Tactile Sensors: Template‐Directed Growth of Hierarchical MOF Hybrid Arrays for Tactile Sensor (Adv. Funct. Mater. 38/2020)

Just as the sense of touch complements vision in various species, several robots could benefit from advanced tactile sensors, in particular when operating under poor visibility. A prominent tactile sense organ, frequently serving as a natural paragon for developing tactile sensors, is the vibrissae of, e.g., rats. Within this study, we present a vibrissa-inspired sensor concept for 3D object scanning and reconstruction to be exemplarily used in mobile robots. The setup consists of a highly flexible rod attached to a 3D force-torque transducer (measuring device). The scanning process is realized by translationally shifting the base of the rod relative to the object. Consequently, the rod sweeps over the object’s surface, undergoing large bending deflections. Then, the support reactions at the base of the rod are evaluated for contact localization. Presenting a method of theoretically generating these support reactions, we provide an important basis for future parameter studies. During scanning, lateral slip of the rod is not actively prevented, in contrast to literature. In this way, we demonstrate the suitability of the sensor for passively dragging it on a mobile robot. Experimental scanning sweeps using an artificial vibrissa (steel wire) of length 50 mm and a glass sphere as a test object with a diameter of 60 mm verify the theoretical results and serve as a proof of concept.

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Soft magnetic skin for super-resolution tactile sensing with force self-decoupling

Science Robotics ◽

10.1126/scirobotics.abc8801 ◽

2021 ◽

Vol 6 (51) ◽

pp. eabc8801

Author(s):

Youcan Yan ◽

Zhe Hu ◽

Zhengbao Yang ◽

Wenzhen Yuan ◽

Chaoyang Song ◽

...

Keyword(s):

External Disturbance ◽

Super Resolution ◽

Tactile Sensor ◽

Human Robot Interaction ◽

Tactile Sensors ◽

Dexterous Manipulation ◽

Robot Interaction ◽

Flexible Film ◽

Challenging Tasks ◽

External Forces

Human skin can sense subtle changes of both normal and shear forces (i.e., self-decoupled) and perceive stimuli with finer resolution than the average spacing between mechanoreceptors (i.e., super-resolved). By contrast, existing tactile sensors for robotic applications are inferior, lacking accurate force decoupling and proper spatial resolution at the same time. Here, we present a soft tactile sensor with self-decoupling and super-resolution abilities by designing a sinusoidally magnetized flexible film (with the thickness ~0.5 millimeters), whose deformation can be detected by a Hall sensor according to the change of magnetic flux densities under external forces. The sensor can accurately measure the normal force and the shear force (demonstrated in one dimension) with a single unit and achieve a 60-fold super-resolved accuracy enhanced by deep learning. By mounting our sensor at the fingertip of a robotic gripper, we show that robots can accomplish challenging tasks such as stably grasping fragile objects under external disturbance and threading a needle via teleoperation. This research provides new insight into tactile sensor design and could be beneficial to various applications in robotics field, such as adaptive grasping, dexterous manipulation, and human-robot interaction.

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STAND-UP MOTION SUPPORT BY A MOBILE MANIPULATOR SYSTEM WITH HIGH SPEED TACTILE SENSORS

International Journal of Information Acquisition ◽

10.1142/s0219878911002458 ◽

2011 ◽

Vol 08 (03) ◽

pp. 181-195

Author(s):

ZHAOXIAN XIE ◽

HISASHI YAMAGUCHI ◽

MASAHITO TSUKANO ◽

AIGUO MING ◽

MAKOTO SHIMOJO

Keyword(s):

Fuzzy Logic ◽

Feedback Control ◽

Experimental Verification ◽

High Speed ◽

Center Of Pressure ◽

Tactile Sensor ◽

Mobile Manipulator ◽

Tactile Sensing ◽

Robot Arm ◽

Tactile Sensors

As one of the home services by a mobile manipulator system, we are aiming at the realization of the stand-up motion support for elderly people. This work is charaterized by the use of real-time feedback control based on the information from high speed tactile sensors for detecting the contact force as well as its center of pressure between the assisted human and the robot arm. First, this paper introduces the design of the tactile sensor as well as initial experimental results to show the feasibility of the proposed system. Moreover, several fundamental tactile sensing-based motion controllers necessary for the stand-up motion support and their experimental verification are presented. Finally, an assist trajectory generation method for the stand-up motion support by integrating fuzzy logic with tactile sensing is proposed and demonstrated experimentally.

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Nonparametric Object Recognition With a New Tactile Sensor

4th Conference on Flexible Assembly Systems ◽

10.1115/detc1992-0448 ◽

1992 ◽

Author(s):

S. Unsal ◽

A. Shirkhodaie ◽

A. H. Soni

Keyword(s):

Decision Making ◽

Object Recognition ◽

Sensory Information ◽

Tactile Sensor ◽

Operating Environment ◽

Tactile Sensors ◽

Binary Array ◽

Software And Hardware ◽

Robotic Applications

Abstract Adding sensing capability to a robot provides the robot with intelligent perception capability and flexibility of decision making. To perform intelligent tasks, robots are highly required to perceive their operating environment, and react accordingly. With this regard, tactile sensors offer to extend the scope of intelligence of a robot for performing tasks which require object touching, recognition, and manipulation. This paper presents the design of an inexpensive pneumatic binary-array tactile sensor for such robotic applications. The paper describes some of the techniques implemented for object recognition from binary sensory information. Furthermore, it details the development of software and hardware which facilitate the sensor to provide useful information to a robot so that the robot perceives its operating environment during manipulation of objects.

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A low-cost, human-like, high-resolution, tactile sensor based on optical fibers and an image sensor

International Journal of Advanced Robotic Systems ◽

10.1177/1729881418783631 ◽

2018 ◽

Vol 15 (4) ◽

pp. 172988141878363 ◽

Cited By ~ 2

Author(s):

Utku Büyükşahin ◽

Ahmet Kırlı

Keyword(s):

High Resolution ◽

Spatial Resolution ◽

Fiber Optic ◽

Low Cost ◽

Experimental Studies ◽

Main Idea ◽

Tactile Sensor ◽

Image Sensor ◽

Sensor Design ◽

Tactile Sensors

Tactile sensors are commonly a coordinated group of receptors forming a matrix array meant to measure force or pressure similar to the human skin. Optic-based tactile sensors are flexible, sensitive, and fast; however, the human fingertip’s spatial resolution, which can be regarded as the desired spatial resolution, still could not be reached because of their bulky nature. This article proposes a novel and patented optic-based tactile sensor design, in which fiber optic cables are used to increase the number of sensory receptors per square centimeter. The proposed human-like high-resolution tactile sensor design is based on simple optics and image processing techniques, and it enables high spatial resolution and easy data acquisition at low cost. This design proposes using the change in the intesity of the light occured due to the deformation on contact/measurement surface. The main idea is using fiber optic cables as the afferents of the human physiology which can have 9 µm diameters for both delivering and receiving light beams. The variation of the light intensity enters sequent mathematical models as the input, then, the displacement, the force, and the pressure data are evaluated as the outputs. A prototype tactile sensor is manufactured with 1-mm spatial and 0.61-kPa pressure measurement resolution with 0–15.6 N/cm2 at 30 Hz sampling frequency. Experimental studies with different scenarios are conducted to demonstrate how this state-of-the-art design worked and to evaluate its performance. The overall accuracy of the first prototype, based on different scenarios, is calculated as 93%. This performance is regarded as promising for further developments and applications such as grasp control or haptics.

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Optical-Tactile Sensor for Lump Detection Using Pneumatic Control

Frontiers in Robotics and AI ◽

10.3389/frobt.2021.672315 ◽

2021 ◽

Vol 8 ◽

Author(s):

Jonathan Bewley ◽

George P. Jenkinson ◽

Antonia Tzemanaki

Keyword(s):

Contact Surface ◽

Medical Diagnosis ◽

Tactile Sensor ◽

Medical Robotics ◽

Robotic Systems ◽

Tactile Sensors ◽

Pneumatic Control ◽

Tactile Contact ◽

Lump Detection ◽

Silicone Matrix

Soft tactile sensors are an attractive solution when robotic systems must interact with delicate objects in unstructured and obscured environments, such as most medical robotics applications. The soft nature of such a system increases both comfort and safety, while the addition of simultaneous soft active actuation provides additional features and can also improve the sensing range. This paper presents the development of a compact soft tactile sensor which is able to measure the profile of objects and, through an integrated pneumatic system, actuate and change the effective stiffness of its tactile contact surface. We report experimental results which demonstrate the sensor’s ability to detect lumps on the surface of objects or embedded within a silicone matrix. These results show the potential of this approach as a versatile method of tactile sensing with potential application in medical diagnosis.

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A Triboelectric-Based Artificial Whisker for Reactive Obstacle Avoidance and Local Mapping

Research ◽

10.34133/2021/9864967 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Peng Xu ◽

Xingyu Wang ◽

Siyuan Wang ◽

Tianyu Chen ◽

Jianhua Liu ◽

...

Keyword(s):

Obstacle Avoidance ◽

Autonomous Robots ◽

Tactile Sensor ◽

Triboelectric Nanogenerator ◽

Tactile Sensors ◽

Biologically Inspired ◽

External Stimulation ◽

Autonomous Surface Vehicles ◽

Electrostatic Induction ◽

Contact Position

Since designing efficient tactile sensors for autonomous robots is still a challenge, this paper proposes a perceptual system based on a bioinspired triboelectric whisker sensor (TWS) that is aimed at reactive obstacle avoidance and local mapping in unknown environments. The proposed TWS is based on a triboelectric nanogenerator (TENG) and mimics the structure of rat whisker follicles. It operates to generate an output voltage via triboelectrification and electrostatic induction between the PTFE pellet and copper films (0.3 mm thickness), where a forced whisker shaft displaces a PTFE pellet (10 mm diameter). With the help of a biologically inspired structural design, the artificial whisker sensor can sense the contact position and approximate the external stimulation area, particularly in a dark environment. To highlight this sensor’s applicability and scalability, we demonstrate different functions, such as controlling LED lights, reactive obstacle avoidance, and local mapping of autonomous surface vehicles. The results show that the proposed TWS can be used as a tactile sensor for reactive obstacle avoidance and local mapping in robotics.

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A Flexible Tactile Sensor Based on Porous Graphene Sponge for Tiny Force Measurement

Volume 1: Additive Manufacturing; Bio and Sustainable Manufacturing ◽

10.1115/msec2018-6366 ◽

2018 ◽

Author(s):

Lingfeng Zhu ◽

Yancheng Wang ◽

Xin Wu ◽

Deqing Mei

Keyword(s):

Force Measurement ◽

High Sensitivity ◽

Tactile Sensor ◽

Tactile Sensors ◽

Force Detection ◽

Pressure Sensing ◽

Porous Graphene ◽

Graphene Sponge ◽

Healthcare Monitoring ◽

Working Principle

Flexible tactile sensors have been utilized for epidermal pressure sensing, motion detecting, and healthcare monitoring in robotic and biomedical applications. This paper develops a novel piezoresistive flexible tactile sensor based on porous graphene sponges. The structural design, working principle, and fabrication method of the tactile sensor are presented. The developed tactile sensor has 3 × 3 sensing units and has a spatial resolution of 3.5 mm. Then, experimental setup and characterization of this tactile sensor are conducted. Results indicated that the developed flexible tactile sensor has good linearity and features two sensitivities of 2.08 V/N and 0.68 V/N. The high sensitivity can be used for tiny force detection. Human body wearing experiments demonstrated that this sensor can be used for distributed force sensing when the hand stretches and clenches. Thus the developed tactile sensor may have great potential in the applications of intelligent robotics and healthcare monitoring.

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Ultra-Sensitive Flexible Tactile Sensor Based on Graphene Film

Micromachines ◽

10.3390/mi10110730 ◽

2019 ◽

Vol 10 (11) ◽

pp. 730 ◽

Cited By ~ 1

Author(s):

Xiaozhou Lü ◽

Liang Qi ◽

Hanlun Hu ◽

Xiaoping Li ◽

Guanghui Bai ◽

...

Keyword(s):

Industrial Robot ◽

Graphene Film ◽

High Sensitivity ◽

Tactile Sensor ◽

Measurement Range ◽

Tactile Sensors ◽

Piezoresistive Effect ◽

Large Measurement ◽

Pet Film ◽

Maximum Measurement

Flexible tactile sensor can be integrated into artificial skin and applied in industrial robot and biomedical engineering. However, the presented tactile sensors still have challenge in increasing sensitivity to expand the sensor’s application. Aiming at this problem, this paper presents an ultra-sensitive flexible tactile sensor. The sensor is based on piezoresistive effect of graphene film and is composed of upper substrate (PDMS bump with a size of 5 mm × 7 mm and a thickness of 1 mm), medial Graphene/PET film (Graphene/PET film with a size of 5 mm × 7 mm, PET with a hardness of 2H) and lower substrate (PI with fabricated electrodes). We presented the structure and reduced the principle of the sensor. We also fabricated several sample devices of the sensor and carried out experiment to test the performance. The results show that the sensor performed an ultra high sensitivity of 10.80/kPa at the range of 0–4 kPa and have a large measurement range up to 600 kPa. The sensor has 4 orders of magnitude between minimum resolution and maximum measurement range which have great advantage compared with state of the art. The sensor is expected to have great application prospect in robot and biomedical.

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Seedless Hydrothermal Growth of ZnO Nanorods as a Promising Route for Flexible Tactile Sensors

Nanomaterials ◽

10.3390/nano10050977 ◽

2020 ◽

Vol 10 (5) ◽

pp. 977

Author(s):

Ilaria Cesini ◽

Magdalena Kowalczyk ◽

Alessandro Lucantonio ◽

Giacomo D’Alesio ◽

Pramod Kumar ◽

...

Keyword(s):

Finite Element ◽

Aspect Ratio ◽

Growth Temperature ◽

Zno Nanorods ◽

Tactile Sensor ◽

Hydrothermal Growth ◽

Tactile Sensors ◽

Polyimide Substrate ◽

Vertically Aligned ◽

Seed Layers

Hydrothermal growth of ZnO nanorods has been widely used for the development of tactile sensors, with the aid of ZnO seed layers, favoring the growth of dense and vertically aligned nanorods. However, seed layers represent an additional fabrication step in the sensor design. In this study, a seedless hydrothermal growth of ZnO nanorods was carried out on Au-coated Si and polyimide substrates. The effects of both the Au morphology and the growth temperature on the characteristics of the nanorods were investigated, finding that smaller Au grains produced tilted rods, while larger grains provided vertical rods. Highly dense and high-aspect-ratio nanorods with hexagonal prismatic shape were obtained at 75 °C and 85 °C, while pyramid-like rods were grown when the temperature was set to 95 °C. Finite-element simulations demonstrated that prismatic rods produce higher voltage responses than the pyramid-shaped ones. A tactile sensor, with an active area of 1 cm2, was fabricated on flexible polyimide substrate and embedding the nanorods forest in a polydimethylsiloxane matrix as a separation layer between the bottom and the top Au electrodes. The prototype showed clear responses upon applied loads of 2–4 N and vibrations over frequencies in the range of 20–800 Hz.

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