How does a magnetostrictive sensor work? What is the working principle of a magnetostrictive sensor?

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How does a magnetostrictive sensor work? What is the working principle of a magnetostrictive sensor? [Copy link]

　Magnetostriction is a process where a ferromagnetic material can change its size or shape when placed in a magnetic field. This device can be used for position control. Magnetostrictive position sensors use a ferromagnetic element to determine the position of a position magnet that is moving along its length. The sensor has good accuracy, vibration resistance, and shock resistance. These sensors can be considered as a stable and reliable device that provides a signal of 30 to 400mV at its output with little or no additional signal conditioning. The important requirement of the sensor is that the waveguide must be as long as the measuring stroke.

　1. How does a magnetostrictive sensor work? What is the working principle of a magnetostrictive sensor?

　In this sensor, a cylinder will be encased in a wire that carries a pulsed current and creates a field in the cylinder. Magnets surround the structure to create a local axial field. The axial magnetic field is provided by the position magnet, which will be attached to the machine tool to be measured. The waveguide wire will be enclosed in a protective cover, which can be attached to the stationary part of the machine. The position of the position magnet is determined by applying a current pulse to the waveguide. During this process, a timer will be started and the current pulse will generate a sound wave and create a sound wave at the location of the positioning magnet.

　The sound wave propagates with the waveguide until it is detected by the pickup. This process stops the timer. The time shown by the timer is the distance between the pickup and the positioning magnet. A small piece of magnetostrictive material will be connected to the waveguide. A small piece of magnetostrictive material called tape will be passed through the coil and magnetized by the permanent magnet. If the sound wave propagates toward the waveguide, stress will be generated in the tape, which will change the magnetic flux density of the tape and therefore the coil will generate an output pulse. This voltage pulse will be detected by the electronic circuit and converted into the desired output.

　2. Structural components of magnetostrictive sensor:

　This sensor consists of a magnetic core to which a small amount of current is applied by using a drive coil around it. The sensor has a steel housing in which the drive coil and the core are located. The housing, piston, and core will act as a closed magnetic flux path. The materials used in this position sensor are transition metals, which are iron, nickel, and cobalt.

　3. Characteristics and functions of magnetostrictive materials:

　The use of magnetoresistance is similar to that of Hall elements, but is simpler because no control current needs to be generated. The magnetostrictive material is exposed to the magnetic field to be sensed. The sensitivity of this device is higher than that of Hall devices, and the bidirectional effect between the magnetic and mechanical states of the magnetostrictive material is a conversion capability for actuation and sensing.

　4. Application of magnetostrictive sensor:

　Can be used for position sensing

　For torque measurement systems

　Can be used for water level sensing

　Accelerometer sensor

　Load sensor

　It is used in sonar applications

　Acoustic equipment application

　Medical and industrial applications

吾妻思萌

This seems to be very popular for medical prostheses, and some companies are researching

Magnetostriction