THE sense of touch is an indispensable requirement for humans to effectively interact with the physical world around them and perform dexterous tasks. Similarly, this should be no different for robots. Imagine, for example, a robot that can open a bottle of medicine and dispense pills to an elderly person. Although this might seem a straightforward task for a human, it remains a significant challenge for a robot. Critically, the completion of the task depends on tactile sensing: the robot needs to receive and interpret the feedback from interacting with the bottle, determine the appropriate force based on the size and hardness of the pills, and adjust its pose to safely dispense them. Each step involves contact-rich interactions that can only be effectively deciphered through tactile sensing. Typically, tactile sensing works in conjunction with other modalities, such as vision, enabling the robot to adjust its actions dynamically and complete the task. In response to this vision of robots interacting with the physical world through touch, tactile robotics has now emerged as a key research area. Tactile robots can be defined as intelligent systems equipped with tactile sensors that can extract and process tactile data to guide their operations and interactions. The development of tactile robots presents scientific challenges, ranging from the design and fabrication of tactile sensors to methodologies for processing tactile data, integrating tactile feedback into task execution, and combining it with other sensory modalities to improve robot perception. As a result, tactile robotics demands collaborative efforts across several disciplines, involving material and data scientists …

The growing use of computing and proliferation of computing devices requires a holistic focus on sustainability as the environmental impacts of computing technologies go beyond their energy consumption.Environmental impacts span all stages of the lifecycle -manufacturing, operation, and disposal.A sustainability mindset must permeate all organizations involved in design, manufacturing, operation, and disposal/recycling of computational devices.This panel will discuss current and new research on sustainability in computing that spans the full lifecycle, all layers of the computing stack and across the computing spectrum from edge to cloud.The panel will also discuss potential crossdisciplinary approaches to sustainable computing and new notions and metrics to quantify sustainability.

The growing use of computing and proliferation of computing devices requires a holistic focus on sustainability as the environmental impacts of computing technologies go beyond their energy consumption. Environmental impacts span all stages of the lifecycle - manufacturing, operation, and disposal. A sustainability mindset must permeate all organizations involved in design, manufacturing, operation, and disposal/recycling of computational devices. This panel will discuss current and new research on sustainability in computing that spans the full lifecycle, all layers of the computing stack and across the computing spectrum from edge to cloud. The panel will also discuss potential cross-disciplinary approaches to sustainable computing and new notions and metrics to quantify sustainability.

This paper presents a fully integrated pH-sensing system-on-ultra-thin-chip (SoUTC) designed in a 0.35-μm CMOS technology. Owing to lower Si-substrate thickness (~30μm) the presented chip can conform to curvilinear surfaces, such as human skin, allowing intimate contact necessary for robust data for continuous monitoring of analytes in body fluids. A current-mode active-pixel ISFET array architecture is presented, with a power consumption of 6.28μW per-pixel from a 2V power supply and low sensitivity to process, voltage, temperature as well as strain-induced (PVTS) variations. The silicon area occupancy of each active-pixel is 44.9 × 33.5 μm2with an ion-sensing area of similar size. The pH sensing SoUTC can operate either in a rolling shutter fashion or in a pseudo-random pixel selection mode allowing the simultaneous detection of pH from different skin regions. From the electrical and electrochemical characterization of the proposed readout circuit on both bulky and ultra-thin version of chips, it was observed degradation in the signal-to-noise ratio (SNR) and total harmonic distortion (THD), in the latter version of the chip. The circuits have been tested in aqueous Dulbecco's Modified Eagle Medium (DMEM) solutions with 59 pH values to demonstrate their potential use for continuous monitoring of body-fluids pH.

The ever-increasing number of devices on wearable and portable systems comes with challenges such as integration complexity, higher power requirements, and less user comfort. In this regard, the development of multifunctional devices could help immensely as they will provide the same functionalities with lesser number of devices. Herein, we present a dual-function flexible loop antenna printed on polyvinyl chloride (PVC) substrate. With a poly(3,4-ethylenedioxythiophene): polystyrene (PEDOT:PSS) section as part of the printed structure, the presented antenna can also serve as a temperature sensor by means of change in resistance. The antenna resonates at 1.2- and 5.8-GHz frequencies. The ohmic resistance of the temperature sensing part decreases by ~70% when the temperature increases from 25 °C to 90 °C. The developed antenna was characterized using a vector network analyzer (VNA) in the same temperature range and the S11 magnitude was found to change by ~3.5 dB. The induced current was also measured in the GSM frequency range and sensitivity of ~1.2%/°C was observed for the sensing antenna. The flexible antenna was also evaluated in lateral and cross-bending conditions and the response was found to be stable for the cross-bending. Due to these unique features, the presented antenna sensor could play a vital role in the drive toward ubiquitous sensing through wearables, smart labels, and the Internet of Things (IoT).

This article presents a smart bandage with wireless strain and temperature sensors and a batteryless near-field communication (NFC) tag. Both sensors are based on conductive poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) polymer. The highly sensitive strain sensor consists of a microfluidic channel filled with PEDOT:PSS in Polydimethylsiloxane (PDMS) substrate. The strain sensor shows 3 order (~1250) increase in the resistance for 10% strain and considerably high gauge factor (GF) of~12 500. The sensor was tested for~30% strain, which is more than typical stretching of human skin or body parts such as chest expansion during respiration. The strain sensor was also tested for different bending and the electrical resolution was~150% per degree of free bending and~12k% per percentage of stretching. The resistive temperature sensor, fabricated on a Polyvinyl Chloride (PVC) substrate, showed a~60% decrease in resistance when the temperature changed from 25 °C to 85 °C and a sensitivity of~1% per °C. As a proof of concept, the sensors and NFC tag were integrated on wound dressing to obtain wearable systems with smart bandage form factor. The sensors can be operated and read from distance of 25 mm with a user-friendly smartphone application developed for powering the system as well as real-time acquisition of sensors data. Finally, we demonstrate the potential use of smart bandage in healthcare applications such as assessment of wound status or respiratory diseases, such as asthma and COVID-19, where monitoring via wearable strain (e.g., respiratory volume) and temperature sensors is critical.

The sensor technology for water quality monitoring (WQM) has improved during recent years. The cost-effective sensorised tools that can autonomously measure the essential physical-chemical-biological (PCB) variables are now readily available and are being deployed on buoys, boats, and ships. Yet, there is a disconnect between the data quality, data gathering, and data analysis due to the lack of standardized approaches for data collection and processing, spatiotemporal variation of key parameters in water bodies and new contaminants. Such gaps can be bridged with a network of multiparametric sensor systems deployed in water bodies using autonomous vehicles, such as marine robots and aerial vehicles to broaden the data coverage in space and time. Furthermore, intelligent algorithms [e.g., artificial intelligence (AI)] could be employed for standardized data analysis and forecasting. This article presents a comprehensive review of the sensors, deployment, and analysis technologies for WQM. A network of networked water bodies could enhance the global data intercomparability and enable WQM at a global scale to address global challenges related to food (e.g., aqua/agriculture), drinking water, and health (e.g., water-borne diseases).

Electronic skin (eSkin) with various types of sensors over large conformable substrates has received considerable interest in robotics. The continuous operation of large number of sensors and the readout electronics make it challenging to meet the energy requirements of eSkin. In this article, we present the first energy generating eSkin with intrinsic tactile sensing without any touch sensor. The eSkin comprises a distributed array of miniaturized solar cells and infrared light emitting diodes (IRLEDs) on soft elastomeric substrate. By innovatively reading the variations in the energy output of the solar cells and IRLEDs, the eSkin could sense multiple parameters (proximity, object location, edge detection, etc.). As a proof of concept, the eSkin has been attached to a 3-D-printed hand. With an energy surplus of 383.6 mW from the palm area alone, the eSkin could generate more than 100 W if present over the whole body (area ~1.5 m2). Further, with an industrial robot arm, the presented eSkin is shown to enable safe human-robot interaction. The novel paradigm presented in this article for the development of a flexible eSkin extends the application of solar cell from energy generation alone to simultaneously acting as touch sensors.

This paper presents van der Waals (vdW) contacted graphene field-effect transistors (GFETs) and logic circuits, both on rigid and flexible substrates. These logic gates exhibit stable performances after 100 cycles of bending. Realized with complementary metal oxide semiconductor (CMOS) compatible technology, the vdW contacted GFETs show performance comparable to the top-contacted GFETs and thus present excellent cost-effective alternatives to top- and edge-contacted GFETs for large-area electronic applications.

Tactile feedback is important to enhance the ability of amputees to interact with various objects. In this regard, this paper presents a 3D-printed prosthetic limb with integrated biomimetic tactile sensors coupled with a feedback actuation mechanism which is integrated to a myo-electric band on the residual limb. The static and dynamic tactile sensors on 3D-printed hand were realized by using a capacitive architecture in tandem with a piezoelectric structure. The capacitive sensing structure exhibited non-linear characteristics with varying sensitivities of 0.25 kPa-1in low pressure range (-1in high pressure while the piezo-structure exhibited a sensitivity of 2.28 kPa-1. Two different types of actuators are employed and integrated to the myo-electric band to offer static and dynamic tactile feedback in the residual limb area.

With robots starting to enter our lives in a number of ways (e.g., social, assistive, and surgery), the electronic skin (e-skin) is becoming increasingly important. The capability of detecting subtle pressure or temperature changes makes the e-skin an essential component of a robot's body or an artificial limb [1], [2]. This is because the tactile feedback enabled by e-skin plays a fundamental role in providing action-related information such as slip during manipulation/control tasks such as grasping, and estimation of contact parameters (e.g., force, soft contact, hardness, texture, and temperature during exploration [3]). It is critical for the safe robotic interaction - albeit as a coworker in the futuristic industry 4.0 setting or to assist the elderly at home.

This special issue provides state-of-the-art coverage of the theoretical, scientific, and practical aspects related to flexible electronic skin.

Sensory feedback from touch is critical for many tasks carried out by robots and humans, such as grasping objects or identifying materials. Electronic skin (e-skin) is a crucial technology for these purposes. Artificial tactile skin that can play the roles of human skin remains a distant possibility because of hard issues in resilience, manufacturing, mechanics, sensorics, electronics, energetics, information processing, and transport. Taken together, these issues make it difficult to bestow robots, or prosthetic devices, with effective tactile skins. Nonetheless, progress over the past few years in relation with the above issues has been encouraging, and we have achieved close to providing some of the abilities of biological skin with the advent of deformable sensors and flexible electronics. The naive imitation of skin morphology and sensing an impoverished set of mechanical and thermal quantities are not sufficient. There is a need to find more efficient ways to extract tactile information from mechanical contact than those previously available. Renewed interest in neuromorphic tactile skin is expected to bring some fresh ideas in this field. This article reviews these new developments, particularly related to the handling of tactile data, energy autonomy, and large-area manufacturing. The challenges in relation with these advances for tactile sensing and haptics in robotics and prosthetics are discussed along with potential solutions.

This paper presents a touch-based system for communication by deafblind people with humans and robots. With presented system the deafblind people can send control signal to robots by writing block letters on an array of 8 × 8 diamond-shaped capacitive touch sensors. For better conformability with curved surfaces, the touch sensors arrays have been fabricated on flexible polyvinyl chloride (PVC) substrate. The characters written by deafblind on the tactile sensing array are recognized by Convolution Neural Network (CNN), which is trained with data from Extended Modified National Institute of Standards and Technology (EMNIST) database. A mobile app was also developed to efficiently recognize and display the written letters. Finally, a Baxter robot was simulated using Robot Operating System (ROS) and was remotely controlled by deafblind through English block letters written on the tactile sensing array. The result shows that the robot could successfully execute the `pick or drop' task. The developed system demonstrates the efficacy of tactile based communication by deafblind people to independently interact with a robot and their environment.

This paper reports recent advances related to the piezoelectric oxide semiconductor field effect transistor (POS-FET) based touch sensing system research. We reported in past, the POSFETs with basic electronics realized on planar silicon substrates using CMOS technology. However, the planar POSFETs could not be used on 3D or curved surfaces such as the fingertip of a robot. To overcome this challenge we are now investigating the ultra-thin-chip approach for obtaining bendable POSFETs tactile sensing array. This paper presents this approach towards obtaining bendable POSFETs. Furthermore, for the first time the theoretical behavior of POSFETs devices are examined by combining the piezoelectric capacitor model proposed and the physics of underlying metal-oxide-semiconductor (MOS) FETs in the linear and saturation regions. The device characteristic equations are simulated using MATLAB and comparable matching is achieved with the experimental measurements. The model result gives a unique insight into geometrical and material properties of piezoelectric polymer on the electrical properties of transistor for flexible electronics applications. Using this model, the Spice simulation of POSFET device in a single-ended op-amp configuration, and the effect of chip thickness on deflection are presented.

This paper presents the directions for computer aided design, modelling and simulation of bendable MOSFET transistors towards futuristic bendable ICs. In order to compensate the bending stress a generalised geometry variation is discussed. Based on drain-current and threshold-voltage parameters varying under the bending stress, a Verilog-A compact model is proposed and describes I-V characteristics of a MOSFET in a standard 0.18-μm CMOS technology. This model has been compiled into Cadence environment to predict value and orientation of the bending stress. The proposed model validates against macro-model simulation results, and agrees for both the electron and hole conduction. It has been found that there is significant performance advantage in process-induced uniaxial stressed n-MOSFET, exhibiting a smaller drain-current variation and thresh old voltage shift by monitoring the bending stress and changing the supply voltage.

The two major components of a robotic tactile-sensing system are the tactile-sensing hardware at the lower level and the computational/software tools at the higher level. Focusing on the latter, this research assesses the suitability of computational-intelligence (CI) tools for tactile-data processing. In this context, this paper addresses the classification of sensed object material from the recorded raw tactile data. For this purpose, three CI paradigms, namely, the support-vector machine (SVM), regularized least square (RLS), and regularized extreme learning machine (RELM), have been employed, and their performance is compared for the said task. The comparative analysis shows that SVM provides the best tradeoff between classification accuracy and computational complexity of the classification algorithm. Experimental results indicate that the CI tools are effective in dealing with the challenging problem of material classification.

This work presents and experimentally evaluates novel POSFET (Piezoelectric Oxide Semiconductor Field Effect Transistor) devices based tactile sensing arrays. The arrays, primarily developed for the robotic applications, consist of 5 × 5 POSFET touch sensing devices or taxels. The POSFET touch sensing devices are developed by spin coating piezoelectric polymer P(VDF-TrFE) film on the gate area of MOS devices and polarizing the film in situ. To detect contact events, the taxels utilize the contact forces induced change in the polarization level (and hence change in the induced channel current) of piezoelectric polymer. Both, individual taxels and the array are designed to match spatio-temporal performance of the human fingertips. Experimental results demonstrate that the POSFET tactile sensing arrays presented here are able to detect complex dynamic contact events such as rolling of an object.

This work presents the development of novel POSFET (Piezoelectric Oxide Semiconductor Field Effect Transistor) devices based tactile sensing system. The tactile sensing system, primarily developed for the robotic applications, consists of 5×5 POSFET touch sensing array and the associated read out and data acquisition system. The POSFET touch sensing devices are obtained by spin coating piezoelectric polymer P(VDF-TrFE), poly(vinylidene fluoride - trifluoroethylene), film on the gate area of MOS (Metal Oxide Semiconductor) devices and polarizing the film in situ. To detect contact events, the taxels utilize the contact forces induced change in the polarization level (and hence change in the induced channel current) of piezoelectric polymer. Both, individual taxels and the array are designed to match spatio-temporal performance of the human fingertips. The data acquisition system is implemented with off-the-shelf electronic components and its design takes into account both the application related requirements as well as the constraints posed by existing hardware on the humanoid robot `iCub'. The biasing scheme for using POSFET devices and the problems thereof are also been discussed.

Starting from human ¿sense of touch,¿ this paper reviews the state of tactile sensing in robotics. The physiology, coding, and transferring tactile data and perceptual importance of the ¿sense of touch¿ in humans are discussed. Following this, a number of design hints derived for robotic tactile sensing are presented. Various technologies and transduction methods used to improve the touch sense capability of robots are presented. Tactile sensing, focused to fingertips and hands until past decade or so, has now been extended to whole body, even though many issues remain open. Trend and methods to develop tactile sensing arrays for various body sites are presented. Finally, various system issues that keep tactile sensing away from widespread utility are discussed.