preliminary detailed design review

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