Development of the optimal control system of slewing and trolley movement mechanisms of a tower crane

Abstract

The development of the structural and functional block diagram of the optimal control system for the trolley movement and slewing mechanisms of a tower crane has been carried out. A detailed description of the individual functional blocks of the system and their logical connection is
presented. The operation of the control system according to the presented structural and functional
block diagram consists in carrying out diagnostic operations of the hardware and software parts of
the system, preliminary calculation of the speed diagrams of the mechanisms, their correction taking into account the optimal laws of the mechanisms movement (this operation is performed taking
into account the limitations of the frequency-controlled drive of the crane mechanisms). The last
operation in the algorithm is connected with the implementation of the movement of the crane
mechanisms according to the corrected diagrams and the adjustment of the final position of the load
in the planes of the trolley movement (along the boom) and the slewing rotation of the crane. The
control system allows one to implement the optimal laws of movement of the mechanisms, taking
into account the actual phase coordinates of the dynamic system, the features of the frequencycontrolled drive mechanisms and ensures the elimination of oscillations of the load on a flexible
suspension.
In addition, recommendations are given on the selection of a microcontroller, sensors and
frequency inverters of drives of slewing and trolley movement, as well as a data transfer protocol
between the elements of the control system. The list of mandatory functions of frequency inverters
acting as power sources for the drives of the tower crane mechanisms and microcontrollers that perform the operations of calculating control signals, collecting data and interacting with the crane operator is given in detail. The manufacturers and ranges of devices designed for the operating conditions of hoisting machinery are presented. For the sensors of the angular and linear positions of the
crane mechanisms, expressions are given to determine the rational accuracy of the sensors (optical
encoders).