scholarly journals Flexible mechanical metamaterials enabling soft tactile sensors with multiple sensitivities at multiple force sensing ranges

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alireza Mohammadi ◽  
Ying Tan ◽  
Peter Choong ◽  
Denny Oetomo
Keyword(s):  
Degrees Of Freedom ◽  
Force Measurement ◽  
Design Procedure ◽  
Tactile Sensor ◽  
Design Parameters ◽  
Force Sensing ◽  
Tactile Sensors ◽  
Human Machine Interaction ◽  
Mechanical Metamaterials ◽  
Sensor Structure

AbstractThe majority of existing tactile sensors are designed to measure a particular range of force with a fixed sensitivity. However, some applications require tactile sensors with multiple task-relevant sensitivities at multiple ranges of force sensing. Inspired by the human tactile sensing capability, this paper proposes a novel soft tactile sensor based on mechanical metamaterials which exhibits multiple sensitivity regimes due to the step-by-step locking behaviour of its heterogenous multi-layered structure. By tuning the geometrical design parameters of the collapsible layers, each layer experiences locking behaviour under different ranges of force which provides different sensitivity of the sensor at different force magnitude. The integration of a magnetic-based transduction method with the proposed structure results in high design degrees of freedom for realising the desired contact force sensitivities and corresponding force sensing ranges. A systematic design procedure is proposed to select appropriate design parameters to produce the desired characteristics. Two example designs of the sensor structure were fabricated using widely available benchtop 3D printers and tested for their performance. The results showed the capability of the sensor in providing the desired characteristics in terms of sensitivity and force range and being realised in different shapes, sizes and number of layers in a single structure. The proposed multi-sensitivity soft tactile sensor has a great potential to be used in a wide variety of applications where different sensitivities of force measurement is required at different ranges of force magnitudes, from robotic manipulation and human–machine interaction to biomedical engineering and health-monitoring.

scholarly journals Magnetic-based Soft Tactile Sensors with Deformable Continuous Force Transfer Medium for Resolving Contact Locations in Robotic Grasping and Manipulation

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4925 ◽  
Author(s):  
Alireza Mohammadi ◽  
Yangmengfei Xu ◽  
Ying Tan ◽  
Peter Choong ◽  
Denny Oetomo
Keyword(s):  
Contact Force ◽  
Learning Algorithm ◽  
Design Procedure ◽  
Tactile Sensor ◽  
Design Parameters ◽  
Robotic Hand ◽  
Tactile Sensors ◽  
Hall Effect Sensor ◽  
Grasping And Manipulation ◽  
Sensor Configuration

The resolution of contact location is important in many applications in robotics and automation. This is generally done by using an array of contact or tactile receptors, which increases cost and complexity as the required resolution or area is increased. Tactile sensors have also been developed using a continuous deformable medium between the contact and the receptors, which allows few receptors to interpolate the information among them, avoiding the weakness highlighted in the former approach. The latter is generally used to measure contact force intensity or magnitude but rarely used to identify the contact locations. This paper presents a systematic design and characterisation procedure for magnetic-based soft tactile sensors (utilizing the latter approach with the deformable contact medium) with the goal of locating the contact force location. This systematic procedure provides conditions under which design parameters can be selected, supported by a selected machine learning algorithm, to achieve the desired performance of the tactile sensor in identifying the contact location. An illustrative example, which combines a particular sensor configuration (magnetic hall effect sensor as the receptor, a selected continuous medium and a selected sensing resolution) and a specific data-driven algorithm, is used to illustrate the proposed design procedure. The results of the illustrative example design demonstrates the efficacy of the proposed design procedure and the proposed sensing strategy in identifying a contact location. The resulting sensor is also tested on a robotic hand (Allegro Hand, SimLab Co) to demonstrate its application in real-world scenarios.

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

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.

scholarly journals Resolution Enhancement Method Used for Force Sensing Resistor Array

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Karen Flores De Jesus ◽  
Marvin H. Cheng ◽  
Lei Jiang ◽  
Ezzat G. Bakhoum
Keyword(s):  
Resolution Enhancement ◽  
Sensor Arrays ◽  
Tactile Sensor ◽  
Force Sensing ◽  
Tactile Sensors ◽  
System A ◽  
Dimensional Measurements ◽  
Enhancement Method ◽  
Multiple Measurements ◽  
Applied Forces

Tactile sensors are one of the major devices that enable robotic systems to interact with the surrounding environment. This research aims to propose a mathematical model to describe the behavior of a tactile sensor based on experimental and statistical analyses and moreover to develop a versatile algorithm that can be applied to different tactile sensor arrays to enhance the limited resolution. With the proposed algorithm, the resolution can be increased up to twenty times if multiple measurements are available. To verify if the proposed algorithm can be used for tactile sensor arrays that are used in robotic system, a16×10force sensing array (FSR) is adopted. The acquired two-dimensional measurements were processed by a resolution enhancement method (REM) to enhance the resolution, which can be used to improve the resolution for single image or multiple measurements. As a result, the resolution of the sensor is increased and it can be used as synthetic skin to identify accurate shapes of objects and applied forces.

scholarly journals Development of Fully Flexible Tactile Pressure Sensor with Bilayer Interlaced Bumps for Robotic Grasping Applications

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 770
Author(s):  
Lingfeng Zhu ◽  
Yancheng Wang ◽  
Deqing Mei ◽  
Chengpeng Jiang
Keyword(s):  
Pressure Sensor ◽  
Tactile Sensor ◽  
External Pressure ◽  
Robotic Hand ◽  
Sensing Element ◽  
Tactile Sensors ◽  
Human Machine Interaction ◽  
Tactile Information ◽  
Sensing Range ◽  
Intelligent Robotics

Flexible tactile sensors have been utilized in intelligent robotics for human-machine interaction and healthcare monitoring. The relatively low flexibility, unbalanced sensitivity and sensing range of the tactile sensors are hindering the accurate tactile information perception during robotic hand grasping of different objects. This paper developed a fully flexible tactile pressure sensor, using the flexible graphene and silver composites as the sensing element and stretchable electrodes, respectively. As for the structural design of the tactile sensor, the proposed bilayer interlaced bumps can be used to convert external pressure into the stretching of graphene composites. The fabricated tactile sensor exhibits a high sensing performance, including relatively high sensitivity (up to 3.40% kPa−1), wide sensing range (200 kPa), good dynamic response, and considerable repeatability. Then, the tactile sensor has been integrated with the robotic hand finger, and the grasping results have indicated the capability of using the tactile sensor to detect the distributed pressure during grasping applications. The grasping motions, properties of the objects can be further analyzed through the acquired tactile information in time and spatial domains, demonstrating the potential applications of the tactile sensor in intelligent robotics and human-machine interfaces.

Design and Simulation of Micro Tactile Sensor for Stiffness Detection of Soft Tissue with Irregular Surface

2020 ◽  
Vol 18 (3) ◽  
pp. 200-209
Author(s):  
Ahmed Fouly ◽  
Ahmed M. R. FathEl-Bab ◽  
A. A. Abouelsoud ◽  
T. Tsuchiya ◽  
O. Tabata
Keyword(s):  
Soft Tissue ◽  
Soft Tissues ◽  
Tactile Sensor ◽  
Sensor Output ◽  
Irregular Surface ◽  
Tissue Stiffness ◽  
Tactile Sensors ◽  
Element Analysis ◽  
Detailed Design ◽  
Sensor Structure

Tactile sensors become an essential part of many applications in our life. Integrating tactile sensors with surgical tools used in MIS is significant to compensate for the shortage of touch feeling of soft tissues and organs comparing with traditional surgeries. This paper presents a detailed design of a micro tactile sensor for measuring the stiffness of soft tissue with an irregular surface. The sensor consists of five cantilever springs with different stiffness. A spring in the middle has a relatively low stiffness surrounded by 4 springs have relatively equal high stiffness to compensate for the soft tissue contact error in the longitudinal and lateral directions. Sensor parameters are selected to ensure high sensitivity and linearity with taking into consideration the cross-talk effect among the sensor springs tips. A detailed design of the sensor structure in the microscale is conducted based on some constraints related to MEMS fabrication. A finite element analysis (FEA) of the sensor structure is conducted to evaluate sensor structure performance using CoventorWare software. Then, an FEA for the piezo-resistors, as a signal transduction method, is conducted which maps the sensor output to an electrical signal. The results prove that the sensor can differentiate among different soft-tissue stiffness within the selected range independent of the applied distance between the sensor and the tissue with an error below 3% even with inclination angle between the sensor and the tissue ±3°. Furthermore, a linear performance has been achieved between the soft-tissue stiffness and the sensor output.

scholarly journals A hybrid tactile sensor-based obstacle overcoming method for hexapod walking robots

2020 ◽  
Author(s):  
Mindaugas Luneckas ◽  
Tomas Luneckas ◽  
Dainius Udris ◽  
Darius Plonis ◽  
Rytis Maskeliūnas ◽  
...  
Keyword(s):  
Degrees Of Freedom ◽  
Flat Surface ◽  
Tactile Sensor ◽  
Legged Robots ◽  
Walking Robots ◽  
Positional Error ◽  
Tactile Sensors ◽  
Robot Locomotion ◽  
Promising Solution ◽  
Novel Method

AbstractWalking robots are considered as a promising solution for locomotion across irregular or rough terrain. While wheeled or tracked robots require flat surface like roads or driveways, walking robots can adapt to almost any terrain type. However, overcoming diverse terrain obstacles still remains a challenging task even for multi-legged robots with a high number of degrees of freedom. Here, we present a novel method for obstacle overcoming for walking robots based on the use of tactile sensors and generative recurrent neural network for positional error prediction. By using tactile sensors positioned on the front side of the legs, we demonstrate that a robot is able to successfully overcome obstacles close to robots height in the terrains of different complexity. The proposed method can be used by any type of a legged machine and can be considered as a step toward more advanced walking robot locomotion in unstructured terrain and uncertain environment.

scholarly journals Facile Fabrication of 3D Porous Sponges Coated with Synergistic Carbon Black/Multiwalled Carbon Nanotubes for Tactile Sensing Applications

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1941 ◽  
Author(s):  
Yousef Al-Handarish ◽  
Olatunji Mumini Omisore ◽  
Wenke Duan ◽  
Jing Chen ◽  
Luo Zebang ◽  
...  
Keyword(s):  
Carbon Black ◽  
High Sensitivity ◽  
Tactile Sensor ◽  
Fast Response ◽  
Wearable Electronics ◽  
Tactile Sensors ◽  
Multiwalled Carbon ◽  
Human Machine Interaction ◽  
External Compression ◽  
Sensing Applications

Recently, flexible tactile sensors based on three-dimensional (3D) porous conductive composites, endowed with high sensitivity, a wide sensing range, fast response, and the capability to detect low pressures, have aroused considerable attention. These sensors have been employed in different practical domain areas such as artificial skin, healthcare systems, and human–machine interaction. In this study, a facile, cost-efficient method is proposed for fabricating a highly sensitive piezoresistive tactile sensor based on a 3D porous dielectric layer. The proposed sensor is designed with a simple dip-coating homogeneous synergetic conductive network of carbon black (CB) and multi-walled carbon nanotube (MWCNTs) composite on polydimethysiloxane (PDMS) sponge skeletons. The unique combination of a 3D porous structure, with hybrid conductive networks of CB/MWCNTs displayed a superior elasticity, with outstanding electrical characterization under external compression. The piezoresistive tactile sensor exhibited a high sensitivity of (15 kPa−1), with a rapid response time (100 ms), the capability of detecting both large and small compressive strains, as well as excellent mechanical deformability and stability over 1000 cycles. Benefiting from a long-term stability, fast response, and low-detection limit, the piezoresistive sensor was successfully utilized in monitoring human physiological signals, including finger heart rate, pulses, knee bending, respiration, and finger grabbing motions during the process of picking up an object. Furthermore, a comprehensive performance of the sensor was carried out, and the sensor’s design fulfilled vital evaluation metrics, such as low-cost and simplicity in the fabrication process. Thus, 3D porous-based piezoresistive tactile sensors could rapidly promote the development of high-performance flexible sensors, and make them very attractive for an enormous range of potential applications in healthcare devices, wearable electronics, and intelligent robotic systems.

scholarly journals Pinch Force Measurement in Minimally Invasive Surgery with Tactile Sensors

2018 ◽  
Vol 1 (1) ◽  
pp. 1056-1061
Author(s):  
Mithat Can Özin ◽  
Bilsay Sümer ◽  
İlker Murat Koç
Keyword(s):  
Minimally Invasive Surgery ◽  
Minimally Invasive ◽  
Invasive Surgery ◽  
Force Measurement ◽  
Tactile Sensor ◽  
Tactile Sensors ◽  
Pinch Force ◽  
Thin Film Sensors ◽  
Real Time Measurement ◽  
Low Elastic Modulus

This study focuses on the real-time measurement of the distributed pinch force in minimally invasive surgery with a piezoresistive tactile sensor. The measurement of the pinch force in distributed form is important because the conventional surgical tools have angular opening/closing mechanism, which causes non-uniform force distribution on the contacting sample. Additionally, the location and the magnitude of the equivalent pinch force is calculated. The grasping of the samples with homogenous and constant pinch force and the characterization of the samples with low elastic modulus can be carried out with tactile sensor included surgery tools. Apprentice surgeons can benefit the advantages of the thin film sensors in their training.

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