University of Nevada, Reno Haptic Interface for Non-Visual Steering A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Computer Science and Engineering by Burkay Sucu Dr. Eelke Folmer/Thesis Advisor May, 2013 THE GRADUATE SCHOOL We recommend that the thesis prepared under our supervision by BURKAY SUCU entitled Haptic Interface For Non-Visual Steering be accepted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Eelke Folmer, Ph. D., Advisor Sergiu Dascalu, Ph. D., Committee Member Cahit Evrensel, Ph. D., Graduate School Representative Marsha H. Read, Ph. D., Dean, Graduate School May, 2013 i Abstract Glare significantly diminishes visual perception, and is a significant cause of traffic acci- dents. Existing haptic automotive interfaces typically indicate when and in which direction to steer, but they don’t convey how much to steer, as a driver typically determines this us- ing visual feedback. We present a novel haptic interface that relies on an intelligent vehicle positioning system to indicate when, in which direction and how far to steer, as to facilitate steering without any visual feedback. Our interface may improve driving safety when a driver is temporarily blinded, for example, due to glare or fog. Three user studies were per- formed, the first study tries to understand driving using visual feedback, the second study evaluates two different haptic encoding mechanisms with no visual feedback present, and a third study evaluates the supplemental effect of haptic feedback when used in conjunction with visual feedback. Studies show this interface to allow for blind steering through small curves and that it can improve a driver’s lane keeping ability when combined with visual feedback. We improved our interface to identify whether this allows for blind steering with no visual feedback by users who are blind. We conducted a user study with an adapted version of our interface that implements self correction and conducted user studies with users who are blind. ii Acknowledgments It is a great pleasure acknowledging the support and help of the kind people around me, without them this thesis would have remained a dream. First of all, I would like to thank the most friendly advisor ever, Dr. Eelke Folmer, who is more like an older brother to me as we talk about everything else more than we talk about work. I have always been very grateful working with him since he is always supportive, encouraging, and understanding. Without him, it would not be possible to complete this work. Secondly, I want to express my deepest gratitude to Dr. Cahit Evrensel, not only because he accepted being in my committee, but also for everything he has done since we met. He is always available for help about anything, and hospitable. His work ethics is admirable, and he is a true role model for his students. I also need to thank another committee member Dr. Sergiu Dascalu, for being very encouraging and having a very positive attitude all the time. Just after couple of weeks we met, he asked me to take a road trip to Lake Tahoe. It was a pleasant welcoming for me to Reno. I should thank my friends in our office, Vinitha, Miran, Ilias, Alex, and Cagri, who turn the working environment into somewhere fun. I would like to thank my friends Sehribani and Bugra. They are the ones who made me come to Reno in the first place. They are my sister and brother here, and they make Reno a much better place. I also want to thank to my family and friends for their support. If I try to list their names, acknowledgments might get as long as thesis itself. Finally and most importantly, I want to thank the three most important people in my life; my mother, my father, and my brother, who always believe in and support me, and I am happily dedicate this work to them. May, 2013 iii Contents Abstract i List of Tables v List of Figures vi 1 Introduction 1 1.1 Background and Related Work . .4 1.1.1 Haptic Steering Interface . .4 1.1.2 Haptic Racing Interface . .7 2 Design of a Haptic Steering Interface 10 2.1 Setup of the Simulation Environment . 11 2.2 Study 1: Understanding Driving . 17 2.2.1 Participants . 17 2.2.2 Instrumentation . 17 2.2.3 Procedure . 18 2.2.4 Results . 19 2.2.5 Haptic Steering Interface . 21 2.3 Study 2: Evaluating Haptic Encoding schemes . 24 2.3.1 Participants . 24 2.3.2 Instrumentation . 24 2.3.3 Procedure . 25 2.3.4 Results . 26 2.4 Study 3: Evaluate Multimodal Effect . 27 2.4.1 Participants . 27 2.4.2 Instrumentation & Procedure . 27 2.4.3 Results . 27 3 A Racing Game with a Haptic Interface 30 3.1 Setup for the Game . 30 3.2 Developing a Dynamic Haptic Feedback System . 32 3.3 User Study: Evaluating The Racing Game . 36 3.3.1 Participants . 36 iv 3.3.2 Instrumentation . 36 3.3.3 Procedure . 37 3.3.4 Results . 38 4 Discussion and Future Work 40 4.1 Haptic Steering Interface . 40 4.2 Haptic Racing Interface . 43 5 Conclusion 45 Bibliography 46 v List of Tables 2.1 Prelim. study results: average deviation (stdev) in meters . 20 2.2 Study 2 results: average deviation (stdev) in meters . 26 2.3 Study 1&3 results: average deviation (stdev) in meters . 28 3.1 User study results of sighted subjects: average deviation (stdev) in meters and total number of hits . 38 3.2 User study results of visually impaired subjects: average deviation (stdev) in meters and number of hits . 38 vi List of Figures 1.1 A driver blinded by the headlights of oncoming car . .2 2.1 Overall setup of the simulation environment . 11 2.2 Graph of the function of wheel position to digital values . 13 2.3 Radius of rotation circle calculation . 14 2.4 Error in position calculation . 15 2.5 Error function plotted using Desmos Graphing Calculator . 16 2.6 Screenshot of simulator we modified to analyze driving behavior using vi- sual feedback. 18 2.7 Four different roads with curve angles: 180◦; 135◦; 90◦; 45◦ ......... 19 2.8 Average steering wheel values for the right turns . 20 2.9 Bott’s dots (left) and rumble strips (right) . 22 2.10 How the system works: steering cues are provided through a vibrotactor integrated in the left and right of the steering wheel. Drivers steer away from a cue felt in either hand, in order to find a dead-band window that indicates the target orientation of the wheel, which changes as the car drives through the curve . 23 2.11 Vibrotactors attached to the left and the right side of the steering wheel, with drivers placing their hands on top of them. 25 2.12 Correlation between steering time and index of difficulty for no magnitude, frequency magnitude, visual and haptic + visual feedback. 29 3.1 Top-down view of the racing game track . 31 3.2 Dynamic calculation of haptic feedback . 33 3.3 Dead-band window as a circular target . 35 3.4 Four-lap play with smallest standard deviation in Group A (clockwise) . 39 3.5 Four-lap play with smallest standard deviation in Group B (clockwise) . 39 4.1 Average steering wheel values for the 180◦ turn . 41 1 Chapter 1 Introduction For this thesis, we developed two projects: (i) a haptic steering interface which can be used in real-life systems to increase driving safety when it is jeopardized due to a temporary blindness arises from glare or fog, (ii) a haptic racing interface for a blind-accessible racing game which is novel in that it only uses haptic feedback to allow a player drive a car on a race track successfully without the need of any visual or audio feedback for steering. Glare, caused by sunlight or headlights is a significant cause of vehicle accidents, as visibility is a basic requirement for safe driving [1]. Especially in winter, due to a lower elevation of the sun and the presence of snow and ice, there is a significant increase in traffic accidents due to glare. Depending on the type of exposure, it may take an eye between 1 and 7 seconds to adjust to glare [2, 3, 4]. As a person ages, the ability to focus and recover from glare continues to diminish [5] and as a result nearly 40% of drivers involved in accidents due to glare are older than 45 years [1]. Though glare can occur in various contexts, one of the more dangerous situations is when a driver is steering through a curve, as there is a greater risk of getting blinded due to the significant change in direction. Unlike driving on a straight road, steering through a curve requires continuous adjustment of the steering wheel, therefore a temporary blindness could have major consequences. In recent years there has been increasing interest in improving automotive safety using haptic interfaces. For example, lane keeping [6] or lane changing [7] systems are com- mercially available where haptic cues warn the driver of impeding danger. Other systems [8, 9, 10] aim to reduce overloaded modalities, where haptic feedback conveys high level navigation instructions. Haptic feedback has some desirable properties over other modal- 2 Figure 1.1: A driver blinded by the headlights of oncoming car ities in that it is private and doesn’t distract any passengers. Haptic feedback provided through the steering wheel allows for robust and efficient communication of rich tactile information [11], as the driver is always holding it.