MSDI Project Review Motion Tracking Technology Evaluation 1

MSD-I Project Review Motion Tracking Technology Evaluation 1 P 10010 SPRING 2010 1/1/2022

Core Team & Roles 2 � David Monahan – Project Manager (ME) � James Stern – Sensor / Human Interface Lead (ME) � Brian Glod – Data Lead (CE) � Assis Ngolo – Communication Lead (CE) � Jahanavi Gauthaman – Sensor Technology Lead (EE) � Cory Laudenslager – Sensor / MCU Interface Lead (EE) 1/1/2022

P 10010 Mission Statement 3 The primary ranges of motion of interest: To research sensors and implementation methods for portable motion tracking systems capable of measuring patients' range of motion in their natural environments. Motion of a human limb, where a limb is defined as a 3 -bar linkage, for example: upper leg, lower leg, and foot. Motion of a human's lower back, where lower back is defined as the lumbar region, with 3 points of contact: sacrum, L 1 -L 2, L 3 -L 5. 1/1/2022

System Overview 4 Human Interface (P 10011) Sensors Interface Circuitry Microcontroller Unit Storage Interface Signal Amplification Active Filtering Communication Interface [www. serverlab. net] Analog-to-Digital Conversion [www. laptoping. com] 1/1/2022

Current State of Design: Project Plan-Execution 5 1/1/2022

Current State of Design: Project Plan-Execution 6 1/1/2022

Project Plan-Execution 7 �Device acquisition �Build test fixtures Goniometer, Pendulum and Angular fixture �Test sensors �Test MCU �Test Data storage and logging – waveform generator �Interface MCU to sensors �Test data logging – Using sensors �Attempt to analyze data and detect issues �Redo Erroneous tests 1/1/2022

Rotational Test Fixture 8 �Analyzed sensors with rotational motion. � 2 DOF, more depending on how sensor is placed on fixture. �Gives golden standard of what angles sensor is supposed to be reading out. 1/1/2022

Rotational Test Fixture 9 1/1/2022

Shock Testing 10 �Shock tests were done in conjunction with P 10011 enclosures to see how robust sensor is. �Test was done on DEACC 3 D with its designated enclosure. �Test showed sensor could handle over 500 G’s. 1/1/2022

Shock Testing 11 1/1/2022

Shock Testing 12 1/1/2022

Shock Test 13 x y z Green (Volts) Blue (Volts) White (Volts) Control 1. 647 1. 656 1. 973 5 in 1. 655 1. 66 1. 973 7. 5 in 1. 656 1. 66 1. 974 10 in 1. 656 1. 66 1. 973 12 in 1. 657 1. 659 1. 973 24 in 1. 656 1. 66 1. 971 30 in 1. 656 1. 659 1. 973 1/1/2022

Goniometer Test Fixture 14 �Medical goniometer ordered from Amazon Standard Nazareth clinic equipment Will be useful for future human testing �Peg holes drilled at 45° increments �Provides simple method of measuring 2 -axis motion 1/1/2022

Flex Test Fixture 15 � Unique functionality of flex sensor necessitated construction of custom fixture � Damped gate hinges � Elaborate handle � Supports variety of tests Bending � Regular � Irregular Life Cycle Evaluation 1/1/2022

Pendulum Test Fixture 16 � Recognized need for fixture with controllable rate of motion � Developed modeling system for pendulum Small θ assumption: <15º Parallel Axis Theorem Yields Tangential & Normal Components (X/Y) � Simulated system in Matlab; facilitates quick comparison with test data All-inclusive M-Files 1/1/2022

Pendulum Test Fixture: MATLAB 17 1/1/2022

Pendulum Test Fixture: MATLAB 18 1/1/2022

MCU Achievements 19 �ATMega 1280 MCU: Samples up to 16 analog channels (10 -bit ADC) 240 Hz worst-case sampling rate for all 16 channels 480 Hz for 8 channels, etc Logs ADC data to 2 GB micro-SD card (preformatted as FAT 16) �PC software: converts 10 -bit ADC values into voltages for angle analysis Trapezoidal rule for discrete integration used to determine angles 1/1/2022

MCU Future work 20 � Depends on implementation! Interrupts for ADC sampling? � Multiple simultaneous operations Full on-chip analysis? Convert digital values to voltages (if necessary) � Integration to obtain positions and angles � Plain old data logger? � Faster sampling rate? Careful not to sample too fast for micro-SD card throughput! � Smaller MCU with more analog inputs � External / more accurate analog-to-digital converters? Smaller… � …but not enough ADCs? � Add calibration curves to ADC � values to increase accuracy � Currently 0 – 10 LSB’s (0 – 50 m. V) of LOST accuracy in just the conversion! (if you can find one!) May require fabrication of custom PCB May need to consider: noise on traces � impedance matching � Capacitive coupling � Other high-f complexities? � 1/1/2022

Data Storage 21 �Local Storage �Micro. SD card – 2 GB �Libellium u. SD Shield �Modified Sd. Fat library �CSV file format Readable directly by Excel, Matlab, C, C++, etc 1/1/2022

Data Storage 22 �A lot of Storage Logging 6 channels � 1 line = 6 inputs + timestamp = 29 bytes/line � Sampling at a frequency of 100 ms, for 6. 9 seconds = 69 lines = 2001 bytes � If run for 12 hours 431999 lines = 12527999 bytes = 0. 012 GB SD card has 2 GB = approximately 166 hours = 6 days 1/1/2022

Tri-axis Accelerometer DE-ACCM 3 D 2 (± 2 g) 23 - Steady State Analysis - Acceleration/Position 1/1/2022

6 Degrees of Freedom Razor Ultra-Thin IMU 24 -Steady State Analysis -Acceleration/Position* -Angular Velocity 1/1/2022

LIS 302 DL Smart Digital Output "Piccolo" Accelerometer 25 - I 2 C/SPI Digital Output Interface - Only has X and Y Acceleration, W/ 1 Gyro 1/1/2022

Atomic IMU - 6 Degrees of Freedom 26 � Cons: • Bulky: NOT Portable • Expensive ($125) • Additional microprocessor • Unnecessary elements that delay functionality for our purpose • UART functionality (not yet explored) = extra processing 300 g sensitivity on pendulum test 1/1/2022

Flex Sensor 27 • Perfect for elbow and/or knee joint 180 160 • Accuracy in specified range • Cost-effective ($10) • Easy to use • Easy to build • Easy to interface • Extreme Portability • Con: Inconsistent among different flex sensors • Future Possibility: Most sensitive (but more expensive) flex sensor is available in the market, for better accuracy. 140 120 100 80 60 40 20 0 0, 7 1, 2 1, 7 2, 2 2, 7 -20 1/1/2022

Customer Specs 28 Design Specification Importance Unit of Measure Marginal Value Ideal Value Spec Met Accuracy of Angles High Degrees ± 10 ± 1 Yes* Accuracy of Position High Centimeters ± 5 ± 2 Yes* Range of Angles High Degrees 270 360 Yes Size of Sensor Medium mm x mm 60 x 30 30 x 15 Yes Degrees of Freedom Medium Axis 1 3 Yes Weight of Data Logger/Micro Controller High kg 1 <. 5 Yes Set-up Time Low Minutes 20 10 Yes* Battery Life of the system High Hours 12 24 Yes* Robustness of Sensor Medium Cycle and Force Weight of Sensors High g 20 10 Yes* Time to transfer data from device to computer Low Minutes 5 3 Yes Simplicity of Data Analysis High N/A text box C 3 D Format No Wirefree Solution Medium N/A Wired Wireless No Budget High Dollars 1000 Yes Data storage capacity High Hours 12 24 Yes Portable Data Storage High SD Card Yes Yes 1/1/2022

Future Recommendations/ Improvements 29 Test Fixtures - Constant Velocity Fixture W/ Stop Points for Rotation - More Accurate and Precise Acceleration Test Fixture - More Accurate Attachment Method for Each Sensor to Testing Platforms 1/1/2022

Future Recommendations/ Improvements 30 MCU - Higher Bit A/D - Faster Sampling - Simpler D/A Conversion - Simplified MCU - MCU Case -Portable Battery Sensors - Kalman Filtering for Gyroscopes - More Accurate and Effective Method to Integrate Acceleration /Angular Velocity - Efficient Method to Route Wires for Complete System 1/1/2022

Project Summary 31 �Adhered to customer needs within scope of project Exception CN 14, E 1: 1 Degree of Accuracy (as explained in improvements section) �No budget changes during MSD 2 �Achieved overall goal: establishing solid foundation of knowledge & infrastructure for future teams KNOWLEDGE � Sensor & MCU Research Selection Matrices Detailed Sensor Information Sensor Evaluation Results � Test Fixtures Research/Manufacturing Plans INFRASTRUCTURE � 4 Test Fixtures � Sensor & MCU Hardware Fully prepared & operational � Extensive MCU Code General Operation Data Storage/Translation � MATLAB Code Testing/Analysis 1/1/2022

QUESTIONS? COMMENTS? IDEAS? 32 PRESENTED BY: David Monahan Jim Stern Assis Ngolo Brian Glod Cory Laudenslager Janvi Gauthaman 1/1/2022