Research And Implementation Of Spatial Flexible Mechanism Location And Vibration Measurement Algorithm Based On Image

In space missions, space flexible deployment mechanism is widely used as the supporting structure of detection load, communication antenna and solar panels. In orbit, aircrafts with flexible deployment mechanism work in a microgravity and vacuum. Affected by the aircraft platform’s movement disturbance, flexible structure is easy to produce elastic vibration. The elastic vibration of the flexible deployable mechanism makes the payload deviate from the expected spatial position, affecting the performance of the payload.In this paper, the measurement system based on machine vision is used to realize the measurement of the spatial position and the vibration information of the flexible rod. The main work is as follows:1. Through the camera calibration procedure, the distortion parameters of camera lens and the camera’s internal and external parameters are obtained. The construction of machine vision measurement system is completed.2. Some image processing algorithms are implemented, such as the image noise filtering algorithm, the spot image segmentation algorithm for point source image and the sub pixel level precision positioning algorithm for spot centroid, ensuring the measurement accuracy of the measurement system3. By binocular vision measurement system, the point light source’s 3D space position’s measurement on flexible rod is completed. Using the video sampling interval time and the spatial position of each point light source on the flexible bar, the swing speed and the flexible joint’s deformation are obtained.4. An algorithm measuring the vibration frequency and amplitude of the flexible rod based on the image LOI(line of interest) is proposed, reducing the quantity of input data, and the calculating speed of the system is improved. By using the sigmoid function to fit the LOI’s the gray value, the sub-pixel location of the edge points is achieved, and the measuring accuracy of the amplitude of the flexible rod is improved.Experiments show that within the scope of 1000 mm the vision measurement system, the X and Y axis direction measurement error less than 2.5mm, the Z axisdirection measurement error less than 4mm, the edge point positioning accuracy of less than 0.05 pixels, each measurement indicators meet the needs of the project, can finish measurement of flexible extension rod position and vibration information.