Haptic Interaction: 5th International Conference, AsiaHaptics 2022, Beijing, China, November 12–14, 2022, Proceedings (Lecture Notes in Computer Science) 3031468384, 9783031468384
This book constitutes the proceedings of the 5th International Conference, AsiaHaptics 2022, in Beijing, China, in Novem
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English Pages 252 [250] Year 2023
Preface
Organization
Contents
Effects of Duration and Envelope of Vibrotactile Alerts on Urgency, Annoyance, and Acceptance
1 Introduction
2 Methodology
2.1 Participants
2.2 Vibrotactile Alert Parameters
2.3 Apparatus and Experimental Task
3 Experiment 1: Effects of Alert Duration
3.1 Experimental Protocol
3.2 Results
4 Experiment 2: Vibrotactile Alert Envelope
4.1 Experimental Setup
4.2 Procedure
4.3 Results
5 Discussion
6 Conclusion
References
Optimal Design of Braille Display Based on Adaptive-Network-based Fuzzy Inference
1 Introduction
2 Design of an Electromagnetically Driven Braille Display
2.1 Design Goals for Braille Display
2.2 Design of Electromagnetically Driven Braille Display
3 Optimization of Design Parameters for Electromagnetic Braille Display
3.1 Components of ANFIS System
3.2 Building an ANFIS Model of the Braille Display
3.3 Model Training
4 Prototype Development of Braille Display
5 Validation Experiments
5.1 Measurement of Dot Support Force
5.2 Measurement of Dot Response Speed
5.3 Measurement of Braille Display Operating Temperature
5.4 Measurement of Braille Display Accuracy
6 Conclusion
References
Modality-Specific Effect of Cueing on Inter-Manual Coordination in Bimanual Force Control Tasks with Accentuated- or Attenuated-Force Production
1 Introduction
2 Methods
2.1 Participants
2.2 Apparatus
2.3 Task Design
2.4 Procedures
2.5 Data Analysis
3 Results
4 Discussion
5 Conclusion
References
Creation of Realistic Haptic Experiences for Materialized Graphics
1 Introduction
2 Materialized Graphics Before 2016
2.1 Single-Focus Amplitude Modulation
2.2 Midair Touch Panel
2.3 Tactile Projector
2.4 HaptoClone
3 Tactile Reproduction Through Ultrasound
3.1 Recent Progress of Haptic Feel Creation
3.2 Spatial Pressure Pattern Generation
3.3 Problems in Pressure Pattern Rendering
3.4 Lateral Modulation
3.5 Static-Pressure Presentation
3.6 Cooling-Sensation Presentation
4 Summary
References
Vibrotactile Encoding of Object Features and Alert Levels for the Visually Impaired
1 Introduction
1.1 Contributions
2 Related Work
2.1 Tactile Travel Aids for the Visually Impaired
2.2 Mental Model of the Visually Impaired
2.3 Vibrotactile Cues for Semantic Features Representation
2.4 Direction Identification and Alert Delivery
3 Design and Implementation
3.1 Design Objectives
3.2 Target Space and Objects
3.3 User-Centered Agile Design Development
3.4 Wearable Prototype Design
3.5 Construction of Tacton
4 Evaluation
4.1 Test 4: User Testing in Lab Settings
4.2 Test 5: User Testing in Natural Settings
5 Conclusion and Future Works
References
Haptic Rendering Algorithm for Manipulating Tiny Objects Attached on Adhesive Surface of Rigid Objects
1 Introduction
2 Dynamics Model
2.1 Force Analysis
2.2 Dynamic Model
3 System Design
3.1 Construction of the Virtual Scene
3.2 Optimization of the Bracket’s Posture
4 System Assessment
4.1 Subjective Data Analysis
4.2 Objective Data Analysis
5 Conclusion and Future Work
References
Ocular Tactile Vibration Intervention in VR and Its Modeling Coupled with Visual Fusion
1 Introduction
2 Psychophysical Experiments
2.1 Experiment 1
2.2 Experiment 2
2.3 General Discussion
3 Modeling
3.1 Theoretical Basis of Modeling
3.2 Modeling Process and Data Fitting
3.3 Model Performance Evaluation
3.4 Discussion
4 Conclusion
References
A Texture Display Device Based on Multi-coil Superposition Driving Method
1 Introduction
2 System Design
2.1 Device Design
2.2 Driving Method
3 Experiment
4 Conclusion and Future Work
References
The Central Mechanism Underlying Extrapolation of Thermal Sensation
1 Introduction
2 Background
2.1 Temperature-Tuning Phenomenons
2.2 A Common Mechanism
2.3 Theories of Thermal Illusion
3 Materials and Methods
3.1 Participants
3.2 Apparatus
3.3 Experiment 1
3.4 Experiment 2
4 Experimental Results
4.1 Experiment 1
4.2 Experiment 2
5 Discussion
5.1 Principal Findings
5.2 Adequacy of Gate Control Model
5.3 Relationship with Gate Control Theory of Pain
6 Conclusion
References
Graphical Tactile Display Application: Design of Digital Braille Textbook and Initial Findings
1 Introduction
2 Related Work
3 Tactile Interface Design of Digital Braille Textbook
3.1 Typesetting Design that Conforms to the Touch Habits of Blind Students
3.2 Tactile Image Design from Ordinary Textbooks to Braille Textbooks
3.3 A Contextual Knowledge Learning Design with Pictures and Texts
4 Typical Design Examples of Digital Braille Textbook
4.1 Lesson “Zhaozhou Bridge” in Chinese Textbook
4.2 Lesson “Know 1–5, Addition and Subtraction” in Mathematics Textbook
4.3 Other Digital Braille Textbook Examples
5 Evaluation and Discussion
5.1 Method
5.2 Results
5.3 Discussion
6 Concluding Remarks
References
DeltaFinger: A 3-DoF Wearable Haptic Display Enabling High-Fidelity Force Vector Presentation at a User Finger
1 Introduction
2 Related Works
3 System Overview
3.1 DeltaFinger Kinematics
4 Haptic Rendering
5 Experimental Evaluation
5.1 Force Vector Rendering Experiment
5.2 Experiment on Direction Recognition of Linear Force Vector
5.3 Conclusion
References
Improvement of Discrimination of Haptic Motion Experience by Reproducing Multi-point Spatial Distribution of Propagated Vibrations at the Wrist
1 Introduction
2 Measurement of Vibration Transmitted from the Fingertip to Wrist
2.1 Method
2.2 Results and Discussion
3 Spatial Vibration Representation During Haptic Motions
3.1 Overview of Intensity Segment Modulation: ISM
3.2 Vibration Measurements of Haptic Motions
3.3 Discrimination Experiment of Haptic Motion
3.4 Discussions
4 Conclusion
References
Peripersonal Space Tele-Operation in Virtual Reality: The Role of Tactile - Force Feedback
1 Introduction
2 Methods
2.1 Participants
2.2 Stimuli and Apparatus
2.3 Experimental Design and Procedure
2.4 Results for Experiment 1
3 Experiment 2
3.1 Participants
3.2 Experimental Design and Procedure
3.3 Results for Experiment 2
4 Discussion
References
CobotTouch: AR-Based Interface with Fingertip-Worn Tactile Display for Immersive Control of Collaborative Robots
1 Introduction
2 System Overview
2.1 Haptic Interface
2.2 DNN-Based Gesture Recognition
3 Experiment on Tactile Perception
3.1 Experimental Results of Tactile Perception
4 User Study Experiment
4.1 Experimental Design
5 Experimental Results
5.1 Average Score of NASA TLX Rating
5.2 Post-Experience Questionnaire
6 Conclusion and Future Work
References
Multi-modal Sensing-Based Interactive Glove System for Teleoperation and VR/AR
1 Introduction
2 Related Work
3 Implementation of the Proposed Glove System
3.1 Overall Design
3.2 VR/AR System Design
3.3 Design of the Remote Operating System
3.4 Working Principle of the System
4 Functional Module Design for the VR/AR Glove System
4.1 Power Supply Module
4.2 Reproducing the Glove Actuator Module
4.3 Design of Bluetooth Communication Module
4.4 Temperature Detection and Temperature Display Module
5 System Effect Verification
5.1 Temperature Change Effect
5.2 Vibration Change Effect
6 User Experience and Experimental Conclusions
6.1 Remote Operation and VR/AR System Temperature and Vibration Sensing Experiments
7 Conclusion
References
Haptic Guidance for Robot Arm Teleoperation Using Ray-Based Holistic Collision Avoidance
1 Introduction
2 Related Works
2.1 Teleoperation
2.2 Haptic Force Feedback in the Teleoperation
3 Ray-Based Holistic Collision Avoidance Haptic Feedback
3.1 Ray-Based Environment Sampling
3.2 Motion-Based Jacobian Approximation
3.3 Implementation
4 Technical Evaluation
4.1 Single-Point Potential Field vs Multi-point Ray-Based Haptic Feedback
4.2 Exact Jacobian vs Approximate Jacobian
5 User Study
5.1 User Study 1: Single-Point Potential Field-Based Vs Multi-point Ray-Based Haptic Feedback
5.2 User Study 2: Exact Jacobian VS Approximate Jacobian
6 Discussion
6.1 Analysis on User Study 1
6.2 Analysis on User Study 2
6.3 Limitations
7 Conclusion
References
QoE-Driven Scheduling for Haptic Communications with Reinforcement learning
1 Introduction
2 Background Knowledge
3 Proposed RL-Based Scheduling Algorithm
4 Experimental Results
4.1 Environmental Setups
4.2 Delay
4.3 Throughput
4.4 QoE and Loss Rate
5 Conclusion
References
Author Index
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LNCS 14063
Dangxiao Wang · Aiguo Song · Qian Liu · Ki-Uk Kyung · Masashi Konyo · Hiroyuki Kajimoto · Lihan Chen · Jee-Hwan Ryu (Eds.)
Haptic Interaction 5th International Conference, AsiaHaptics 2022 Beijing, China, November 12–14, 2022 Proceedings
Lecture Notes in Computer Science Founding Editors Gerhard Goos Juris Hartmanis
Editorial Board Members Elisa Bertino, Purdue University, West Lafayette, IN, USA Wen Gao, Peking University, Beijing, China Bernhard Steffen , TU Dortmund University, Dortmund, Germany Moti Yung , Columbia University, New York, NY, USA
14063
The series Lecture Notes in Computer Science (LNCS), including its subseries Lecture Notes in Artificial Intelligence (LNAI) and Lecture Notes in Bioinformatics (LNBI), has established itself as a medium for the publication of new developments in computer science and information technology research, teaching, and education. LNCS enjoys close cooperation with the computer science R & D community, the series counts many renowned academics among its volume editors and paper authors, and collaborates with prestigious societies. Its mission is to serve this international community by providing an invaluable service, mainly focused on the publication of conference and workshop proceedings and postproceedings. LNCS commenced publication in 1973.
Dangxiao Wang · Aiguo Song · Qian Liu · Ki-Uk Kyung · Masashi Konyo · Hiroyuki Kajimoto · Lihan Chen · Jee-Hwan Ryu Editors
Haptic Interaction 5th International Conference, AsiaHaptics 2022 Beijing, China, November 12–14, 2022 Proceedings
Editors Dangxiao Wang Beihang University Beijing, China Qian Liu Dalian University of Technology Dalian, China Masashi Konyo Tohoku University Sendai, Japan Lihan Chen Peking University Beijing, China
Aiguo Song Southeast University Nanjing, China Ki-Uk Kyung Korea Advanced Institute of Science and Technology (KAIST) Daejeon, Korea (Republic of) Hiroyuki Kajimoto The University of Electro-Communications Tokyo, Japan Jee-Hwan Ryu Korea Advanced Institute of Science and Technology (KAIST) Daejeon, Korea (Republic of)
ISSN 0302-9743 ISSN 1611-3349 (electronic) Lecture Notes in Computer Science ISBN 978-3-031-46838-4 ISBN 978-3-031-46839-1 (eBook) https://doi.org/10.1007/978-3-031-46839-1 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors, and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. This Springer imprint is published by the registered company Springer Nature Switzerland AG The registered company address is: Gewerbestrasse 11, 6330 Cham, Switzerland Paper in this product is recyclable.
Preface
AsiaHaptics is one of the four major international conferences in the field of haptics. It is an international academic conference featuring interactive demonstrations. In 2022, AsiaHaptics was held in China for the first time since its establishment. The conference was jointly organized by Beihang University, Beijing Society for Image and Graphics, IEEE Technical Committee on Haptics, IEEE Computer Society, and the Virtual Reality Society of Japan. The conference aimed to demonstrate the latest research achievements in the field of haptics and provide an international platform for communication and exchange among haptics professionals. For the first time in AsiaHaptics’ history, we held the conference in 4 venues due to the Covid situation, including the main venue in Beijing, and 3 satellite venues in Nanjing, Tokyo and Daejeon. AsiaHaptics 2022 provided a wide variety of activities, including plenary sessions (i.e. Haptics in Robotics & HCI, Haptics in Metaverse, and Special Industrial Session), keynote talks provided by world-famous researchers in haptic technology, including Zhonglin Wang from the Beijing Institute of Nanoenergy and Nanosystems, Hong Z. Tan from Purdue University, and Domenico Prattichizzo from the University of Siena, as well as live and video demonstrations. The AsiaHaptics conference series is well known for its interactive demonstration sessions. AsiaHaptics 2022 presented the latest developments of haptic hardware in education, culture, tourism, medicine, elderly care and disability assistance. With the rise of the metaverse, AsiaHaptics 2022 also included showcases of multimodal perception (e.g. vision, hearing and touch) systems in XR environments. We received a total of 46 regular papers and 77 short papers, and finally accepted 17 regular papers and 39 short papers to present at the conference. On behalf of the organizers and Program Committee of AsiaHaptics 2022, we thank all authors for their submissions and camera-ready copies of papers, and all participants for their thought-provoking ideas and active participation in the conference. We also acknowledge the sponsors, members of the organizing committees, Program Committee members, and other supporting committees and individuals who gave their continuous help and support in making the conference a success. Thank you! August 2023
Dangxiao Wang Aiguo Song Qian Liu Ki-Uk Kyung Masashi Konyo Hiroyuki Kajimoto Lihan Chen Jee-Hwan Ryu
Organization
General Chairs Dangxiao Wang Aiguo Song
Beihang University, China Southeast University, China
Program Chairs Qian Liu Ki-Uk Kyung Masashi Konyo
Dalian University of Technology, China KAIST, South Korea Tohoku University, Japan
Award Chair Edward Colgate
Northwestern University, USA
Publication Chairs Hiroyuki Kajimoto Lihan Chen Jee-Hwan Ryu
UEC, Japan Peking University, China KAIST, South Korea
Publicity Chairs Seungmoon Choi Feng Tian Yon Visell Shoichi Hasegawa Claudio Pacchierotti Shana Smith Ingvars Birznieks
POSTECH, South Korea Software Institute of CAS, China UC at Santa Barbara, USA TokyoTech, Japan IRISA, France National Taiwan University, Taiwan University of New South Wales, Australia
viii
Organization
Workshop Chairs Yingqing Xu Ildar Farkhatdinov
Tsinghua University, China Queen Mary University of London, UK
Web Chairs Tao Zeng Shuai Li Inwook Hwang
Xiamen University, China Beihang University, China ETRI, South Korea
Local Organization Chairs Yue Liu Guangyang Liu Han Jiang
Beijing Institute of Technology, China Beihang University, China Beihang University, China
Live Demo Chairs Xiao Xu Minghui Sun Wenzhen Yang
Technical University of Munich, Germany Jilin University, China Zhejiang Science and Technology University, China
Industry Chairs Hongwei Zhou Haoyang Liu Francois Conti Munchae Joung
Pico Technology Co., Ltd., China Noitom Ltd., China Force Dimension Inc., Switzerland LG Electronics Inc., South Korea
Sponsorship Chairs Xiaoying Sun Dongdong Weng
Jilin University, China Beijing Institute of Tech., China
Contents
Effects of Duration and Envelope of Vibrotactile Alerts on Urgency, Annoyance, and Acceptance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ahmed Elsaid, Wanjoo Park, Sohmyung Ha, Yong-Ak Song, and Mohamad Eid Optimal Design of Braille Display Based on Adaptive-Network-based Fuzzy Inference . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chang Liu, Zhongzhen Jin, Kaiwen Chen, Wentao Tao, Hongbo Liang, and Wenzhen Yang Modality-Specific Effect of Cueing on Inter-Manual Coordination in Bimanual Force Control Tasks with Accentuated- or Attenuated-Force Production . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cong Peng, Xin Wang, Xingwei Guo, Jin Liang, and Dangxiao Wang Creation of Realistic Haptic Experiences for Materialized Graphics . . . . . . . . . . . Hiroyuki Shinoda
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Vibrotactile Encoding of Object Features and Alert Levels for the Visually Impaired . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Liwen He, Yun Wang, Hu Luo, and Dangxiao Wang
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Haptic Rendering Algorithm for Manipulating Tiny Objects Attached on Adhesive Surface of Rigid Objects . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Xiaohan Zhao, Quanmin Guo, and Dangxiao Wang
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Ocular Tactile Vibration Intervention in VR and Its Modeling Coupled with Visual Fusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pei Kang, Yan Liu, Hang Wang, Enshan Ouyang, and Tao Zeng
80
A Texture Display Device Based on Multi-coil Superposition Driving Method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Xuesong Bian, Yuan Guo, Yuru Zhang, and Dangxiao Wang
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The Central Mechanism Underlying Extrapolation of Thermal Sensation . . . . . . 105 Junjie Hua, Masahiro Furukawa, and Taro Maeda Graphical Tactile Display Application: Design of Digital Braille Textbook and Initial Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121 Yang Jiao, Qixin Wang, and Yingqing Xu
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Contents
DeltaFinger: A 3-DoF Wearable Haptic Display Enabling High-Fidelity Force Vector Presentation at a User Finger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135 Artem Lykov, Aleksey Fedoseev, and Dzmitry Tsetserukou Improvement of Discrimination of Haptic Motion Experience by Reproducing Multi-point Spatial Distribution of Propagated Vibrations at the Wrist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147 Kosuke Yamaguchi, Masamune Waga, Masashi Konyo, and Satoshi Tadokoro Peripersonal Space Tele-Operation in Virtual Reality: The Role of Tactile - Force Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 Yiru Liu, Nicholas Katzakis, Frank Steinicke, and Lihan Chen CobotTouch: AR-Based Interface with Fingertip-Worn Tactile Display for Immersive Control of Collaborative Robots . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176 Oleg Sautenkov, Miguel Altamirano Cabrera, Viktor Rakhmatulin, and Dzmitry Tsetserukou Multi-modal Sensing-Based Interactive Glove System for Teleoperation and VR/AR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189 Xinwei Yao, Ming Chen, Chuan Cao, Lei Zhang, Wenzhen Yang, Mukherjee Mithun, and Hujun Bao Haptic Guidance for Robot Arm Teleoperation Using Ray-Based Holistic Collision Avoidance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 Hyunsoo Kim, Wonjung Park, Taeyun Woo, and Jinah Park QoE-Driven Scheduling for Haptic Communications with Reinforcement learning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 226 Junru Chen, Zhuoru Yu, and Qian Liu Author Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
Effects of Duration and Envelope of Vibrotactile Alerts on Urgency, Annoyance, and Acceptance Ahmed Elsaid , Wanjoo Park , Sohmyung Ha , Yong-Ak Song , and Mohamad Eid(B) Engineering Division, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi 129188, United Arab Emirates [email protected] Abstract. Vibrotactile feedback has been receiving increasing attention as an effective modality to draw the user’s attention to an urgent situation. The current study examines the effects of alert duration and envelope on perceived urgency, annoyance, and acceptance using a dualtask condition. Participants are instructed to complete a simple arithmetic task (primary) during which the vibrotactile alert (secondary) is provided via a wristband attached to the non-dominant hand. Experiment 1 investigates the effects of the alert duration and found that an alert duration of 1,950 ms significantly increases the perceived urgency and acceptance, while significantly decreasing annoyance. Experiment 2 compares three vibration envelope patterns (constant, increasing, and decreasing intensity) and found that a constant vibration intensity of 2.25g significantly increases the perceived urgency without significantly changing the perceived annoyance and acceptance. These findings inspire the development of vibrotactile alert systems. Keywords: Vibrotactile Alerts · Alert Duration Urgency · Annoyance · Acceptance
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· Alert Envelope ·
Introduction
In many applications where visual and auditory channels are becoming increasingly loaded, vibrotactile alerts present a viable alternative to elicit a sense of urgency. Vibrotactile feedback does not increase visual and auditory demands [1,2], is robust to audible noise [3], affordable [4], and confidential [5]. On the other hand, given how vibrotactile signals come into physical contact with the skin, they may also be perceived as highly annoying or unacceptable. Therefore, vibrotactile alerts must be designed to provide a desirable level of urgency with minimal effects on annoyance and acceptance. A number of temporal parameters of the vibrotactile signal are studied in the literature. Key factors, including the pulse rate, inter-pulse duration (IPD), number of pulses, waveform, and the envelop, are known to affect the perceived Supported by New York University Abu Dhabi. c The Author(s), under exclusive license to Springer Nature Switzerland AG 2023 D. Wang et al. (Eds.): AsiaHaptics 2022, LNCS 14063, pp. 1–10, 2023. https://doi.org/10.1007/978-3-031-46839-1_1
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urgency [6–9]. An early study examined how the pulse duration (PD), IPD, and the number of pulses influence the perceived urgency [10]. The results demonstrate that a short vibration (200 ms) heightens the perceived urgency while a longer one (600 ms) diminishes its strength. Moreover, the largest differences in perceived urgency as a function of IPD occurred at the smallest PD [7]. Other studies demonstrated that the perceived urgency increases with an increase in pulse rate [6,7], however, pulse rate was found to have more impact on urgency than on annoyance [6]. The effects of the vibration waveform on perceived urgency were also studied [8] where a fade-in envelope led to a lower sense of urgency. It is known that the subjective judgment of perceived urgency can be affected by a primary task [11]. Therefore, in this study, the effects of vibrotactile alert duration and envelope on perceived urgency, annoyance, and acceptance, are studied in a dual-task scenario. In this study, urgency is defined as the quality of being very important and needing immediate attention, annoyance is defined as a mental state that is characterized by irritation and distraction from one’s conscious thinking of a primary task, and acceptance represents the general agreement that something is satisfactory. The urgent feedback may affect how quickly the user should recognize and respond to the alert. The annoyance may influence whether the user will ignore the alert, particularly in situations with many false alerts. Finally, the acceptance may influence the user’s decision to enable/disable the alert. Experiment 1 examines how the alert duration influences the perceived urgency, annoyance, and acceptance whereas experiment 2 investigates the effects of the signal envelope (constant, increasing, and decreasing intensity) on the perceived urgency, annoyance, and acceptance. The aim is to inspire the design of vibrotactile alerts that significantly enhance the perceived urgency, reduce annoyance, and achieve a higher sense of acceptance.
2 2.1
Methodology Participants
A total of 30 participants (15 females, 15 males, ages 18–27 years) are recruited for the study. The inclusion criteria are: (1) participants above 18 years old, (2) right-handed, and (3) with no known sensorimotor, developmental, or cognitive disorders. The study is approved by the Institutional Review Board for Protection of Human Subjects at New York University Abu Dhabi (Project #HRPP-2021-64). 2.2
Vibrotactile Alert Parameters
A vibrotactile alert is defined as an arrangement of repeatable sequences of the vibration motor’s “on” and “off” state, with a specific duration assigned to each state. The duration of the “on” state is known as the pulse duration (PD) whereas that of the “off” state is referred to as the inter-pulse duration (IPD).
Urgency, Annoyance, and Acceptance in Vibrotactile Alerts
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Fig. 1. Experimental setup: wristband with vibration motor and the primary task shown on the screen.
Based on previous research [12], the PD and the IPD are set to 350 ms and 40 ms, respectively, in order to provide a clearly perceptual but non-irritating experience (this is also verified through a pilot study). The total duration for the number of repetitions of the “on” and “off” states is known as the alert duration. On the other hand, the alert envelope is defined by varying the intensity of vibration over time. Three envelopes are considered, increasing, decreasing, and constant intensities. 2.3
Apparatus and Experimental Task
The vibrotactile feedback prototype is in the form of a wristband as shown in Fig. 1. A vibration motor (Pico Vibe 310-177, Precision Microdrives) is attached to the volar wrist (palm side) of the wristband to provide vibrotactile feedback. The vibration motor is attached to the volar wrist due to its ability to affect the sensorimotor cortex of the brain without interfering with the hand movements performing a primary task [13]. The vibration motor is 10 mm in diameter and 2.7 mm in thickness. An ATMEGA328 microcontroller unit is utilized to control the vibration motor and connect through a serial connection over a USB cable to a laptop. The stimulation intensity is controlled by adjusting the duty cycle of the pulse width modulation (PWM) signal that feeds the vibration motor. Increasing the duty cycle of the PWM signal would increase the effective voltage
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applied to the actuator and thus the vibration intensity. The alert envelope is characterized by a vibration intensity that varies linearly between the least perceived intensity of 0.5g and the maximum vibration intensity of 2.26g. The experimental setup is shown in Fig. 1. Urgency, annoyance, and acceptance are evaluated using a slider ranging from -1 to +1 (the default value is 0, representing a neutral opinion). The user controls the slider to rate each of the parameters, and once completed press the submit button to save the ratings before moving to the next trial. The user has the option to early quit the application via the exit button. An arithmetic task is developed in order to simulate a realistic scenario where the participant is engaged in a primary task when receiving the vibrotactile alert. The participant is asked to complete a five-digit addition task on the screen during which the vibrotactile alert is provided, as shown in Fig. 1. The perceived urgency, annoyance, and acceptance are evaluated in a more realistic context.
3
Experiment 1: Effects of Alert Duration
The objective of experiment 1 is to examine how the vibrotactile alert duration influences perceived urgency, annoyance, and acceptance. Increasing the alert duration is likely to have a strong influence on urgency up to a point when the alert becomes too annoying and potentially unacceptable. The vibrotactile alert duration consists of a repetition of the vibration cycle (PD and IPD) ranging from 2 up to 10 repetitions. Additional repetitions beyond 10 were found too annoying and unacceptable during a pilot study. 3.1
Experimental Protocol
After introducing the experiment’s purpose and setup, participants were asked to complete the consent form. The wristband was then attached to the nondominant hand of the participant. The participants were told to not move their hands throughout the experiment. Each participant completed 18 trials of vibrotactile alerts (ranging from two to ten and back to two repetitions). On each trial, the participant felt the vibrotactile alert and then was asked to rate the urgency, annoyance, and acceptance after the stimulation. Once the participant submits their response, the next trial started. The independent variable was the alert duration. The dependent variables were the ratings for urgency, annoyance, and acceptance for each alert duration. Statistical analysis was performed to confirm whether the participant’s response was significantly higher or lower compared to neutral rating. The pvalue was corrected for multiple comparisons using the Bonferroni method. 3.2
Results
Figure 2 shows the results for the perceived urgency ratings. Vibrotactile alerts with two and three repetitions were rated as significantly lower than neutral for
Urgency, Annoyance, and Acceptance in Vibrotactile Alerts
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Fig. 2. Perceived urgency ratings. The blue and red triangles indicate significantly lower and higher ratings compared to neutral status, respectively. Wilcoxon signedrank test or One-sample t-test was utilized depending on the Jarque-Bera test to check if the data follows the normal distribution. p-value is corrected using the Bonferroni method. The triangles indicate p