A Quasi-zero Stiffness Absolute Displacement Sensor Based on Electromagnetic Positive Stiffness

Abstract

The invention discloses a quasi-zero stiffness absolute displacement sensor based on electromagnetic positive stiffness, relates to the technical field of vibration measurement, and comprises an eddy current displacement sensor unit, a negative stiffness unit, an intermediate connecting body, a positive stiffness unit, a bottom shell and a motion shaft. It can effectively reduce the damping of the mechanism, improve the service life of the system, and reduce the volume of the mechanism. By adjusting the number of layers of permanent magnets and coils in the electromagnetic positive stiffness unit and negative stiffness unit and controlling the magnitude of the current in the coil, the electromagnetic force between the permanent magnet and the electromagnetic coil can be changed, and the positive stiffness and negative stiffness can be adjusted to realize the whole Control of system stiffness. The positive stiffness and negative stiffness are approximately linear within a certain range, which can eliminate the influence of nonlinearity. After the positive and negative stiffness are superimposed, the overall stiffness of the system can be minimized, quasi-zero stiffness can be achieved, and higher measurement accuracy can be obtained. Selecting the initial position and motion range of the permanent magnet can make the system reach a quasi-zero stiffness state with a certain load capacity.

Description

technical field [0001] The invention relates to the technical field of vibration measurement, in particular to a quasi-zero stiffness absolute displacement sensor based on electromagnetic positive stiffness. Background technique [0002] In engineering practice, the measurement of system displacement plays a key role in system control and vibration isolation. With the continuous improvement of intelligence and automation in various fields, the requirements for displacement sensors in various industrial fields are also increasing. However, in many cases, the measurement object does not have an absolutely static reference point, so the absolute displacement of the system cannot be directly measured. Indirect measurement often brings errors and time delays. Some system controls with relatively high precision requirements and relatively short time response cannot achieve good control results because they cannot directly measure the absolute displacement of the system. Although s...

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Problems solved by technology

However, many times the measurement object does not have an absolutely static reference point, and the absolute displacement of the system cannot be directly measured

Indirect measurement often brings errors and time delays. Some system controls with relatively high precision requirements and relatively short time response cannot achieve good control results because they cannot directly measure the absolute displacement of the system. Although some existing advanced measurement technologies can Applied to the measurement of absolute displacement (such as inertial sensors, radar or laser technology, etc.), but these measurement technologies have problems such as low precision, poor real-time performance, and high cost, and cannot be used in occasions with harsh working conditions; traditional quasi-zero stiffness based on electromagnetic The absolute displacement sensor uses a mechanical spring as a positive stiffness mechanism. At ultra-low frequencies, its damping cannot be ignored, which affects the measurement accuracy

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