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This paper aims to illustrate the increasingly important role played by tactile sensing in robotics by considering three specific fields of application.
Abstract
Purpose
This paper aims to illustrate the increasingly important role played by tactile sensing in robotics by considering three specific fields of application.
Design/methodology/approach
Following a short introduction, this paper first provides details of tactile sensing principles, technologies, products and research. The following sections consider tactile sensing applications in robotic surgery, collaborative robots and robotic grippers. Finally, brief conclusions are drawn.
Findings
Tactile sensors are the topic of an extensive and technologically diverse research effort, with sensing skins attracting particular attention. Many products are now available commercially. New generations of surgical robots are emerging which use tactile sensing to provide haptic feedback, thereby eliminating the surgeon’s total reliance on visual control. Many collaborative robots use tactile and proximity sensing as key safety mechanisms and some use sensing skins. Some skins can detect both human proximity and physical contact. Sensing skins that can be retrofitted have been developed. Commercial tactile sensors have been incorporated into robotic grippers, notably anthropomorphic types, and allow the handling of delicate objects and those with varying shapes and sizes. Tactile sensing uses will inevitably increase because of the ever-growing numbers of robots interacting with humans.
Originality/value
This study provides a detailed account of the growing use of tactile sensing in robotics in three key areas of application.
Details
Keywords
R. Benhadj, B. Dawson and M.M.A. Safa
The mainstream of current research work in array tactile sensors concentrates on using a soft compliant membrane as a means of transmitting the effect of variable external stimuli…
Abstract
The mainstream of current research work in array tactile sensors concentrates on using a soft compliant membrane as a means of transmitting the effect of variable external stimuli to the discrete sensing elements. The soft compliant devices are usually made of a thin flexible substrate such as pressure sensitive pads, conductive materials, conductive coatings, piezoelectric polymers or elastomers. A large number of tactile sensor designs using these types of materials have been investigated by researchers. These include the use of anisotropically conductive silicone rubber (ACS), sponges containing carbon particles or felted carbon fibres, piezoelectric polymers such as polyvinylidene fluoride (PVF2) and conductive elastomers such as Dynacom materials consisting of silicone rubber mixed with metallic compounds.
R. Benhadj and R.L. Roome
This paper describes the development and the performance characteristics of a pneumatic proximity‐to‐tactile sensing device for automated recognition of manufacturing parts within…
Abstract
This paper describes the development and the performance characteristics of a pneumatic proximity‐to‐tactile sensing device for automated recognition of manufacturing parts within flexible manufacturing environments. This tactile sensing device utilises a densely packed line array of IC piezoresistive pressure sensors, providing continuous variable back pressure output. The sensing elements incorporate a corresponding line matrix of air jets which form an air cushion between the sensing plane and the target when striking the object of interest. The back pressure output levels form the basis for the tasks of object detection and recognition. The system described is a research prototype and has been evaluated on a simple test rig: in this form it is not at a stage where it can be applied to a recognition situation on the shop floor.
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Keywords
This paper aims to provide details of recent developments in robotic tactile sensing.
Abstract
Purpose
This paper aims to provide details of recent developments in robotic tactile sensing.
Design/methodology/approach
Following a short introduction, this paper first provides an overview of tactile sensing effects and technologies. It then discusses recent developments in tactile sensing skins. Tactile sensing for robotic prosthetics and hands is then considered and is followed by a discussion of “tactile intelligence”. Various experimental results are included. Finally, brief concluding comments are drawn.
Findings
This shows that many advanced, sensitive and technologically varied tactile sensing devices are being developed. These devices are expected to impart robots with a range of enhanced capabilities such as improved gripping and manipulation, object recognition, the control and robotic hands and prosthetics and collision detection.
Originality/value
Tactile sensing has an increasingly important role to play in robotics, and this paper provides a technical insight into a number of recent developments and their applications.
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Keywords
Dalibor Petković, Mirna Issa, Nenad D. Pavlović and Lena Zentner
The aim of this paper is to investigate implementations of carbon‐black filled silicone rubber for tactile sensation.
Abstract
Purpose
The aim of this paper is to investigate implementations of carbon‐black filled silicone rubber for tactile sensation.
Design/methodology/approach
The sensor‐elements for this tactile sensing structure were made by press‐curing from carbon‐black filled silicone rubber.
Findings
The behaviour of the silicone rubber shows strong non‐linearity, therefore, the sensor cannot be used for accurate measurements. The greatest advantage of this material lies in its high elasticity.
Originality/value
A new method for artificial tactile sensing skin for robotic applications.
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Javad Dargahi and Siamak Najarian
This paper describes the design, fabrication, testing, and mathematical modeling of a supported membrane type polyvinylidene fluoride (PVDF) tactile sensor. Using the designed…
Abstract
This paper describes the design, fabrication, testing, and mathematical modeling of a supported membrane type polyvinylidene fluoride (PVDF) tactile sensor. Using the designed membrane type sensor (MTS), it is shown that the entire surface of the PVDF film can be employed as a means of detecting the force magnitude and its application point. This is accomplished by utilizing only three sensing elements. Unlike the array type tactile sensors, in which the regions between the neighboring sensing elements are not active, all the surface points of the sensor are practically active in this MTS. A geometric mapping process is introduced, thereby, the loci of the isocharge contours for the three sensing elements are determined by applying force on various points of the sensor surface. In order to form a criterion for the comparison between the experimental findings and the theoretical analysis data, and also to determine the magnitude of the stresses generated in the membrane, finite element modeling is used. The correlation between the theoretical predictions and experimental findings is proven to be reasonable. Potentially, the designed MTS can be incorporated into various medical probes for tactile imaging.
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Xuefeng Zhang, Yulong Zhao and Xuelei Zhang
The purpose of this paper is to provide a thin tactile force sensor array based on conductive rubber and to offer descriptions of the sensor design, fabrication and test.
Abstract
Purpose
The purpose of this paper is to provide a thin tactile force sensor array based on conductive rubber and to offer descriptions of the sensor design, fabrication and test.
Design/methodology/approach
The sensor array consists of a sandwich structure. Sensing elements are distributed discretely in the sensor. Each sensing element has two electrodes and a piece of conductive rubber with piezoresistive property. The electrodes, as well as the conductive trace for signal transmission, are printed on the substrate layer by the screen printing technique. A scanning circuit based on zero potential method and an experimental set‐up based on balance to characterize the sensor array are designed and implemented in the test of the sensor array.
Findings
Experimental results verify the validity of the sensor array in measuring the vertical tactile force between the sensing elements and the object.
Research limitations/implications
In this paper, all the sensors are tested without calibration procedures and the procedure of the dynamic test is implemented by manual operation.
Practical implications
The sensor array could be applied to measure the plantar force for gait detection in clinical applications.
Originality/value
The paper presents a tactile force sensor array with discrete sensing elements to essentially restrict the cross‐talk among sensing elements. This paper will provide many practical details that can help others in the field.
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Keywords
Hamid Roham, Siamak Najarian, Seyed Mohsen Hosseini and Javad Dargahi
The paper aims to discuss the design, fabrication, communication, testing, and simulation of a new tactile probe called Elastirob used to measure the modulus of elasticity of…
Abstract
Purpose
The paper aims to discuss the design, fabrication, communication, testing, and simulation of a new tactile probe called Elastirob used to measure the modulus of elasticity of biological soft tissues and soft materials.
Design/methodology/approach
Both finite element modeling and experimental approaches were used in this analysis. Elastirob, with the ability to apply different rates of strain on testing specimens, is accompanied by a tactile display called TacPlay. This display is a custom‐designed user‐friendly interface and is able to evaluate the elasticity in each part of the stress‐strain curve.
Findings
A new device is being constructed that can measure the modulus of elasticity of a sensed object. The results of Elastirob applied on two specimens are reported and compared by the results of experiments obtained by an industrial testing machine. Acceptable validations of Elastirob were achieved from the comparisons.
Research limitations/implications
The designed system can be miniaturized to be used in minimally invasive surgeries in the future.
Practical implications
Elastirob determines the elasticity by drawing the stress‐strain curve and then calculating its slope. The combination of the force sensing resistor, microcontroller and stepper motor provides Elastirob with the ability to apply different rates of strain on testing specimens.
Originality/value
It can be employed in both in vivo and in vitro tests for measuring stiffness of touch objects. For the first time, a device has been designed and tested which is a few orders of magnitude smaller than its industrial counterparts and has considerably lower weight.
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Keywords
Javad Dargahi and Siamak Najarian
Reviews the benefits and potential application of tactile sensors for use with robots.
Abstract
Purpose
Reviews the benefits and potential application of tactile sensors for use with robots.
Design/methodology/approach
Includes the most recent advances in both the design/manufacturing of various tactile sensors and their applications in different industries. Although these types of sensors have been adopted in a considerable number of areas, the applications such as, medical, agricultural/livestock and food, grippers/manipulators design, prosthetic, and environmental studies have gained more popularity and are presented in this paper.
Findings
Robots can perform very useful and repetitive tasks in controlled environments. However, when the robots are required to handle the unstructured and changing environments, there is a need for more elaborate means to improve their performance. In this scenario, tactile sensors can play a major role. In the unstructured environments, the robots must be able to grasp objects (or tissues, in the case of medical robots) and move objects from one location to another.
Originality/value
In this work, the emphasis was on the most interesting and fast developing areas of the tactile sensors applications, including, medical, agriculture and food, grippers and manipulators design, prosthetic, and environmental studies.
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Zengxin Kang, Jing Cui, Yijie Wang, Zhikai Hu and Zhongyi Chu
Current flexible printed circuit (FPC) assembly relies heavily on manual labor, limiting capacity and increasing costs. Small FPC size makes automation challenging as terminals…
Abstract
Purpose
Current flexible printed circuit (FPC) assembly relies heavily on manual labor, limiting capacity and increasing costs. Small FPC size makes automation challenging as terminals can be visually occluded. The purpose of this study is to use 3D tactile sensing to mimic human manual mating skills for enabling sensing offset between FPC terminals (FPC-t) and FPC mating slots (FPC-s) under visual occlusion.
Design/methodology/approach
The proposed model has three stages: spatial encoding, offset estimation and action strategy. The spatial encoder maps sparse 3D tactile data into a compact 1D feature capturing valid spatial assembly information to enable temporal processing. To compensate for low sensor resolution, consecutive spatial features are input to a multistage temporal convolutional network which estimates alignment offsets. The robot then performs alignment or mating actions based on the estimated offsets.
Findings
Experiments are conducted on a Redmi Note 4 smartphone assembly platform. Compared to other models, the proposed approach achieves superior offset estimation. Within limited trials, it successfully assembles FPCs under visual occlusion using three-axis tactile sensing.
Originality/value
A spatial encoder is designed to encode three-axis tactile data into feature maps, overcoming multistage temporal convolution network’s (MS-TCN) inability to directly process such input. Modifying the output to estimate assembly offsets with related motion semantics overcame MS-TCN’s segmentation points output, unable to meet assembly monitoring needs. Training and testing the improved MS-TCN on an FPC data set demonstrated accurate monitoring of the full process. An assembly platform verified performance on automated FPC assembly.
Details