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Preliminary Detailed Design Review
Periodontal Measurement Test SystemFebruary 1, 2013
Periodontal Measurement Test System
• Current method• Goals of new method
Customer Needs
Specifications
Pugh Matrix
PHANTOM TOOTH
Canadianawareness.org
Specifications
Spec Description CN
3.1 The phantom tooth shall be made of non-biological materials that mimic human tissue with respect to ultrasonic wave propagation properties. 8, 9, 10
3.2 The phantom tooth shall be able to be quickly replaced within the phantom holding fixture. 3, 11
3.3 The phantom tooth geometry shall allow for quick alterations of the physical relationship between the tooth and the gums. 1, 4
Phantom Design
Phantom Design
Relevant US Properties
• Density• Speed of sound• Acoustic impedance
Material Selection
Contacts
• Dr. Phillips – RIT bio medical engineering• Dr. Maria Helguera – RIT imaging science– Biomed ultrasound
• Eastman Dental Clinic – Dr. Caton• Bradley Rogge – RIT’s Pre-dental association• Professor Lamkin-Kennard – RIT Mechanical
Engineering• Hamad Ghazle, Jodie Crowley – RIT Ultrasound
FIXTURE DESIGN
SpecificationsSpecification Description Customer
Needs1.0 Test Probe Fixture 1.1 The test probe fixture must be able to move through 3 axis. 51.2 The test probe fixture shall be compact and portable. 3, 4, 11, 12
1.3The test probe fixture shall be simply constructed to allow for maintenance to be performed by untrained personnel relying only on a maintenance manual (to be provided). 3, 4, 11, 12
1.4
The test probe fixture shall allow for position changes on or about any axis to a programmatically specified point to within 0.1 mm for linear movement or 1° for angular movement. 2, 5, 6
1.5The test probe fixture shall hae minimal impact on the environment and noise levels within the surrounding area while active.
5, 7, 8, 9, 10, 11
2.0 Phantom Holding Fixture 2.1 The phantom holding fixture must be able to move through 2 axis. 5
2.2The phantom holding fixture shall be simply constructed to allow for maintenance to be performed by untrained personnel relying only on a maintenance manual (to be provided). 3, 4, 11, 12
2.3
The phantom holding fixture shall allow for position changes on or about any axis to a programmatically specified point to within 0.1 mm for linear movement or 1° for angular movement. 2, 5, 6
2.4The phantom holding fixture shall allow for the phantom tooth to be replaced by a human mandible. 11
2.5The phantom holding fixture shall be simply constructed to allow for maintenance to be performed by untrained personnel relying only on a maintenance manual (to be provided). 3, 4, 11, 12
Positioning System Model
Power Screw
Turn Table
Assembly Drawing
Pitch Movement
Power Screw Assembly
Power Screw Specs Power Screw Specs Nut Specs
Material 303 Stainless Self Lubricating Polyacetal
Total Length (in) 24 1.9
Pitch (in) 0.25 0.25
Diameter (in) 0.375 0.375
Supplier Haydon Kirk Haydon Kirk
Price 62.83 29.87
Efficiency (%) 70 70
Thread Direction Right Right
Dynamic Load - 10
Drag Torque (oz-in) - 1 to 5
Nut Detailed Drawing
Turn Table Drawing
Pitch Axis Drawing
Mounting Table Drawing
Guide Rail Clamp
Pitch Selection Calculations
Maximum Screw Pitch to Meet Accuracy Req's
Expected Stepper Motor Speeds
w/o Micro-Stepping (rev/sec) 16
w/ Micro-Stepping (rev/sec) 2 Pmax (mm) 36
Motor Angular Accuracy (deg) 1 Pmin (in) 1.417323
Desired Linear Accuracy (+/- mm) 0.1 Maximum Screw Pitch to Meet Travel Time Req's
Estimated Screw Length (in) 10
Estimated Screw Length (mm) 254
Estimated Time of Travel (s, full L) 12 Pmax (mm) 10.58333
Chosen Screw Pitch (in) 0.25 Pmax (in) 0.416667
Torque Requirement CalculationsProperty Symbol Units Value Required Torque to Overcome FrictionScrew Pitch P rev/in 4Load on Screw W oz 16Screw Efficiency e 0.7 Tfric (oz-in) 0.036378
Static Friction Coeff-nut on screw μs 0.04
Accel of Gravity G in/sec2 384 Jload 0.02533Time to reach constant Vel t sec 0.1Density of Screw ρ oz/in3 4.624 Jscrew 0.089772Length of Screw L in 10Radius of Screw R in 0.1875Load on Screw W oz 16
Ang velocity of motor ω rad/sec 12.5663706 Taccel (oz-in) 0.395513Screw Pitch P rev/in 4Motor Inertia Jmotor oz-in^2 1.0934959
Total Torque (oz-in) 0.431891
Note: All values for 1lb load on horizontal screw
Bearing Selection
• Very low radial loads– Guide rail support
• Small axial loads– Low friction nut– Guide rail support
• Basic radial bearing should handle loads
Bearing Specs
Bearing Specs
Style Double Sealed
ID (in) 0.375
OD (in) 0.6875
Width (in) 0.3125
Dyn. Load Cap (lbs) 255
Price (ea) 8.38
Quantity 6
Couplings
Coupling Specs
Material Steel
ID (in) 0.25
OD (in) 0.5
Length (in) 0.75
Set Screw Size 10-32
Max RPM 3450
Max Torque 59
Price 6.93
Collars
Collar Specs
Material Steel
ID (in) 0.25
OD (in) 0.5
Length (in) 0.28125
Set Screw Size 10-32
Price 0.63
ELECTRICAL
Specifications
• 4.0 – Proof of concept put together, proved we could attain appropriate control required for final system
• 5.0 – Unable to test, waiting on probe, able to communicate with an oscilloscope, but no data has been attained from probe to date due to lack of probe
• 6.0 – Have data logging already written in code, working on limit comparison programming
BLOCK DIAGRAM
WIRING DIAGRAM
PROGRAMMING FLOWCHART
ELECTRICAL BOM AND COST
Preferred List
Item Part Number Manufacturer Lead Time Cost Qty Extended Cost
Arduino UNO UNO R3 Arduino 3-5 days $ 24.95 1 $ 24.95
Servo HS-225MG Hitec 3-5 days $ 35.99 2 $ 71.98
Stepper RB-SOY-14 SOYO 3-5 days $ 44.28 3 $ 132.84
EasyDriver B004G4XR60 Sparkfun 3-5 days $ 14.95 6 $ 89.70
Misc Budget $ 100.00 1 $ 100.00
$ 419.47
Justification
Control System• Arduino is very compatible with
LabVIEW• Arduino is low cost and as a skill
is going to be part of the new Control System curriculum at RIT
• EasyDriver motor control boards are inexpensive and individually replaceable if damaged.
• EasyDriver allows us to do Full, stepping to increase control.
Motors• Servos were chosen for
combination of price, mobility, and durability.
• Metal servo with high torque rating to allow ease of use with system design
• Stepper motors were picked based off of Voltage, Current, torque, and Driver limitations
Risk Assessment
High Risk Items
• Non-bio materials– Availability– Similarity to human tooth
• Formation of phantom– Processes available hinge on materials chosen
• Probe!
Questions/Comments/Suggestions