| The application of Tunnel Boring Machine(TBM)has become the mainstream of tunnel construction.In the process of excavation,the cutters are gradually worn out when breaking the rock,which affects the efficiency of excavation.Therefore,the changing process of the worn cutters has become an indispensable task in the construction process.At present,low efficiency and high risk of manual cutter changing have gradually attracted attention and "machine replacing human" cutter changing has become a research hotspot in the field.Domestic and foreign organizations have carried out a lot of researches on this,and put forward a variety of cutter changing robot schemes,but few have made further progress in physical experiments and engineering applications.In this paper,based on the cutter changing robot of 7.8m diameter TBM,a scale physical prototype is built.The cutter changing range,trajectory planning methods and motion control strategies are studied,and the control system is designed by using CANopen bus.Then verifying the design indexes by experiments,which provides the design basis for the engineering application of the cutter changing robot.The specific research contents are as follows:1)Based on the prototype TBM cutter changing robot scheme,the structure parameters and motion parameters of the scale robot are determined by using the similarity theory.According to the structure parameters,the structure design of each part of the scale robot is completed,and according to the motion parameters,the driving sources selection of each joint of the robot is completed.The overall design scheme of the scale cutter changing robot is proposed,and the cutter changing range is analyzed.The simulation results show that 81.8% of the face cutters can be changed by the robot.2)Trajectory planning is carried out in joint space,and optimization indexes based on impact and time are proposed.On this basis,a hybrid interpolation algorithm based on seven degree polynomial and trapezoidal velocity curve is designed.The simulation results show that there is no impact and vibration during the operation of the robot,and the maximum changing time of one cutter is 137.44 s,which improves the efficiency.3)The kinematics of the robot is analyzed by using the improved D-H method,and the transformation matrices between the joint coordinate systems are obtained.Then,the dynamic model of the robot is deduced by using Lagrangian dynamics method,which builds a foundation for the design of trajectory tracking control algorithm.Without considering the joint friction,the force and torque of each joint are obtained by simulation,which provides a basis for the selection of driving sources.4)In order to control the robot to track the planned trajectory,two control algorithms are proposed in this paper,which are the Fuzzy Self-Adaptive-Tuning PD control algorithm based on gravity and friction compensation and the Fuzzy Self-Adaptive-Tuning PD control algorithm based on computed torque method.On this basis,the simulation systems are built based on Simulink,and the control effect of the two control algorithms is compared.The results show that the Fuzzy Self-Adaptive-Tuning PD algorithm based on computed torque method has higher control accuracy,and its trajectory tracking error of each joint is less than 1 mm.5)Based on CAN bus,the control system of the scale cutter changing robot is built.Then the effectiveness of the trajectory planning algorithm and the practicability of the cutter changing robot are verified by experiment.Taking the changing process of the last face cutter in the direction of cutter head radius as an example,the experiment is carried out.The results show that the trajectory tracking error of each joint of the robot is less than 1 mm,and there is no impact and vibration in the working process,which meets the requirements of high efficiency and stability.The practicability of the robot is verified. |
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