Research Of Control System For Segment Erector Based On Visual Servoing

Segment erector is a machine used for assembling segments in a shield machine.By adjusting the position and posture of the segment,it can be moved to the specified posture to realize the segment assembly process.Due to the low efficiency and long time consumption of the segment erector,the tunneling efficiency is severely limited.Therefore,in order to improve the efficiency of tunnel excavation,it is very important to ensure the efficiency of segment assembly.Methods like the electro-hydraulic composite control are adopted in most of the existing control systems for segment erectors on the basis of manual remote control.In this way,the operating speed of the segment erector will be improved so as to achieve the improvement of tube segments assembly efficiency under the condition of reducing the inertia of the segment erector as much as possible.However,the proficiency of workers is a kind of limits for the improvement of efficiency in the method.So it is necessary to propose an automatic segment assembly control system to realize the automation of segment assembly and improve the segment assembly efficiency.In this paper,a new type of segment erector designed according to the segment erector which is used in the project is taken as the research object,the non-contact measurement method of cameras is introduced,the kinematic analysis and the control system of the new segment erector based on the image-based visual servo method are studied.The control strategy and method of the segment erector based on the visual servo method are given,and the validity of the proposed algorithm is verified through experiments,which provides a set of solutions and ideas for the automated assembly of segment erector control method.(1)Based on the existing one used in engineering,a new segment erector is designed.By determining the tube segment erector which the design refers to,the design technical requirements are determined,and then by analyzing and comparing the advantages and disadvantages of different design schemes,the design scheme of the new segment erector is determined.Finally the specific structure,the types of motors and sensors are given and the construction of the new tube segment erector is completed.(2)Kinematic analysis and speed control of end posture adjustment mechanism of the segment erector are studied.Based on the above-mentioned new segment erector,the kinematic analysis of the end posture mechanism is performed,the newton iterative method is used for the solve solution,the relationship between the rotation speed and the push rod speed is analyzed,and further,the change of loads in the segment assembling process is analyzed.According to this characteristic,adaptability of different controllers to the change of loads is analyzed and the speed closed-loop control is realized,which provides the basis for the subsequent servo control of the segment erector.(3)The servo control method of the segment erector based on the image-based visual servo(IBVS)is researched.The mutual relationship of the image coordinates during the segment assembling is obtained by analyzing the image coordinates of different marked feature points,and the target point prediction model is established based on machine learning methods.Further,the accuracy of the established model is analyzed.The control strategy of the designed new segment erector is proposed based on the image-based visual servo method,and the calculation method of the control law is derived.Finally,the validity of the proposed control strategy and method is verified with experiments.