MSD P15280 RIT HOT WHEELZ TEST BENCH

AGENDA ❖ Review Problem Definition Material ❖ System Level Design Review ▪Functional Decomposition ▪Morphological Chart & Pugh Chart ▪Benchmarking ▪Concept Selection & Systems Architecture ▪Feasibility Analysis ▪Risk Assessment ▪Further Engineering Analysis Needed

PROJECT BACKGROUND ❖ The RIT Hot Wheelz Electric Vehicle Team is a group of all female undergraduate engineers who come together to form a team of innovative and creative race enthusiasts. ❖ The team seeks to enter the 2016 Formula Hybrid competition in the Electric-only class. ❖ A test bench is needed to test the drivetrain of the vehicle and ensure timely completion of the vehicle.

CUSTOMER REQUIREMENTS

PROJECT PLANNING

OPEN ITEMS FROM LAST REVIEW ❖ No existing design for Hot Wheelz electromechanical drive system ➢ Working closely with Hot Wheelz team to understand needs ❖ "Surrogate" customer ➢ Working well for us ❖ Interdependence between MSD team and Hot Wheelz ➢ Resolving issues as they arise and planning for future conflicts ❖ Budget unclear ➢ Working with customer to finalize budget Estimated Budget Powertrain Test Bench Labview Software$3, Electrical Components$3, Motor$2, Bench Components$ Mounting Hardware$ Powertrain to Bench Connection$ TOTAL9,500.00

SYSTEM LEVEL DESIGN

Functional Decomposition

Pugh Chart

PUGH CHART

BENCHMARKING- Dyno Visit ❖ Visit provided insight into loading mechanisms ➢ Eddy Current Brake ➢ Generator - Resistor Bank ❖ Sample GUI ➢ Easy to view dials ➢ Large window to view results ❖ Example of safety precautions ➢ Straps, fans, ventilation ❖ Output data as Excel file

BENCHMARKING- Example Test Benches ❖ Speed Control Test Bench (Left) ➢ Allows the study of the operation of a servodrive when a variety of loads are applied to the motor. ➢ Powder Brake to vary motor load ➢ Main Components: ■Motor Voltage ■Motor Temperature ■Load amount and type ❖ Motor Test Bench (Below) ➢ Robust, multi-compatible ➢ Flexibility through modular design ➢ Motor Torque, Power & Efficiency

SELECTED CONCEPT- MECHANICAL ❖ Two mechanical structures ➢ Mobile Cart to mimic Hot Wheelz Chassis ➢ Enclosed T-framed structure to house motors and moving parts ➢ UI will be located on top of the T-framed enclosure. ➢ All pieces are portable and compact Above: Preliminary CAD model of a 36in by 30in T-slot aluminum framing enclosure with two removable plexiglass panels for access and electrical attachment.

Selected Concept - Electrical User InterfaceLoading Mechanism Sensors MCU Hot Wheelz System

ELECTRICAL FEASIBILITY ANALYSIS ❖ How often will the tach counter need to be polled to avoid aliasing? ➢ max speed=4,500 rpm=75 rev/sec = Nyquist Rate of 150 Hz ➢ microcontroller will need to handle a count rate of 150 counts/second ➢ tach counter will need to be polled at a frequency greater than 150 Hz ➢ A frequency of 150 Hz should be no problem considering MCU can run up to 15MHz ❖ How close to real time can the data from the sensors be displayed on screen? ➢ Assuming uC clock runs at 15MHz -> 66.6ns/cycle ➢ Assuming max sample rate of 10us/sample ➢ Max clock cycles to obtain sample = less than 100 ➢ Max clock cycles to send data to computer = less than 100 ➢ Assuming baud rate of 115,200 bits/second ➢ Assumption that computer side delay is negligible ➢ Total time = (2x100x66.6x10^-9)+(12bits)(1/115200)+(10x10^-6) = 127us delay

MECHANICAL FEASIBILITY ANALYSIS- Load Calculations ❖ Determine Track Requirements (New Hampshire Motor Speedway) ➢ Longest Straightaway 77m ➢ Hairpin Turn- Minimum 9m Diameter ➢ Constant Turn- Minimum Diameter 30m ➢ Drag Race- 75m ❖ Determine Approximate Speeds and Acceleration Rates ➢ Max Endurance/Autocross Speed of 65-70MPH ➢ Hairpin Turns 10-15MPH (~1G) ➢ Constant Turns 25-30MPH(~1G) ➢ Drag Race 75MPH (~1.5G) ❖ Estimated Vehicle Parameters ➢ Mass = 340kg ➢ Wheel Diameter = 23 inches = m ➢ Friction Coefficient = 0.90 ➢ Drag Coefficient =0.95 ➢ Grade Angle = 4 degrees

MECHANICAL FEASIBILITY ANALYSIS- Load Calculations

MECHANICAL FEASIBILITY ANALYSIS ❖ Potential Hot Wheelz Motor Specs ➢ 250 Nm → 2500 RPM ❖ Proposed Test Bench Load Varying Motor ➢ 125 Nm → 5000 RPM ❖ 2:1 Gear Ratio Between Test Bench and Hot Wheelz Motor Test Bench: 2 X RPM ½ X Torque Hot Wheelz Motor: ½ X RPM 2 X Torque

MECHANICAL FEASIBILITY ANALYSIS ❖ Hot Wheelz Motor ~ $11,000 ❖ Proposed Test Bench Motor $ 2,500 → Within Test Bench Budget ❖ Will be able to vary loads similar to: ➢ Endurance Race Conditions ➢ Long Runs ➢ Most Autocross Race Conditions ❖ Will not be able to vary loads similar to: ➢ Drag Race ➢ Max Acceleration ❖ Still allows for testing most scenarios, check for safety, tune and debugging

Golisano Institute of Sustainability (GIS) Dynamometer vs. Hot Wheelz Test Bench Using the Existing GIS Dyno Pros:Cons: ●Capabilities: the machine already exists and has the capabilities that we need. ●Cost: we would not need to build a load varying system at all. ●Complexity: ensures project will be completed in one senior design session. ●Testing/Calibrating: decrease in magnitude of systems to test and calibrate. ●Availability of the Dyno: we would have to work by the schedule of the dyno to run testing and to work out integration issues. ●Location: drive system would have to be transported to dyno to run testing. ●Interface with dyno: concrete existing hardware and software, no flexibility; also would have to create partial chassis to allow testing. Using a Test Bench of Our Own Design and Construction Pros:Cons: ●Convenience: custom tailored to our specific need ●Expandability: bench would be an investment for future HW team vehicles. ●Availability: ability to use the device when needed without prior scheduling and arranging ●Cost: expensive to source a load varying device ●Timeframe: difficulty in adhering to strict schedule if problems arise ●Testing/Calibrating: increase in magnitude of systems to test and calibrate.

❖ Compromise between budget and load variance ❖ Test bench will have limited capabilities ❖ Max Load Testing will be done at GIS Dyno GIS Dynamometer vs. Hot Wheelz Test Bench

RISK ASSESSMENT Scale:

RISK ASSESSMENT Scale:

ENGINEERING ANALYSIS NEEDED ❖ Mechanical ➢ Safety Calculations ■Moving Objects ➢ Connection of Test Bench Motor to Vehicle Motor ➢ Structural Integrity Analysis ➢ Cooling Solutions for Motor ■Make vs. Buy Cost Analysis ❖ Electrical ➢ Control power dissipation method ➢ System Integration - Whether the test bench will communicate with Hot Wheelz electrical system to obtain results from its sensors

QUESTIONS? FEEDBACK?