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Lafayette College Division of Electrical and Computer Engineering

LFEV-Y7-2019 Preliminary Design Review

Tuesday, September 15, 2018

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Table of Contents 1. Introduction 4 2. Summary of Individual Teams & Goals 5 3. Work Breakdown Structure (WBS) 6 4. Overall System Diagram 7 5. Individual Subsystems 9

a. SCADA 9 i. Analysis of Current Design 9

ii. Goals 9 iii. System Level Diagrams 10 iv. Task Delegation 10 v. Work Breakdown Structure 12

vi. Acceptance Testing Strategy 12 vii. Software Design 12

viii. Mechanical Design 14 ix. Budget 15

b. GLV 15 i. Analysis of Current Design 15

ii. Goals 15 iii. System Level Diagrams 17 iv. Task Delegation 17 v. Work Breakdown Structure 18

vi. Acceptance Testing Strategy 18 vii. Mechanical Design 19

viii. Budget 23 c. TSI 23

i. Analysis of Current Design 23 ii. Goals 24

iii. System Level Diagrams 25 iv. Task Delegation 25 v. Work Breakdown Structure 26

vi. Acceptance Testing Strategy 26 vii. Mechanical Design 27

viii. Budget 28 d. TSV 28

i. Analysis of Current Design 28 ii. Goals 29

iii. System Level Diagrams 30

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iv. Task Delegation 34 v. Work Breakdown Structure 34

vi. Acceptance Testing Strategy 34 vii. Mechanical Design 35

viii. Budget 39 e. COOLING 39

i. Analysis of Current Design 39 ii. Goals 39

iii. System Level Diagrams 41 iv. Task Delegation 41 v. Work Breakdown Structure 42

vi. Acceptance Testing Strategy 42 vii. Mechanical Design 43

viii. Budget 43 f. INTERCONNECT 44

i. Analysis of Current Design 44 ii. Goals 44

iii. System Level Diagrams 45 iv. Task Delegation 48 v. Work Breakdown Structure 48

vi. Acceptance Testing Strategy 48 vii. Budget 49

6. Overall Acceptance Testing Plan 50 7. Maintainability Plan 50 8. Cost and Budget Assessment 51

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1. Introduction The Electrical and Computer Engineering (ECE) division of Lafayette College

Engineering will continue the interdisciplinary effort to design and construct a Formula Hybrid Electric Vehicle Competition rule compliant electric vehicle .The ECE Team will form a single team in cooperation with a group of Mechanical Engineering students from the Mechanical Engineering division of Lafayette Engineering. The team of 23 students will work together to develop a functional electric vehicle. In doing this, the team will design, fabricate, test, and incorporate all the electrical systems that go into a vehicle. The team will also work to include the errata from previous years in order to learn from and improve upon previous designs.

Other deliverables that will be provided by the team in order to give regular progress checks and provide a clear plan include:

1. Critical Design Review (CDR) - A revision to the PDR, updating designs and address criticisms for the overall vehicle design plan

2. User Manuals - Complete documentations for all the systems in the design including: Operation, Start Up Procedures, Maintenance, Catalog of Physical Components and User Interfaces, FAQs, and Troubleshooting

3. Maintenance Manual - Schematics and high level information about the calibration of the device

4. Acceptance Testing Plan (ATP) - Documents how the full system will be verified for proper functionality and in the event of error how functionality should be restored. Should be based on Formula Hybrid Electric Vehicle Competition rule compliance.

5. Acceptance Test Report (ATR) - Documentation of the findings from the Acceptance Testing Plan

6. Project Website - A website regularly updated with all the project happenings including status updates, testing plans, schematics, and designs.

7. Project Poster - A poster summarizing the efforts of the team and documenting high level accomplishments completed over the course of the project.

8. Photo and Video Documentation - A detailed documentation of team efforts as the project progresses for later demonstration.

The team will work to have a complete understanding of a mutual goal and follow a structured breakdown of progress following a “100% Rule” in order to complete all materials in a timely and structured manner. In order to track the progress of the work breakdown structure, weekly Status Letters will be submitted detailing the progress on responsibilities of each individual team member. This work breakdown structure will also be available in flowchart and list form for simplified visual progress checking. These weekly goals will be reviewed at a full team meeting each Monday afternoon, ensuring full team understanding of progress and focus on the necessary tasks.

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2. Summary of Individual Teams & Goals The following is a list of the Subsystem Teams and their high level goals:

● SCADA/DYNO ○ Team: Samuel Mwaura, Zian Geng ○ Goal: Produce a data acquisition software capable of recording and controlling

both the DYNO room and the Car and prepare the DYNO room for testing ● Grounded Low Voltage (GLV)

○ Team: Maxwell McFarlane, Robson Adem ○ Goal: Provide the low voltage systems for all systems of the car which exclude

the motor ● Tractive System Interface (TSI)

○ Team: Tianyu Zhu, Xiaonan Chen, Antonio Exposito, Hongbo Du ○ Goal: Provide a high voltage to the motor and a safe method of interfacing with

high power systems ● Tractive System Voltage (TSV)

○ Team: Yishak Desta, Clement Hathaway, Weston Lickfeld ○ Goal: Provide battery packs capable of supplying 96 V to the motor and produce a

system for acquiring diagnostic information and charging ● Cooling

○ Team: Hongbo Du ○ Goal: Provide a method by which to handle the temperature control of the heat

producing aspects of the vehicle ● Interconnect

○ Team: Drew Carleton, Weston Lickfeld ○ Goal: Produce and manage the wires that will be used to connect all of the

subsystems throughout the vehicle. Provide documentation for how systems are to be connected and how subsystems interface with one another

● Management ○ Team: Alex Kmetz, Katherine Lee, Hayden Dodge, Yuqiu Zhang, Robson Adem ○ Goals: Oversee the progress of the vehicle and deliverables, compile documents,

and provide aid to subsystem teams ■ Project Managers: Alex Kmetz, Katherine Lee ■ System Engineers: Hayden Dodge, Yuqiu Zhang ■ Finance Officer: Robson Adem

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3. Work Breakdown Structure The following is a Work Breakdown Structure, detailing all of the tasks to be completed in order to produce a rule compliant vehicle following the 100% Rule, meaning all divisions of tasks add up to 100% of the complete project. Top Level WBS:

Figure 1 Top Level WBS

All of the WBS forms and sheets can be found on the project website, along with the same WBS in a checklist format. The website can be found at https://sites.lafayette.edu/motorsports/ under the Management tab and WBS section.

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4. Overall System Diagram

Below is an overall system diagram, showing all connections between systems of the vehicle.

Figure 2 Top Level Wiring Diagram

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Below is a simplified model of the system diagram, showing only an abstraction of connections.

Figure 3 Simplified System Diagram

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5. Individual Subsystems a. SCADA

i. Analysis of Current Design

While the current VSCADA is in generally good condition and functional, there is poor documentation from previous years and the design is messy. The VSCADA is functional but the design is messy. The design is not modular and similar methods are not grouped together. Most of the functionality of the program is in the main file.

ii. Goals The VSCADA subsystem will be responsible for collecting, storing, and

responding to data collected by all other subsystems. The VSCADA will be completely rewritten in C++ to capitalize on the the work done by the Fall 2017 CS 205 class, which built SCADAs for Professor Nadovich. All members of the VSCADA subsystem team were in this class and therefore have a better understanding of C++ than Python which the current system utilizes. C++ also has more control in general since there are fewer layers of libraries compared to Python. In addition to changing the language in which the VSCADA is written, the team has laid out twelve goals:

1. Lost Data - The test plan will include checking VSCADA values against measured values on the various subsystems to determine if data is being missed and fix the bottleneck if it is. 2. Configurable - Make system more configurable (sample rates, refresh rates) by adding sample rate to the list of sensors and their properties instead of a constant universal rate. 3. Error Handling - Error handling will be enhanced to show useful information upon malfunction. This will entail talking with teams from other subsystems to determine what information they would find useful. 4. CAN network Accuracy - Test that data values on CAN network match actual values (especially current values). Test plan will include checking VSCADA data against probe-measured data from other subsystems e.g. TSI. 5. Driver Display - Use LEDs on driver display to notify driver of important changes. An LCD display will be installed on the dashboard to show important information instead of proposed LEDs. 6. Real Time Clock - Add real time clock for raspberry pi to ensure real-time accuracy. A real time clock module will be connected to the raspberry pi board to keep real time from resetting. 7. Raspberry Pi for Testing - Set up a second raspberry pi with all necessary parts for testing outside of the Dyno/car. Use an old TSI board or a new spare TSI

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board. A second raspberry pi is already in place for development outside the car system. Other components required by the VSCADA will be ordered for this ‘remote’ development environment. 8. CANBus Configuration - Use CAN to send configurable values to TSI upon startup. Discussion will be held with those responsible for TSI to determine what signals need to be sent upon startup. 9. VSCADA Relay - Control VSCADA relay on GLV board to directly monitor safety loop status by probing the safety loop signal in between subsystems. VSCADA will not control the safety loop. Instead, it will monitor whether the safety loop is open or closed. 10. Graphing - A method or program will be developed to easily graph SCADA data in the CSV files. Data will be graphed on the VSCADA UI from the database to show trends. Only one data set will be graphed at a time. User will be able to select data to be graphed. 11. Better Display - A second database table and new object is an option to eliminate the ugly dictionary at the top of getCANdata.py. A list of CAN sensors will be stored in the database, and only retrieved during program initialization and stored in an array. 12. Cruise Control - Cruise control will only be considered after the rest of the VSCADA system is implemented due to time constraints and degree of complexity.

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iii. System Level Diagrams

Figure 4 VSCADA High Level Diagram

iv. Task Delegation

SCADA Communication: Sam SCADA Software Designed and Implemented: Sam Testing and Demonstrations: Zian SCADA User Interfaces : Zian SCADA Recording and Outputting Data: Sam Subsystem Integration: Zian SCADA Deliverables: Sam

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v. Work Breakdown Structure

Figure 5 VSCADA WBS

The green tasks represent Sam’s responsibilities, the red tasks represent Zian’s responsibilities

vi. Acceptance Testing Strategy Tests will be performed on the following modules:

● I/O Control ● Data Calibration ● Monitor/Control Center ● Data Management ● Screen Display ● Configuration

vii. Software Design

The Configuration and Initialization module will perform the following duties in sequence:

1. Read Configuration files 2. Store sensor metadata in a multidimensional array to allow for easy access by

other modules 3. Initialize other modules 4. Detect the presence of all expected interfaces, e.g. PiCAN 5. Detect preliminary system states 6. Begin sensor data collection

Configuration files will information about sensors (sensor index, sensor name, respective subsystem, lower threshold, upper threshold, default sampling rate, CAN address, GPIO pin, and calibration multiplier.) and sampling rates (idle sampling rate and drive mode sampling rate).

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The I/O Control provides an interface for the VSCADA system to communicate with the other subsystems. The CANbus receives packed sensor data from the TSV, TSI, Cooling System, and Motor Control System. Data includes, but is not limited to, cell temperatures, cell voltages, cell current, car speed, motor speed, and paddle voltages. Additionally, the CANBus will coordinate multithread reading to handle multiple data points at the same time. The GPIO receives status signals from TSI and GLV. It is flexible and fast which is convenient for efficient and clear debugging. This year the Raspberry Pi and PiCAN board will be modified to make the GPIO pins accessible. The USB port provides a way to save collected and calibrated data directly to a flash drive or copy the data at a later time.

The Data Calibration module will calibrate raw data from the other subsystems and send them out to the Data Monitor and Control as well as Data Management. The Data Calibration Module will receive the raw data about the other subsystems of the car including sensor data, cells, motors etc. from the CANBus as a multidimensional array. It will then be broken down the data into individual arrays. This allows the data to be transformed into a useful form and thus easier to work with. The goal is to make the data easily understandable by other subsystems and users alike.

The Data Monitor and Control module will be responsible for checking incoming data against configured thresholds, changing system and subsystem states depending on incoming data, and storing system and subsystem states. The data monitor will have access to configuration data through globally defined arrays.

The Data Flow Management module is meant to streamline data movement between the program, the database, and external hardware components. This module will run independent single threads that will facilitate reading/writing data to/from each software and hardware module in the system. This module uses threading to ensure that no single hardware/software module receives read/write requests simultaneously so as to avoid unpredictable behavior. This will be implemented using a stack or heap. The hardware/software modules above include the Database, I/O Control Ports, and Display.

The Database will only store long-term data that may be useful in future analysis of other car subsystems. Note that operational data will not be recorded in the database since reading/writing to the database is an expensive process. Data stored by the database includes time-stamped sensor data collected from different subsystems. Time-stamped changing system states, and configuration parameters. Data will be written/read to/from the database in a single stream to avoid issues with being ‘locked out’ while the database is busy. An underlying database engine will facilitate easier use of database functions.

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viii. Mechanical Design

There will be two displays that the SCADA will output to, the Dashboard Display Driver and the Back Display Driver.

The Dashboard Display Driver is responsible for visualizing the important data to the driver when the vehicle is turned on. The dashboard will receive data from the Data Manager through the I/O control. After that, it can plot graphs or simply display the important data includes the amount of electricity in the cell, the speed of the car or the state of the car, etc. By doing so, the driver can easily obtain data about the current state of the car. This dashboard has been designed to make it easier for the driver to read the data on the screen.

The Back Display Driver is responsible for displaying the data of the current state of the vehicle with labels. This display is the GUI of the VSCADA which will read data from the database through the I/O control. After that, it will list the data related to the specific sensor from the specific subsystem and appropriately label the data to help the user understand the data means. The labelling will include the name of the subsystem, the current state, the temperature, the speed, the running time, etc. Moreover, the user can select a specific sensor to be visualized in a graph. Additionally, the error message of the subsystem will be displayed on the Back Display to help the user find the source of the error. The Back Display is redesigned to fit to data from more sensors and give more specific error messages. The graphing function is also added to help the user analyze the trend of the data.

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ix. Budget

b. GLV

i. Analysis of Current Design The electrical design of the current GLV is acceptable and functional, but the

mechanical design can be improved. While the screw terminals on the Break Out Board (BOB) PCB are convenient for probing, the board is difficult to take out of the board for more rigorous testing and the likelihood of misconnecting a wire on reinstallation is high.

The GLV battery is unprotected from the elements which means the 2018 team elected not to undergo the rain test at competition. As a result, the team would not have been allowed to compete if the conditions were deemed “wet” by the organizers.

ii. Goals

The GLV Team has defined six goals to improve upon the current GLV design 1. Pi I/O Accessibility - The GLV subsystem will work with the VSCADA to utilize

the I/O pins on the Raspberry Pi to add more functionality in the VSCADA’s ability to communicate with other subsystems.

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2. GLV Real Time Clock- The system has no real time clock or reliable network access for NTP. GLV Power is shut off routinely, so the car systems (SCADA especially) lose any knowledge of real time making it impossible to timestamp data. This is a flaw that should be corrected. The car needs a clock.

3. Molex Connectors - Molex connectors will be used to replace screw terminals. This will allow the BOB to be taken out and put back into the GLV enclosure more efficiently with less chance of miswiring.

4. Misplugging Toleration - 5. GLV Test-Fixture - The test fixtures for the AMS and PacMan boards have been

exceedingly useful. A test fixture for the GLV board does not exist, but should. Such a fixture should be designed that allows full testing of the GLV board features.

6. Waterproof GLV - The battery enclosure should waterproof the battery. It will also have an internal fuse and switch so the status of the battery is safe and maintainable. The proposed GLV enclosure design hides the cable facing to waterproof the subsystem.

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iii. System Level Diagrams

Figure 6 GLV High Level Diagram

iv. Task Delegation

GLV Safety Loop: Max GLV PCB: Robson GLV Installed and Integrated: Max Side Panels Complete: Robson Pedal System Electronics Complete: Max Dashboard Electronics Complete: Sam GLV Battery Installed: Robson GLV Deliverables: Robson

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v. Work Breakdown Structure

Figure 7 GLV WBS

The orange tasks represent Max’s responsibilities, the purple tasks represent Robson’s responsibilities, the green tasks represent Sam’s responsibilities

vi. Acceptance Testing Strategy

The GLV testing plan will test the following items: ● Energize GLV Subsystems ● Energize AIRs ● Shutdown when GLVMS is pulled or side BRBs are pushed ● Fault when the following occurs and restart after appropriate measures have been

taken to remedy fault: ○ Subsystem breaks safety loop ○ Driver BRB pressed ○ Crash detected ○ TSVMS turned off

● Safety loop is correctly wired

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vii. Mechanical Designs

Figure 8 Proposed Redesign of GLV Enclosure

The design of this new enclose will reduce the volume compared to the previous box. Also, the cable facings will be removed so they can be redesigned. Both display screens will be visible on

the same face of the box.

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Figure 9 Alternative Proposed Redesign of GLV Enclosure

This design hides the cable facing so that it is more waterproof. The volume should be significantly reduced and the box will be easier to debug.. Finally, the displays are much more

visible.

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Figure 10 Battery Enclosure Design

The battery enclosure should waterproof the battery. It also has an internal fuse and switch so that the status of the battery is safe and maintainable.

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Figure 11 Pi2CAN Adapter

This design is made with the intention of making the GPIO pins accessible to the Raspberry Pi zero.

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viii. Budget

c. TSI

i. Analysis of Current Design The basic architecture of the TSI is sound provided ideal conditions. This means no dust in the box and low humidity which cause problems with the high impedance nodes. The location of the TSI on the car makes it difficult to access and maintain. There are indicators for sensor outputs and internal states, but the indicators are inconveniently inside the TSI box. The fasteners used to restrain wires is not a good system and the connecting and mounting strategy is complicated. Finally, there are a lot of bugs in the code in addition to several functions not being fully implemented.

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ii. Goals The goals of the TSI subsystem are as follows: 1. GLV/TSV segregation - Ensure the spacing of GLV/TSV is rules

compliant. The “through air” spacing underneath the boards will also be considered. Additionally, there will be more thoughtful placement of components such as the current sensors.

2. Debug - Eliminate bugs in the current code and finish implementing functionality. Existing code must be commented and all new code will have documentation.

3. Indicator - An indicator outside of the TSI enclosure will be created to display sensor outputs and internal states.

4. Maintenance Redesign - The entire box will be redesigned for easier maintenance access. The TSI and Motor Control System (MCS) will be incorporated into the same enclosure with the water tube from the cooling system integrated with the MCS.

5. Boards - A spare TSI board will be manufactured, taking care to eliminate the high impedance nodes. There will be a redesign to eliminate hazards, such as adding coating and spacing.

6. Current Sensor - An optical isolator will be used for the current sensor to transmit a digital signal. This will be done to satisfy the rules requirement about GLV.TSV separation.

7. Isolation- The wiring will be checked for GLV.TSV isolation. 8. Read Voltage Measurement - the Voltage measurement can only be read

when the AIRs are closed, which is inconvenient. A DC-DC converter will be added from GLV to TSI to power the voltage and current measurements when the AIRs are open.

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iii. System Level Diagrams

Figure 12 TSI Top Level Diagram

iv. Task Delegation New TSI/MCS Enclosure Built and Delivered: Xiaonan TSI Board: Xiaonan CANBus Connectivity Delivered: Hongbo MCS Incorporated into TSI Enclosure: Antonio Cooling System Integrated into TSI: Hongbo TSI Demonstrated and Accepted: Tianyu TSI Deliverables: Tianyu

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v. Work Breakdown Structure

Figure 13 TSI WBS The purple tasks represent Xiaonan’s responsibilities, the red tasks represent Tianyu’s

responsibilities, the yellow tasks represent Hongbo’s responsibilities, the orange tasks represent Antonio’s responsibilities

vi. Acceptance Testing Strategy

Tests will be run on the following components: ● Pedal Cluster ● Throttle Plausibility ● Brake Lights ● TSAL ● IMD ● System Measurements ● IMD ● RTDS ● CANBus communication ● Precharge Relay ● Brake Overtravel ● Drive States ● Status/Debug Lights ● Power system ● Isolators ● Sensors

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vii. Mechanical Design

Figure 14

Figure 15

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Figure 16 TSI Enclosure

The above three figures show different views of the proposed TSI Enclosure that will incorporate the MCS.

viii. Budget

d. TSV

i. Analysis of Current Design

In its current state, the TSV subsystem would be unusable in competition as it violates a large number of rules for the Formula Hybrid Electric Vehicle Competition.

Currently, the system is operating without an Accumulator Management System (AMS). The current design is unreliable and over complicated, causing more problems when it is included in operation than when it is gone without. A review of both the AMSs and the Pack Management boards is necessary moving forward in order to produce functional and safe battery packs for competition.

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The software in the TSV also is problematic as it is largely unconfigurable. This leads to difficulty in troubleshooting and potentially more problems that would be impossible to work around without a complete redesign.

ii. Goals The TSV subsystem will work to achieve the following goals over the course of

the semester in order to produce a functional and safe high voltage system for the vehicle: 1. Rule Compliance - The current vehicle violates a large number of rules that need

to be addressed in order to participate in competition this year. The mechanical design of the battery packs from previous years will not be allowed to participate in the competition in the future, so this is the highest priority for the team. This will also lead to larger budget considerations for the TSV team, as they will need a large amount of money for the new design without being able to reuse much of the previous materials.

2. GLV/TSV Isolation - A persistent problem with the current battery packs is that there is an unclear division between the high and low voltage systems of the vehicle. This was an issue in the previous year at the competition and led to a rough work around. In order to accomplish this, the team will work to simply the electronics in the TSV system to reduce the amount of interaction between the high and low voltage regions to ensure rule compliance. This includes an overhaul of the PackMan and AMS design, which would lead to a simpler electrical system inside of the TSV packs.

3. Firmware Stability - Currently there is a large amount of uncertainty inside of the computer systems in the TSV subsystem. There are several bugs which lead to a high probability of faults in the system, which would be necessary to avoid in order to drive the vehicle.

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iii. System Level Diagrams

Figure 17 Accumulator High Level Block Diagram

Some components have been moved from previous designs, including the PackMan and the wiring I/O.

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Figure 18 Interconnect Plan

Diagram of New Wiring and Interconnection Plan for updated AMS design. Many of the wires will be replaced by a wireless communication system.

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Figure 19 Page 1 of New PacMan Implementation Design

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Figure 20 Page 2 of New PacMan Implementation Design

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iv. Task Delegation TSV Pack Redesign Delivered: David TSV Packs Rule Compliance: Weston AMS Board Redesign Delivered: Yishak PackMan Boards Delivered: Max Demonstrated and Accepted: Weston TSV Deliverables: Yishak

v. Work Breakdown Structure

Figure 21 TSV WBS The blue tasks represent the ME responsibilities, the green tasks represent Weston’s

responsibilities, the orange tasks represent Yishak’s responsibilities, the yellow tasks represent Max’s responsibilities

vi. Acceptance Testing Strategy

The TSV testing plan will include testing to the following items: ● AMS Boards ● PackMan Boards ● Assembled Packs ● Firmware ● Wiring ● Rule Compliance

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vii. Mechanical Design The packs for the TSV will likely undergo a large amount of mechanical redesign

this year. Depending on budget, there are two different avenues to explore for the packs, both of which require a substantial amount of mechanical redesign. The first would be to assemble completely new packs with a new design entirely different from what currently exists. In this new design, there would only be 2 packs instead of 4, which introduces new benefits and risks. These new packs would be constructed with an aluminum frame and fiberglass sheets as the walls of the boxes. These enclosures would be significantly lighter than the current construction of the packs, thus reducing the overall weight of the car by a significant amount. This new design would have a completely insulated interior, thus removing the concern of high and low voltage isolation and having a completely conductive enclosure like the current design. There will be less connectors and fewer wires in the packs, leading to less possibilities for failure and external disturbances. The plan would now include only 1 PackMan for 14 cells, instead of the current 1 PackMan for 7 cells, thus simplifying the electronics further. All of these redesigns would produce a significant reduction in the length of the battery pack enclosures, therefore allowing for a reduction in the length of the vehicle’s wheelbase. Finally, the new design would greatly improve the access to the cells in the battery which is currently a major problem as replacing or repairing a cell in the packs takes a huge amount of time and effort.

A different option would be to update the previous pack design to be rule compliant. This would still be a large amount of work as the current pack design is in need of a large redesign to be rule compliant. To do this, the AMS and PackMan system would need a great deal of attention in order to function correctly. In addition to this, the enclosure for the packs would need to be remade as they currently provide little to no isolation between high and low voltages.

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Figure 22 Full Pack Redesign

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Figure 23 Interior View of TSV Packs

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Figure 24 Exposed Cells in TSV Pack for easy access

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viii. Budget

e. COOLING

i. Analysis of Current Design In its current state, the cooling system is functional and was tested in previous

years. The cooling system was tested in the Dyno room in the past and was shown to be functional, however due to its size it was not installed on the car.

The cooling system would need to be retested to ensure that it is still functional along with some other minor general updates to the system. Much of the cabling needs to be redone throughout the system and the tubing for the cooler need to be remade. Many of the tubes for the current system are too short, so they would need to be made longer to ensure complete functionality when installed in the vehicle.

ii. Goals

The Cooling subsystem will work to achieve the following goals over the course of the semester in order to produce a functional cooling system for the vehicle:

1. Install the Cooling System on the Car - The cooling system is functional, but has never been able to be fully installed on the car due to its size. The main priority

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for this year will be to get the cooling system integrated into the vehicle design so that it will be able to be used.

2. Design a New Enclosure - The old enclosure for the cooling system was too large and caused the system to not be included on the car. A new enclosure would need to be designed in order to fit everything onto the vehicle, or the layout of the subsystems on the car must be redone to include space for the cooling system.

3. Update Cables - Much of the cabling is sloppy and poorly done. Organizing and cleaning up these cables would be useful to simply the system.

4. Tube Length - The tubes for the cooling system are currently too short. In order to be used in the future, these tube lengths would need to be increased.

5. Motor Controller Temperature Display - Incorporate either CAN or USB communication coming from the motor controller which displays the current temperature of the device. The controller already has this capability, it just is unimplemented at this time.

6. Easily Mountable and Testable - Ensure that the cooling system is easily mounted into both the DYNO and in the Car. This would speed up the process of testing and integrating the system.

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iii. System Level Diagrams

Figure 25 High Level Block Diagram of the Cooling System

iv. Task Delegation

Cooling System Design Completed: Hongbo Fan Controller Algorithm: Hongbo Cooling Safety Loop Integration: Hongbo Cooling TSI Integration: Hongbo Cooling Communication Implemented: Hongbo Cooling Mechanical Assembly Complete: Hongbo Cooling Deliverables: Hongbo

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v. Work Breakdown Structure

Figure 26 Cooling WBS

The blue tasks are Hongbo’s responsibilities

vi. Acceptance Testing Strategy The testing plan for the Cooling system will test the following items:

● The sealing property of the water tubes ○ Tubes will be filled with water and then run through the loop to check if

any water escapes the loop while running or still ● Connect the cooling system to GLV or TSI in the DYNO room

○ Connect all tubing together, wire the sensors, fan, and pump, and power the system. Check for displays on cooling information in regards to the controller and fan

● Measure the temperature of the motor controller ○ Use the USB port on the controller with and without the cooling system in

place to see if the temperature is significantly lowered

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vii. Mechanical Design

The existing mechanical design for the cooling is system is sound and functional. The only changes that would be made in this project for the cooling mechanical design would be to the size of the system. This may also be proven to be unnecessary if other subsystems are reduced in size in order to allow for better management of space on the vehicle.

viii. Budget Completely New Cooling System:

Reutilizing Previous Cooling System:

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f. INTERCONNECT

i. Analysis of Current Design In its current state, the wiring and interconnection of the vehicle is in need of a

massive organizational overhaul. Almost none of the wires are labeled in any meaningful way, causing a confusion when working on the car.

There is currently no efficient method by which to test wires and cables for good connectivity. This makes debugging issues with the car and connections between components unnecessarily difficult.

The highlevel wiring and block diagram for the complete vehicle is also too complicated and messy. This will need to be cleaned up in order to produce a more logical and easily understood diagram.

Materials used for producing new connections between systems of the car are also running low and will factor into budget considerations.

ii. Goals

The Interconnect subsystem will work to achieve the following goals over the course of the semester in order to produce a functional wiring and connectivity system for the vehicle:

1. Develop a Wire Organization System - A single method by which all cables are named, organized, and labeled will decrease problems caused by improper wiring and decrease the amount of time needed to trace wires when debugging a problem.

2. Update and Provide a Wiring Diagram - This diagram would show the full interconnectedness of all the aspects of the vehicle and provide an organization to the overall system. This will be a large graphic to be printed and posted in easily accessible locations.

3. Produce a Wire Tester - Build a platform for testing wires in a simple and quick manner. Would eliminate the need for probing aimlessly with a multimeter and will allow for immediate validation of wires after construction.

4. Connect All Subsystems of the Vehicle - The main responsibility of this team is to get all of the communication between all subsystems wired together and tested and verified in order to ensure full vehicle operation.

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iii. System Level Diagrams

Figure 27 High Level Block Diagram of Full System Wiring and Connections

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Figure 28 High Level TSV Wiring Diagram

(TODO: Redesign 2 pack system)

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Figure 29 Full Car Block Diagram

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iv. Task Delegation

Wiring Layout Delivered: Weston I/O Layout Delivered: Drew Rule Compliant Wiring: Weston DYNO Wired: Weston Car Wired: Drew Interconnect Deliverables: Weston

v. Work Breakdown Structure

Figure 30 Interconnect WBS The green tasks are Weston’s responsibilities, the purple tasks are Drew’s responsibilities

vi. Acceptance Testing Strategy

In order to produce a functional interconnectivity between all components of the car, the following items will be tested:

1. All 4/6 Pin Deutsch Connectors - All of these type connectors will be verified that the wire is correctly made and makes a good electrical connection between both ends of the cable.

2. Orange HV Cable Grounding - Each cable will be heavily inspected for grounding braid fraying and tested to ensure that no point has an unsafe ungrounded region.

3. Orange HV Power Lock Connectors - Test that the latches have no damage on them and that the cable is labeled with the gauge, max temperature, and max voltage.

4. Wire Label Checking - Visually inspect all wires for gauge, max temperature, and max voltage labels

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vii. Budget

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6. Overall Acceptance Testing Plan The main goal of the test strategy is to prove that all systems can integrate with each

other. To perform this functionality we will build the dynamometer room to match the car as closely as possible. Each team has detailed how they intend to effectively and completely test their systems. One item that needs to be enforced is that people will need to be able to justify numerical values. This will involve error and certainty analysis. To be able to test the car as a whole every single part will be integrated into the dynamometer room. This will allow teams to try to integrate as quickly as possible as soon as they have completed their relevant subsystems. VSCADA GLV TSI Cooling Interconnect

7. Maintainability Plan The following actions will be taken by the team in efforts to promote a fully maintainable

project for future endeavours: ● All Drawings (Electrical or Mechanical) Posted Online

○ Any and all drawings produced by the team will be posted online regularly to the project website. The deliverables will be clearly labeled and easily found on the website.

● All Schematics Clearly Labeled with a Key ○ Any form of schematic will be posted with clear labels for all items contained

within it. This includes all element sizes, dimensions, and values. ● All Budget and Purchase Orders Posted Online

○ Any monetary transaction will be documented online including the part, description, purpose, and vendor information.

● All Code Posted on GitHub ○ All code written for any subsystem on the project will be posted online in a timely

manner. The GitHub repository will be easily accessible for future users as it will be disconnected from Lafayette accounts.

● All Code Fully and Meaningfully Commented ○ Any piece of code written will be fully documented with the intention to allow

any person viewing it be able to understand what they are reading. The goal would be to allow even somebody unfamiliar with the code to be able to quickly understand the aim of what they are looking at.

● Complete Documentation of all Subsystems ○ Any piece of design produced for any of the subsystems in the vehicle must be

completely documented. This includes interconnectivity documents, technical

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drawings, schematics, and troubleshooting guides. These will help future team members to quickly begin working and understand design decisions made.

8. Cost and Budget Assessment

The Lafayette Formula Electric Vehicle is proposing three budgets; one to build an entirely new car, one to build a car using existing parts from the 2018 car, and one to make the 2018 car rules compliant. Shipping, taxes, and miscellaneous costs are estimated to be 15% of the subtotal (excluding registration fees based on data from previous years.

Subsystem/Purpose New Car Use 2018 Car Components

Rules Compliant 2018 Car

Registration Fee $2300 $2300 $2300

VSCADA/DYNO $525 $185 $7

GLV $780 $230 $0

TSI/MCS $1500 $1300 $270

TSV $4187 $1422 $1422

Cooling $620 $100 $100

Interconnect $1500 $1050 $625

Chassis/Body $5000 $3000 $500

Steering $2500 $1500 $600

Brakes $3500 $2000 $500

Suspension $2200 $1100 $30

Motor $4000 $200 $150

Pedal/Controls $2000 $1000 $800

Shipping / Taxes / Miscellaneous

$4247 $1963 $750

Total $34,589 $17350 $8054

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The above three options have their respective benefits as well as risks. In an effort to weigh the benefits with the risks associated, we discuss the pros and cons of each option as follows. The first option to build an entirely new competition-ready car from totally new parts leads to a better car design with a higher scale of maintainability and performance. Although it presents the most challenge, it provides a great opportunity to learn and to grow for the whole team. In addition, if this option is successful, the department will have two functional cars which in turn adds prestige to not only the department but also to the College. On the other hand, this option presents a number of risks including the estimated cost being almost twice as expensive as that of the second option and four times as expensive as that of the third option. Besides being the most expensive option, it also has the highest risk of running out of the budget which leads to not being able to complete the car. There is also the risk that the car will not be completed and the department loses the competition registration fee of $2300. While going to competition doesn’t have to be the overall goal of the project be an option, we as a team are committed to going to the competition to showcase our engineering and problem-solving skills at the highest level.

As far as the second option to build a new competition-ready car using some parts of the 2018 car is concerned, the benefits are a significantly less expensive cost and a higher chance of making it to the competition. However, this option means the department will not have two functional cars. On top of that, reusing some parts might lead to not eliminating poor designs which directly contributes to poor performance at the competition.

The third option to modify the 2018 car to fully rule compliant is four times cheaper than the first option, and its cost is almost half the cost of the second option. Moreover, despite the fact that this option presents the highest chance of making it to the competition, it is not as intellectually rewarding as the previous options. In addition, it will perpetuate the poor designs of the 2018 car.