Device and method for measuring vibration of flexible cantilever beam based on machine vision

Abstract

The invention discloses a measuring device and method for the vibration of a flexible cantilever on the basis of machine vision. The measuring device comprises a fixed bracket, the flexible cantilever, a camera bracket, a CCD (Charge Coupled Device) camera, a lens, a plurality of LED (Light-Emitting Diode) light-emitting tubes and a PC (Personal Computer), wherein one end of the flexible cantilever is fixed on the fixed bracket; all the LED light-emitting tubes are arranged on the upper surface of the flexible cantilever in sequence; the top of the fixed bracket is provided with the camera bracket; the CCD camera is fixed on the camera bracket and is provided with the lens; and an output port of the CCD camera is connected with the PC. The CCD camera measures each frame image of the vibration of the LED light-emitting tubes, and conveys the images to the PC; and the PC processes a detected image sequence, extracts the position of the mass center of the light spots of the LED light-emitting tubes and acquires the vibration displacement of all the LED light-emitting tubes and parameters for reflecting the low-frequency vibration of the flexible cantilever structure. The measuring device and method disclosed by the invention has the advantages that the non-contact effect is achieved, the measuring range is wide and the vibration characteristic of a measured object is not changed and the like, and can be widely applied.

Description

technical field [0001] The invention relates to a method for measuring the vibration of a large flexible cantilever beam, in particular to a machine vision-based measuring device and method for the vibration of a flexible cantilever beam. Background technique [0002] A solar panel is a device that collects solar energy and is usually used to power satellites and spacecraft. The modal damping of this kind of large flexible structure is small, and once it is subjected to some kind of exciting force, its large amplitude vibration will last for a long time. This will not only affect the work of the aerospace structure, but also cause premature fatigue failure of the structure, affect the service life of the structure, or cause damage to the instruments in the structure. Therefore, it is necessary to measure and suppress the vibration of the flexible structure of such spacecraft, especially for the structural vibration of the flexible cantilever beam that simulates the solar pa...

AI Technical Summary

Problems solved by technology

[0003] In the prior art, vibration measurements of flexible cantilever beams simulating solar panels mainly use piezoelectric sheets, accelerometer sensors, angular rate gyroscope sensors, photoelectric position sensors (Position Sensitive Detector) and fiber grating sensors (Fiber Grating Sensor) Other methods: signal delay and phase lag will be caused by various links such as signal amplification and filtering during piezoelectric film measurement, the measurement speed is slow and the range is limited; the accelerometer sensor and angular rate gyroscope sensor are sensitive to noise and have hysteresis and temperature drift And other problems affect its accuracy, and can only measure the displacement of a certain point on the object. To obtain all information, several accelerometers or angular rate gyroscopes must be arranged on the cantilever beam; the measurement range of the photoelectric position sensor is small, and the structure Complexity, difficult operation, cumbersome calculation process and high cost; the main problem of fiber grating sensor is the demodulation of sensing signal, because fiber grating is relatively fragile, it is very easy to be damaged in harsh working environment, so it needs to be packaged can only be used, the packaging process and protection measures are complex

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