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Human and Biomimetic Sensors
Published in Patrick F. Dunn, Fundamentals of Sensors for Engineering and Science, 2019
A stimulus can be characterized by its energy, location, intensity, and duration. Human sensory receptors respond to mechanical, chemical, thermal, and electromagnetic energy, as presented in Table 3.1. These are called mechanoreceptors, chemoreceptors, thermoreceptors, and photoreceptors, respectively. The stimuli of chemoreceptors are molecules that bind to the receptor site. Stimuli include oxygen, hydrogen (thus, pH), and more complex molecules. Mechanoreceptor stimuli are strain, vibration, acceleration, pressure, and sound. Light photons (electromagnetic energy) stimulate photoreceptors. Thermoreceptors are stimulated by temperature and changes in temperature. Each sensor description, its signal pathway, and sensor characteristics are presented in the following.
Chapter 3 Physics of the Senses
Published in B H Brown, R H Smallwood, D C Barber, P V Lawford, D R Hose, Medical Physics and Biomedical Engineering, 2017
Mechanoreceptors respond to the stimulus of a mechanical load. There are several ways in which we might describe the load (directly, or as a pressure or a stress), but fundamentally we are interested in describing the mechanical stimulus to the receptor. In general the load will be time dependent, and the detailed design and structure of the mechanoreceptor will provide an efficient response to some characteristic of the loading function. In particular some mechanoreceptors are designed to respond to the intensity of the load and some are designed to respond to the rate of change of load. The former are described as slowly adapting (SA) receptors and the latter as rapidly adapting (RA) receptors. In the limit an SA receptor simply responds to a static load. In principle we might hope that the rate of generation of impulses might be proportional to the intensity of the stimulus, or at least that it might be constant for a constant stimulus. In practice the response is distinctly non-linear, and furthermore there is a fatigue effect so that the rate is not constant even for constant stimulus. Models of stimulus intensity against response are discussed in more detail with respect to the special senses.
Haptic Interface
Published in Julie A. Jacko, The Human–Computer Interaction Handbook, 2012
A micropin array looks similar to an object-oriented-type force display, but it can only create the sensation of skin. The stroke distance of each pin is short, so the user cannot feel the 3D shape of a virtual object directly. The major role of a tactile display is to convey a sense of fine texture of an object’s surface. Latest research on tactile displays focuses on selective stimulation of mechanoreceptors of the skin. As mentioned in Section 9.2.1, there are four types of mechanoreceptors in the skin: (1) Merkel disks, (2) Ruffini capsules, (3) Meissner corpuscles, and (4) Pacinian corpuscles. By stimulating these receptors selectively, various tactile sensations such as roughness or slip can be presented. Micro-air jets (Asamura, Yokoyama, and Shinoda 1999) and microelectrode arrays (Kajimoto et al. 1999) are used for selective stimulation. Notes 9.3–9.5 describe four types of finger/hand haptics.
Morphological computation in haptic sensation and interaction: from nature to robotics
Published in Advanced Robotics, 2018
Julius E. Bernth, Van Anh Ho, Hongbin Liu
The star-nosed mole is a mostly blind animal that uses its ultra-sensitive snout to ‘see’ the surrounding environment and search for prey [53]. Each snout has 22 tentacles (or rays) that are sensitive to touch and can hunt or grab prey such as insects or worms. These tentacles, therefore, have similar functionality with manatees’ vibrissae. While manatees receive tactile stimuli indirectly via the movements of vibrissae, the star-nosed mole’s tentacles possess an ultra-high density of mechanoreceptors distributed under its skin which are directly stimulated by the environment. Authors in [54] have examined how these animals use their nose and found that the surface of each tentacle is covered in dome-like structures known as Eimer’s organs. The Eimer’s organs, illustrated in Figure 5, have a column of central free nerve endings (CF) starting just beneath the outer-most layer of skin. Distributed around this column are finer peripheral axons (PF). It also contains classical mechanoreceptors such as a Merkel cells (MC) and Pacinian corpuscles (PC). This organ’s structure results in high stimulation of nerves from external stimuli and creates a highly receptive and sensitive organ.
Perception of impact is affected by stimulus intensity
Published in Sports Biomechanics, 2021
Ana Paula Silva Azevedo, Katia Brandina, Juliana Pennone, Alberto Carlos Amadio, Júlio Cerca Serrão
On this, results also reveal that the human body is capable to perceive impact in tasks involving varied intensity stimuli, which is in accordance with other studies (Gaudino et al., 2015; Lake & Lafortune, 1998; Lieberman et al., 2010; Lovell et al., 2013; McCaw et al., 2000; Robbins & Gouw, 1991; Stiles & Dixon, 2007). The perception of external load is an important way to report the mechanical stress imposed to human body (Bastiaanse et al., 2000; Dietz & Duysens, 2000; Duysens et al., 2000). Mechanoreceptors placed in muscles, joints and skin deform according to mechanical stimulus. The nervous system is responsible for interpreting peripheral receptors, identifying intensity of the load applied to human body and respond to the stimuli, adjusting appropriately the segments and structures (Bastiaanse et al., 2000; Dietz & Duysens, 2000; Duysens et al., 2000). However, the nervous system has different functions, being composed by the perceptual and motor systems. Evidence suggests that perceptual thresholds are higher than those engaged in motor behaviour. In this way, it is important to consider that motor responses to sustained loads applied to the limb exhibit exquisite scaling with the load magnitude, even at very low levels of load, while the perceptual system may exhibit limitations in rating mechanical loads (Crevecoeur, Kurtzer, & Scott, 2012). Thus, higher and different intensities of load are believed to improve sensorimotor system and sensory feedback, leading to a better prediction of impact and adjustments in movement through both ways (motor and perceptual responses). As the movement tested in this study induced varied loads, an increased perception input and an improved control of external load may be achieved. Such assumptions could explain the results observed in this study.
Gaze Interaction With Vibrotactile Feedback: Review and Design Guidelines
Published in Human–Computer Interaction, 2020
Jussi Rantala, Päivi Majaranta, Jari Kangas, Poika Isokoski, Deepak Akkil, Oleg Špakov, Roope Raisamo
Tactile stimulation is sensed via mechanoreceptors in the skin. The four main types of mechanoreceptors—Merkel receptors, Meissner corpuscles, Pacinian corpuscles, and Ruffini endings—each respond to different touch stimuli (Gardner, Martin, & Jessell, 2000) that can vary between pressure, taps, skin stretch, and vibration (Goldstein, 1999). Efficient use of these stimuli for communicating information requires knowledge of touch perception across different body parts.