1
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On the intrinsic curvature of animal whiskers. PLoS One 2023; 18:e0269210. [PMID: 36607960 PMCID: PMC9821693 DOI: 10.1371/journal.pone.0269210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Accepted: 12/05/2022] [Indexed: 01/07/2023] Open
Abstract
Facial vibrissae (whiskers) are thin, tapered, flexible, hair-like structures that are an important source of tactile sensory information for many species of mammals. In contrast to insect antennae, whiskers have no sensors along their lengths. Instead, when a whisker touches an object, the resulting deformation is transmitted to mechanoreceptors in a follicle at the whisker base. Previous work has shown that the mechanical signals transmitted along the whisker will depend strongly on the whisker's geometric parameters, specifically on its taper (how diameter varies with arc length) and on the way in which the whisker curves, often called "intrinsic curvature." Although previous studies have largely agreed on how to define taper, multiple methods have been used to quantify intrinsic curvature. The present work compares and contrasts different mathematical approaches towards quantifying this important parameter. We begin by reviewing and clarifying the definition of "intrinsic curvature," and then show results of fitting whisker shapes with several different functions, including polynomial, fractional exponent, elliptical, and Cesàro. Comparisons are performed across ten species of whiskered animals, ranging from rodents to pinnipeds. We conclude with a discussion of the advantages and disadvantages of using the various models for different modeling situations. The fractional exponent model offers an approach towards developing a species-specific parameter to characterize whisker shapes within a species. Constructing models of how the whisker curves is important for the creation of mechanical models of tactile sensory acquisition behaviors, for studies of comparative evolution, morphology, and anatomy, and for designing artificial systems that can begin to emulate the whisker-based tactile sensing of animals.
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2
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Demonstration of three-dimensional contact point determination and contour reconstruction during active whisking behavior of an awake rat. PLoS Comput Biol 2022; 18:e1007763. [PMID: 36108064 PMCID: PMC9477318 DOI: 10.1371/journal.pcbi.1007763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Accepted: 05/06/2022] [Indexed: 11/19/2022] Open
Abstract
The rodent vibrissal (whisker) system has been studied for decades as a model of active touch sensing. There are no sensors along the length of a whisker; all sensing occurs at the whisker base. Therefore, a large open question in many neuroscience studies is how an animal could estimate the three-dimensional (3D) location at which a whisker makes contact with an object. In the present work we simulated the shape of a real rat whisker to demonstrate the existence of several unique mappings from triplets of mechanical signals at the whisker base to the three-dimensional whisker-object contact point. We then used high speed video to record whisker deflections as an awake rat whisked against a peg, and used the mechanics resulting from those deflections to extract the contact points along the peg surface. These results demonstrate that measurement of specific mechanical triplets at the base of a biological whisker can enable 3D contact point determination during natural whisking behavior. The approach is viable even though the biological whisker has non-ideal, non-planar curvature, and even given the rat’s real-world choices of whisking parameters. Visual intuition for the quality of the approach is provided in a video that shows the contour of the peg gradually emerging during active whisking behavior.
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3
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Starostin EL, Goss VGA, van der Heijden GHM. Whisker Sensing by Force and Moment Measurements at the Whisker Base. Soft Robot 2022; 10:326-335. [PMID: 35994004 DOI: 10.1089/soro.2021.0085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We address the theoretical question which forces and moments measured at the base of a whisker (tactile sensor) allow for the prediction of the location in space of the point at which a whisker makes contact with an object. We deal with the general case of three-dimensional deformations as well as with the special case of planar configurations. All deformations are treated as quasi-static, and contact is assumed to be frictionless. We show that the minimum number of independent forces or moments required is three but that conserved quantities of the governing elastic equilibrium equations prevent certain triples from giving a unique solution in the case of contact at any point along the whisker except the tip. The existence of these conserved quantities depends on the material and geometrical properties of the whisker. For whiskers that are tapered and intrinsically curved, there is no obstruction to the prediction of the contact point. We show that the choice of coordinate system (Cartesian or cylindrical) affects the number of suitable triples. Tip and multiple point contact are also briefly discussed. Our results explain recent numerical observations in the literature and offer guidance for the design of robotic tactile sensory devices.
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Affiliation(s)
- E L Starostin
- School of Engineering, London South Bank University, London, United Kingdom.,Department of Civil, Environmental and Geomatic Engineering, University College London, London, United Kingdom
| | - V G A Goss
- School of Engineering, London South Bank University, London, United Kingdom
| | - G H M van der Heijden
- Department of Civil, Environmental and Geomatic Engineering, University College London, London, United Kingdom
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4
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Sayegh MA, Daraghma H, Mekid S, Bashmal S. Review of Recent Bio-Inspired Design and Manufacturing of Whisker Tactile Sensors. SENSORS (BASEL, SWITZERLAND) 2022; 22:2705. [PMID: 35408319 PMCID: PMC9003453 DOI: 10.3390/s22072705] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 03/19/2022] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
Whisker sensors are a class of tactile sensors that have recently attracted attention. Inspired by mammals' whiskers known as mystacial vibrissae, they have displayed tremendous potential in a variety of applications e.g., robotics, underwater vehicles, minimally invasive surgeries, and leak detection. This paper provides a supplement to the recent tactile sensing techniques' designs of whiskers that only sense at their base, as well as the materials employed, and manufacturing techniques. The article delves into the technical specifications of these sensors, such as the resolution, measurement range, sensitivity, durability, and recovery time, which determine their performance. The sensors' sensitivity varies depending on the measured physical quantity; for example, the pressure sensors had an intermediate sensitivity of 58%/Pa and a response time of around 90 ms, whereas the force sensors that function based on piezoelectric effects exhibited good linearity in the measurements with a resolution of 3 µN and sensitivity of 0.1682 mV/µN. Some sensors were used to perform spatial mapping and the identification of the geometry and roughness of objects with a reported resolution of 25 nm. The durability and recovery time showed a wide range of values, with the maximum durability being 10,000 cycles and the shortest recovery time being 5 ms. Furthermore, the paper examines the fabrication of whiskers at the micro- and nanoscales, as well as their contributions to mechanical and thermal behavior. The commonly used manufacturing techniques of 3D printing, PDMS casting, and screen printing were used in addition to several micro and nanofabrication techniques such as photolithography, etching, and chemical vapor deposition. Lastly, the paper discusses the main potential applications of these sensors and potential research gaps in this field. In particular, the operation of whisker sensors under high temperatures or high pressure requires further investigation, as does the design of sensors to explore larger topologies.
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Affiliation(s)
- Mohamad-Ammar Sayegh
- Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia; (M.-A.S.); (H.D.); (S.B.)
| | - Hammam Daraghma
- Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia; (M.-A.S.); (H.D.); (S.B.)
| | - Samir Mekid
- Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia; (M.-A.S.); (H.D.); (S.B.)
- Interdisciplinary Research Center for Intelligent Manufacturing and Robotics, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
| | - Salem Bashmal
- Department of Mechanical Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia; (M.-A.S.); (H.D.); (S.B.)
- Interdisciplinary Research Center for Intelligent Manufacturing and Robotics, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia
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5
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Zheng X, Kamat AM, Cao M, Kottapalli AGP. Creating underwater vision through wavy whiskers: a review of the flow-sensing mechanisms and biomimetic potential of seal whiskers. J R Soc Interface 2021; 18:20210629. [PMID: 34699729 DOI: 10.1098/rsif.2021.0629] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Seals are known to use their highly sensitive whiskers to precisely follow the hydrodynamic trail left behind by prey. Studies estimate that a seal can track a herring that is swimming as far as 180 m away, indicating an incredible detection apparatus on a par with the echolocation system of dolphins and porpoises. This remarkable sensing capability is enabled by the unique undulating structural morphology of the whisker that suppresses vortex-induced vibrations (VIVs) and thus increases the signal-to-noise ratio of the flow-sensing whiskers. In other words, the whiskers vibrate minimally owing to the seal's swimming motion, eliminating most of the self-induced noise and making them ultrasensitive to the vortices in the wake of escaping prey. Because of this impressive ability, the seal whisker has attracted much attention in the scientific community, encompassing multiple fields of sensory biology, fluid mechanics, biomimetic flow sensing and soft robotics. This article presents a comprehensive review of the seal whisker literature, covering the behavioural experiments on real seals, VIV suppression capabilities enabled by the undulating geometry, wake vortex-sensing mechanisms, morphology and material properties and finally engineering applications inspired by the shape and functionality of seal whiskers. Promising directions for future research are proposed.
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Affiliation(s)
- Xingwen Zheng
- Engineering and Technology Institute Groningen, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Amar M Kamat
- Engineering and Technology Institute Groningen, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Ming Cao
- Engineering and Technology Institute Groningen, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands
| | - Ajay Giri Prakash Kottapalli
- Engineering and Technology Institute Groningen, Faculty of Science and Engineering, University of Groningen, Nijenborgh 4, 9747AG Groningen, The Netherlands.,MIT Sea Grant College Program, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, USA
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6
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Boublil BL, Diebold CA, Moss CF. Mechanosensory Hairs and Hair-like Structures in the Animal Kingdom: Specializations and Shared Functions Serve to Inspire Technology Applications. SENSORS (BASEL, SWITZERLAND) 2021; 21:6375. [PMID: 34640694 PMCID: PMC8512044 DOI: 10.3390/s21196375] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/20/2021] [Accepted: 09/21/2021] [Indexed: 11/17/2022]
Abstract
Biological mechanosensation has been a source of inspiration for advancements in artificial sensory systems. Animals rely on sensory feedback to guide and adapt their behaviors and are equipped with a wide variety of sensors that carry stimulus information from the environment. Hair and hair-like sensors have evolved to support survival behaviors in different ecological niches. Here, we review the diversity of biological hair and hair-like sensors across the animal kingdom and their roles in behaviors, such as locomotion, exploration, navigation, and feeding, which point to shared functional properties of hair and hair-like structures among invertebrates and vertebrates. By reviewing research on the role of biological hair and hair-like sensors in diverse species, we aim to highlight biological sensors that could inspire the engineering community and contribute to the advancement of mechanosensing in artificial systems, such as robotics.
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Affiliation(s)
| | | | - Cynthia F. Moss
- Department of Psychological and Brain Sciences, Johns Hopkins University, 3400 N Charles St., Baltimore, MD 21218, USA; (B.L.B.); (C.A.D.)
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7
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Bush NE, Solla SA, Hartmann MJZ. Continuous, multidimensional coding of 3D complex tactile stimuli by primary sensory neurons of the vibrissal system. Proc Natl Acad Sci U S A 2021; 118:e2020194118. [PMID: 34353902 PMCID: PMC8364131 DOI: 10.1073/pnas.2020194118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Across all sensory modalities, first-stage sensory neurons are an information bottleneck: they must convey all information available for an animal to perceive and act in its environment. Our understanding of coding properties of primary sensory neurons in the auditory and visual systems has been aided by the use of increasingly complex, naturalistic stimulus sets. By comparison, encoding properties of primary somatosensory afferents are poorly understood. Here, we use the rodent whisker system to examine how tactile information is represented in primary sensory neurons of the trigeminal ganglion (Vg). Vg neurons have long been thought to segregate into functional classes associated with separate streams of information processing. However, this view is based on Vg responses to restricted stimulus sets which potentially underreport the coding capabilities of these neurons. In contrast, the current study records Vg responses to complex three-dimensional (3D) stimulation while quantifying the complete 3D whisker shape and mechanics, thereby beginning to reveal their full representational capabilities. The results show that individual Vg neurons simultaneously represent multiple mechanical features of a stimulus, do not preferentially encode principal components of the stimuli, and represent continuous and tiled variations of all available mechanical information. These results directly contrast with proposed codes in which subpopulations of Vg neurons encode select stimulus features. Instead, individual Vg neurons likely overcome the information bottleneck by encoding large regions of a complex sensory space. This proposed tiled and multidimensional representation at the Vg directly constrains the computations performed by more central neurons of the vibrissotrigeminal pathway.
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Affiliation(s)
- Nicholas E Bush
- Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL 60208
| | - Sara A Solla
- Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208
- Department of Physiology, Northwestern University, Chicago, IL 60611
| | - Mitra J Z Hartmann
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208;
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208
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8
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Huang S, Wu H. Texture Recognition Based on Perception Data from a Bionic Tactile Sensor. SENSORS 2021; 21:s21155224. [PMID: 34372461 PMCID: PMC8347799 DOI: 10.3390/s21155224] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 11/16/2022]
Abstract
Texture recognition is important for robots to discern the characteristics of the object surface and adjust grasping and manipulation strategies accordingly. It is still challenging to develop texture classification approaches that are accurate and do not require high computational costs. In this work, we adopt a bionic tactile sensor to collect vibration data while sliding against materials of interest. Under a fixed contact pressure and speed, a total of 1000 sets of vibration data from ten different materials were collected. With the tactile perception data, four types of texture recognition algorithms are proposed. Three machine learning algorithms, including support vector machine, random forest, and K-nearest neighbor, are established for texture recognition. The test accuracy of those three methods are 95%, 94%, 94%, respectively. In the detection process of machine learning algorithms, the asamoto and polyester are easy to be confused with each other. A convolutional neural network is established to further increase the test accuracy to 98.5%. The three machine learning models and convolutional neural network demonstrate high accuracy and excellent robustness.
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9
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Design of a Sensitive Balloon Sensor for Safe Human-Robot Interaction. SENSORS 2021; 21:s21062163. [PMID: 33808860 PMCID: PMC8003634 DOI: 10.3390/s21062163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 03/16/2021] [Accepted: 03/17/2021] [Indexed: 11/16/2022]
Abstract
As the safety of a human body is the main priority while interacting with robots, the field of tactile sensors has expanded for acquiring tactile information and ensuring safe human-robot interaction (HRI). Existing lightweight and thin tactile sensors exhibit high performance in detecting their surroundings. However, unexpected collisions caused by malfunctions or sudden external collisions can still cause injuries to rigid robots with thin tactile sensors. In this study, we present a sensitive balloon sensor for contact sensing and alleviating physical collisions over a large area of rigid robots. The balloon sensor is a pressure sensor composed of an inflatable body of low-density polyethylene (LDPE), and a highly sensitive and flexible strain sensor laminated onto it. The mechanical crack-based strain sensor with high sensitivity enables the detection of extremely small changes in the strain of the balloon. Adjusting the geometric parameters of the balloon allows for a large and easily customizable sensing area. The weight of the balloon sensor was approximately 2 g. The sensor is employed with a servo motor and detects a finger or a sheet of rolled paper gently touching it, without being damaged.
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10
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Mérida-Calvo L, Feliu-Talegón D, Feliu-Batlle V. Improving the Detection of the Contact Point in Active Sensing Antennae by Processing Combined Static and Dynamic Information. SENSORS 2021; 21:s21051808. [PMID: 33807706 PMCID: PMC7962043 DOI: 10.3390/s21051808] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 02/25/2021] [Accepted: 02/27/2021] [Indexed: 11/23/2022]
Abstract
The design and application of sensing antenna devices that mimic insect antennae or mammal whiskers is an active field of research. However, these devices still require new developments if they are to become efficient and reliable components of robotic systems. We, therefore, develop and build a prototype composed of a flexible beam, two servomotors that drive the beam and a load cell sensor that measures the forces and torques at the base of the flexible beam. This work reports new results in the area of the signal processing of these devices. These results will make it possible to estimate the point at which the flexible antenna comes into contact with an object (or obstacle) more accurately than has occurred with previous algorithms. Previous research reported that the estimation of the fundamental natural frequency of vibration of the antenna using dynamic information is not sufficient as regards determining the contact point and that the estimation of the contact point using static information provided by the forces and torques measured by the load cell sensor is not very accurate. We consequently propose an algorithm based on the fusion of the information provided by the two aforementioned strategies that enhances the separate benefits of each one. We demonstrate that the adequate combination of these two pieces of information yields an accurate estimation of the contacted point of the antenna link. This will enhance the precision of the estimation of points on the surface of the object that is being recognized by the antenna. Thorough experimentation is carried out in order to show the features of the proposed algorithm and establish its range of application.
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Affiliation(s)
- Luis Mérida-Calvo
- Instituto de Investigaciones Energéticas y Aplicaciones Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain;
| | - Daniel Feliu-Talegón
- Robotics, Vision and Control Group, Universidad de Sevilla, 41092 Sevilla, Spain;
| | - Vicente Feliu-Batlle
- Escuela Técnica Superior de Ingeniería Industrial de Ciudad Real, Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain
- Correspondence: ; Tel.: +34-926-295-364
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11
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Palermo F, Konstantinova J, Althoefer K, Poslad S, Farkhatdinov I. Automatic Fracture Characterization Using Tactile and Proximity Optical Sensing. Front Robot AI 2021; 7:513004. [PMID: 33501300 PMCID: PMC7805870 DOI: 10.3389/frobt.2020.513004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 10/19/2020] [Indexed: 12/01/2022] Open
Abstract
This paper demonstrates how tactile and proximity sensing can be used to perform automatic mechanical fractures detection (surface cracks). For this purpose, a custom-designed integrated tactile and proximity sensor has been implemented. With the help of fiber optics, the sensor measures the deformation of its body, when interacting with the physical environment, and the distance to the environment's objects. This sensor slides across different surfaces and records data which are then analyzed to detect and classify fractures and other mechanical features. The proposed method implements machine learning techniques (handcrafted features, and state of the art classification algorithms). An average crack detection accuracy of ~94% and width classification accuracy of ~80% is achieved. Kruskal-Wallis results (p < 0.001) indicate statistically significant differences among results obtained when analysing only integrated deformation measurements, only proximity measurements and both deformation and proximity data. A real-time classification method has been implemented for online classification of explored surfaces. In contrast to previous techniques, which mainly rely on visual modality, the proposed approach based on optical fibers might be more suitable for operation in extreme environments (such as nuclear facilities) where radiation may damage electronic components of commonly employed sensing devices, such as standard force sensors based on strain gauges and video cameras.
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Affiliation(s)
- Francesca Palermo
- School of Electronic Engineering and Computer Science, Queen Mary University of London, London, United Kingdom
| | - Jelizaveta Konstantinova
- School of Electronic Engineering and Computer Science, Queen Mary University of London, London, United Kingdom.,Robotics Research, Ocado Technology, London, United Kingdom
| | - Kaspar Althoefer
- School of Electronic Engineering and Computer Science, Queen Mary University of London, London, United Kingdom.,The Alan Turing Institute, Programme - Artificial Intelligence, London, United Kingdom
| | - Stefan Poslad
- School of Electronic Engineering and Computer Science, Queen Mary University of London, London, United Kingdom
| | - Ildar Farkhatdinov
- School of Electronic Engineering and Computer Science, Queen Mary University of London, London, United Kingdom.,The Alan Turing Institute, Programme - Artificial Intelligence, London, United Kingdom.,Department of Bioengineering, Imperial College of Science, Technology and Medicine, London, United Kingdom
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12
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Dougill G, Starostin EL, Milne AO, Heijden GHM, Goss VGA, Grant RA. Ecomorphology reveals Euler spiral of mammalian whiskers. J Morphol 2020; 281:1271-1279. [DOI: 10.1002/jmor.21246] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 06/17/2020] [Accepted: 07/18/2020] [Indexed: 11/10/2022]
Affiliation(s)
- Gary Dougill
- Department of Natural Sciences Manchester Metropolitan University Manchester UK
| | - Eugene L. Starostin
- School of Engineering, London South Bank University London UK
- Department of Civil, Environmental and Geomatic Engineering University College London London UK
| | - Alyx O. Milne
- Department of Natural Sciences Manchester Metropolitan University Manchester UK
| | - Gert H. M. Heijden
- Department of Civil, Environmental and Geomatic Engineering University College London London UK
| | | | - Robyn A. Grant
- Department of Natural Sciences Manchester Metropolitan University Manchester UK
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13
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Collinson DW, Emnett HM, Ning J, Hartmann MJZ, Brinson LC. Tapered Polymer Whiskers to Enable Three-Dimensional Tactile Feature Extraction. Soft Robot 2020; 8:44-58. [PMID: 32513071 DOI: 10.1089/soro.2019.0055] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Many mammals use their vibrissae (whiskers) to tactually explore their surrounding environment. Vibrissae are thin tapered structures that transmit mechanical signals to a wealth of mechanical receptors (sensors) located in a follicle at each vibrissal base. A recent study has shown that-provided that the whisker is tapered-three mechanical signals at the base are sufficient to determine the three-dimensional location at which a whisker made contact with an object. However, creating biomimetic tapered whiskers has proved challenging from both materials and manufacturing standpoints. This study develops and characterizes an artificial whisker for use as part of a sensory input device that is a biomimic of the biological rat whisker neurosensory system. A novel manufacturing process termed surface conforming fiber drawing (SCFD) is developed to produce artificial whiskers that meet the requirements to be a successful mechanical and geometric mimic of the biological rat vibrissae. Testing the sensory capabilities of the artificial whisker shows improved performance over previous nontapered filaments. SCFD-manufactured tapered whiskers demonstrate the ability to predict contact point locations with a median distance error of 0.47 cm.
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Affiliation(s)
- David W Collinson
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Hannah M Emnett
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Jinqiang Ning
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Mitra J Z Hartmann
- Department of Mechanical Engineering, Northwestern University, Evanston, Illinois, USA.,Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA
| | - Lynda Catherine Brinson
- Department of Mechanical Engineering and Materials Science, Duke University, Durham, North Carolina, USA
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14
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Effects of Multi-Point Contacts during Object Contour Scanning Using a Biologically-Inspired Tactile Sensor. SENSORS 2020; 20:s20072077. [PMID: 32272766 PMCID: PMC7180713 DOI: 10.3390/s20072077] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/03/2020] [Accepted: 04/04/2020] [Indexed: 11/17/2022]
Abstract
Vibrissae are an important tactile sense organ of many mammals, in particular rodents like rats and mice. For instance, these animals use them in order to detect different object features, e.g., object-distances and -shapes. In engineering, vibrissae have long been established as a natural paragon for developing tactile sensors. So far, having object shape scanning and reconstruction in mind, almost all mechanical vibrissa models are restricted to contact scenarios with a single discrete contact force. Here, we deal with the effect of multi-point contacts in a specific scanning scenario, where an artificial vibrissa is swept along partly concave object contours. The vibrissa is modeled as a cylindrical, one-sided clamped Euler-Bernoulli bending rod undergoing large deflections. The elasticae and the support reactions during scanning are theoretically calculated and measured in experiments, using a spring steel wire, attached to a force/torque-sensor. The experiments validate the simulation results and show that the assumption of a quasi-static scanning displacement is a satisfying approach. Beyond single- and two-point contacts, a distinction is made between tip and tangential contacts. It is shown that, in theory, these contact phases can be identified solely based on the support reactions, what is new in literature. In this way, multipoint contacts are reliably detected and filtered in order to discard incorrectly reconstructed contact points.
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15
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Furuta T, Bush NE, Yang AET, Ebara S, Miyazaki N, Murata K, Hirai D, Shibata KI, Hartmann MJZ. The Cellular and Mechanical Basis for Response Characteristics of Identified Primary Afferents in the Rat Vibrissal System. Curr Biol 2020; 30:815-826.e5. [PMID: 32004452 PMCID: PMC10623402 DOI: 10.1016/j.cub.2019.12.068] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 07/09/2019] [Accepted: 12/20/2019] [Indexed: 01/06/2023]
Abstract
Compared to our understanding of the response properties of receptors in the auditory and visual systems, we have only a limited understanding of the mechanoreceptor responses that underlie tactile sensation. Here, we exploit the stereotyped morphology of the rat vibrissal (whisker) array to investigate coding and transduction properties of identified primary tactile afferents. We performed in vivo intra-axonal recording and labeling experiments to quantify response characteristics of four different types of identified mechanoreceptors in the vibrissal follicle: ring-sinus Merkel; lanceolate; clublike; and rete-ridge collar Merkel. Of these types, only ring-sinus Merkel endings exhibited slowly adapting properties. A weak inverse relationship between response magnitude and onset response latency was found across all types. All afferents exhibited strong "angular tuning," i.e., their response magnitude and latency depended on the whisker's deflection angle. Although previous studies suggested that this tuning should be aligned with the angular location of the mechanoreceptor in the follicle, such alignment was observed only for Merkel afferents; angular tuning of the other afferent types showed no clear alignment with mechanoreceptor location. Biomechanical modeling suggested that this tuning difference might be explained by mechanoreceptors' differential sensitivity to the force directed along the whisker length. Electron microscopic investigations of Merkel endings and lanceolate endings at the level of the ring sinus revealed unique anatomical features that may promote these differential sensitivities. The present study systematically integrates biomechanical principles with the anatomical and morphological characterization of primary afferent endings to describe the physical and cellular processing that shapes the neural representation of touch.
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Affiliation(s)
- Takahiro Furuta
- Department of Oral Anatomy and Neurobiology, Graduate School of Dentistry, Osaka University, 1-8 Yamada-Oka, Suita, Osaka 565-0871, Japan; Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Yoshida Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan.
| | - Nicholas E Bush
- Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL 60208, USA
| | - Anne En-Tzu Yang
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Satomi Ebara
- Department of Anatomy, Meiji University of Integrative Medicine, Kyoto 629-0392, Japan
| | - Naoyuki Miyazaki
- National Institute for Physiological Sciences, 38 Nishigonaka Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Kazuyoshi Murata
- National Institute for Physiological Sciences, 38 Nishigonaka Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Daichi Hirai
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Yoshida Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Ken-Ichi Shibata
- Department of Morphological Brain Science, Graduate School of Medicine, Kyoto University, Yoshida Konoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Mitra J Z Hartmann
- Department of Mechanical Engineering, Northwestern University, Evanston, IL 60208, USA; Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA.
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16
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Sim M, Lee KH, Shin KS, Shin JH, Choi JW, Choi H, Moon C, Kim HS, Cho Y, Cha SN, Jung JE, Sohn JI, Jang JE. Electronic Skin to Feel "Pain": Detecting "Prick" and "Hot" Pain Sensations. Soft Robot 2019; 6:745-759. [PMID: 31335257 DOI: 10.1089/soro.2018.0049] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
An artificial tactile system has attracted tremendous interest and intensive study, since it can be applied as a new functional interface between humans and electronic devices. Unfortunately, most previous works focused on improving the sensitivity of sensors. However, humans also respond to psychological feelings for sensations such as pain, softness, or roughness, which are important factors for interacting with others and objects. Here, we present an electronic skin concept that generates a "pain" warning signal, specifically, to sharp "prick" and "hot" sensations. To simplify the sensor structure for these two feelings, a single-body tactile sensor design is proposed. By exploiting "hot" feeling based on the Seebeck effect instead of the pyroelectric property, it is possible to distinguish points registering a "hot" feeling from those generating a "prick" feeling, which is based on the piezoelectric effect. The control of free carrier concentration in nanowire induced the appropriate level of Seebeck current, which enabled the sensor system to be more reliable. The first derivatives of the piezo and Seebeck output signals are the key factors for the signal processing of the "pain" feeling. The main idea can be applied to mimic other psychological tactile feelings.
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Affiliation(s)
- Minkyung Sim
- Department of Information and Communication Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Kyung Hwa Lee
- IMEP-LAHC, Grenoble Institute of Technology(Minatec), Grenoble, France
| | - Kwon Sik Shin
- Department of Information and Communication Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Jeong Hee Shin
- Department of Information and Communication Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Ji-Woong Choi
- Department of Information and Communication Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Hongsoo Choi
- Department of Robotics Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Cheil Moon
- Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
| | - Hyun Sik Kim
- Department of Applied Physics and Material Science, California Institute of Technology, Pasadena, California
| | - Yuljae Cho
- Department of Electrical Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Seung Nam Cha
- Department of Electrical Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Jae Eun Jung
- Department of Chemical Engineering and Material Science, Hongik University, Seoul, Korea
| | - Jung Inn Sohn
- Department of Electrical Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Jae Eun Jang
- Department of Information and Communication Engineering, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu, Korea
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17
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Prediction of Choice from Competing Mechanosensory and Choice-Memory Cues during Active Tactile Decision Making. J Neurosci 2019; 39:3921-3933. [PMID: 30850514 PMCID: PMC6520515 DOI: 10.1523/jneurosci.2217-18.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 01/11/2019] [Accepted: 01/16/2019] [Indexed: 01/15/2023] Open
Abstract
Perceptual decision making is an active process where animals move their sense organs to extract task-relevant information. To investigate how the brain translates sensory input into decisions during active sensation, we developed a mouse active touch task where the mechanosensory input can be precisely measured and that challenges animals to use multiple mechanosensory cues. Male mice were trained to localize a pole using a single whisker and to report their decision by selecting one of three choices. Using high-speed imaging and machine vision, we estimated whisker-object mechanical forces at millisecond resolution. Mice solved the task by a sensory-motor strategy where both the strength and direction of whisker bending were informative cues to pole location. We found competing influences of immediate sensory input and choice memory on mouse choice. On correct trials, choice could be predicted from the direction and strength of whisker bending, but not from previous choice. In contrast, on error trials, choice could be predicted from previous choice but not from whisker bending. This study shows that animal choices during active tactile decision making can be predicted from mechanosensory and choice-memory signals, and provides a new task well suited for the future study of the neural basis of active perceptual decisions.SIGNIFICANCE STATEMENT Due to the difficulty of measuring the sensory input to moving sense organs, active perceptual decision making remains poorly understood. The whisker system provides a way forward since it is now possible to measure the mechanical forces due to whisker-object contact during behavior. Here we train mice in a novel behavioral task that challenges them to use rich mechanosensory cues but can be performed using one whisker and enables task-relevant mechanical forces to be precisely estimated. This approach enables rigorous study of how sensory cues translate into action during active, perceptual decision making. Our findings provide new insight into active touch and how sensory/internal signals interact to determine behavioral choices.
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18
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Astreinidi Blandin A, Bernardeschi I, Beccai L. Biomechanics in Soft Mechanical Sensing: From Natural Case Studies to the Artificial World. Biomimetics (Basel) 2018; 3:E32. [PMID: 31105254 PMCID: PMC6352697 DOI: 10.3390/biomimetics3040032] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 09/14/2018] [Accepted: 10/12/2018] [Indexed: 12/25/2022] Open
Abstract
Living beings use mechanical interaction with the environment to gather essential cues for implementing necessary movements and actions. This process is mediated by biomechanics, primarily of the sensory structures, meaning that, at first, mechanical stimuli are morphologically computed. In the present paper, we select and review cases of specialized sensory organs for mechanical sensing-from both the animal and plant kingdoms-that distribute their intelligence in both structure and materials. A focus is set on biomechanical aspects, such as morphology and material characteristics of the selected sensory organs, and on how their sensing function is affected by them in natural environments. In this route, examples of artificial sensors that implement these principles are provided, and/or ways in which they can be translated artificially are suggested. Following a biomimetic approach, our aim is to make a step towards creating a toolbox with general tailoring principles, based on mechanical aspects tuned repeatedly in nature, such as orientation, shape, distribution, materials, and micromechanics. These should be used for a future methodical design of novel soft sensing systems for soft robotics.
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Affiliation(s)
- Afroditi Astreinidi Blandin
- Center for Micro-BioRobotics, Istituto Italiano di Tecnologia, Pontedera, 56025 Pisa, Italy.
- The BioRobotics Institute, Scuola Superiore Sant'Anna, Pontedera, 56025 Pisa, Italy.
| | - Irene Bernardeschi
- Center for Micro-BioRobotics, Istituto Italiano di Tecnologia, Pontedera, 56025 Pisa, Italy.
| | - Lucia Beccai
- Center for Micro-BioRobotics, Istituto Italiano di Tecnologia, Pontedera, 56025 Pisa, Italy.
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19
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Seale M, Cummins C, Viola IM, Mastropaolo E, Nakayama N. Design principles of hair-like structures as biological machines. J R Soc Interface 2018; 15:20180206. [PMID: 29848593 PMCID: PMC6000178 DOI: 10.1098/rsif.2018.0206] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/08/2018] [Indexed: 12/02/2022] Open
Abstract
Hair-like structures are prevalent throughout biology and frequently act to sense or alter interactions with an organism's environment. The overall shape of a hair is simple: a long, filamentous object that protrudes from the surface of an organism. This basic design, however, can confer a wide range of functions, owing largely to the flexibility and large surface area that it usually possesses. From this simple structural basis, small changes in geometry, such as diameter, curvature and inter-hair spacing, can have considerable effects on mechanical properties, allowing functions such as mechanosensing, attachment, movement and protection. Here, we explore how passive features of hair-like structures, both individually and within arrays, enable diverse functions across biology. Understanding the relationships between form and function can provide biologists with an appreciation for the constraints and possibilities on hair-like structures. Additionally, such structures have already been used in biomimetic engineering with applications in sensing, water capture and adhesion. By examining hairs as a functional mechanical unit, geometry and arrangement can be rationally designed to generate new engineering devices and ideas.
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Affiliation(s)
- Madeleine Seale
- School of Biological Sciences, Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, UK
- School of Engineering, Institute for Integrated Micro and Nano Systems, University of Edinburgh, Edinburgh, UK
- SynthSys Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, UK
| | - Cathal Cummins
- School of Biological Sciences, Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, UK
- SynthSys Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, UK
- School of Engineering, Institute for Energy Systems, University of Edinburgh, Edinburgh, UK
| | - Ignazio Maria Viola
- School of Engineering, Institute for Energy Systems, University of Edinburgh, Edinburgh, UK
| | - Enrico Mastropaolo
- School of Engineering, Institute for Integrated Micro and Nano Systems, University of Edinburgh, Edinburgh, UK
| | - Naomi Nakayama
- School of Biological Sciences, Institute of Molecular Plant Sciences, University of Edinburgh, Edinburgh, UK
- SynthSys Centre for Synthetic and Systems Biology, University of Edinburgh, Edinburgh, UK
- Centre for Science at Extreme Conditions, University of Edinburgh, Edinburgh, UK
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