Haptic Interactions in Virtual Reality MQP Major Qualifying Project Report: Submitted to the Faculty of In partial fulfillment of the requirements for the Degree of Bachelor of Science In association with By _________________ Richard Matthew Rafferty RBE _________________ Jiaqi Ren RBE/ME _________________________ __________________________ Professor Gregory S. Fischer Advisor Professor Robert W. Lindeman Co-Advisor Page | 1 Table of Contents Abstract ................................................................................................................................................. 5 Executive Summary ............................................................................................................................... 6 I. Background ................................................................................................................................. 6 II. Functional Requirements ............................................................................................................. 6 III. System Design ......................................................................................................................... 7 IV. Results ..................................................................................................................................... 7 V. Discussion ................................................................................................................................... 8 1. Introduction ................................................................................................................................. 9 2. Background Research ................................................................................................................ 10 2.1. Virtual Reality ....................................................................................................................... 10 2.2. Haptics .................................................................................................................................. 14 2.3. Rehabilitation ........................................................................................................................ 16 2.4. Human Hand Dynamics ......................................................................................................... 18 2.5. Current Solutions ................................................................................................................... 18 2.5.1. CyberGrasp and Virtual Hand SDK by CyberGlove Systems{CyberGlove, 2015 #10} ... 19 2.5.2. Falcon by Novint {Novint, 2015 #12} ............................................................................ 20 2.5.3. Geomagic Haptic Devices {Geomagic, #25} .................................................................. 20 3. Methodology ............................................................................................................................. 22 3.1. Project definition ................................................................................................................... 22 3.2. System Requirements ............................................................................................................ 24 3.3. Sub-Systems Design Decisions .............................................................................................. 25 3.3.1. Hand Pose Tracking System ........................................................................................... 25 3.3.2. Simulation System .......................................................................................................... 26 3.3.3. Force Exertion System: Mechanical Structure ................................................................. 27 Page | 2 3.3.4. Control System ............................................................................................................... 30 3.3.5. Communication Design Decision .................................................................................... 32 3.3.6. Virtual Environment Viewing System ............................................................................. 35 3.3.7. Simulation System and Force Exertion System Communication ..................................... 36 3.4. Demo Application: Rehabilitating Hand Learned Non-Use through Visual Feedback Distortion 38 3.4.1. Procedure Steps .............................................................................................................. 38 3.4.2. Demo Requirements ....................................................................................................... 39 4. Final Design .............................................................................................................................. 40 4.1. System Implementation ......................................................................................................... 40 4.2. Force Exertion System ........................................................................................................... 40 4.2.1. Bowden Cable Exoskeleton ............................................................................................ 42 4.2.2. DC Brushed Motors ........................................................................................................ 43 4.2.3. Microcontroller ............................................................................................................... 44 4.2.4. Motor Controller Shield .................................................................................................. 45 4.2.5. Current Sensing Module ................................................................................................. 46 4.2.6. Force Exertion Control ................................................................................................... 48 4.3. Hand Pose Tracking System .................................................................................................. 49 4.4. Simulation System ................................................................................................................. 50 4.4.1. Environment and Development Tools ............................................................................. 51 4.4.2. User and Object Representations..................................................................................... 51 4.4.3. Interaction Forces ........................................................................................................... 52 4.4.4. Force Communication ..................................................................................................... 54 4.5. Visualization System ............................................................................................................. 57 4.6. Demonstrative Application: Learned Non-Use Rehabilitation ................................................ 58 Page | 3 .............................................................................................................................Results and Discussion ............................................................................................................................................................ 59 5. Results and Discussion ..................................................................................................................... 59 5.1. Hand Pose Tracking System Functional Analysis ................................................................... 59 5.2. Force Exertion System Functional Analysis ........................................................................... 60 5.2.1. Exoskeleton Stiffness ...................................................................................................... 63 5.2.2. Exoskeleton Safety ......................................................................................................... 64 5.3. Simulation System Functional Analysis ................................................................................. 64 5.3.1. Haptic Interaction Generation ......................................................................................... 65 5.4. Serial Communication Issue and Sub-System Integration ....................................................... 65 5.5. Visualization System Functional Analysis ............................................................................. 67 5.6. Demo Application Functional Analysis .................................................................................. 68 5.7. Development Guide ............................................................................................................... 68 5.8. Overall System Functional Analysis ...................................................................................... 69 6. Future Work .............................................................................................................................. 70 6.1. Sub-System Enhancement ...................................................................................................... 70 6.2. Virtual Reality Presence Sub-Systems ................................................................................... 70 6.3. Application Development ...................................................................................................... 70 6.4. System Marketing and Distribution ........................................................................................ 71 7. Conclusion ................................................................................................................................ 72 8. Bibliography ............................................................................................................................