Research Of Climbing Robot Design For Cable Surface Defects Detection

As an important component of cable-stayed bridge,the cable is related to the safety and stability of the bridge.Under the influence of harsh environment such as sun and water,the cable surface sheath will crack,damage and other defects,resulting in the corrosion of the internal steel wire,which poses a threat to the normal use of the bridge.Therefore,regular inspection of cable surface is an effective way to find and repair defects in time,which can ensure the safety of the bridge.At present,the detection and maintenance of the cable mainly adopts the detection method of manual climbing,which has high risk factor,high labor intensity and low detection efficiency.Therefore,an alternative to manual cable climbing detection device is needed to meet the demand.In this thesis,the whole process of cable surface defect detection is studied,including the robot based detection device carrying equipment,surface defect detection method based on visual image,and a set of selfinspection cable surface defect detection scheme is formed.The main research work of this thesis is as follows:(1)Design the structure and control system of the climbing robot for detection of cable surface defects: put forward the design system scheme and design parameters of the robot combined with the actual working conditions of the cable,and carry out numerical calculation and Matlab simulation of the climbing process;The module selection and program design of the control system are based on STM32.The weight of key structural components is optimized based on topology optimization method,and the overall structure and control system of the climbing robot for detection of cable surface defects are finally determined.(2)Study on the dynamics characteristics of a climbing robot for detection of cable surface defects: The dynamics model of the robot was established and the dynamics characteristics of the robot were analyzed under different working conditions.The results showed that the robot could climb steadily and continuously along the cable under the limit working condition of the cable tilt of 90°,and it had a good obstacle surmounting ability,and could still ensure the smooth operation under the condition of single drive failure.(3)Study on cable surface defect detection technology is carried out: the surface defect image is preprocessed by ROI extraction,gray level processing,denoising,etc.The image Mosaic technology based on SIFT algorithm is studied to achieve image registration and image fusion,and obtain the panoramic image of cable surface.Based on edge detection and morphological operation,surface defect image detection was carried out to extract cable surface defect features.(4)Experimental research on a climbing robot for detection of cable surface defects was carried out: A prototype climbing robot for detection of cable surface defects was developed,and climbing tests and surface defect identification tests were carried out under different working conditions.The results show that the climbing cable has a diameter of 100mm-200 mm,a maximum inclination Angle of 90°,a maximum bump height of 5mm over obstacles,and a maximum load of 12 kg.The robot runs stably during climbing.The surface detection algorithm can effectively distinguish the defect image and meet the detection requirements.There are 102 figures,15 tables,70 references in this thesis.