Dynamic characteristics analysis of automatic cutting and profiling control system for roadheader

An analysis method was proposed for dynamic characteristics of automatic cutting and profiling control system for roadheader base on transfer function model. Composition and main structure of the system were expounded, and transfer function model of each part of the system was obtained. Dynamic characteristics of the system were simulated when cutting head moved horizontally. The simulation results show that the transfer function of the system is an open-loop transfer function which is composed of proportional, integral and two order oscillation, and the system is a type I system; when adjustable gain is 14, the system outputs a good response with no overshoot and smooth curves, the shorter rising time is 0.428 s, and adjusting time is 0.797 s; the system has no zero point, and characteristic roots are in the left half of S plane with a positive amplitude margin and a phase margin, which shows the system has good stability. The field test shows that vertical cutting error of the cutting head is less than 40 mm, unilateral positioning precision of cutting tunnel section is less than 50 mm as well as repeatability precision is less than 20 mm.