System-Level Design Phase

This phase of our project design enabled our team to make informed decisions on the future design path for our project. We were able to deliberate multiple solutions of varying feasibility that satisfied the customer requirements and engineering requirements presented to our team. From there, we compared the theoretical solutions against one another to determine the ideal project path before purchasing the specific components for the upcoming Detailed Design Phase.

Our team goals for this phase were as follows:

With our goals established, we accomplished the following during this phase:

Revised Requirements

Updated Customer Requirements

Updated Customer Requirements

Updated Customer Requirements

A working document of the Customer Requirements can be found: https://docs.google.com/spreadsheets/d/1PiWiCmXyhGVuLG3a6Nnke63W18Wcn8_lX0GDFy26cww/edit#gid=0

Updated Engineering Requirements

Updated Engineering Requirements

Updated Engineering Requirements

A working document of the Engineering Requirements can be found: https://docs.google.com/spreadsheets/d/1PiWiCmXyhGVuLG3a6Nnke63W18Wcn8_lX0GDFy26cww/edit#gid=0

Updated Risk Assessment

 Risk Assessment 1

Risk Assessment 1

 Risk Assessment 2

Risk Assessment 2

 Risk Assessment 3

Risk Assessment 3

A working document of the Engineering Requirements can be found: https://docs.google.com/spreadsheets/d/1uTs5DxRef5OmfrblO7XCYaX0OTRneTzGMSV83dLWO_A/edit?usp=sharing

FMEA

FMEA

FMEA

Functional Decomposition

Functional Decomposition

Functional Decomposition

Transformation Diagram

Transformation Diagram

Transformation Diagram

Benchmarking

Benchmarking Analysis

Benchmarking Analysis

Microcontroller Benchmarks

Microcontroller Benchmarks

General Design

General Design and Location of Major Subsystems

General Design and Location of Major Subsystems

System State Diagram

System State Diagram

Morphological Chart and Concept Selection

A Morphological Chart presents the challenges or functions required of our project and then proposes several reasonable solutions that our team is to analyze. These solutions have been pictorially displayed for clarity.

Pugh Chart and Concept Selection

With concept ideas for the overall system generated from the Morphological Chart, Pugh Charts were used to analyze the brainstormed solutions against one another and determine a score. This process was determined to be most effective when analyzing individual subsystems of our design rather than analyzing the entire system at once. A Pugh Chart works by comparing solutions of a (sub)system against various functional and aesthetic requirements of specified importance. A datum is selected and each solution is then determined to be better than (designated by a +) or worse than (designated with a -) the datum. Each solution option then tallies the total positive and negative scores as a form of grading each concept against the others. Some criteria are weighted higher than others based on perceived importance; this has been factored into the final scores for each solution. Using this information, the best option(s) for the design can then be identified.

Clutch System Pugh Chart

Clutch System Pugh Chart

Shifter System Pugh Chart

Shifter System Pugh Chart

Mounting Method Pugh Chart

Mounting Method Pugh Chart

Haptic Feedback Pugh Chart

Haptic Feedback Pugh Chart

ECU System Morph Chart

ECU System Morph Chart

Data Management System Pugh Chart

Data Management System Pugh Chart

Communication Protocol Pugh Chart

Communication Protocol Pugh Chart

Feasibility: Prototyping, Analysis, Simulation

Clutch Pedal Design

The clutch pedal module is believed to have the largest range of possible physical and mechanical structures. Basic concepts for the Pugh Chart clutch pedal designs were drawn for a better idea of what they may look like.

Clutch Pedal Designs Clutch Pedal Designs Continued

Three prototypes were then created for clutch pedal designs. The first was a simple linear spring (Top). The second was a clamp with a torsion spring (Middle). The third design was a more complicated one, with a small hydraulic piston and multiple brackets and joints (Bottom). This third setup was found in the surplus items of the senior design lab. It was a very viable design, so we included it in our prototyping.

Spring Clutch Prototype

Spring Clutch Prototype

Clamp Clutch Prototype

Clamp Clutch Prototype

Hydraulic Piston Clutch Prototype

Hydraulic Piston Clutch Prototype

For each of our three designs, the force needed to depress the pedal a given distance was found and a curve was generated. The exact numbers are not important, as they very could vary greatly depending on the exact size of each component and the strength of the spring or hydraulic. The shape of the curve is the important aspect of these graphs.

Typical Force per Distance graph as found from online examples

Typical Force per Distance graph as found from online examples

Some of the force curves we found in our research did not have the dip in force when the pedal was near full deppression, they simply leveled out. Either of those curves would be acceptable.

Hypothetical Force per Distance graph of a linear spring clutch

Hypothetical Force per Distance graph of a linear spring clutch

Hypothetical Force per Distance graph of a torsional spring clutch

Hypothetical Force per Distance graph of a torsional spring clutch

Hypothetical Force per Distance graph clutch with a hydraulic setup similar to the prototype

Hypothetical Force per Distance graph clutch with a hydraulic setup similar to the prototype

After testing the prototypes we compared them with the desired force per distance graph, as well aa a few other factors shown in the benchmarking table below. Our team found the third setup with the hydraulic piston to feel really smooth and natural, which we thought was a high-priority component of the clutch pedal design. With a few modifications to the structure of the rustic prototype, a clutch pedal using a hydraulic piston was determined to be a very viable solution.

Benchmarking Comparison of Clutch Prototypes

Benchmarking Comparison of Clutch Prototypes

Vehicle Dimensional Data

A feasibility analysis was conducted to determine if a clutch pedal system similar to that of a 2012 Chevy Cruze would fit in a 2010 Ford Fusion to fulfill the Customer Requirements. Data collection, as seen in the tables below, was performed prior to the analysis.

Dimensions and Data Collected for 2012 Chevy Cruze

Dimensions and Data Collected for 2012 Chevy Cruze

Dimensions and Data Collected for 2010 Ford Fusion

Dimensions and Data Collected for 2010 Ford Fusion

The available region of space comprising the floor of the Ford Fusion is 10.5cm by 27cm, providing an area of 283.5cm2 for the clutch pedal subsystem design to fit. The clutch pedal itself for our design will be roughly 6cm by 6cm, an area of 36cm2. It is constrained to be located 3-6cm from the brake pedal, which the 10.5cm width of space on the floor of the Fusion more than accommodates.

Communication and Data Rates

Data Rates

Data Rates

The above table captures various data points that may be present on the communications bus between each subsystem. This assumes a worst-case scenario to better understand the highest potential level of throughput required to maintain stable communications. This does not reflect the final implementation.

Display Mockup

Display Mockup

Display Mockup

This is the initial mockup design for the display module. It indicates the RPM for the manual vehicle as well as the current gearing. There are two gear displays: one for which gear the user is in and the other for the "correct" gear. There are also indicators for initial teaching which will instruct the user approximately when to shift either up or down. There is also a feedback messages window which display the results of the shifting or any error messages needed.

Systems Architecture

System Architecture

System Architecture

Subsystem Physical Layer Connection

Subsystem Physical Layer Connection

Standards

The following standards were referenced by our team for the O-Shift device.
O-Shift Reference Standards

O-Shift Reference Standards

Plans for next phase

Updated Schedule

Updated Schedule

Steven Keil

Tyler Smith

Kevin Gates

Kevin Ramirez

Matt Wagner

John Jenco


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