Electro-hydraulic control of high-speed segment erection processes

To improve the efficiency of constructing a tunnel lining, an effective high-speed segment erection system is desired. Due to the excessive positioning errors and large joint forces caused by high speed and large inertia loads, a conventional segment erector is unable to achieve a high-speed erection process. To reduce the steady-state positioning error of a segment erector under high-speed working conditions, this work presents a speed and position compound control system (SPCS) based on the electro-hydraulic proportional control technology. A combined motion law with a smooth and continuous changing speed is adopted for the erecting motion to reduce joint force. Experiments are carried out on a Φ2.2 m segment erector test rig to evaluate the performances of the designed control system. Experimental results show that the SPCS is superior to the position feedback control system (PFCS) in terms of accuracy and joint force under high-speed working conditions. The maximum rotation speed of the erector with the SPCS can reach up to thrice that of the conventional segment erection system without decreasing the positioning precision and increasing the joint force. To further increase the segment erecting efficiency, a parallel speed and position compound control system (PSPCS) with multi-axis simultaneous movements is proposed. The coupling effects of the three positioning motions are analyzed. According to the experimental results, the time consumed by the erection system with PSPCS on the segment positioning process is further reduced to approximate one third of that by the erection system with SPCS.