Motion Control of Disc Cutter Changing Robot Body for Tunnel Boring Machine

The manual disc cutter changing operation in tunnel boring machine (TBM) construction seriously restricts the safety and efficiency of tunnel engineering. To realize robot cutter changing in the narrow space inside TBM, a PPRP type serial robot is studied. The overall coverage rate of disc cutter replacement is 41.3%, and that of forward disc cutter replacement is 57.6%. Based on the trapezoidal velocity curve and quintic polynomial curve, a hybrid curve trajectory planning method for the disc cutter changing robot is proposed. Compared with the quintic polynomial curve, the motion time of the hybrid curve method is reduced by 16.1%, and the joint has no impact. Aiming at the problem of obtaining the compensation term of the control system model, the kinematics and dynamics equations of the robot are derived according to its body structure. A variable structure PID controller based on dynamic model compensation is designed. The simulation results show that the relative error of the robot end displacement in X, Y, and Z directions is less than 0.01%, and the maximum absolute error is only -0.0227 mm. The control performance is good.