UNIVERSITY OF CINCINNATI Date: 22-Jul-2010 I, Aniket Arora , hereby submit this original work as part of the requirements for the degree of: Master of Science in Mechanical Engineering It is entitled: Concurrent consideration of product usability and functionality: Development of integrated design guidelines Student Signature: Aniket Arora This work and its defense approved by: Committee Chair: Anil Mital, PhD, PE Anil Mital, PhD, PE 11/1/2010 428 Concurrent consideration of product usability and functionality: Development of integrated design guidelines A thesis submitted to the Graduate School of the University of Cincinnati in partial fulfillment of the requirements for the degree of Master of Science in the Department of Mechanical Engineering of the College of Engineering by Aniket Arora July 2010 Committee Chair: Dr. Anil Mital ii ABSTRACT Previous works have established separate design guidelines for consumer product usability and consumer product functionality. Since realistic product designs require simultaneous consideration of product usability and functionality, we have integrated previously developed design guidelines for product usability and functionality. The first section presents the procedural details for developing these integrated design guidelines. A comprehensive and unified approach for simultaneous optimization of usability and functionality was considered in integrating existing design guidelines. A coherent framework for a design process inclusive of several design criteria, such as performance, ease of use, safety, and environmental affinity, was established for accomplishing the design objective. An example case was used to first integrate and then generalize the comprehensive guidelines. The generic design guidelines are presented in the form of checklists. Later, generalized integrated design guidelines are validated by applying them to a consumer product that is directly used by consumers. Statistical analysis has been performed for evaluating the design guidelines developed for the studied product and to highlight the customer preferences of different design requirements, in detail. The last part of this study deals with the application of the generalized integrated design guidelines to a complex consumer product which despite of being a consumer product has very little human interface. The transmission system for cars was used for this reason. iii iv ACKNOWLEDGEMENTS Words are not enough to express my gratitude to Dr. Anil Mital, my advisor, for all his untiring support, encouragement and guidance he has given me. He has shown me ways to decisively shape my ideas and improve my overall thinking process. It has been a privilege for me to get an opportunity to work under him and learn so much from him. I would also like to thank Dr. Dave Thompson and Dr. Ron Huston for taking time out of their busy schedules to serve as members of my defense committee. I would also like to express my special thanks to all the volunteers whose efforts were important in collecting data for my work. Also want to thank my colleagues for helping me find the right methods for analyzing the data. I want to thank Prahit, Shubham Sah, Vivek and all my other friends for helping me in innumerable ways and for making my stay at Cincinnati such a pleasure. Finally, I would like to thank my family – my parents and my brother Abhishek for their unrelenting support and their right guidance throughout my life. v TABLE OF CONTENTS ABSTRACT............................................................................................................................(III) 1. INTRODUCTION..............................................................................................................12 1.1 Customer Requirement Management............................................................................14 1.2 Developing Product Attributes......................................................................................15 2. LITERATURE REVIEW.................................................................................................18 2.1 CURRENT SCOPE OF USABILITY & FUNCTIONALITY......................................18 2.1.1 Design for Environment.....................................................................................24 2.1.2 Reliability.......................................................................................................,,,,25 2.1.3 Safety..................................................................................................................26 2.1.4 Aesthetics...........................................................................................................27 2.2 Market Research Tools...................................................................................................28 2.2.1 Qualitative Techniques..........................................................................................28 2.2.2 Quantitative Research Techniques.........................................................................29 3. OBJECTIVE & METHODOLOGY.................................................................................33 3.1 THE APRROACH..........................................................................................................33 3.1.1 Phase 1................................................................................................................33 3.1.2 Phase 2................................................................................................................34 3.1.3 Phase 3................................................................................................................35 3.2 PROCEDURE FOR DEVELOPMENT OF GENERIC DESIGN GUIDELINES........35 3.2.1 Step 1..................................................................................................................35 3.2.2 Step 2..................................................................................................................36 3.2.3 Step 3..................................................................................................................38 vi 4. CAN OPENER ILLUSTRATION................................................................................40 4.1 Identifying Linkages...................................................................................................41 4.1.1 Can Opener Assembly.....................................................................................41 4.1.2 Establishing Technical Requirements & Generating Product Features..........41 4.1.3 Process Deployment........................................................................................43 4.1.4 Manufacturing deployment..............................................................................44 5. DEVELOPMENT OF GENERIC GUIDELINES........................................................46 6. GUIDELINES DEVELOPMENT: MOUNTAIN TOURING BIKE..........................65 6.1 MOUNTAIN TOURING BIKES.................................................................................65 6.2 COMPONENTS AND ARCHITECTURE OF THE MOUNTAIN BIKE..................66 6.3 Bicycle Manufacturing Process....................................................................................69 6.4 CUSTOMIZED DESIGN & MANUFACTURING GUILDELINES.........................70 6.4.1 Development Procedure...................................................................................70 6.4.1.1 Description of Group………………............................................................71 6.4.2 User Requirements...........................................................................................72 6.4.3 Mapping Design Dimensions...........................................................................73 6.4.4 Linkage Identification......................................................................................74 6.4.4.1 Technical Requirement Deployment..........................................................74 6.4.4.2 Product Feature Generation......................................................................74 6.4.4.3 Process Characteristics.............................................................................75 6.5 Checklist Development................................................................................................77 6.6 SURVEY DEPLOYMENT AND TESTING..............................................................93 vii 6.6.1 Data Collection and Data Analysis....................................................................93 6.6.2 Test Results & Discussion...................................................................................95 I. Reliability & Validity........................................................................................95 II. Variable Screening............................................................................................96 7. GUIDELINES DEVELOPMENT: AUTOMATIC TRANSMISSION...........................98 7.1 Components of Automatic Transmission........................................................................98 7.2 PERFORMANCE (FUNCTION) AND USABILITY OF AUTOMATIC TRANS-MISSIONS: AS PERCEIVED BY USERS......................................................99 7.2.1 Usability-Functionality Design Criteria.............................................................100 7.2.1.1 Description of Group…………………………………………..….…..100 7.3 DEVELOPMENT OF LINKAGES USING FLOW DIAGRAMS..............................102 7.4 DEVELOPMENT OF DESIGN GUIDELINES............................................................104 7.5 SURVEY