Scooterizers Detailed Design Review “Making last-mile transportation safer, easier, and more efficient” 1

2 Review of Project Goals and Specs Project Deliverables 1. Model the Electrical System 2. Variable Throttle and Brake 3. Clutch for the Motor Control/Electrical Overview 4. Simplify Series-Parallel Circuit 5. Circuit Protection Mechanisms 6. Combine the Control System Project Budget Breakdown Project Risks and Problems Project Schedule

The goals of this project are twofold: Produce a prototype scooter that is lightweight and foldable, easy to use, and provides an electronic boost for uphill travel. Provide future design teams with a database of knowledge, so that they can benefit from our project learning and experience. Project Goals 3

Project Specifications 4 GeneralSpecificAcceptableRanking Efficiency Total system efficiency.> 51%. 2 Weight Must be lightweight; easy to carry.20lbs. 3 Human Input Must have intuitive human input and control. Have both mechanical and regenerative brake controls. Twist throttle and handbrakes. 2 Total Scooter Cost Must be affordable.< $ Energy Storage/Propulsion Must store electrical energy. Ultracapacitors provided by IVUS. 2 Ease of Use The scooter frame must be foldable, and the propulsion and regeneration systems should be transparent to the user. Collapsible frame with brake regeneration. 3

5 Review of Project Goals and Specs Project Deliverables 1. Model the Electrical System 2. Variable Throttle and Brake 3. Clutch for the Motor Control/Electrical Overview 4. Simplify Series-Parallel Circuit 5. Circuit Protection Mechanisms 6. Combine the Control System Project Budget Breakdown Project Risks and Problems Project Schedule

Project Deliverables 6 1.Model the Electrical System 2.Improve Voltage Regulation / Protection Circuits. 3.Add Parallel-Series Ultra-Capacitor Switching Circuit. 4.Combine the Fragmented Control System. 5.Add Variable Throttle / Regenerative Brake. 6.Add a Clutch to the current Motor System

7 Review of Project Goals and Specs Project Deliverables 1. Model the Electrical System 2. Variable Throttle and Brake 3. Clutch for the Motor Control/Electrical Overview 4. Simplify Series-Parallel Circuit 5. Circuit Protection Mechanisms 6. Combine the Control System Project Budget Breakdown Project Risks and Problems Project Schedule

Model the Electrical System What has been done ? We came up with simply circuits to test each component separately Fortunately, all work GREAT Each component will be connected to other components with confidence Will be completely done by the time of submitting the final report

9 Review of Project Goals and Specs Project Deliverables 1. Model the Electrical System 2. Variable Throttle and Brake 3. Clutch for the Motor Control/Electrical Overview 4. Simplify Series-Parallel Circuit 5. Circuit Protection Mechanisms 6. Combine the Control System Project Budget Breakdown Project Risks and Problems Project Schedule

Variable Throttle and Brake (Scooterizers’ Choice) Twist throttle Specifications Item Code: Throttle-ES (Hole Effect Type) Price: $ tax Supply Voltage: 5Vdc Voltage on Full: 4.27Vdc Voltage on Zero: 827milivolts Green wire voltage increases as the throttle is turned 6mA maximum current

11 Review of Project Goals and Specs Project Deliverables 1. Model the Electrical System 2. Variable Throttle and Brake 3. Clutch for the Motor Control/Electrical Overview 4. Simplify Series-Parallel Circuit 5. Circuit Protection Mechanisms 6. Combine the Control System Project Budget Breakdown Project Risks and Problems Project Schedule

Clutch for the Motor Miniature Electromechanical Clutch From Reell Precision Manufacturing Pros: Lightweight Small Easy to integrate into existing design Works well with this scooter’s various user scenarios Cons: Requires 24 Volts to function Needs a human interface or remote sensor to activate Electronic Leads must be securely fastened to avoid damaging the clutch

Fabrication and Integration Mill a new mounting plate for the motor and drive train Manufacture a new input shaft adapter for the clutch Securing the wire leads

14 Review of Project Goals and Specs Project Deliverables 1. Model the Electrical System 2. Variable Throttle and Brake 3. Clutch for the Motor Control/Electrical Overview 4. Simplify Series-Parallel Circuit 5. Circuit Protection Mechanisms 6. Combine the Control System Project Budget Breakdown Project Risks and Problems Project Schedule

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18 Review of Project Goals and Specs Project Deliverables 1. Model the Electrical System 2. Variable Throttle and Brake 3. Clutch for the Motor Control/Electrical Overview 4. Simplify Series-Parallel Circuit 5. Circuit Protection Mechanisms 6. Combine the Control System Project Budget Breakdown Project Risks and Problems Project Schedule

Simplify Series-Parallel Switch Jet-Tread Series-Parallel Switch 19

Simplify Series-Parallel Switch 20 SPDT Relay 12 Relays 30 Amps Current 15ms Switch Time 2.7Vdc Parallel Mode 13.5Vdc Drive Mode

Simplify Series-Parallel Switch 21 Preliminary tests using batteries indicates an extremely low or nil voltage drop through the system. Testing with Ultracapacitors is needed Testing in regen mode with the motor is needed

22 Review of Project Goals and Specs Project Deliverables 1. Model the Electrical System 2. Variable Throttle and Brake 3. Clutch for the Motor Control/Electrical Overview 4. Simplify Series-Parallel Circuit 5. Circuit Protection Mechanisms 6. Combine the Control System Project Budget Breakdown Project Risks and Problems Project Schedule

23 Circuit Protection Mechanisms Electrical Isolation Voltage Regulation Current Limitation

24 Circuit Protection Mechanisms Relay Circuit 1: Prevent ESC Destruction when in Regen mode Status: Partially assembled (to be finished soon)

25 Circuit Protection Mechanisms Relay Circuit 2: Prevent damage to Ultracapacitors when in Regen mode Status: Partially assembled (to be finished soon)

26 Review of Project Goals and Specs Project Deliverables 1. Model the Electrical System 2. Variable Throttle and Brake 3. Clutch for the Motor Control/Electrical Overview 4. Simplify Series-Parallel Circuit 5. Circuit Protection Mechanisms 6. Combine the Control System Project Budget Breakdown Project Risks and Problems Project Schedule

Combine the Control System 27 Modularity = Future Usability Have several minor control systems under the direction of master control system Regen Control System Clutch Control System Master Control System Ultracapacitor Control System Motor Control System

Combine the Control System 28 Regenerative Control System ADC hardware to sense Ultracapacitor circuit voltage

Combine the Control System 29 Regenerative Control System Analog comparitor to sense if H-bridge voltage ever goes higher than 2.7Vdc while in regen mode

Combine the Control System 30 Clutch Control System Receives signal from Master Control System when throttle is sensed, and activates the clutch

Combine the Control System 31 Master Control System Interprets signal from throttle and regen brake button, then sends commands to other control system circuits. No Throttle 1ms Pulse Full Throttle 2ms Pulse

Combine the Control System 32 Master Control System – Interface with ESC Required extensive reverse-engineering No Throttle 1ms Pulse Full Throttle 2ms Pulse

Combine the Control System 33 Ultracapacitor Control System Receives signal from Master Control System when throttle is sensed, and activates drive or regen configuration on UCB relays Assembly completed this weekend Motor Control System Receives signal from Master Control System when throttle is sensed, and activates drive or regen configuration on UCB relays Assembly will be completed this weekend

34 Review of Project Goals and Specs Project Deliverables 1. Model the Electrical System 2. Variable Throttle and Brake 3. Clutch for the Motor Control/Electrical Overview 4. Simplify Series-Parallel Circuit 5. Circuit Protection Mechanisms 6. Combine the Control System Project Budget Breakdown Project Risks and Problems Project Schedule

Current Bill of Materials (BoM) Purchased Items: Electromechanical Clutch Twist Throttle NiMH 24V Battery Pack Battery Pack Charger Shunt Resistor Atmel ATMega48 Chip (8) Relays (21) Relay Drivers (8) Additional Materials Acquired: Electrical Wiring Chip Sockets Aluminum Sheet Metal Stock Brass Stock

Project Budget McMasterCCZ $ (82.52) Scooter CatalogCC $ (31.94) McMasterCCZ $ (82.49) credit $ DigikeyCC $ (15.76) AlliedCC $ (20.52) All BatteryCC $ (74.17) RC ElectronicsCC $ (35.40) DigikeyColin $ (109.67)

37 Review of Project Goals and Specs Project Deliverables 1. Model the Electrical System 2. Variable Throttle and Brake 3. Clutch for the Motor Control/Electrical Overview 4. Simplify Series-Parallel Circuit 5. Circuit Protection Mechanisms 6. Combine the Control System Project Budget Breakdown Project Risks and Problems Project Schedule

Project Risks and Scope 38 Systems we will not be able to deliver: DC/DC1 Power Supply Current Limiter DC/DC2 Power Supply

Project Risks and Scope 39 DC/DC1 Power Supply Idea was tested Voltage level on DC/AC inverter did not act as expected Finding: Oscillators controlling AC output shut down abruptly +

Project Risks and Scope 40 Current Limiter Idea has been evaluated by EE grad student Current limiter would need a prohibitively large heatsink Not enough time resources

Project Risks and Scope 41 DC/DC2 Power Supply (control voltage level during regen) Not enough time to implement Voltage control is managed by regen circuit microcontroller

Previous Project Risks and Scope 42 Perceived Risks: Unexpected problems with the Electronic Speed Controller means that we will have to shift focus to getting it to work. This will use a lot of extra time resources. Need Future Design Work: Drive-mode and Regenerative Mode Power Supplies (EE Oriented) Custom-Built Electronic Speed Controller (CompE, EE Oriented) Future-Proof Designs: (Place Most Effort) Modular Control System Durable Series-Parallel Switch Design Throttle/Brake/Clutch Controls System Modeling Clutch for Motor THESE ARE STILL ON TRACK TO BE DONE ON TIME!

43 Review of Project Goals and Specs Project Deliverables 1. Model the Electrical System 2. Variable Throttle and Brake 3. Clutch for the Motor Control/Electrical Overview 4. Simplify Series-Parallel Circuit 5. Circuit Protection Mechanisms 6. Combine the Control System Project Budget Breakdown Project Risks and Problems Project Schedule

Client Review[November 19 (Today)] Finish Assembly[November 19-November 29] Final Testing[November 29-December 3] Documentation[December 3-December 9] Knowledge Database 44

Questions ? 45