Wind Loading Analysis On Six-Driven Parallel Robot Of High Altitude

A new generation of 500 m caliber spherical radio telescope(FAST)is a six-cable driven parallel robot,this paper will feed the cabin cable system for random vibration simulation analysis to get a reliable wind speed-displacement curve and resonant frequency and provide some reference and protection for the FAST debugging and operation.First the suspension model in the cabin system is analyzed by static analysis.The suspension model can be described by catenary,which is helpful to calculate the accuracy of the model.Based on the horizontal tension in six suspension cables,the parallel mechanism of the cable is analyzed.By establishing the static equilibrium equation,the catenary equation of the cable in the practical application is deduced,and the cable force and cable length expression are received.The solution of the nonlinear static equilibrium equation also lays the foundation for the subsequent suspension finite element modeling.According to the four parts of the feed support system in the FAST project: the feed tank,the supporting cable,the supporting tower and the driving mechanism,the working condition of the cabin cable system is introduced,and the coordinates of the anchorage point of the cabin cable system are calculated by MATLAB.A three-dimensional model of the feed compartment was established.The source and formation process of wind load are studied,and the static and dynamic wind loads are calculated and simplified to the cabin cable system.The foundation of the cabin cable system dynamics analysis and wind load spectrum analysis is laid.The finite element model is used to build the finite element model of the cabin system in ANSYS.The modal analysis of the cabin cable system and the PSD response of the wind load spectrum are carried out.When the wind speed is 4m/s,the resonant low frequency is between 2~4Hz,which is far greater than the low order natural frequency of the FAST cabin system,and no resonance occurs.The maximum displacement of the feed tank is about 22 mm at the normal working wind speed of 4m / s,which is in the feed compartment space position error maximum of 48 mm range and much smaller than that of FAST of the work space.The wind speed-displacement curve is drawn after the data is collected by the wind load random vibration analysis.It does not affect the normal operation of FAST and provides reliable reference data for FAST debugging and operation.Aiming at the finite element simulation analysis,the FAST system structure is simulated and gathering the data of the changing wind.The maximum displacement of the feed tank in three directions of X,Y and Z is sorted out.Compared with the finite element model And the results are basically the same,which verifies the accuracy and reliability of finite element dynamics analysis of FAST prototype.