Anti-Sway Control Of A Tower Crane Based On Virtual Prototype Technology

Tower cranes are widely used in the construction industry because of the advantages of large working range,easy operation and small footprint.In order to improve the construction efficiency,the travelling mechanism of the tower crane usually runs at high speed.However,the frequent starting and stopping of the travelling mechanism will cause the cargo to swing.Excessive swing will not only affect the positioning accuracy of the cargo and reduce construction efficiency,but also pose a threat to the safety of the staff.In addition,due to the large overall size of tower cranes and the fact that they generally work outdoors,the cargo is very susceptible to wind loads,which increases the uncertainty of the swing.Therefore,a special control system for tower cranes is needed to suppress cargo sway.In this thesis,a combined open and closed loop control strategy is proposed for anti-sway during the operation of tower cranes,and the control strategy is constructed,tested and validated based on virtual prototype technology.The main research contents are as follows.（1）The dynamics models of cargo swing of tower crane under wind load are established based on Lagrangian function and the wind load calculation method based on wind scale is proposed.The influence of different working condition on cargo swing characteristics is analyzed by numerical simulation,and the simulation curves are compared with experimental results to verify the accuracy of the dynamics models.（2）Based on the structural dimensions and working parameters of QTZ5613 tower crane,the virtual prototype of the tower crane is established by using Solid Works software and ADAMS software.Then the model verification,strength verification and stability verification were carried out.The simulation of the virtual prototype is carried out according to the actual working conditions,and the cargo swing curve obtained from the virtual prototype is compared with the curve obtained from the dynamics model to verify the accuracy of the virtual prototype in simulating the cargo swing.（3）The PD combined with input shaping controller applicable to the tower crane is designed based on the cargo swing dynamics models,and the specific parameters of the controller are determined.The virtual prototype of the tower crane is exported to the Matlab/Simulink environment.The communication between ADMAS software and MATLAB software is completed.The PD combined input shaping control system is established in the Matlab/Simulink environment to control the virtual prototype.The co-simulation parameters of the virtual prototype are adjusted,and the established control system is tested.（4）A co-simulation of the tower crane virtual prototype using MATLAB software and ADAMS software is conducted to verify the actual effect of the designed PD combined with input shaping control system in suppressing cargo sway under no wind,upwind and downwind conditions,respectively,and it is compared with the standard PD feedback control system.The simulation results show that the designed PD combined with input shaping control system can effectively suppress the cargo sway of the tower crane,but the effect of the control system will gradually diminish as the wind load increases.