Analysis of point positioning control technology of tower crane
                                                   HUANG Ji,  LIANG Jiejin, YAN Bo, CHEN Chunchao, ZHOU Li
                            (Guangxi institute of special equipment Supervision and inspection, Nanning 530219, China)

Abstract: Aiming at the condition of the tower crane lifting point positioning accuracy was bad, combining with the working characteristics of tower crane and technical defects, a set of fixed automatic control system was developed.In this system, the range and height of the tower crane were obtained by multiring absolute encoder, horizontal absolute angle value of big arm was gotten through the electronic compass, will the data through MCU for unpacking and efficacy, thus hook threedimensional space coordinates was established. In MCU, the fixedpoint coordinates were compared with the current hook coordinate data to calculate the optimal fixedpoint location data through adaptive algorithm and fuzzy neural algorithm.The point about the height of the tower crane, the amplitude and angle was set, using highprecision total station to measure the parameters, and then testing system. The results show that the the system has high positioning accuracy, accurate and reliable, as well as good repeatability.With the continuous deepening of selflearning and the increase of test times, the positioning accuracy of the system is gradually improved.

Key words: tower crane; multiring absolute encoder; digital compass; control system