Scooterizers Detailed Design Review

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

3. Project Goals • 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.

4. Project Specifications

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

8. 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

10. Variable Throttle and Brake • (Scooterizers’ Choice) Twist throttle • Specifications • Item Code: Throttle-ES (Hole Effect Type) • Price: $ 24.99 + 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

12. Clutch for the Motor • Pros: • Lightweight • Small • Easy to integrate into existing design • Works well with this scooter’s various user scenarios Miniature Electromechanical Clutch From Reell Precision Manufacturing • 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

13. 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

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

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

21. Simplify Series-Parallel Switch • 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

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 Ultracapacitorswhen in Regen mode Status: Partially assembled (to be finished soon)

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

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

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

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

31. Combine the Control System • 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

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

33. Combine the Control System • 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

35. 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

36. Project Budget

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

39. Project Risks and Scope • 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 +

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

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

42. Previous Project Risks and Scope • 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!

44. 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

45. Questions?