Body Design And Control Law Comparison Of Telescopic TBM Cutter-Changing Robot

TBM has been widely used in tunnel excavation for its advantages of fast,high quality,safety and economy.Higher excavation efficiency and safer operation mode have become the development trend of TBM,but the existing cutter change mode has affected the excavation efficiency and construction safety,and the industry problem of cutter change risk has become the bottleneck restricting the construction safety and efficiency of complex geological tunnels.Therefore,it is imperative to realize the efficient and safe operation mode of automatic cutter change.Robot fuselage is an important part of tool changing robot.Its structure design,trajectory planning and motion control are very important.The narrow space,the complex distribution of the slag board on the back of the cutter head and the end load of the robot weighing up to 600 kg pose great challenges to the structure design of the fuselage and the trajectory planning of the joints.In order to solve these problems,the main work of this paper is as follows:(1)Aiming at the problem of the narrow workspace of the fuselage,a PPRP series robot mechanism is designed.The direction of motion of each joint coincides with the narrow space inside the TBM.The limited space inside the TBM is effectively utilized,and the freedom of the last two joints of the mechanism is compatible with the polar coordinate arrangement of the hob,thus avoiding the later inverse kinematics solution.(2)In order to ensure the rigidity of the fuselage,a new type of telescopic structure is designed based on the structural characteristics of the space shear elevator and the telescopic plate.Static analysis of the fuselage arm and the rest of the fuselage is carried out.The results show that the deformation of each part is less than 1%,and the maximum stress is less than 300 MPa.(3)In order to ensure that the fuselage trajectory is fast and impact-free,a new trajectory planning method is designed based on the characteristics of trapezoidal velocity curve and quintic polynomial curve,and the method to obtain the shortest trajectory planning time is designed.Finally,the joint 1 is taken as an example to plan.The results show that the new method shortens the trajectory time by 16.1% compared with quintic polynomial interpolation.(4)In order to ensure that the tool changing process is unmanned,this paper designs a variable structure PID control based on dynamic model compensation,and compares it with the PID control based on model compensation.The results show that the stability time of the new method is reduced by 0.085% compared with the traditional method,and the motion tracking situation is basically the same,and the driving force extreme value is the same.(5)Aiming at the validation problem of the robot system,this paper designs a corresponding tool changing experiment platform according to the structure characteristics of TBM,and simulates all hobs in the lower half of the cutter head by changing the position and posture of a single hob,which provides a platform basis for the later experimental validation of the tool changing robot system.