Shulou(Shulou.com)11/24 Report--

This article comes from the official account of Wechat: knowledge Automation (ID:zhishipai), the original title: "Lin Xueping | the future trend of sensors", author: Lin Xueping

Let the intelligent world go back to square one, and the sensor is waiting here. The foundation of intelligence is perception, and the sensor is the entrance of perception. The sensor is developing in the direction of intelligence, thinking, analysis and diagnosis. As a more and more obvious intelligent micro-system, the sensor is more and more independent and has the ability of self-correction. So, with what ability will sensors detonate the future and drive the digital transformation?

Figure 1 Twenty trends of sensor development (Source: Singapore start-up consulting firm Twimbit) 3D sensor technology can build 3D images and fully meet the needs of human vision. It can use time of flight ToF (time of flight), structured light, 3D interference and so on to obtain 3D vision data. Among them, the ToF sensor has attracted a lot of attention in the mobile phone field, which provides an exciting point for the mobile phone, which has been busy improving the lens function. It uses the time difference of the laser pulse of each pixel on the infrared sensor to obtain the three-dimensional depth of field and form a three-dimensional 3D model.

However, the ToF camera in the mobile phone industry is a roller coaster experience, "take advantage of the fun to come, disappointed and gone." Its application peaked in 2018, with mid-and high-end models such as Samsung, Huawei, OPPO and Xiaomi all equipped with ToF lenses. When everyone thinks that this is the development direction of mobile phone images in the future, this kind of mobile phone suddenly and quickly disappears. Just like the figure of the delivery guy, the ToF lens comes quickly and goes quickly.

The reason is simple: ToF technology lacks rigid application support, and no widely used killer application can provide power for the further development of ToF lenses. ToF can be used to scan the shape of an object and then automatically build a 3D model. But for ordinary consumers, the establishment of a model has no practical effect. A mobile phone with a ToF lens can be used as a ruler, but it is not accurate enough. Besides, who would take it seriously when measuring with a mobile phone as a tape measure?

In the current intelligent world, any hard technology depends on the synchronization of software. Without software applications, it is difficult to support the iterative progress of hardware technology. Unless the rise of meta-universe, that is, AR / VR apps, may save the use of TOF lenses on mobile phones.

However, the floor-sweeping robot can replace the single-line mechanical scanning lidar with a wide-angle TOF camera, making it easier to build a "combat sand table" for the room, better planning the path, and making the floor-sweeping robot look less stupid. Otherwise, the sweeping robot will either hit the leg of the table or roll up socks and cables, and the effect of avoiding obstacles is too poor. But the premise is still that it is not too expensive.

On the other hand, the ranging and perception of the driving environment, the man-machine cooperation of the industrial cooperative robot and the intelligent logistics vehicle can also make the ToF sensor play a real role. But ToF sensor lenses are still too expensive for industry. From the perspective of industrial chain, the current infrared sensors of ToF lenses are mainly controlled by Sony, Infineon, on, Texas Instruments, Panasonic, while optical lenses include Liguang, Zhejiang Shunyu Optics, and AAC Technology. The CMOS image sensor is the core part, mainly from three bitter rivals for years: Sony, Samsung and Weil's Howie.

3D depth sensors are more ambitious militarily. The Defense Advanced Research projects Agency (DARPA) is developing 3D sensing technology for military use to facilitate covert operations at night.

Generally speaking, any autopilot system usually requires some form of active lighting to achieve autonomous navigation at night. However, the radiation signal will appear when the headlight is turned on or the transmitting system of the lidar (LiDAR) is turned on. In military situations, it will enable the enemy to detect the presence of these vehicles from a long distance. DARPA is trying to develop 3D vision sensors using weak thermal signals from a variety of living and inanimate objects in the wild. The "invisible headlights" project will explore the information contained in all kinds of thermal radiation in the environment, because all objects emit heat. The goal of DARPA is to explore how to capture information and develop passive sensors based on a very small amount of thermal radiation to generate 3D maps for navigation. It will greatly expand the autopilot system and can be run covertly.

The most important feature of acoustic technology is that it is relatively cheap compared with sensors of other technologies and can explore a variety of applications. The saw SAW technology, which is widely used in filter signal processing, shines brilliantly on smart phone speakers. In the world, the SAW filter market is mainly occupied by Japanese companies, including Murata Murata, TDK, Sun induced Power Taiyo Yuden are representative manufacturers, accounting for a total market share of about 82%. The Murata family can account for nearly half of the global SAW filter market. Among domestic RF filter companies, Shenzhen Maijie Microelectronics Technology is in the vanguard of domestic replacement of filters and integrated inductors. It has also entered Huawei's supply chain with revenue of 1.3 billion in 2021.

Saw SAW technology is relatively used in low frequency, is also sensitive to temperature, and occupies all the opportunities in the 4G era. However, in the high-frequency field, and in the case of multi-signal processing to avoid interference, bulk acoustic wave BAW resonator technology is more widely used, it comes from the 5G era and the Internet of things era. In this respect, the United States is even more technologically advanced. Both American Qorvo and Texas Instruments have an advantage. In this zone, it is also difficult for China to break through the pain in the neck, Texas Instruments also used this technology in 2019 on the integrated clock function. With the increasing speed of big data's transmission, there are stringent requirements for clock signals. The data processing system DPS, which needs 18G capacity per second, has become an urgent problem for many chip manufacturers. On the other hand, the body sound wave BAW can well realize the clock technology under the high frequency signal. Although saw is relatively cheap, from the overall technological development trend, BAW is replacing the position of saw, and has been used in high-end mobile devices such as iPhone.

A sensor is a power station. A sensor has two directions. One is an integrated sensor, which is integrated with other devices to share energy input, and the other is an independent sensor. The latter is like Robinson living on a desert island, it is best to survive on its own without taking care of it. Incoming calls are the first challenge to bear the brunt.

Self-powered sensor is attracting wide attention, and it is very suitable for remote monitoring, wireless connection and continuous monitoring.

This often requires the deployment of energy collectors with sensors, and these micro-energy recovery systems can generate micro-currents from solar energy, vibration and thermal energy for their own use. In other words, a sensor is an electric power generation device and energy storage device. Since an electric car can be an energy storage system, why not a small sensor?

Parker Hannifen Parker, an American supplier of motion and power control systems, acquired Lord Lord, an adhesive and vibration management equipment company, for $3.7 billion in 2019, which has been providing accurate measurement wireless and pressure sensors for aerospace and petrochemical companies. Hank is diversifying from its traditional powertrain business, especially to strengthen the technical advantages of its engineering materials division in order to fully meet emerging trends such as electrification and lightweight. With annual sales of $1.1 billion, Lord's accumulation of paints, springs, sensor hardware and sensor clouds perfectly caters to Pike's needs.

Fig. 2 the new favorite of the old power sensor (Source:Parker Lord official website) while Lod's MicroStrain sensing business already uses piezoelectric materials to convert the strain energy of the materials into electrical energy storage. The era of an independent power station for sensors began.

Machine learning is everywhere from intelligent robots to intelligent sensors. If the algorithm is not only placed in the machine equipment, but also can be placed in the smallest sensing unit-the sensor, then embedded artificial intelligence will vigorously promote the development of intelligent sensors.

Of course, machine learning is only one of the directions. Most sensors have shifted from interactive to predictive, shifting the initiative of machine intelligence to sensor intelligence in part. The sensor with the function of intelligent real-time data analysis and process correction will greatly improve the interactive ability of the equipment. This also means that edge computing will be a further step forward at the edge of the machine.

However, the parameters that a sensor can measure are limited, so why not integrate multiple sensors together? As a result, a variety of combined sensors come one after another, such as temperature + humidity, pressure + flow, vibration + acceleration + deceleration and other sensors, become the most widely used combination. The sensor fleet is mixed to realize the "multi-purpose" of multi-parameter detection, and the application of closed-loop automation is formed by detecting various parameters. This ushered in a wide range of development space in the field of intelligent manufacturing.

The other direction is the fusion sensor Fusion. Intelligent sensors are accelerating the development of self-driving vehicles, and the multi-function fusion of sensors will take advantage of different sensors to provide data analysis and control capabilities, so as to have embedded intelligence. This is especially important in military aircraft. The American F35 fighter has been connecting and analyzing multi-domain data, and the core is to use fusion sensors to realize high-speed analysis of multi-dimensional data, and to be able to make use of data from different platforms. whether it is sea, air, sea and land sensor data, a variety of heterogeneous data concurrent processing.

Howie, owned by Weir Semiconductor, has just launched a composite sensor that combines CIS with event vision sensor EVS on the basis of the existing image sensor CIS (CMOS Image Sensor). EVS is a bionic sensor that does not require exposure time limits. This will be a super boon for AR helmet players, and the photo image of the phone will be further improved. This characteristic of integrating image and vision sensors on a chip belongs to pixel-level sensor fusion, which is undoubtedly an important direction in the future.

Pulse flow, blood flow, heartbeat flow, where the great health has become the focus of future development, health prevention and diagnosis, can be achieved through the widely used sensors. Regardless of life-support implant devices, long-term monitoring of severe patients, and robotic surgery. The Leonardo da Vinci surgical robot, which was born in 2000, is the most successful surgical robot in the world. At first, it was just a stabilizer to assist doctors in surgery, but its ability is getting stronger and stronger. It has stepped onto the operating table and become the best companion for surgeons. The Leonardo da Vinci robot detonated the robot surgery on its own.

According to a report in the Journal of the American Medical Association (JAMA), the proportion of robotic surgery in surgery has increased from 2% to 15% in the past five years from 2016 to 2021, and is accelerating. At present, there should be more than 150 machines installed in China, and 40,000 surgeries are performed through Leonardo da Vinci's surgical robot each year.

It has great advantages in 3D imaging and precise control. With its assistance, doctors can create 3D images of the lesion with 10-15 times magnification without difficulty (traditional imaging systems can only provide 2-3 times two-dimensional images), and then operate the robot to perform surgery accurately. And the hero behind this is nearly 500 sensors. Leonardo da Vinci robot is expensive, a machine is tens of millions of yuan. The optical torque sensor accounts for about 5% of the cost composition of the surgical robot.

For medical and family diagnostics, this is just the beginning. The popularity of the Internet of things and wearable sensors have boomed in health applications. These sensors can be used in a non-invasive way for geriatric nursing monitoring and daily health monitoring. Sleep monitoring on watches is only pediatrics, while the prevention of diseases such as diabetes is becoming a hot spot.

There is no doubt that the innovation of wearable sensors has brought about changes in the way of health monitoring. Wearable and implantable sensors transmit health data in real time, providing quantitative motion data and a variety of physiological data, thus achieving accurate diagnosis. Different sensors are used in these key devices, including CMOS, vibration, blood glucose and optical sensors used in mobile phone imaging. The four ring sensors behind the Apple Watch iWatch judge the movement and pulse of blood vessels by reflecting LED light on the skin.

Where is the pulse flow, blood flow, heartbeat flow? All human health data flow to a digital channel in the form of a data stream. All the data of the human body is stored on an Internet of things digital health platform. Big data's analysis automatically gives people a comprehensive portrait of their health: the existing health prevention model is about to undergo profound changes.

According to the data in the CB Insights report in 2020, a total of US $80.6 billion in financing and 55,000 venture capital investments have taken place in this area. There were nearly 200 health care financing of more than $100 million in 2020, setting a new record. And the medical giant has more than $550 billion in cash, waiting to dig deep in this field of digital medicine. Sensors, on the other hand, bear the brunt of this kind of medical investment.

Without sensors to tackle key problems, the industrial Internet will always play a supporting role in the development of the industrial Internet, which puts forward higher requirements for sensors. The performance of these sensors and the controller system largely determine the ability of managers to remotely use the industrial Internet platform to achieve key control functions. For automation companies like Honeywell, while consolidating the dominance of control systems, it has an obsessive pursuit of sensors-which is why it has been on a buying spree in recent years, including temperature and humidity sensors. Most typically, it acquired the British Citeytech sensor, the originator of the gas sensor, in 2019. Only by strengthening the hard core technology of control and sensor, can the industrial Internet platform be truly implemented.

It is estimated that by 2023, the number of industrial Internet device connections will reach 21.5 billion. The industrial Internet needs to solve six problems: connection, perception, control, analysis, communication and application. Connection is only physical work, analysis is not of great use, communication will become a general technology, and its application will be nothing but eye-catching before the analysis and mechanism model are built. Who is controlling the device and who is perceiving the data are crucial. This is the key of the industrial Internet platform. Unfortunately, in China, a lot of industrial Internet has been far away from this core battlefield, playing tricks on the application layer, only doing a little spray on a huge amount of junk data.

Soft sensor is also a sensor soft sensor (soft sensor) is an interesting thing. Unlike the soft body of a soft robot, a soft sensor is actually a virtual sensor, which is, to put it bluntly, software. It can handle multiple measurements at the same time.

Based on the control theory, the soft sensor may process dozens or even hundreds of measurements at the same time through indirect use. In the aspect of data fusion, soft sensor plays a great role. It combines different static data and dynamic measurement data together, so it can be used in fault diagnosis and control applications. The most classic soft sensor can start with the Kalman filter. It is a kind of data processing technology to remove noise and restore real data, and it can be regarded as data filtering calculated by software. This is also seen as a soft sensor. Of course, the latest soft sensors use neural networks or fuzzy computing. Soft sensor is a software program that uses the information of other sensors to estimate physical quantities, rather than direct measurement.

This trend is most significant in process automation, in which many control functions are activated by software and completed by computer assistance. High reliability and high precision are the hallmarks of soft sensors, such as soft sensors based on pH values, which can easily trigger the load of water treatment and peak detection.

Soft sensor can also be regarded as the integrator of digital technology, which is integrated by advanced automation, Internet of things, big data real-time analysis, sensors and so on.

More sensor technology, the combination of optical technology and sensors, is benefiting from the emerging optoelectronic technology. The development of the chip is mainly made of silicon, and the optical and electronic parts can be integrated on the silicon chip, thus forming optoelectronic technology (photonics). It superimposes the rapid upgrading ability of electronics on optical instruments that have been making slow progress for many years, thus stimulating a new vitality, thus bringing about a moving moment for optical sensors, which will also benefit the solar industry and the industrial Internet.

IO-Link can achieve digital connection, directly transfer data from the sensor to the Internet of things interface and programmable logic controller PLC. Compared with the traditional independent module connection sensor technology, IO-Link technology has outstanding cost-effectiveness and technology improvement. The traditional independent module, often a module is an independent network node. For each node deployed, a set of chips is needed, and when there are more control points, the solution cost of the system will rise greatly. On the other hand, IO-Link adopts master and slave mode, which means that a master station can expand up to 128control points to reduce network burden and improve efficiency. At the same time, thanks to the standardization of IO-link communication, it is more convenient to configure such as RFID, valve island and sensor, not only for state monitoring, but also for parameter configuration and maintenance.

Tianjin Yike's IO / Link is widely used in power lithium battery factories. The factory production line of lithium electricity industry is relatively long, there are many and dense testing points, there are certain requirements for dust protection, at the same time, a high degree of automation, requires the cooperation of a variety of components, and hot-swappable continuous production and a certain performance-to-price ratio is also necessary. Based on the above requirements, the IO-Link scheme is very suitable for the characteristics of lithium power industry. The great development of domestic power battery industry has also brought great opportunities to domestic sensors.

Wireless sensor network is also developing rapidly, it has very high requirements for low energy consumption. As you can imagine, there are many development scenarios.

Figure 3 different wireless standards (ISM industrial, scientific, medical frequency band) need to monitor the body temperature of thousands of cows on a daily basis to prevent animal diseases such as foot-and-mouth disease. If you use wireless network technology, it can be easily achieved as long as a temperature sensor with a wireless transmitter is installed on each cow to read the body temperature and transmit it to a main terminal at any time. This kind of low-energy sensor cluster can greatly improve the efficiency and speed of wireless networks, but this kind of sensor networks must ensure low power consumption before they can be widely used. The two most important characteristics of wireless sensor network WSN are reliability and low power, while the cost ranks third.

Non-contact sensing technology, whether light, wave, magnetism, laser, sound and so on, is developing rapidly. Infrared temperature sensors have been used to detect the temperature of the epidemic in the last two years. With higher accuracy and more application scenarios, contactless sensors will also increase significantly. Similarly, rapid detection of biosensors is also developing rapidly in order to promote timely diagnosis and in vitro diagnosis.

Sensors in drones are also a focus. In fact, a drone is a collection of sensors, which can be thought of as a flying group of sensors. UAV widely uses lidar, tilt sensor, inertial measurement unit and so on. Shenzhen DJI is undoubtedly a leader, and US arms suppliers Lockheed Martin and Boeing are also actively involved. The drone market has undoubtedly exploded from photo entertainment, while military use has greatly increased its attention. The market is still in its infancy, and there are huge opportunities for all kinds of sensors.

Lidar, as a non-contact sensor, is being respected. It can capture millions of data points in real time, making it the most direct application in self-driving cars. At present, the domestic progress is not bad, Huawei, Suiteng Juchuang, Wesai science and technology all have very good products. In the field of handling robot AGV, warehouse intelligent management also promotes the application of lidar, including Sike Optoelectronics Sick, the largest sensor manufacturer in Germany, Beiyang Hokuyo, the largest lidar manufacturer in Japan, and so on. Drones and robots are also good applications.

Another direction of the sensor is a friendly natural interface, which is developed around the ability of human senses to capture. Since the birth of the computer, the interactive interface has been ranked first by the keyboard, while the mouse has triggered the second round of graphical interface. But since then, there has been no decisive progress in human-computer interaction. Who can become the third place in the human-computer interface? Voice, touch and gesture, these natural interfaces that are highly consistent with human biological characteristics are all possible. However, the performance of intelligent voice in speaker control is very disappointing, and voice control does not detonate the family as desired. The era of smart speakers launched by Amazon's Echo, followed by Google's Nest and domestic Xiaomi, proved to be nothing more than an illusory orgy of interface interaction. The interface of smart home is still waiting for a new master. Natural interface sensors, there is still a huge room for development.

Note: the role of pit sensors cannot be overemphasized. Sensors are the facial features of the automation system and the vanguard of digital technology. It is also a super deficiency that goes unnoticed in China, one of the reasons is that its applications are too scattered. There are more than 30,000 kinds of sensors in the world, with a small number of narrow applications. However, the pits it left behind in the smart world are all quiet. If you only look up to the sky and chase the stars, it is easy to fall in these dark pits.

Note: part of the content comes from the sensor report "Trends of change: paradigm shift from 2021 to 2023" by Twimbit, a Singapore consulting firm. This paper reconstructs the viewpoint and content.

A brief introduction to Lin Xueping: general manager of Beijing Lianxun Power Consulting Co., Ltd., and part-time professor of Jingyi College of Tianjin University

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