Electronic Textiles (e-textiles) are fabrics that feature electronics and interconnections woven into them, presenting physical flexibility and typical size that cannot be achieved with other existing electronic manufacturing techniques. Components and interconnections are intrinsic to the fabric and thus are less visible and not susceptible of becoming tangled or snagged by surrounding objects. E-textiles can also more easily adapt to fast changes in the computational and sensing requirements of any specific application, this one representing a useful feature for power management and context awareness. The vision behind wearable computing foresees future electronic systems to be an integral part of our everyday outfits. Such electronic devices have to meet special requirements concerning wearability. Wearable systems will be characterized by their ability to automatically recognize the activity and the behavioral status of their own user as well as of the situation around her/him, and to use this information to adjust the systems' configuration and functionality. This review focuses on recent advances in the field of Smart Textiles and pays particular attention to the materials and their manufacturing process. Each technique shows advantages and disadvantages and our aim is to highlight a possible trade-off between flexibility, ergonomics, low power consumption, integration and eventually autonomy.

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Wearable Electronics and Smart Textiles: A Critical Review

Soft robotics enables the design of soft machines and devices at different scales. The compliance and mechanical properties of soft robots make them especially interesting for medical applications. Depending on the level of interaction with humans, different levels of biocompatibility and biomimicry are required for soft materials used in robots. In this Review, we investigate soft robots for biomedical applications, including soft tools for surgery, diagnosis and drug delivery, wearable and assistive devices, prostheses, artificial organs and tissue-mimicking active simulators for training and biomechanical studies. We highlight challenges regarding durability and reliability, and examine traditional and novel soft and active materials as well as different actuation strategies. Finally, we discuss future approaches and applications in the field. Soft robots have broad applications in medicine. In this Review, biomedical applications, including surgery, drug delivery, prostheses, wearable devices and artificial organs, are discussed in the context of materials, actuation strategies and challenges.

Biomedical applications of soft robotics

The emerging field of soft robotics makes use of many classes of materials including metals, low glass transition temperature (Tg) plastics, and high Tg elastomers. Dependent on the specific design, all of these materials may result in extrinsically soft robots. Organic elastomers, however, have elastic moduli ranging from tens of megapascals down to kilopascals; robots composed of such materials are intrinsically soft − they are always compliant independent of their shape. This class of soft machines has been used to reduce control complexity and manufacturing cost of robots, while enabling sophisticated and novel functionalities often in direct contact with humans. This review focuses on a particular type of intrinsically soft, elastomeric robot − those powered via fluidic pressurization.

Soft Robotics: Review of Fluid‐Driven Intrinsically Soft Devices; Manufacturing, Sensing, Control, and Applications in Human‐Robot Interaction

Wireless sensor network (WSN) technologies are considered one of the key research areas in computer science and the healthcare application industries for improving the quality of life. The purpose of this paper is to provide a snapshot of current developments and future direction of research on wearable and implantable body area network systems for continuous monitoring of patients. This paper explains the important role of body sensor networks in medicine to minimize the need for caregivers and help the chronically ill and elderly people live an independent life, besides providing people with quality care. The paper provides several examples of state of the art technology together with the design considerations like unobtrusiveness, scalability, energy efficiency, security and also provides a comprehensive analysis of the various benefits and drawbacks of these systems. Although offering significant benefits, the field of wearable and implantable body sensor networks still faces major challenges and open research problems which are investigated and covered, along with some proposed solutions, in this paper.

Wearable and Implantable Wireless Sensor Network Solutions for Healthcare Monitoring

Smart textiles research represents a new model for generating creative and novel solutions for integrating electronics into unusual environments and will result in new discoveries that push the boundaries of science forward A key driver for smart textiles research is the fact that both textile and electronics fabrication processes are capable of functionalizing large-area surfaces at very high speeds In this article we review the history of smart textiles development, introducing the main trends and technological challenges faced in this field Then, we identify key challenges that are the focus of ongoing research We then proceed to discuss fundamentals of smart textiles: textile fabrication methods and textile interconnect lines, textile sensor, and output device components and integration of commercial components into textile architectures Next we discuss representative smart textile systems and finally provide our outlook over the field and a prediction for the future

Smart textiles: Challenges and opportunities

This paper reports on the full realization of a garment embedded patient monitoring system, including wireless communication and inductive powering. The developed system is primarily intended for the continuous monitoring of the electrocardiogram (ECG) of children with an increased risk of Sudden Infant Death Syndrome (SIDS). The sensors and the antenna are made out of textile materials. All electronics are mounted on a flexible circuit to facilitate integration in the baby's pajamas. A significant increase in the comfort of patient and nursing staff is achieved by this integration in textiles. A prototype baby suit was fabricated and successfully tested.

Integrating wireless ECG monitoring in textiles

This paper reports for the first time on the realization of a garment embedded patient monitoring system, including wireless communication and inductive powering. The developed system is primarily intended for the continuous monitoring of the electrocardiogram (ECG) of children with an increased risk of SIDS (sudden infant death syndrome). The sensors and the antenna are made out of textile materials. All electronics are mounted on a flexible circuit to facilitate integration in the baby's pyjamas. A significant increase in the comfort of patient and nursing staff is achieved by this integration in textiles. A prototype baby suit was fabricated and successfully tested by a 21 weeks old baby.

This paper reports on the development of an autonomous monitoring system, capable of continuously measuring the pressure inside the bladder. The capsule features wireless bi-directional communication and can be inductively powered anywhere inside the bladder. Short-circuiting the resonant LC tank for the data transmission maximizes the operating range of the passive telemetry. A novel clock extraction method is presented, based on lock-in of a Schmitt-trigger oscillator into the external radio-frequency field. A prototype was built using only discrete components. The system measures the pressure with a resolution of 0.04 kPa at a sampling rate of 10 Hz.

An autonomous bladder pressure monitoring system

A readout circuit for a passive telemetric intra-ocular pressure (IOP) sensor is being developed. The intra-ocular sensor consists of a capacitive pressure sensor in parallel with a planar coil. This inductor–capacitor (LC) resonant circuit transduces the pressure into a shift of resonance frequency. A voltage controlled oscillator (VCO) is used to excite the sensor over a large frequency range (20–40 MHz), hereby detecting resonance of the internal sensor, and thus enabling the measurement of the intra-ocular pressure. This low power circuit is extremely compact, making it suitable for long-term ambulant patient monitoring. The circuit allows wireless readout of the smallest pressure transducers. Tests show promising results at mutual coil distances up to 7.5 mm.

A readout circuit for an intra-ocular pressure sensor

As the intelligence and the functionality of microrobots increase, there is a growing need to incorporate sensors into these robots. In order to limit the outer dimensions of these microsystems, this research investigates sensors that can be integrated efficiently into microactuators. Here, a pneumatic piston-cylinder microactuator with an integrated inductive position sensor was developed. The main advantage of pneumatic actuators is their high force and power density at microscale. The outside diameter of the actuator is 1.3 mm and the length is 15 mm. The stroke of the actuator is 12 mm, and the actuation force is 1 N at a supply pressure of 1.5 MPa. The position sensor consists of two coils wound around the cylinder of the actuator. The measurement principle is based on the change in coupling factor between the coils as the piston moves in the actuator. The sensor is extremely small since one layer of 25 μm copper wire is sufficient to achieve an accuracy of 10 μm over the total stroke. Position tests with a PI controller and a sliding mode controller showed that the actuator is able to position with an accuracy up to 30 μm. Such positioning systems offer great opportunities for all devices that need to control a large number of degrees of freedom in a restricted volume.

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Johan Coosemans

Papers

Integrating wireless ECG monitoring in textiles

Integrating wireless ECG monitoring in textiles

An autonomous bladder pressure monitoring system

A readout circuit for an intra-ocular pressure sensor

Characterization and control of a pneumatic microactuator with an integrated inductive position sensor