Design And Analysis For A Cable-Link Scanning Robot Of Wind Turbine Blades Surface

In view of the defects in the rigid linkage structure of existing detection device of wind turbine blades,a cable-link scanning robot of wind turbine blades is designed,making the movement of the end-effector more flexible,equipped with portable ultrasonic testing equipment,ensuring the accuracy and deducing the overall cost of the equipment.The content of this paper is as follows:Firstly,according to the theory of nondestructive detecting technology,the structure and detection method of the existing detection device are analyzed.Combined with the wire-driven techology,a new type of Rod-Cable scanning robot of wind turbine blades is put forward.The whole model design of the robot is built in Solidworks,the components and working method are respectively introduced,the optimization design for the key parts-driving device and walking mechanism are presented,and the degree of freedom of the robot end-effector is analyzed,preliminarily proved the mechanism is feasible.Secondly,the kinematics analysis for the scanning robot was carried out.Based on the establishment of the coordinate system and the determination of the parameters of the mechanism,the forward and inverse kinematics analysis models of the parallel detection platform are obtained by space vectors method and Newton-Raphson iteration respectively,and the correctness of above models are verified by detailed numerical calculation.The velocity Jacobian matrix of the system is deduced by geometry,and the velocity and acceleration variation curves of each branched chain in the movement process of the end-effector are plotted in MATLAB,which prove the mechanism is stable and continuous in the work.Again,the static mechanical analysis of the detection platform is carried out.The statics equations are listed by stress balance.From the equation satisfying the principle of vector closure,the existence of the stable space that the driving force is greater than zero,that is,the single way force characteristics of the cables and link are satisfied is proved.The relationship between the driving force of the branched chains and the output force is deduced by virtual displacement,and then the force Jacobian matrix of the system is obtained.The trend variable chart and the coordinate axis decomposition diagrams of the driving force of each branched chain during the movement and at the determined pose of the end-effector are plotted with MATLAB and the singularity of the detection platform is analyzed by the derived force Jacobian matrix.Finally,according to the constraint equations established by the limit positions and length of the motion pairs of the detection platform,the workspace of the platform is worked out by the boundary search method and the position workspace diagram with a fixed orientation is drawn,laying a theoretical foundation for the research on trajectory planning and real time control of the detection device.