Do you know how wide the application fields of MEMS IMU are?

The full name of IMU is inertial measurement unit, so how much do you know about IMU? First of all, we know that imu is composed of three single-axis accelerometers and three single-axis gyroscopes. The accelerometer detects the acceleration signal of the object in three independent axes of the carrier coordinate system. The gyroscope detects the angular velocity signal of the carrier relative to the navigation coordinate system. For After processing these signals, the attitude of the object can be obtained. calculated.

         Secondly, I would like to share with you some areas where MEMS IMU can be applied. Its application areas are quite extensive. I hope it can help you. The following are the areas where imu can be applied:

North seeking in logging tools/gyro tools

Pointing, steering and guiding in advanced mining/drilling equipment

Initial alignment in weapon/UAV launch systems

Direction pointing and tracking in satellite antenna, target tracking system

Guidance and navigation in navigation grade MEMS weapon system

Orientating and positioning in railway train system

Precision platform attitude measuring and controls

Precision attitude, position measuring in navigation grade MEMS IMU/INS

North finding and positioning in land surveying/land mobile mapping system

Petroleum exploration

Bridge, tall building, tower, dam monitoring

Rock and soil monitoring

Mining

More information:

Web: https://www.ericcointernational.com/inertial-measurement-units

Email: ericco741@163.com

Whatsapp: 13630231561

Wechat: 13992884879

Do You Know Excellent Performance of MEMS North Finder ER-MNS-05?

 The data is acquired from the gyroscope and accelerometer in the MEMS north finder ER-MNS-05, which is used to calculate the system parameters.

Ericco always believes that products win with performance. In order to ensure the excellent performance of products, our technical team will conduct many repeated tests during the research and development process.

If you are interested in the north seeker product, you can send message to me or send quote to contact info, https://www.ericcointernational.com/north-finders
Contact us:
Email: info@ericcointernational.com
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The Difference between Tilt Sensor and Gyro Sensor

 

The tilt sensor senses the angle of inclination deviation, only data feedback but no command feedback.

The gyroscope measures the angular velocity, senses the action variable, and then controls the steering gear to carry out the repair action command.

The tilt sensor uses Newton’s second law as its working principle. According to the law, we know that when the inclination sensor is stationary, because the side of the object and the vertical direction are affected by other forces, only the action of gravity, that is to say, it acts on the all it has on it is the acceleration of gravity. Therefore, the resulting angle between the vertical axis of gravity and the sensitive axis of the acceleration sensor is what we call the inclination angle, which is the angle we seek.

Tilt sensors are divided into three different working principles and are divided into three types. The first type of inclination sensor is the solid pendulum type, the second type of inclination sensor is called the liquid pendulum type, and the last type of inclination sensor is the gas pendulum type. The working principles of these three different types of inclination sensors will be different. Because of their different working principles, they will have different advantages and disadvantages.

No matter which type of tilt sensor it is, it will be substantially different from a gyroscope. Like inclination sensors, no matter which type it is, it measures the inclination angle at rest. Compared with the inclination sensor, the gyroscope measures the inclination in motion, and the measurement result of the inclination in static is not accurate. So when we measure the inclination in our daily life, whether to choose the inclination sensor or the gyroscope, we can choose according to this essential difference. If the inclination is measured at rest, then the inclination sensor must be selected, and the inclination in motion is measured, and of course the gyroscope is selected. The specific differences are summarized as follows:

1.Different definitions

The gyroscope is an angular motion detection device that uses the momentum moment-sensitive shell of a high-speed revolving body relative to the inertial space around one or two axes that are orthogonal to the axis of rotation. There are many varieties of gyroscopes, which can be divided into sensing gyroscopes and indicating gyroscopes according to their uses. The ER-MG2-022 is a single-axis MEMS angular rate sensor (gyroscope) capable of measuring angular velocity up to a maximum of ±100°/s with digital output compliant to SPI slave mode 3 protocol.  Angular rate data is presented as a 24-bit word, intended for north seeking applications.  An advanced, differential sensor design rejects the influence of linear acceleration, enabling the ER-MG2-022 to operate in exceedingly harsh environments where shock and vibration are present.

The sensor gyroscope is used in the automatic control system of the flying body movement, as a horizontal, vertical, pitch, heading and angular velocity sensor. The indicating gyroscope is mainly used for the indication of the flying condition, and is used as a driving and piloting surface.

2.Different functions

The tilt sensor measures the inclination of all stops. Compared with the inclination sensor, the gyroscope measures the inclination angle during the movement, and the measurement result of the inclination angle in the static state is inaccurate. The gyroscope is not a measuring device, but an auxiliary device. Just like the tank barrel, in order to allow the tank to shoot accurately during the trek, a gyroscope is installed to automatically control the viewpoint of the barrel.

3.Different applications

The tilt sensor is often used for the level measurement of the system. From the working principle, it can be divided into three types of inclination sensors: “solid pendulum”, “liquid pendulum” and “gas pendulum”. The inclination sensor can also be used to measure the inclination relative to the horizontal plane. The amount of change.

The gyroscope sensor was originally used on the helicopter model, and it has been widely used in mobile portable devices such as mobile phones. Not only that, the modern gyroscope is an instrument that can accurately determine the orientation of moving objects, so the gyroscope Sensors are essential controls in modern aviation, marine, aerospace and defense industrial applications.

What are the Methods of North Finding?

 Definition of north finding

The definition of north finding is to find true north, not magnetic north, and the north seeking methods mentioned in this article are all described closely around true north.

True north refers to the Earth’s north pole, which is the intersection of 90° north latitude or the meridian. It is also known as true north. It is the direction that passes through a point on the Earth and points toward the Earth’s geographical north pole. The tangent direction of the true meridian passing through a certain point on the earth’s surface becomes the true meridian direction of that point.

Magnetic north is the north indicated by a compass, primarily because the poles of the Earth’s magnetic field do not coincide with the geographic north and south poles. Therefore, the north indicated by a compass is magnetic north, not true north, and magnetic north changes over time.

North finding uses a gyroscope to measure the component of the earth’s rotation angular velocity combined with the acceleration value, and then calculates the angle with true north to obtain the azimuth angle value.

The methods of north finding

North seeking mainly includes two north seeking methods: static north seeking and dynamic north seeking. The application principles of these two north seeking methods are introduced below.

Principle of static north finding

Static north seeker includes MEMS gyro north seeker and fiber optic gyro north finder.

Principle: The rotation axis of the gyroscope maintains a constant direction relative to the inertial space, while the Earth rotates around the polar axis relative to the inertial space at its rotational angular velocity. If you use the Earth as a reference, you will see that the gyroscope’s axis of rotation rotates relative to the Earth, so the gyroscope can track and measure the angular velocity of the Earth’s rotation.

MEMS gyro north seeker, which has an input axis and a rotation axis. The sensor includes a motor drive structure, a motor signal output from the motor drive structure, a gyroscope, and a sensor rate for the sensor rate signal output from the gyroscope.

Fiber optic gyro north seekers are mainly used to quickly and autonomously determine the true north direction. The Earth’s rotation angular velocity is obtained through high-precision fiber optic gyroscope tracking, and the Earth’s rotation angular velocity signal is decomposed and solved to calculate the angle between the gyroscope’s main axis and the Earth’s true north to provide the carrier with orientation information.

Principles of dynamic north finding

Dynamic north seeking includes fiber optic gyro compass and fiber optic gyro compass (vehicle, ship, airborne)

Principle: Use the strapdown compass effect to find the direction of true north.

The fiber optic gyro compass consists of: three-axis dynamically adjustable gyroscope, three-axis acceleration sensor, data acquisition and processing module, secondary power supply, optocoupler isolated input and output serial port circuit and other related structural parts.

With so many methods available, they are suitable for different circumstances and are not one-size-fits-all. For north seekers used in most fields, inertial measurement device FOG north seekers and MEMS north seekers are relatively advanced in technology.

Comparison of various gyro north seeking systems

By comparing two gyro north-seeking systems, we discovered the similarities and differences between the static north-seeking method and the dynamic north-seeking method.

Common points:

1.They all use the precession and axis fixation of the gyroscope to be sensitive to the earth’s rotation angular speed.

2.The working principle uses the characteristics of the edge of the gyro chamber, that is, the effect of gravity.

Differences:

1.Theoretical differences

The gyroscopic north seeker uses the output of the gyroscope and accelerometer to calculate its azimuth relative to true north to achieve north seeking. Compared with gyro azimuth and gyro compass, it has the advantage of fast north finding speed. However, during the process of north seeking, due to the short start time of the gyro when the gyro north seeker seeks north, there is a gyro drift trend term that is difficult to eliminate, and this term gradually decreases as the gyro starts. The time increases, so the length of time the gyroscope is activated when the north-seeking instrument seeks north has a great influence on its north-seeking accuracy.

2.Differences in application scenarios

Gyrocompasses are mainly used for navigation, such as ships, submarines, UAVs, weapon systems and reconnaissance platforms, providing high-precision azimuth, attitude, navigation and control information. The ER-FGC-2C high-precision gyrocompass has the characteristics of small size, good stability, and high precision, and is fully suitable for navigation in ships, submarines, drones, etc.

Gyro theodolite is mainly used for measurement of large-scale projects such as mines and tunnels. The gyroscope part provides accurate azimuth reference. At the same time, gyro-theodolite can also be used for weapon system aiming.

Gyro-theodolite has high north-finding accuracy, but it cannot be used on mobile carriers such as airplanes and ships because the suspended gyroscope is suspended from the instrument box with a flexible metal belt. On a moving carrier, the instrument shell moves with the carrier. Severe vibrations will cause the flexible metal belt to loosen and fail to maintain a tight state, causing the gyroscope’s movement to lose its original pattern and become unable to work.

3.Differences in performance features (north seeking time and north seeking accuracy)

The north seeking time of the gyro north seeker is short, generally within 5 minutes, and the accuracy can reach about 0.1’. At the same time, there are very few north seekers that can achieve this level of accuracy. ERICCO’s ER-FNS-02 high-precision FOG north seeker has an accuracy of (0.02°-0.1°) and is used for high-precision initial alignment and direction control solutions, which provides a lot of convenience for work. Accuracy can improve relatively over time. The north-finding time of a gyro-theodolite generally takes about 5 to 20 minutes, and the accuracy can reach 10”.

Most recommended north finding equipment

Through the analysis of the two types of north seeking methods, the most suitable north seeking tools for us to use in most fields are MEMS north seekers, FOG north seekers, etc.

The fiber optic gyroscope north seeker uses a closed-loop fiber optic gyroscope as the core component. It is mainly composed of an inertial measurement unit (IMU), a digital signal processing unit and a mechanical part. Provides true north azimuth for the carrier.

The ER-MNS-06 MEMS north seeker is the world’s smallest three-axis MEMS north seeker. It consists of a three-axis MEMS gyroscope and an accelerometer and can measure true north. It has the characteristics of small size, light weight, low power consumption and resistance to harsh mechanical environments, and is widely used in mining, tunnel construction and other fields.

When choosing the most appropriate north-finding device, both gyro-theodolite and gyro-north-finder achieve north-finding on a static basis. Therefore, we can start from the respective characteristics of these two types of devices and complement each other in research or use to achieve coordination of north-seeking accuracy and north-seeking speed.

This article introduces the brief knowledge of the north-finding method. I hope you have a basic and clear understanding of the north-seeking method. If you want to know more about north seeking, you can find useful content in “More Technical Questions”. If you are interested in north finder related products, you can click on “Products in article”. For any questions, please leave your opinions in ‘Ask a Question’ below.

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Tilt Sensor Test Bridge Deflection

Tilt sensors measure bridge deflection is applicable to the deflection test of any bridge span length at any position, and belongs to the field of bridge detection technology, in particular, it relates to a high-precision and high-efficiency bridge deflection test method in the process of bridge detection.

Background technique

In bridge testing, it is necessary to measure the deflection of the bridge, and the accuracy of the deflection measurement data is directly related to the assessment of the bridge state. Meanwhile, the timeliness of the bridge testing is required. Therefore, in the process of bridge inspection, the high precision and high efficiency bridge deflection testing system is very important. In the prior art, the field test of bridge deflection generally adopts the following methods: 1.Optical measuring instruments such as level are used to measure bridge deflection. Although the operation is simple, the measurement accuracy is low, and the measurement results are greatly affected by human influence and interference, which cannot be applied to the test of bridge dynamic deflection and the error is large. 2.The use of dial meters, dial meters and other displacement meters to test the bridge deflection, the scaffolding needs to be set up below the beam body, so as to install the deflection test instrument on the scaffold, but in the scaffolding under the bridge, there is a complex process, time-consuming and laborious, and higher scaffolding has a greater safety risk, its own shaking and uneven settlement at the bottom will affect the test results of bridge deflection. 3.The use of photoelectric image principle, through the acquisition of image signals, the use of data processing method, to obtain the deflection value of the bridge, its working principle is complex, image data acquisition is limited by weather, light and other specific conditions, data processing is complex, and the cost is high, the accuracy is low, the actual operability is poor. 4.Based on the principle of connecting pipe, the deflection of bridge is directly measured according to the change of liquid level in the open connecting pipe. This method is simple in principle, but due to the viscous resistance between liquid and pipe wall and the capillary action between water and pipe wall, the test accuracy is not high, and it cannot be applied to the test of dynamic deflection of bridge.

Therefore, the existing bridge deflection testing device has the following defects: 1.Low test accuracy and large error; 2.The test device installation is complicated, the data collection is more complicated, the labor cost is high, the work efficiency is low; 3.It cannot be applied to the detection of dynamic deflection of Bridges and the deflection of bridges across large rivers and grand canyon.

How do inclinometer measure bridge deflection?

Tilt sensor measurement of bridge deflection is a bridge deflection test method based on dip angle, which converts the dip angle change of bridge section into the change of bridge deflection. In other words, the inclinometers is arranged in 5 sections of the bridge to measure the angle of section. The (electrical) signal of the change of dip angle is timely transmitted to the acquisition system through signal cables, and the mathematical relationship formula between bridge deflection and dip angle is calculated by using the dip angle value of section. And then calculate the deflection at any one position.

For example, if we want to measure the deflection of a bridge at any position, we place an ER-TS-4258CU current type biaxial tilt sensor at this position of the bridge, so that the tilt sensor of the 5 sections can be measured, and the signal of the inclinometer change is transmitted to the data acquisition system in real time through the current. We can use the dip value measured by the tilt sensor of the section arrangement to calculate the mathematical relationship between the deflection and the dip angle of the bridge, and then calculate the deflection that needs to be measured at the bridge position.

The disturbance is, in layman’s terms, the amount of deformation. The disturbance of the steel structure such as the cantilever beam should meet the corresponding specifications. The deformation should not be too large, and the formula of the material mechanics can be used for calculation. The deflection of the bridge has a corresponding relationship with the corner angle of the section. The deflection of the bridge can be measured by a double-axis inclination sensor mounted on the bridge. The method uses the structural finite element model to calculate the deflection curve of the unit load acting at different positions. The deflection curve is used as the reference displacement mode, and the true deflection is the linear combination of the reference displacement modes. The combination coefficient is determined by using the minimum inclination test data. The method of two-square fitting effectively reduces the influence of test errors.

Summary: The tilt sensor measure bridge deflection is easy to operate and the test data are accurate, the measurement efficiency is high, and the performance is stable and reliable, and it is not affected by the change of bridge structure form and bridge section. It can solve the problems such as the difficulty of deflection testing and the poor accuracy of measurement data of bridges spanning large rivers and grand canyon.

Do you Know the Working Principle of Inclinometer ?

 The working principle of inclinometer

Let me briefly introduce the inclinometer commonly used in petroleum logging, which is a kind of in-situ monitoring instrument for measuring the dip angle and azimuth of borehole. The required data can be obtained through all kinds of sensor components in the survey sensor, and then the data can be recorded from the high-temperature memory to obtain the relevant azimuth angle, dip angle, temperature data, depth, tool face angle and other parameters that engineers want to know, so as to determine the specific situation of the drilling.

In foreign countries, inclinometer has been used for position monitoring in earth dam, roadbed, slope and tunnel and other geotechnical engineering since 1950s. Our country began to introduce inclinometer sensors from the United States, Japan, Britain and other foreign countries and monitor some important geotechnical engineering in the 1980s. In order to better develop the exploration of oil, coal, offshore oil well development of China’s research and development in this area is also as a large project to carry out, and some related research institutions developed resistance strain type, accelerometer type and electronic meter type and other intelligent inclinometer.

Up to now, various inclinometers have been widely used in the fields of water conservancy and hydropower, mineral metallurgy, transportation and geotechnical engineering for urban construction, and have played an important role in ensuring the safety of geotechnical engineering design, construction and use.

Inclinometer application fileds: borehole survey, foundation pit, foundation, wall, dam slope, oil field logging, marine logging exploration, coal mine exploration, etc.

How does the inclinometer work?

Working principle of inclinometer when measuring angle probe from bottom to top in the dip tube piecewise sliding when measuring, the probe’s sensor is sensitive to reflect the dip tube in the angle changes in the depth of each segment, and then according to the tilt angle and the horizontal displacement at different elevation of the incremental, from the bottom of the dip tube station began to piecewise accumulative, can get the horizontal displacement at any height, when the inclinometer observation, in order to eliminate and reduce the zero drift and assembly error of the instrument, the data should be measured and read once in the positive direction of displacement and in the opposite direction after the probe turns 180 degrees, and the algebraic average value of the measured data in the positive and negative directions should be taken as the measurement value of inclination.

Designed based on the principle ER-TS-12200-Modbus high precision wireless transmission tilt senor  is a wireless inclination sensor with ultra-low power consumption, small size and high performance, which is aimed at the industrial application of users without power supply or real-time dynamic measurement of object attitude angle. Powered by lithium battery, based on Internet of things technology Bluetooth and ZigBee (optional) wireless transmission technology, all internal circuits have been optimized and designed, and various measures such as industrial MCU, three proof PCB board, imported cable, wide temperature metal shell are adopted to improve the industrial level of the product. With good long-term stability and small zero drift, it can automatically enter the low-power sleep mode, so as to get rid of the dependence on the use environment.

The product has compact structure, precise design, re compensation for temperature and linearity, and integrated comprehensive protection functions such as short circuit, instantaneous high voltage, polarity, surge, etc. It is simple and convenient to use. The wireless digital signal transmission method eliminates the cumbersome wiring and noise interference caused by long cable transmission; The industrial design has extremely high measurement accuracy and anti-interference ability. The wireless sensor nodes can form a huge wireless network, support thousands of measuring points to monitor the inclination at the same time, and support professional computer software. Without field survey, it can measure and record the state of the measured object in real time; The safety monitoring system is suitable for remote real-time monitoring and analysis of industrial sites, dilapidated houses, ancient buildings, civil engineering, tilt deformation of various towers and other needs.

How is IMU used?

 The concept of IMU

 

The inertial measurement unit, referred to as IMU, is a device that measures the three-axis attitude angle (or angular velocity core) and acceleration of an object. Gyroscopes and speedometers are devices of an inertial navigation system.

With the built-in speed sensor and gyroscope, the IMU can measure linear acceleration and rotational angular velocity from three directions, and can obtain information such as the vehicle's attitude, speed, and torsion through calculation.

IMU working principle

 

The IMU is a module composed of various sensors such as a three-axis accelerometer, a three-axis gyroscope, and a three-axis magnetometer.

1. The working principle of three-axis accelerometer

 

Most three-axis acceleration sensors use piezoresistive, piezoelectric and capacitive working principles. The acceleration generated is proportional to changes in resistance, voltage and capacitance, and is collected through corresponding amplification and filtering circuits. This is based on the same principle as the ordinary acceleration sensor, so with certain technology, three single axes can be turned into a three-axis. For most sensor applications, two-axis acceleration sensors can already meet most applications.

2. The working principle of three-axis gyroscope

 

The working principle of the three-axis gyroscope is based on the gyroscopic effect. When the gyroscope's axis of rotation is perpendicular to the direction of a force, it will feel the effect of the force, thereby generating a torque that causes it to rotate in the coordinate system. The three gyroscopes in the three-axis gyroscope are installed on three mutually perpendicular axes. They sense the angular velocity on the x, y, and z axes respectively, and output the signals to the relevant circuits for processing.

3. The working principle of three-axis magnetometer

 

The magnetometer uses three mutually perpendicular magnetoresistive sensors. The sensor in each axis detects the strength of the geomagnetic field in that direction. For example, alloy materials with some crystal structures. They are very sensitive to external magnetic fields, and changes in the strength of the magnetic field will cause changes in the resistance value of the magnetoresistive sensor. In addition, the three-axis magnetometer can also use the Lorentz force principle. The current flows through the magnetic field to generate force, thereby driving changes in capacitance and so on.

Application of high performance quartz accelerometer

 

Inertial navigation IMU has a wide range of application scenarios and is often used for pointing, steering and guidance in advanced mining/drilling equipment, ships, automobiles, drones, robots, oil exploration, bridge exploration, high-rise buildings, iron towers, dam monitoring, rock Soil monitoring, navigation and positioning of transportation vehicles such as mining and missiles, and north-finding positioning in geodetic/land mobile mapping systems.

 In the aviation field, inertial navigation IMU can realize motion control of aircraft such as climbing, descending, turning and taxiing, improving flight safety and accuracy.

In the automotive field, inertial navigation IMU can help vehicles achieve autonomous driving and traffic jam identification, improving driving performance and safety.

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