Machine-vision-based device and method for measuring vibration of flexible double-joint mechanical arm

Abstract

The invention discloses a machine-vision-based device and a machine-vision-based method for measuring vibration of a flexible double-joint mechanical arm. The device comprises the flexible double-joint mechanical arm, a CCD (charge coupled device) camera, a camera fixing device, an absolute value coder, multiple LED (light-emitting diode) luminotrons and a PC (personal computer), wherein the absolute value coder is arranged on a rotating motor; the LED luminotrons are arranged at the tail ends of two arm rods; the CCD camera is arranged at a middle joint; output ports of the CCD camera and the coder are connected with the PC. A lens of the camera is positioned in the direction of an angle bisector of an included angle formed by the two arm rods through the camera fixing device, and each frame of image detected by the CCD camera and real-time positioning data of the coder are sent to the PC, and are processed and compared with the positions of light spots which are static at a movement position by the PC, so as to obtain the vibration displacement of a light source for further analysis on vibration characteristics of the mechanical arm. According to the device and the method, the vibration characteristics of the two arm rods can be measured without contact and without changing vibration characteristics of a measured object, comparison and researching are facilitated, and the device and the method can be widely applied.

Description

Technical field: [0001] The invention relates to a method for measuring the vibration of a flexible double-joint manipulator, in particular to a device and method for measuring the vibration of a flexible double-joint manipulator based on machine vision. Background technique: [0002] Multi-joint robotic arms, also known as joint robots, are one of the most common forms of industrial robots in the industrial field today. It is suitable for mechanical automation operations in many industrial fields, such as automatic assembly, painting, handling, welding and other work. The modal damping of this type of flexible structure is small, and once it is subjected to a certain exciting force, its large-amplitude vibration will last for a long time. This will not only affect the work of the 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. There is therefore a need to m...

AI Technical Summary

Problems solved by technology

[0003] In the prior art, the vibration measurement of the flexible joint manipulator mainly adopts methods such as piezoelectric sheet, accelerometer sensor, angular rate gyroscope sensor, photoelectric position sensor (Position Sensitive Detector) and fiber grating sensor (Fiber Grating Sensor): Signal delay and phase lag will be caused by signal amplification, filtering and other links during electric 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 there are problems such as hysteresis and temperature drift that affect them. Accuracy; the measurement range of photoelectric position sensors is small, the structure is complex, the operation is difficult, the calculation process is cumbersome and the cost is expensive; the main problem of fiber grating sensors is the demodulation of sensing signals. It is very easy to damage, so it needs to be packaged before it can be used, and the packaging process and protection measures are complicated

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