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Automated Bridge ScourInspection
FSU/FAMU College of EngineeringTeam 7
Concept Design Review
12/1/2010
Vertical Motion
Design Updates / Improvements- Concepts considered- Selection criteria - Risks associated with selection
Schedule / Budget Updates- Analysis time exceeded- Fabrication time overestimated- Proposed equipment within budgeted amount
Vertical Motion
Analysis Method / Assumptions - Operating parameters for DC Motor
- Critical Operation Point- Gearing for adequate ascent/descent speed
Analysis Results- Minimum load torque: 6.5 N*m - 5:1 gear reduction ratio
- Adequate speed: 20 cm/sec- Sufficient output torque: 32 N*m
Vertical Motion
Revised Specification- System weight inflated 10%: 44 lbs.- Motor load under 80%
Proposed Equipment- Maxon Motors RE 35 Brushed DC Motor
- 24V Operation- Maxon Motors 32 HP Planetary Gearhead
- 28:1 Reduction ratio- Combined Cost: $ 468.00
Circumferential Motion Design Updates / Improvements- Concepts considered- Selection criteria - Risks associated with selection
Schedule / Budget Updates- Analysis time overestimated- Fabrication time overestimated- Proposed motor within budget amount- Guiderail cost pending
Circumferential Motion
Analysis Method / Assumptions - Operation at low speed, low displacement
- Low drag- Focus on precision positioning
Analysis Results- 12 V DC Motor- Minimum 200 oz-in stall torque
Circumferential Motion
Proposed Equipment- Pololu 12V 131:1 DC Gearmotor- Combined 64 CPR Encoder- Cost: $ 40.00
SONAR TiltDesign Updates- Maintain previous design - Lower priority- Low risk
Schedule / Budget Updates- Analysis and specification pending- Budget on par
Design Structure
•Design Updates and Improvements
•Circular Guide Rail
•Component Housing
•Localization
•Risks
Design Updatesand Improvements
•Circular Guide Rail
•Bishop-Wisecarver
•Single Edged PRT
•24” Diameter
•11.5 lbs
•Custom Hinge
Power Old Design Use 2 separate battery sources - DC Motors, Motor Controller - AGM battery - Microcontroller, Sensors - NiMH Better efficiency, less power loss
The New Design - Motor Driver outputs 5V for
Microcontroller,Sonar,servo. Eliminates 2nd battery - Use 1 LiFePO4 or SLA Battery to power
everything
Block Design for Powering Components
- Motor Driver has a feature that can power the DC motors and also some low power
components.
Sabertooth dual 25A motor driver
Controls 2 Brushed DC Motors independently
5V Output Terminal for Microcontroller Power
Lithium protection mode
Built-in Overcurrent & Thermal Protection
Screw-in Terminals for Easy,Secure Connections
Continuous Output per channel
25 Amps
Peak Output per channel
50 Amps
Nominal input Voltage
6-24 Volts
Max Voltage 30 Volts
Size 2.6''x3.2''x0.8''
DC motors
Vertical motion motor
- Nominal Voltage 24V
- Starting Current 41A
- Cont. Current 3.36A
Circumferential motion motor
- 12V ~300mA
Battery
- Weight and Cost are issues
- Lead Acid vs Lithium Polymer
1. Sealed Lead Acid Battery
- Cheaper, but heavier
2. Polymer LiFePo4 Battery
- More expensive, but lighter
Technical Risks - hook up battery to motor driver reverse polarity.
This will damage and void the driver!! Add a diode to prevent this. Product is expensive ~$125
- Motor overheating,
The motor driver peaks at 50Amps and has over-current protection built-in. DC motors are within the motor driver's capabilities...6V-24V
continuous run < 25Amps. Starting run < 50Amps
The Next Step..
- Choose battery type and capacity Ah
- Choose/Purchase DC Motors and Motor Controller
- Purchase a Battery for testing purposes
- More detailed design to integrate into system (wiring, positioning electronics in casing, protection, i.e.)
MicrocontrollerBeagle Board
• $149
• ARM ® Cortex TM A8 MHz @ 1 GHz
• LPDDR RAM 512MB
• SD Card Expansion
• 3D graphics accelerator
• 5 Volts
• 16 I/O IC2 ports
• RS-232 Port
• Large active community
Autonomous Programming
• Language - C++
• Computer Environments - Eclipse - Netbeans
• Beagle Board Packages - Bash task - Nativ-sdk - gdb - samba
Autonomous Programming
• 3 Modules - Vertical Movement - Circumference Movement - Sonar Servo Movement
• Outputs - Motor Controller - Servo
• Inputs - Encoders - Sonar
Current Progress
- Preliminary pseudo code finished
- Detailed information on I/0 Communication
- Write Detailed pseudo code
- Begin programming using Eclipse and/or Netbeans
SONAR• Old Design:
• Test multiple sensors
• Use Fish Finder transducers
• Lower costs
• Compatibility issues w/ microcontroller
• Time Constraints
• New Plan:
• Only test 1 or 2 sensors
• SONAR altimeters
• Higher costs
• Connect directly to microcontroller via RS-232
Benthos PSA-916
Frequency: 200 kHz
Beam Width: 14 degrees conical
Range: 0.8 m – 100 m
Output: RS-232 (digital)
0 – 5 VDC (analog)
Resolution: RS-232: 1 cm
Analog: 2.5 cm
Power: 6 – 24 VDC; 100mA @ 6V
Dimensions: 2.25” Diameter X 9.38” Long
Weight: 1.4 lb (air); 0.8 lb (water)
Kongsberg 1007 Series
Frequency: 675 kHz
Beam Width: 2.5 degrees nominal
Range: 0.61 m – 30.48 m
Output: RS-232; 9600 baud rate
Resolution: 2.4 mm
Power: 22 – 26 VDC; 250mA
Dimensions: 3.49” Diameter X 7.75” Long
Weight: 5.2 lb (air); 2.4 lb (water)
Tritech PA500
Frequency: 500 kHz
Beam Width: 6 degrees conical
Range: 0.3 m – 50 m
Output: RS-232; 9600 baud rate
Resolution: RS-232: 1 mm
Analog: 0.025%
Power: 24 VDC @ 80 mA; 12 VDC @ 160 mA
Dimensions: 1.85” Diameter X 6.30” Long
Weight: 2.43 lb (air); 1.76 lb (water)
Risks
• Physical Damage to sensor
– O-ring
– Abrasion from sediment
• Operation Angle
• Weak Signal Received
• Obstacles