Scooterizers
Detailed Design Review
“Making last-mile transportation safer, easier, and more efficient”
1
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
2
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.
3
Project Specifications
General
Specific
Acceptable Ranking
Efficiency
Total system efficiency.
> 51%.
2
3
Weight
Human Input
Must be lightweight; easy to carry.
Must have intuitive human input and
control. Have both mechanical and
regenerative brake controls.
< $750.
Ultracapacitors
provided by
Energy
IVUS.
Storage/Propulsion Must store electrical energy.
Collapsible
The scooter frame must be foldable, and frame with
the propulsion and regeneration systems brake
should be transparent to the user.
regeneration.
Ease of Use
Total Scooter Cost
Must be affordable.
20lbs.
Twist throttle
and
handbrakes.
2
1
2
3
4
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
5
Project Deliverables
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
6
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
7
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
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
9
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
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
11
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
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
14
15
16
17
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
18
Simplify Series-Parallel Switch
Jet-Tread Series-Parallel Switch
19
Simplify Series-Parallel Switch
•
•
•
•
•
12 Relays
30 Amps Current
15ms Switch Time
2.7Vdc Parallel Mode
13.5Vdc Drive Mode
SPDT Relay
SPDT Switch
20
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
21
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
22
Circuit Protection Mechanisms
• Electrical Isolation
• Voltage Regulation
• Current Limitation
23
Circuit Protection Mechanisms
Relay Circuit 1:
Prevent ESC Destruction when in Regen mode
Status:
Partially assembled (to be finished soon)
24
Circuit Protection Mechanisms
Relay Circuit 2:
Prevent damage to Ultracapacitors when in
Regen mode
Status:
Partially assembled (to be finished soon)
25
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
26
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
Ultracapacitor Control System
Motor Control System
27
Combine the Control System
Regenerative Control System
•
ADC hardware to sense Ultracapacitor circuit voltage
28
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
29
Combine the Control System
Clutch Control System
•
Receives signal from Master Control System when throttle is
sensed, and activates the clutch
30
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
31
Combine the Control System
Master Control System – Interface with ESC
Required extensive reverse-engineering
No Throttle
1ms Pulse
Full Throttle
2ms Pulse
32
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
33
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
34
Current Bill of Materials (BoM)
Purchased Items:
Additional Materials Acquired:
Electromechanical Clutch
Electrical Wiring
Twist Throttle
Chip Sockets
NiMH 24V Battery Pack
Aluminum Sheet Metal Stock
Battery Pack Charger
Brass Stock
Shunt Resistor
Atmel ATMega48 Chip (8)
Relays (21)
Relay Drivers (8)
Project Budget
McMaster
Scooter
Catalog
CC
McMaster
CC
Z0729924
$
CC
(82.52)
$
$
(82.49)
credit
$
82.52
Digikey
CC
$
(15.76)
Allied
CC
$
(20.52)
All Battery CC
RC
Electronics CC
$
(74.17)
$
(35.40)
Digikey
$ (109.67)
Colin
Z0729924
(31.94)
-369.95
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
37
Project Risks and Scope
Systems we will not be able to deliver:
• DC/DC1 Power Supply
• Current Limiter
• DC/DC2 Power Supply
38
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
+
39
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
40
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
41
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!
42
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
43
Project Schedule
Client Review
[November 19 (Today)]
Finish Assembly
[November 19-November 29]
Final Testing
[November 29-December 3]
Documentation
Knowledge Database
[December 3-December 9]
44
Questions?
45