Research on Three-point Centering Device of Cylindrical Drill Pipe

In the process of tightening up and screwing off the iron roughneck, it is required that the center of clamping pliers and the center of drill pipe are coincident, so as to avoid the damage of the circular guide in clamping system, and to ensure the iron roughneck work normally. While the traditional method of centering is artificial in iron roughneck, its precision is low, so it is easy to damage the drill pipe because of the great eccentricity between clamping pliers and drill pipe, besides, its work efficiency is low. Aiming at the cylindrical drill pipes, a method of three-point centering based on the ultrasonic sensors is proposed in this paper, that is to say, through comparing the feedback of three ultrasonic sensors which are arranged on the same the circle of clamping pliers’ nips, the center of clamping pliers is adjusted to be coincident with the center of drill pipe. In this paper, the related hardware and software system of the automatic centering are designed, and the simulation experiment is demonstrated by the SimMechanics. The result of simulation indicates that the method of automatic centering is feasible, and valuable to engineering application.