Recently, drones are on fire again! Whether it is drones spraying disinfectant, or drones delivering, or even drones “calling” to wear masks, they have entered a wider range of real life, allowing the public to have a new understanding of it, and no longer It is a relatively simple “toy” in the traditional concept. One of the key factors in this improvement is the use of high-performance microelectromechanical systems (MEMS) sensors.
In fact, with the penetration of AI in the Internet of Things and the enhancement of edge computing capabilities in recent years, MEMS sensors are gradually becoming the most popular micro-sensors due to a series of advantages such as small size, light weight, low power consumption, high reliability and high sensitivity. The main force has a great tendency to replace traditional mechanical sensors.
Zhao Yanhui, Director of ADI’s Asia Pacific MEMS Product Line, delivered a speech at the ADI China 25th Anniversary Media Technology Day
“MEMS technology is ubiquitous, and its applications have covered all fields of life such as robots, smart cities, medical equipment, condition monitoring, smart agriculture, and autonomous driving.” Zhao Yanhui, director of ADI’s Asia-Pacific MEMS product line, pointed out that professional research institutions The data also validates Zhao Yanhui’s point of view. According to Yole Développement, the global MEMS market reached US$11.6 billion in 2018 and is expected to continue to grow at a compound annual growth rate (CAGR) of 8.2% by 2024. Among them, consumer applications will account for 60% of the MEMS market, automotive applications will account for 20%, and the remaining 20% will include applications such as telecommunications, medical, industrial and aerospace. The advantages of MEMS sensors are obvious. Zhao Yanhui used the three popular applications as examples to introduce the huge application prospects of MEMS sensors in emerging markets in detail.
Rejecting interference, MEMS sensor-based IMU acts as the “last barrier” for autonomous driving
In the era of the Internet of Things, most applications are more or less associated with location services, especially for moving objects, the need for positioning is more obvious. According to Zhao Yanhui, China Mobile recently invested over 336 million yuan to purchase 4,400 sets of high-precision satellite positioning reference stations, and stepped up the deployment of the Internet of Things, indicating that communication operators have entered the implementation stage of high-precision location services.
As a typical application scenario of high-precision location services, autonomous driving is also developing in controversy. It involves many key technical links and a long industrial chain. Accelerating the commercialization of autonomous driving is inseparable from the parallel development of all related industries and technologies.
Therefore, the accuracy of the navigation system in the field of autonomous driving cannot be guaranteed only by high-precision satellites. The inertial measurement unit (IMU) based on MEMS sensor technology is the last barrier to ensure autonomous driving. Because whether it is a camera, millimeter-wave radar, lidar, or satellite navigation and positioning, it will be affected by the external environment. Only the inertial navigation based on IMU can provide continuous, high-precision, high-speed automatic driving systems without being affected by the external environment. Reliable vehicle position, direction, speed and other multi-dimensional information to ensure the safe driving of the vehicle.
ADI is one of the earliest technology providers to conduct research in this field. Before passenger car autonomous driving technology entered the public eye, ADI IMU has been widely used in agricultural automation, which is equivalent to low-speed L4 level autonomous driving.
ADI’s IMU applications and product lines are also very extensive. Since the launch of the first IMU product in 2007, after more than ten years of innovation and development, its IMU products have continued to improve in performance and smaller in size. According to Zhao Yanhui, in November last year, ADI launched the latest mass-produced IMU product ADIS1650x series, paying more attention to the needs of the industrial “sports Internet of things” and its requirements for precise geographic positioning. More precise navigation and guidance due to turbulence, vibration, wind, temperature and other environmental disturbances. “Although the volume of the ADIS1650x is much smaller, it still uses a differential structure to achieve very good vibration suppression characteristics.” Zhao Yanhui emphasized: “Compared with other similar high-precision products, the ADIS1650x series IMU has a 5 times wider dynamic range, To adapt to extreme situations; 2 times wider bandwidth to capture rapid changes; 10 times more vibration suppression characteristics and 10 times more improved low-noise accelerometers.”
Industrial control security, detection first, ADI industrial control solutions based on condition detection
As an important driving force for a new round of technological revolution and industrial transformation, new manufacturing is setting off a wave of innovation in China. In intelligent industrial production, MEMS sensors are allowing cold machines to “talk” to us, such as enabling vibration analysis and diagnosis, lubrication analysis, infrared thermal imaging, ultrasonic testing, and more. Zhao Yanhui said that at this stage, industrial equipment has generally achieved digitization and interconnection, and is helping to transform production tools. Using the IIoT (Industrial Internet of Things) to monitor the health of machines helps enable predictive maintenance, allowing industry personnel to predict failures, resulting in significant operational cost savings. Of the physical quantities that can be measured, vibration spectrum measurements provide the most information on the root causes of problems in rotating machines and have been reliably applied to the most critical equipment in a variety of industrial applications.
Since 2018, ADI has successively acquired OtoSense and Test Motors, and plans to combine OtoSense’s software with Test Motors’ monitoring capabilities to create a solution that provides more advanced and comprehensive health monitoring for machines by capturing a wider range of potential faults. In fact, ADI’s condition monitoring solution has been able to provide customers with a complete system for early anomaly detection, in which various types of precise MEMS sensors also play a pivotal role.
Advanced Features to Support Structural Health Monitoring For condition monitoring and structural health monitoring, measurement range is an important parameter. Zhao Yanhui gave an example: “ADXL100x series MEMS accelerometers can achieve high-resolution vibration measurement and are suitable for most fault (sliding bearing damage, unbalance, friction, looseness, gear defects, bearing wear and cavitation) monitoring applications in industrial conditions. These accelerations The meter has a full-scale range of ±100g (ADXL1001), ±50g (ADXL1002), and ±500g (ADXL1004), and has an ultra-low noise density of 25 μg/√Hz to 125 μg/√Hz over a wide frequency range. In addition, these The accelerometer has an integrated full electrostatic self-test (ST) function and out-of-range (OR) indication feature, operates from a single 3.3V to 5.25V supply, and has low power consumption, which also aids in the design of wireless sensing products.”
At the same time, in order to simplify the design, ADI increasingly provides products ranging from components to complete functional modules. For example, ADI provides a complete solution using the ADcmXL3021 model to implement triaxial measurement. This 3.3 V supply voltage product includes 3 ADXL1002-based measurement chains, a temperature sensor, a processor, and a FIFO. All of the above components are packaged in an aluminum housing (23.7mm x 26.7mm x 12mm) module for instant installation on rotating machines. The product is ±50g in full size, has an extremely low noise level of only 25μg/√Hz, and a 10kHz bandwidth, which enable it to capture vibration signatures in a wide range of applications.
It is important to point out that, regardless of the type of condition monitoring, even with the most intelligent monitoring concepts, there is no 100% guarantee that there will be no risks such as unplanned downtime, failure or safety, but these efforts are sufficient to reduce the occurrence of risks. Because of this, more and more condition-based monitoring is becoming a key topic in industry, seen as a clear prerequisite for the sustainable success of future production facilities.
“Internet celebrity” application – the key indicators behind the earthquake early warning system
The new opportunities created by MEMS sensors in the industrial and infrastructure markets are far more than that. For example, there is an “Internet celebrity” application that has recently begun to gradually enter the life of ordinary people – earthquake early warning system. “The development of MEMS accelerometers and big data technology is the main driving force for this ‘Internet celebrity’ application. Low-density professional earthquake monitoring equipment is equipped with high-density auxiliary seismic monitoring equipment (MEMS accelerometer), which can increase the time of earthquake prediction in advance. , to achieve earlier warning.” Zhao Yanhui explained.
Seismic waves are divided into three types according to their propagation modes: longitudinal waves (P waves), transverse waves (S waves), and surface waves (L waves). The mixed waves generated after encountering on the surface are extremely destructive. The seismic system uses the longitudinal wave to transmit the fastest speed. After the longitudinal wave is detected, it uses the high-speed transmission of the communication network to issue an early warning.
Therefore, the two most important characteristics of MEMS accelerometers in earthquake early warning systems are low noise and low power consumption. Earthquakes have different levels. The lower the level, the smaller the amplitude. The accelerometer must have low enough noise identification. At the same time, low power consumption is also important. After all, the timing of the earthquake is uncertain, so the MEMS accelerometer must be kept in normal working condition since the laying. “If you combine these two features, then the ADXL355 is definitely the first in the market.” Zhao Yanhui added, “Of course, the ADXL362 provided by ADI has much lower power consumption than the ADXL355, but its noise is also very high, so it is only suitable for level 5 and above. earthquake, because the noise mainly distinguishes the intensity of the earthquake, and the power consumption determines the monitoring time of the product.”
In addition, earthquake monitoring has further application expansion. In earthquake-prone areas, it is necessary to monitor the magnitude of the earthquake when it occurs. If an earthquake of magnitude 5 or above occurs, certain potential dangers must be dealt with in time, such as automatically shutting down households. Gas to prevent it from leaking due to strong earthquakes, thereby causing poisoning or explosion, and preventing the occurrence of secondary disasters. ADI MEMS accelerometers are also used in some applications.
For such sensitive applications, the long-term stability of the sensor is also a major consideration, as the sensor is subject to thermal and mechanical stress. If you want to improve this problem, you must pay attention to system design and chip selection. If the system structure is difficult to isolate thermal stress and mechanical stress, it is best to give priority to ceramic packaged devices.
Witness the best era of MEMS industry
The rapid development of the Internet of Things has brought many new opportunities for MEMS sensors, such as smart homes, wearable devices, smart industries, smart medical care, and smart transportation. In Zhao Yanhui’s view, ADI has repeatedly demonstrated its technical strength with innovative milestone products during the long development of the MEMS industry: ADI has been investing in the research and development of MEMS sensors since 1987, and it is also the first company in the industry to engage in MEMS research and development; 1991 , ADI released the industry’s first high-g value MEMS accelerometer, focusing on the application of automotive airbag collision monitoring, leading the research direction of MEMS sensors for almost ten years; in 1996, it released the industry’s first Low-g MEMS sensor, focusing on Human motion monitoring application… After more than 30 years of experience accumulation, ADI has become the leader of today’s MEMS industry with one “industry first” after another, and is witnessing the best era of the MEMS industry!