Lu Nanshu, who is currently a University of Texas at Austin ( UT-Austin ), a tenured professor appointed by the Temple Foundation, believes that the development trend of human technology must be that machines are becoming more and more like human beings. Like a machine. "In the era of artificial intelligence, the integration of humans and machines is inevitable, otherwise it will be out of touch with the times" SpaceX CEO Elon Musk 's speech at the 2017 World Government Summit impressed Lu Nanshu.
(Source: Pixabay)
In recent years, flexible wearable devices have made great progress in monitoring human biological signals. The use of flexible patches to monitor blood pressure and pulse is just around the corner. However, the existing wearable pressure sensor has a big problem: high sensitivity and wide working range cannot be achieved at the same time. Even a very slight pressure will greatly reduce the sensitivity of the sensor.
"The flexible pressure sensor track is very crowded. After two decades of development, research has encountered bottlenecks because there is still no good way to solve the contradiction between pressure and sensitivity," Lu Nanshu said.
Recently, the team led by Lu Nanshu has filled this gap by innovating the first hybrid sensor method in history. "This is the first sensor that uses a piezoresistive-pressure-capacitance hybrid response to withstand pressure without significantly reducing sensitivity. ." She told DeepTech.
is the first to combine capacitance with resistance to balance the wide pressure range and sensitivity
The "hybrid response pressure sensor (HRPS)" invented by Lu Nanshu's research group was recently published in Advanced Materials.
Through the combination of a conductive porous microstructure and an ultra-thin insulating layer, researchers have discovered for the first time that the mixed response of distributed piezoelectric resistors and piezoelectric capacitors can enable flexible pressure sensors to have both high sensitivity and wide operating range.As small as the weight of a fruit fly (0.07 pa), as large as the pressure generated by a person's footsteps (125 kPa), it can be sensitively sensed.
Figure | Hybrid response pressure sensor (HRPS)
According to reports, the sensor is made of a conductive nanocomposite (porous nanocomposite, PNC) with ultra-high porosity , Ultra-thin insulating layer (PMMA) and Au/PI electrode are composited. Among them, the porous nanocomposite (PNC) is composed of Ecoflex silica gel doped with carbon nanotubes (CNT).
Figure | Composite response pressure sensor HRPS application demonstration.
To show how sensitive the sensor is to tiny pressure signals, the researchers measured a fruit fly weighing only 0.7 milligrams, the airflow blown by a blower 3 cm above the sensor, three successively falling water droplets, and the human neck The pulses of the arteries and temporal arteries are beating.
The experimental results show that the pressure of HRPS on the fruit fly's own weight is only 0.07 Pa, and the pressure response caused by the tiny airflow and the dripping of water droplets is accurate and rapid, and the response time is only 94 milliseconds.
In terms of health monitoring, members of Lu Nanshu's research group attached a soft and thin HRPS to the carotid artery of the subject, which can clearly detect pulse fluctuations. The carotid artery and the frontotemporal artery are minute pulsations, and their measurement requires extremely high sensitivity of the equipment.
Even if additional pressure is applied to the sensor in advance, such as wearing a virtual reality ( VR ) helmet for the subject, a pre-pressure of 8 kPa is generated on the HRPS, and the temporal artery pulsation signal can still be clear Measured.
"This is the first time that the temporal artery pulsation signal has been non-invasively measured by a capacitive pressure sensor."Lu Nanshu said.
In the measurement of high pressure, HRPS also showed good sensitivity. In the supplementary video of the paper, the team members put HRPS on the sole of a subject weighing 80 kg, Measure the pressure generated by walking on the yoga mat, and the maximum recorded value of the final measurement is 125 kPa, which is consistent with the pressure generated by walking on human feet measured by other previous studies.
This study mainly shows the HRPS in human health monitoring In addition, Lu Nanshu has a more ambitious vision for the flexible sensor they developed. She is studying how to wrap this flexible sensor on other soft objects (such as robotic hands) to make it human The sensitivity of the skin. By simulating the real touch of human beings, the robot has the ability to recognize objects through touch.
From electronic tattoos to electronic skins, how do humans and machines approach each other?
In 2012, Lu Nanshu relied on " The invention of “electronic tattoo” was selected by the “MIT Technology Review” in the “35 people under the age of 35 in technological innovation” global region list.
Traditional smart wearable devices are large in size, inconvenient to carry, and have poor wearing comfort. "Electronic Tattoo or E-Tattoo" has non-invasive, thin and excellent deformation capabilities, and transmits various body information such as ECG, EMG, and E-Tattoo to mobile phones, computers and other terminals. This one-time Electronic patches have great market prospects in the fields of medical treatment or human-computer interaction, and are considered to be the "ultimate sensor form of wearable devices."
Figure | Multi-layer, modular "electronic tattoos" can achieve wireless charging And wireless data transmission
Lu Nanshu obtained a bachelor's degree and a doctorate degree from Tsinghua University and Harvard University respectively, and later worked as a Beckman postdoctoral researcher at University of Illinois at Urbana-Champaign Her research fields involve flexible electronics mechanics, materials, manufacturing and human body integration.
At present, Lu Nanshu constructs his own scientific research building from two aspects. One is the electronic tattoo (E-tattoo), which is thin and soft, so that it can fit human skin well, capture biological signals, and sense human life. Signs. The human body is an analog biological signal system, while the machine and electronic world are digital. Therefore, if you want to realize human-computer interaction, people need to be "digitalized", and "electronic tattooing" is considered to be one of the effective ways to "digitize" human beings.
Figure | Multi-layer, modular "electronic tattoo" can achieve wireless charging and wireless data transmission
The other is electronic skin (E-skin), through flexible pressure, temperature and other sensors, let Soft robots have sensitivities similar to human skin, giving them vivid sense of touch, sight, hearing, taste and smell. The research published this time is a new type of hybrid corresponding electronic skin that broadens the pressure working range of the sensor and maintains tactile sensitivity.
Lu Nanshu's ultimate goal is to complete the closed loop of human-computer interaction: the human body is connected to the digital world through electronic tattoos, and the robot simulates the human perception environment through electronic skin. Therefore, her team has been focusing on "flexible bioelectronic systems" in the following four aspects:
The first is the study of flexible/stretchable junction structural mechanics . Such as the deformation mechanism of the passive and active (piezoelectric) meandering ribbon structures and the bending of the upper and lower layers due to the mismatch of the Young's modulus between the layers of the multilayer flexible electrons decoupling .
The second is two-dimensional materials and nano-materials, including graphene electronic tattoo (Graphene E-Tattoo or GET), the mechanism of nano-bubbles and nano-tents formed by two-dimensional materials, and PNC.
The third is the preparation process and transfer technology, including the "cut-weld-paste" process and water-assisted transfer of wireless electronic tattoos.
The fourth is the bio-electronic interface, including the conformal mechanism between the device and the uneven surface of biological tissue ,The conformal artificial retina inspired by paper cutting, and the stable and reusable dry bonding interface brought by the surface pit array.
Human-computer interaction, open smart elderly care era
When asked about his most anticipated application scenarios, Lu Nanshu said: "I personally prefer medical applications, especially elderly care". At that time, she was a little moved, and she described it as "the whip is beyond reach".
Lu Nanshu's grandmother, grandfather, and grandmother are nearly 100 years old, but she has been abroad for a long time, and affected by the epidemic, she cannot return to China to take care of her parents and the elderly at home at any time. The real-time monitoring of the elderly’s activities and health through electronic tattoos, and the use of robotic caregivers to make up for the huge gaps and elderly care problems in the market are the future Lu Nanshu is looking forward to. Yes. Making electronic skins for robots, giving them the gentleness and tactility comparable to those of enemies, will greatly alleviate this kind of professional gap." When asked about artificial intelligence replacing human jobs, Lu Nanshu said: "Humans Emotional communication is irreplaceable, but transactional work can be done.”
(Source: Pixabay)
The Institute of Senior Citizens of the Chinese Academy of Social Sciences estimates that the business opportunities in China’s elderly care market are about 4 trillion yuan, which is expected to increase to 2030. 13 trillion yuan. “The elderly care service industry not only highlights the characteristics of people’s livelihood, but also shows its great attraction as a sunrise industry.”
The 7th census data shows that China’s aging population over the age of 65 reached 190 million, accounting for up to 190 million people. 13.5%, China is accelerating its entry into an aging society. The traditional old-age care model can no longer fully meet the current needs. It has become an inevitable trend to seek a new type of diversified and composite governance solution to solve the multi-level needs of the elderly through scientific and technological means. A small piece of the puzzle is missing.
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