Structure Design And Trajectory Planning Research Of Highway Tunnel Overhead Camera Cleaning Robot

Camera is the front-end collection component to obtain road information,which is an important infrastructure to ensure the safe operation of highway tunnels.Due to the relatively closed tunnel environment,the oily pollutants in car exhaust mixed with dust tend to adhere to the camera mirrors,resulting in blurred captured images and affecting the safety monitoring function of the cameras.The small size of the camera mirror,high installation height,different posture,shooting direction and the direction of the same direction or perpendicular to the direction of travel,resulting in camera cleaning has been a difficult point of highway tunnel maintenance,at present,still manually stand on the high platform to carry out cleaning operations,work intensity,low operational efficiency,there are safety risks.To this end,this paper researches camera cleaning process parameters,cleaning robot structure and its trajectory planning method,aiming to develop a safe and efficient intelligent camera cleaning robot to achieve mechanized camera cleaning,improve camera cleaning rate and operational efficiency,reduce the safety hazards of cleaning operations,and help tunnel safety operation.(1)The tunnel camera working condition research was carried out,and the camera cleaning scheme of "aerial work lifting platform + multi-degree of freedom tandem robot arm+ high-pressure water jet" was proposed,and the technical requirements of cleaning operation were determined.In order to obtain the high-pressure water jet cleaning process parameters,set up an indoor camera cleaning test platform,using the single-factor comparison method to carry out the cleaning parameters optimization test,based on the "graying + sharpening +binarization" image processing method to evaluate the cleaning rate,to determine a better combination of cleaning parameters for cleaning pressure 0.5MPa,cleaning distance 1m,cleaning time 0.4s(with 0.2s interval rinsing 2 times),which can make the cleaning rate reach more than 99%.(2)Two robotic arm structure schemes were proposed,and "2 telescopic + 3 rotating" was determined as the better scheme,and the whole machine structure was designed.The results show that the strength and stiffness of key parts meet the design requirements and the robot will not resonate due to the vibration source,which verifies that the robot arm structure meets the design requirements.(3)The kinematic model of the robot was established by the modified D-H method,and the kinematic simulation experiments of the robot were carried out with the Robotics Toolbox of MATLAB to verify the correctness of the D-H parameters,the effectiveness of the forward and inverse kinematic solution method,and the feasibility of the robot workspace.The workflow and task path conditions of the robot were analyzed,the robot time-impact optimal trajectory planning model was established,the time nodes of the trajectory were optimized based on the NSGA-II algorithm and the weight function method,and the trajectory of each joint was constructed by using the 5 times B spline function.The experimental results of trajectory planning show that the motion trajectory of each joint of the cleaning robot is smooth,continuous and without sudden changes,which reduces the motion shock while ensuring the efficiency of the robot.(4)The mechanical body of the robot was machined and assembled,and integrated with the electronic control system to build a prototype of the cleaning robot,and carried out indoor trajectory planning prototype experiments and field cleaning experiments.The results show that the motion trajectory of the joints of the cleaning robot is continuous,smooth,without large abrupt changes,and with high positioning accuracy,and the positioning error of the end nozzle is 7.3mm,including 2.7mm in x direction,4.3mm in y direction and 5.2mm in z direction,which meets the positioning accuracy requirements of camera cleaning.The water jet effectively acts on the mirror surface of the tunnel camera and obtains high image clarity.The operation time of cleaning a single camera is less than 1 minute,which meets the efficiency requirements of cleaning operation.The designed cleaning robot lays the foundation for intelligent and efficient cleaning of tunnel cameras,and effectively solves the problem of difficult cleaning of tunnel cameras.