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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