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

2 Review of First Semester 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 Project Risks 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 First Semester 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 Project Risks Project Schedule

Project Deliverables from First Semester 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 Control. 6.Add a Clutch to the current Motor System

7 Review of First Semester 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 Project Risks Project Schedule

Model the Electrical System Why: To make the project well documented. To make it easy to test, assemble and validate. What do we mean? Any diagram, circuit, chart or graph has to be: Clear. Well explained. Tested.

9 Review of First Semester 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 Project Risks Project Schedule

Colin10 Variable Throttle and Brake (Jet- Tread’s Choice) Thumb throttle Options Push Button Linear Motion Potentiometer Rotational Motion Potentiometer

Variable Throttle and Brake (Scooterizers’ Choice) Twist throttle Specifications Item Code: Throttle-ES (Hole Effect Type) Price: $ tax Supply Voltage: 12v Return Voltage: 4v Handle Bar Diameter: (approx) 22mm / 7/8" Three wires red, green, black The supply voltage = red and black wires. Green wire voltage increases as the throttle is turned. Fits 24 and 48v scooters.

12 Review of First Semester 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 Project Risks Project Schedule

Clutch for the Motor Reell Precision Manufacturing Miniature Electromechanical Clutch Model: EC30XP Cost: $77.82 Accelerate loads from zero to full speed in less than three milliseconds. Apply electricity and these clutches rapidly engage; turn off the power, and they instantly disengage. Due to the rapid acceleration and nonslip design of these clutches, some applications may need a slip clutch, coupling, or other shock- absorbing device. These clutches drive in one direction only. Max. rpm is They operate on 24 VDC and include wire leads for hardwiring

Design Characteristics Colin14 Single Direction Wrap spring clutches provide torque only in the direction in which they wrap down. This allows for overrunning. Relative High Shock Due to the EC30XP's rapid acceleration, system inertia effects can be significant. In some applications an in-line slip device may be used for shock absorption. Please contact a Reell Sales Representative for more information regarding this option. Engagement Relative to Speed The EC30XP relies on relative motion between the input and output for engagement. Thus, the slower the speed, the longer the time until engagement. Operating Parameters EC30XP performance is best within the following conditions: 0°- 40° C (32°-104° F) rpm typical, 1400 rpm max. Minimum load friction torque 0.05 N-m (6.0 oz- in) plus customer input bearing torque. TechnologyElectromechanical wrap spring clutch Low Wattage The EC30XP requires only 3.5 watts of power for engagement High Torque, Small Package Size The EC30XP provides 3.39 N-m (30 lb- in) of total load over a life of 1 million actuations with an outside diameter of about 33mm (1.3 inches), and a shaft length of about 27mm (1 inch). Rapid Acceleration After spring wrap-down, the EC30XP will accelerate loads from zero to full speed in less than 3 milliseconds. Consistent Performance Engagement is made with virtually no slippage and disengagement is almost instantaneous. Power Source All Reell clutches operate on either filtered or unfiltered dc power. The use of filtered power is recommended for better life at high speed. Application Considerations

15 Review of First Semester 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 Project Risks Project Schedule

Control and Electrical Introduction Lacked good voltage regulation Lacked current limiting No master control system RESULT: Reliability and usability issues 16

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19 Review of First Semester 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 Project Risks Project Schedule

Simplify Series-Parallel Switch PROBLEM: Hard to use Jet-Tread Series-Parallel Switch 20

Simplify Series-Parallel Switch USAGE SCENARIOS Regenerative Mode: 2.7Vdc Drive Mode: 24.3Vdc (9*2.7Vdc) 21

Simplify Series-Parallel Switch Design No. 1: SPDT Relay Design No. 1: SPST Relay 22

Simplify Series-Parallel Switch Design Choice: Design No. 1 (SPDT Relays) Cheapest Most Reliable Fewest Points of Failure 23

24 Review of First Semester 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 Project Risks Project Schedule

25 Circuit Protection Mechanisms Electrical Isolation Voltage Regulation Current Limitation

26 Circuit Protection Mechanisms Electrical Isolation KISS: SPDT Relays!

27 Circuit Protection Mechanisms Voltage Regulation Drive Mode 12-24Vdc Input 12Vdc Output Regenerative Mode 0-15Vdc Input 2.7Vdc Output

28 Circuit Protection Mechanisms Voltage Regulation Custom Design: Best idea, but lacking time/expertise Commercial Solution: EXPENSIVE Inverter-Power Supply Combo: Best fit for this project Drive Mode

29 Circuit Protection Mechanisms Voltage Regulation Inverter-Power Supply Combo: Best fit for this project +

30 Circuit Protection Mechanisms Voltage Regulation Regenerative Mode

Circuit Protection Mechanisms Current Limitation Current Limiter: MOSFET + Microcontroller Solution

32 Review of First Semester 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 Project Risks Project Schedule

Combine the Control System 33 Modularity = Future Usability SOLUTION: Have several minor control systems under the direction of master control system Utilize ATMega48 Chips Very cheap ($2) 21 I/O Points PWM ADCs Expandable

Combine the Control System 34

35 Review of First Semester 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 Project Risks Project Schedule

Project Budget WHATSYSTEMCOST 24V NiMH 2000Ah BatteryControl34,99 24V NiMH Battery ChargerControl29,99 5V RegulatorControl0 ATMega48 ChipControl2,84 16 SPDT 40A Relays with 24V CoilUltracapCircuit46,56 ATMega48 ChipUltracapCircuit2,84 3 Relay Driver ICsUltracapCircuit1,2 5V RegulatorUltracapCircuit0 150Watt 10 Ohm ResistorUltracapCircuit10 5V RegulatorClutchCircuit0 ATMega48 ChipClutchCircuit2,84 SPST 40A Relays with 24V CoilClutchCircuit2,91 Relay Driver ICClutchCircuit0,4 5V RegulatorMotorCircuit0 ATMega48 ChipMotorCircuit2,84 3 SPDT 40A Relays with 24V CoilMotorCircuit8,73 1 Relay Driver ICMotorCircuit0,4 LM7812C Voltage RegulatorRegenCircuit5 Various Small Capacitors/ResistorsRegenCircuit10 3 TIP2955 TransistorsRegenCircuit10 5V RegulatorRegenCircuit0 ATMega48 ChipRegenCircuit2,84 SPDT 40A Relays with 24V CoilRegenCircuit2,91 Relay Driver ICRegenCircuit0,4 Used Computer Power SupplyDriveCircuit5 24Vdc/240Vac InverterDriveCircuit40 Power MOSFETDriveCircuit5 5V RegulatorDriveCircuit0 ATMega48 ChipDriveCircuit2,84 MOSFET Driver ICDriveCircuit5 Sense/Shunt ResistorDriveCircuit23,95 Shipping CostsALL40 Manual PCB CostsALL30 WiringALL30 Other ComponentsALL50 PCB CostsALL80 TOTAL489,5 Electromechanical ClutchMotor77,82 Twist ThrottleMachine Interface31,94 TOTAL109,8 COMBINED TOTAL599,2

37 Review of First Semester 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 Project Risks Project Schedule

Project Risks and Scope 38 Risk: Variable Regenerative Brake The regenerative break itself will be implemented. However, we may not have time to make it variable. This will be done given enough time. Future-Proof Designs: (Place Most Effort) Modular Control System Durable Series-Parallel Switch Design Throttle/Brake/Clutch Controls System Modeling Need Future Design Work: Drive-mode Power Supply Regenerative-mode Power Supply (possibly) Motor (hub?) Frame

39 Review of First Semester 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 Project Risks Project Schedule

Detailed Design Review[October 8] Order Parts[Early October] Individual Fabrication[Mid/Late October] Individual Assembly Final Assembly[Early/Mid November] Client Review[November 19] Documentation[November/December] Knowledge Database 40

Questions ? 41