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Takahashi C, Azad M, Rajasekaran V, Babič J, Mistry M. Human Stiffness Perception and Learning in Interacting With Compliant Environments. Front Neurosci 2022; 16:841901. [PMID: 35757537 PMCID: PMC9215212 DOI: 10.3389/fnins.2022.841901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 04/19/2022] [Indexed: 11/19/2022] Open
Abstract
Humans are capable of adjusting their posture stably when interacting with a compliant surface. Their whole-body motion can be modulated in order to respond to the environment and reach to a stable state. In perceiving an uncertain external force, humans repetitively push it and learn how to produce a stable state. Research in human motor control has led to the hypothesis that the central nervous system integrates an internal model with sensory feedback in order to generate accurate movements. However, how the brain understands external force through exploration movements, and how humans accurately estimate a force from their experience of the force, is yet to be fully understood. To address these questions, we tested human behaviour in different stiffness profiles even though the force at the goal was the same. We generated one linear and two non-linear stiffness profiles, which required the same force at the target but different forces half-way to the target; we then measured the differences in the learning performance at the target and the differences in perception at the half-way point. Human subjects learned the stiffness profile through repetitive movements in reaching the target, and then indicated their estimation of half of the target value (position and force separately). This experimental design enabled us to probe how perception of the force experienced in different profiles affects the participants' estimations. We observed that the early parts of the learning curves were different for the three stiffness profiles. Secondly, the position estimates were accurate independent of the stiffness profile. The estimation in position was most likely influenced by the external environment rather than the profile itself. Interestingly, although visual information about the target had a large influence, we observed significant differences in accuracy of force estimation according to the stiffness profile.
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Affiliation(s)
- Chie Takahashi
- School of Computer Science, University of Birmingham, Birmingham, United Kingdom
- Edinburgh Centre for Robotics, School of Informatics, University of Edinburgh, Edinburgh, United Kingdom
- School of Metallurgy and Materials, University of Birmingham, Birmingham, United Kingdom
- Department of Psychology, University of Cambridge, Cambridge, United Kingdom
| | - Morteza Azad
- School of Computer Science, University of Birmingham, Birmingham, United Kingdom
| | - Vijaykumar Rajasekaran
- School of Computer Science, University of Birmingham, Birmingham, United Kingdom
- School of Metallurgy and Materials, University of Birmingham, Birmingham, United Kingdom
| | - Jan Babič
- Laboratory for Neuromechanics and Biorobotics, Department for Automation, Biocybernetics and Robotics, Jožef Stefan Institute, Ljubljana, Slovenia
- Faculty of Electrical Engineering, University of Ljubljana, Ljubljana, Slovenia
| | - Michael Mistry
- School of Computer Science, University of Birmingham, Birmingham, United Kingdom
- Edinburgh Centre for Robotics, School of Informatics, University of Edinburgh, Edinburgh, United Kingdom
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Doi K, Sakaguchi S, Nishimura T, Fujimoto H, Ino S. Assessing the Stiffness Perception of Acupressure Massage Beginning Learners: A Pilot Study. Sensors (Basel) 2021; 21:s21072472. [PMID: 33918315 PMCID: PMC8038168 DOI: 10.3390/s21072472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/03/2021] [Accepted: 03/06/2021] [Indexed: 11/16/2022]
Abstract
Visually impaired licensed therapists must have the ability to perceive stiffness through their fingertips in the school for the blind. The teachers strive to provide careful introductory education based on a quantitative assessment of new students’ basic stiffness perception. However, assessment materials to help teachers understand new students’ stiffness perception are lacking. This study aimed to develop suitable fundamental assessment materials that visually impaired licensed teachers could use to quantitatively assess the difference in the stiffness perception ability of beginning learners in the early stages of learning. They were asked to discriminate the presented materials one at a time, which consisted of thermoplastic elastomers with different degrees of stiffness. We used these materials to compare the beginning learners’ ability to perceive stiffness with that of teachers and found that teachers answered correctly at an overall significantly higher rate. Specifically, the teachers’ correct response rate (78.8%) for the stiffness perception of all presented stimuli was approximately 15% higher than the beginning learners’ correct response rate (64.2%). These results revealed areas of stiffness that are difficult for beginning learners to identify.
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Affiliation(s)
- Kouki Doi
- Department of Information and Support, National Institute of Special Needs Education, Yokosuka 239-8585, Japan
- Correspondence:
| | - Saito Sakaguchi
- Graduate School of Human Sciences, Waseda University, Tokorozawa 359-1192, Japan;
| | - Takahiro Nishimura
- Center for Promoting Education for Persons with Developmental Disabilities, National Institute of Special Needs Education, Yokosuka 239-8585, Japan;
| | - Hiroshi Fujimoto
- Faculty of Human Sciences, Waseda University, Tokorozawa 359-1192, Japan;
| | - Shuichi Ino
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8566, Japan;
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Farajian M, Leib R, Kossowsky H, Zaidenberg T, Mussa-Ivaldi FA, Nisky I. Stretching the skin immediately enhances perceived stiffness and gradually enhances the predictive control of grip force. eLife 2020; 9:52653. [PMID: 32292163 PMCID: PMC7176431 DOI: 10.7554/elife.52653] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 04/02/2020] [Indexed: 01/29/2023] Open
Abstract
When manipulating objects, we use kinesthetic and tactile information to form an internal representation of their mechanical properties for cognitive perception and for preventing their slippage using predictive control of grip force. A major challenge in understanding the dissociable contributions of tactile and kinesthetic information to perception and action is the natural coupling between them. Unlike previous studies that addressed this question either by focusing on impaired sensory processing in patients or using local anesthesia, we used a behavioral study with a programmable mechatronic device that stretches the skin of the fingertips to address this issue in the intact sensorimotor system. We found that artificial skin-stretch increases the predictive grip force modulation in anticipation of the load force. Moreover, the stretch causes an immediate illusion of touching a harder object that does not depend on the gradual development of the predictive modulation of grip force.
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Affiliation(s)
- Mor Farajian
- Department of Biomedical Engineering, Ben-Gurion University of the Negev, Be'er Sheva, Israel.,Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Raz Leib
- Department of Biomedical Engineering, Ben-Gurion University of the Negev, Be'er Sheva, Israel.,Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Hanna Kossowsky
- Department of Biomedical Engineering, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Tomer Zaidenberg
- Department of Biomedical Engineering, Ben-Gurion University of the Negev, Be'er Sheva, Israel
| | - Ferdinando A Mussa-Ivaldi
- Shirley Ryan AbilityLab, Chicago, United States.,Department of Biomedical Engineering, Northwestern University, Evanston, United States
| | - Ilana Nisky
- Department of Biomedical Engineering, Ben-Gurion University of the Negev, Be'er Sheva, Israel.,Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Be'er Sheva, Israel
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Leib R, Rubin I, Nisky I. Force feedback delay affects perception of stiffness but not action, and the effect depends on the hand used but not on the handedness. J Neurophysiol 2018; 120:781-794. [PMID: 29766763 DOI: 10.1152/jn.00822.2017] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Interaction with an object often requires the estimation of its mechanical properties. We examined whether the hand that is used to interact with the object and their handedness affected people's estimation of these properties using stiffness estimation as a test case. We recorded participants' responses on a stiffness discrimination of a virtual elastic force field and the grip force applied on the robotic device during the interaction. In half of the trials, the robotic device delayed the participants' force feedback. Consistent with previous studies, delayed force feedback biased the perceived stiffness of the force field. Interestingly, in both left-handed and right-handed participants, for the delayed force field, there was even less perceived stiffness when participants used their left hand than their right hand. This result supports the idea that haptic processing is affected by laterality in the brain, not by handedness. Consistent with previous studies, participants adjusted their applied grip force according to the correct size and timing of the load force regardless of the hand that was used, the handedness, or the delay. This suggests that in all of these conditions, participants were able to form an accurate internal representation of the anticipated trajectory of the load force (size and timing) and that this representation was used for accurate control of grip force independently of the perceptual bias. Thus these results provide additional evidence for the dissociation between action and perception in the processing of delayed information. NEW & NOTEWORTHY Introducing delay to force feedback during interaction with an elastic force field biases the perceived stiffness of the force field. We show that this bias depends on the hand that was used for probing but not on handedness. At the same time, both left-handed and right-handed participants adjusted their applied grip force while using either their left or right hands in anticipation of the correct magnitude and timing despite the delay in load force.
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Affiliation(s)
- Raz Leib
- Department of Biomedical Engineering, Ben-Gurion University of the Negev, Beersheba, Israel.,Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Inbar Rubin
- Department of Biomedical Engineering, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Ilana Nisky
- Department of Biomedical Engineering, Ben-Gurion University of the Negev, Beersheba, Israel.,Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beersheba, Israel
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Leib R, Karniel A, Nisky I. The effect of force feedback delay on stiffness perception and grip force modulation during tool-mediated interaction with elastic force fields. J Neurophysiol 2015; 113:3076-89. [PMID: 25717155 PMCID: PMC4455557 DOI: 10.1152/jn.00229.2014] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Accepted: 02/23/2015] [Indexed: 11/22/2022] Open
Abstract
During interaction with objects, we form an internal representation of their mechanical properties. This representation is used for perception and for guiding actions, such as in precision grip, where grip force is modulated with the predicted load forces. In this study, we explored the relationship between grip force adjustment and perception of stiffness during interaction with linear elastic force fields. In a forced-choice paradigm, participants probed pairs of virtual force fields while grasping a force sensor that was attached to a haptic device. For each pair, they were asked which field had higher level of stiffness. In half of the pairs, the force feedback of one of the fields was delayed. Participants underestimated the stiffness of the delayed field relatively to the nondelayed, but their grip force characteristics were similar in both conditions. We analyzed the magnitude of the grip force and the lag between the grip force and the load force in the exploratory probing movements within each trial. Right before answering which force field had higher level of stiffness, both magnitude and lag were similar between delayed and nondelayed force fields. These results suggest that an accurate internal representation of environment stiffness and time delay was used for adjusting the grip force. However, this representation did not help in eliminating the bias in stiffness perception. We argue that during performance of a perceptual task that is based on proprioceptive feedback, separate neural mechanisms are responsible for perception and action-related computations in the brain.
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Affiliation(s)
- Raz Leib
- Department of Biomedical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Amir Karniel
- Department of Biomedical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ilana Nisky
- Department of Biomedical Engineering, Ben-Gurion University of the Negev, Beer-Sheva, Israel
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Wu B, Klatzky R, Lee R, Shivaprabhu V, Galeotti J, Siegel M, Schuman JS, Hollis R, Stetten G. Psychophysical evaluation of haptic perception under augmentation by a handheld device. Hum Factors 2015; 57:523-537. [PMID: 25875439 PMCID: PMC4480420 DOI: 10.1177/0018720814551414] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Accepted: 08/19/2014] [Indexed: 06/04/2023]
Abstract
OBJECTIVE This study investigated the effectiveness of force augmentation in haptic perception tasks. BACKGROUND Considerable engineering effort has been devoted to developing force augmented reality (AR) systems to assist users in delicate procedures like microsurgery. In contrast, far less has been done to characterize the behavioral outcomes of these systems, and no research has systematically examined the impact of sensory and perceptual processes on force augmentation effectiveness. METHOD Using a handheld force magnifier as an exemplar haptic AR, we conducted three experiments to characterize its utility in the perception of force and stiffness. Experiments 1 and 2 measured, respectively, the user's ability to detect and differentiate weak force (<0.5 N) with or without the assistance of the device and compared it to direct perception. Experiment 3 examined the perception of stiffness through the force augmentation. RESULTS The user's ability to detect and differentiate small forces was significantly improved by augmentation at both threshold and suprathreshold levels. The augmentation also enhanced stiffness perception. However, although perception of augmented forces matches that of the physical equivalent for weak forces, it falls off with increasing intensity. CONCLUSION The loss in the effectiveness reflects the nature of sensory and perceptual processing. Such perceptual limitations should be taken into consideration in the design and development of haptic AR systems to maximize utility. APPLICATION The findings provide useful information for building effective haptic AR systems, particularly for use in microsurgery.
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Affiliation(s)
- Bing Wu
- Arizona State University, Mesa, Arizona
| | | | - Randy Lee
- University of Pittsburgh, Pennsylvania
| | | | - John Galeotti
- Carnegie Mellon University, Pittsburgh, Pennsylvania
| | - Mel Siegel
- Carnegie Mellon University, Pittsburgh, Pennsylvania
| | | | - Ralph Hollis
- Carnegie Mellon University, Pittsburgh, Pennsylvania
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