Motion Tracking SystemResearch and Testing

Rochester Institute of Technology

DAVID J. MONAHAN (ME)

JAMES K. STERN (ME)

JAHANAVI S. GAUTHAMAN (EE)

ASSIS E. NGOLO (CE)

CORY B. LAUDENSLAGER (EE)

BRIAN D. GLOD (CE)

BACKGROUND: National Science Foundation (NSF) has extensively helped RIT’s Assistive Devices family develop a strong relationship with the Nazareth College Physical Therapy Clinic. Physical therapists at Nazareth have long expressed a desire for portable motion tracking devices enabling monitoring of patients’ motion in their natural environments. Previously, two motion tracking projects, one tasked to track limb motion, and the second focusing on lower back (lumbar) motion were slated. Due to challenges identified from these prior motion tracking projects, the two were combined to create this P10010, project. Instead of creating a fully functional motion tracking system, P10010 will focus on developing a foundation of knowledge for future motion tracking projects.

MISSION STATEMENT:To research sensors and implementation methods for portable motion tracking systems capable of measuring patients' range of motion in their natural environments. The various aspects of a motion tracking system: sensors, a portable micro-controller, interface circuitry, software, and human interfaces are explored. The primary ranges of motion of interest:• 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 it is defined as the lumbar region, with 3 points of contact: sacrum, L1-L2, L3-L5.

TEST PLAN OVERVIEW:Component

Measurement of Interest

Test FixtureDegrees of Freedom & Range

Test FixtureAccuracy of Individual Measurements

Test Fixture Accuracy over Time

Test FixtureSafety/Nondestructive Testing

Sensors Output SignalSensors PowerSensors Output Signal QualitySensor Power

SensorsAccuracy of Individual Measurements

Sensors Accuracy over Time

SensorsDegrees of Freedom & Range

SensorsAccuracy/DOF with Enclosures

MCU  Read and StoreMCU PrecisionMCU FunctionalityMCU-PC Data FormatMCU DataMCU-Sensor Amplify SignalMCU-Sensor FilterMCU-Sensor PowerSensors & MCU's

Dimensions, Weight

P10010

ACKNOWLEDGEMENTS:Nazareth Physical Therapy Institute (Primary Customer)

Dr. Elizabeth DeBartolo (Team Guide), RIT Dept. of Mechanical EngineeringDr. Daniel Phillips (Sensors Guide), RIT Dept. of Electrical Engineering

Dr. Roy Czernikowski (Micro-controller Guide), RIT Dept. of Computer Engineering

CUSTOMER NEEDS:• The Product should be Portable • The Product should be Accurate • The Product should be Easy to Use • The Product Should be Sanitary • The Product should be Comfortable for Patient • The Product should be Durable

TEST FIXTURE DESIGNS CONCEPTS:

SELECTED MICRO-CONTROLLER:

Arduino Mega Microcontroller

PROJECT DELIVERABLES: • Provide future research teams with

sufficient tools to create a portable motion tracking device.

• Enhance the knowledge base of the RIT Biomedical Systems and Technologies

Track regarding sensor usage in human motion tracking. SYSTEM OVERVIEW:

+/-2g Tri-axis Accelerometer

6 DoF Razor Ultra-Thin IMU Output

ADDITIONAL INFORMATION: For additional information visit our team website online at: https://edge.rit.edu/content/P10010/public/Home.This material is based upon work supported by the National Science Foundation under Award No. BES-0527358. Any opinions, findings, and conclusions or

recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation.

FINAL KNOWLEDGESensor & MCU: Research, Selection Matrices, Detailed Sensor Information, & Sensor Evaluation ResultsTest Fixtures Research & Manufacturing PlansTest Plan Procedure for Testing & Analyzing Data

FINAL INFRASTRUCTURE4 Completed Test FixturesSensor & MCU HardwareExtensive MCU Code

General Operation , Data Storage/Translation

MATLAB Code: Testing/Analysis

FUTURE APPLICATIONS •RIT Multidisciplinary Senior Design

Teams •Physical Therapy Clinics

•Entertainment (Video Gaming, Animation)

• Bio-robotics• Medical Applications

6 DoF- Atomic IMU on Pendulum Fixture: Output vs. MATLAB Model

6 DoF- Atomic IMU

6 DoF Razor Ultra-Thin IMU

SENSOR RESULTS OVERVIEW:

6 DoF- Atomic IMU

The ATMega1280 MCU is capable of sampling 16 analog inputs with a worst-case sample rate of 240 Hz. Currently the MCU logs the 10-bit A/D conversions to a 2GB micro-SD card provided by Libelium. The data is then converted back into voltages for analysis. Angles are determined by double integration using the trapezoidal rule.