Haptic perception using optoelectronic robotic flesh for embodied artificially intelligent agents

Twisted Optical Micro/Nanofibers Enabled Detection of Subtle Temperature Variation

The detection of subtle temperature variation plays an important role in many applications, including proximity sensing in robotics, temperature measurements in microfluidics, and tumor monitoring in healthcare. Herein, a flexible miniaturized optical temperature sensor is fabricated by embedding twisted micro/nanofibers in a thin layer of polydimethylsiloxane. Enabled by the dramatic change of the coupling ratio under subtle temperature variation, the sensor exhibits an ultrahigh sensitivity (-30 nm/°C) and high resolution (0.0012 °C). As a proof-of-concept demonstration, a robotic arm equipped with our sensor can avoid undesired collisions by detecting the subtle temperature variation caused by the existence of a human. Moreover, benefiting from the miniaturized and engineerable sensing structure, real-time measurement of subtle temperature variation in microfluidic chips is realized. These initial results pave the way toward a category of optical sensing devices ranging from robotic skin to human-machine interfaces and implantable healthcare sensors.

An optical-based multipoint 3-axis pressure sensor with a flexible thin-film form

Multipoint 3-axis tactile pressure sensing by a high-resolution and sensitive optical system provides rich information on surface pressure distribution and plays an important role in a variety of human interaction-related and robotics applications. However, the optical system usually has a bulky profile, which brings difficulties to sensor mounting and system integration. Here, we show a construction of thin-film and flexible multipoint 3-axis pressure sensor by optical methods. The sensor can detect the distribution of 3-axis pressure on an area of 3 centimeter by 4 centimeter, with a high-accuracy normal and tangential pressure sensing up to 360 and 100 kilopascal, respectively. A porous rubber is used as a 3-axis pressure-sensitive optical modulator to omit the thick and rigid focusing system without sacrificing the sensitivity. In addition, by integrating thin and flexible backlight and imager, the sensor has a total thickness of 1.5 milimeter, making it function properly even when bent to a radius of 18 milimeter.

Flexible Optoelectronic Multimodal Proximity/Pressure/Temperature Sensors with Low Signal Interference

Multimodal tactile sensors are a crucial part of intelligent human-machine interaction and collaboration. Simultaneous detection of proximity, pressure, and temperature on a single sensor can greatly promote the safety, interactivity, and compactness of interaction systems. However, severe signal interference and complex decoupling algorithms hinder the actual applications. Here, this work reports a flexible optoelectronic multimodal sensor capable of detecting and decoupling proximity/pressure/temperature by integrating a light waveguide and an interdigital electrode (IDE) into a compact fibrous sensor. Negligible signal interference is realized by combining heterogeneous sensing mechanisms of optics and electronics, which encodes proximity into capacitance, pressure into light intensity and temperature into resistance. The sensor exhibits a large sensing distance of 225 mm with fast responses for proximity detection, a pressure sensitivity of 0.42 N-1 , and a temperature sensitivity of 7% °C-1 . As a proof of concept, a doll equipped with the sensor can accurately discriminate and detect various stimuli, thus achieving safe and immersive interactions with the user. This work opens up promising paths for self-decoupled multimodal sensors and related human/machine/environment interaction applications.

Emerging MXene-Based Flexible Tactile Sensors for Health Monitoring and Haptic Perception

Due to their potential applications in physiological monitoring, diagnosis, human prosthetics, haptic perception, and human-machine interaction, flexible tactile sensors have attracted wide research interest in recent years. Thanks to the advances in material engineering, high performance flexible tactile sensors have been obtained. Among the representative pressure sensing materials, 2D layered nanomaterials have many properties that are superior to those of bulk nanomaterials and are more suitable for high performance flexible sensors. As a class of 2D inorganic compounds in materials science, MXene has excellent electrical, mechanical, and biological compatibility. MXene-based composites have proven to be promising candidates for flexible tactile sensors due to their excellent stretchability and metallic conductivity. Therefore, great efforts have been devoted to the development of MXene-based composites for flexible sensor applications. In this paper, the controllable preparation and characterization of MXene are introduced. Then, the recent progresses on fabrication strategies, operating mechanisms, and device performance of MXene composite-based flexible tactile sensors, including flexible piezoresistive sensors, capacitive sensors, piezoelectric sensors, triboelectric sensors are reviewed. After that, the applications of MXene material-based flexible electronics in human motion monitoring, healthcare, prosthetics, and artificial intelligence are discussed. Finally, the challenges and perspectives for MXene-based tactile sensors are summarized.

Stretchable reflective coating for soft optical waveguides and sensors

Soft robots must embody mechanosensing capabilities to merge with and act in the environment. Stretchable waveguides are making a mark in soft mechanical sensing since they are built from pristine elastomers. Therefore, they are insensitive to electromagnetic fields and weakly affect the deformations of the robot. However, issues in light-shielding, signal decoupling, and core-cladding interfaces are still open challenges. In this work, titanium oxide particles (TiO₂) are dispersed in silicone elastomers to develop a soft optical shield coating. Results show that the added particles do not harden the matrix and reduce light transmission. Almost full NIR shielding is achieved by adding 1.0 vol% of TiO₂ in 150 μm thick films. These properties make the proposed shielding coating an excellent candidate for soft mechanosensing. An open-access tool is developed to design soft optical devices by programming light transmittance at desired wavelengths by tuning, both, TiO₂ concentration and film thickness. Finally, two proof-of-concepts are demonstrated, a soft waveguide and a soft strain sensor, by integrating the developed material to shield a transparent PDMS resin and a semi-transparent Ecoflex00-10 matrix, respectively. The soft waveguide can stretch up to 40% with very low optical loss, while the optical strain sensor can detect strain up to 90%. In both cases, bending, folding, and indentation of the devices have a significantly low impact on light transmission. These results can pave the way to design new optical transmission devices and sensors that exploit light reflection and that allow for discriminating different types of mechanical stimuli in soft robots.

Robots and Robotics in Nursing

Technological advancements have led to the use of robots as prospective partners to complement understaffing and deliver effective care to patients. This article discusses relevant concepts on robots from the perspective of nursing theories and robotics in nursing and examines the distinctions between human beings and healthcare robots as partners and robot development examples and challenges. Robotics in nursing is an interdisciplinary discipline that studies methodologies, technologies, and ethics for developing robots that support and collaborate with physicians, nurses, and other healthcare workers in practice. Robotics in nursing is geared toward learning the knowledge of robots for better nursing care, and for this purpose, it is also to propose the necessary robots and develop them in collaboration with engineers. Two points were highlighted regarding the use of robots in health care practice: issues of replacing humans because of human resource understaffing and concerns about robot capabilities to engage in nursing practice grounded in caring science. This article stresses that technology and artificial intelligence are useful and practical for patients. However, further research is required that considers what robotics in nursing means and the use of robotics in nursing.