Post on 25-Feb-2016
description
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
General Specific Acceptable RankingEfficiency 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. < $750. 1
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 System2. 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
Colin 10
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: $ 24.99 + 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 MotorReell 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 1400. They operate on 24 VDC and include wire leads for hardwiring
Colin 14
Design Characteristics
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)•100-800 rpm typical, 1400 rpm max.•Minimum load friction torque 0.05 N-m (6.0 oz-in) plus customer input bearing torque.
Technology Electromechanical 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 SourceAll 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
17
18
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: • 2.7VdcDrive Mode:• 24.3Vdc (9*2.7Vdc)
21
Simplify Series-Parallel Switch
Design No. 1: SPDT Relay Design No. 1: SPST Relay
SPST SwitchSPDT Switch
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 MechanismsElectrical Isolation
KISS: SPDT Relays!
SPDT Switch
27
Circuit Protection MechanismsVoltage Regulation
Drive Mode• 12-24Vdc Input• 12Vdc Output
Regenerative Mode• 0-15Vdc Input• 2.7Vdc Output
28
Circuit Protection MechanismsVoltage Regulation
Custom Design: Best idea, but lacking time/expertiseCommercial Solution: EXPENSIVEInverter-Power Supply Combo: Best fit for this project
Drive Mode
29
Circuit Protection MechanismsVoltage Regulation
Inverter-Power Supply Combo: Best fit for this project
+
30
Circuit Protection MechanismsVoltage RegulationRegenerative Mode
Circuit Protection MechanismsCurrent 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 BudgetWHAT SYSTEM COST24V NiMH 2000Ah Battery Control 34,9924V NiMH Battery Charger Control 29,995V Regulator Control 0ATMega48 Chip Control 2,8416 SPDT 40A Relays with 24V Coil UltracapCircuit 46,56ATMega48 Chip UltracapCircuit 2,843 Relay Driver ICs UltracapCircuit 1,25V Regulator UltracapCircuit 0150Watt 10 Ohm Resistor UltracapCircuit 105V Regulator ClutchCircuit 0ATMega48 Chip ClutchCircuit 2,84SPST 40A Relays with 24V Coil ClutchCircuit 2,91Relay Driver IC ClutchCircuit 0,45V Regulator MotorCircuit 0ATMega48 Chip MotorCircuit 2,843 SPDT 40A Relays with 24V Coil MotorCircuit 8,731 Relay Driver IC MotorCircuit 0,4LM7812C Voltage Regulator RegenCircuit 5Various Small Capacitors/Resistors RegenCircuit 103 TIP2955 Transistors RegenCircuit 105V Regulator RegenCircuit 0ATMega48 Chip RegenCircuit 2,84SPDT 40A Relays with 24V Coil RegenCircuit 2,91Relay Driver IC RegenCircuit 0,4Used Computer Power Supply DriveCircuit 524Vdc/240Vac Inverter DriveCircuit 40Power MOSFET DriveCircuit 55V Regulator DriveCircuit 0ATMega48 Chip DriveCircuit 2,84MOSFET Driver IC DriveCircuit 5Sense/Shunt Resistor DriveCircuit 23,95Shipping Costs ALL 40Manual PCB Costs ALL 30Wiring ALL 30Other Components ALL 50PCB Costs ALL 80
TOTAL 489,5
Electromechanical Clutch Motor 77,82Twist Throttle Machine Interface 31,94
TOTAL 109,8
COMBINED TOTAL 599,2
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 SystemDurable Series-Parallel Switch DesignThrottle/Brake/Clutch ControlsSystem Modeling
Need Future Design Work:Drive-mode Power SupplyRegenerative-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
Project ScheduleDetailed 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