Abstract: Aiming at the problem of calculating the thrust of hydraulic cylinder of luffing mechanism for highaltitude platform, the theoretical calculation methods of luffing mechanism of six hinge points was compared and analyzed. The error reasons of existing theoretical calculation methods was summarized, and a safer calculation idea was put forward. The moment balance method and the virtual displacement method were used for calculation. The method of the virtual displacement principle was classified, respectively using the whole analytical method and the fractional analytical method to calculate. The derivation results of the three methods were taken into a specific model of the sixhinge point luffing mechanism for verification. The results indicate that different error factors will lead to different calculation values. The safety performance of the mechanism can be improved effectively through selecting the maximum value in the calculation results. The above method can be extended to the theoretical calculation of other luffing mechanism, and provides a reference for the application of the virtual work principle.
Key words: sixpoint luffing mechanism; hydraulic cylinder driving force; principle of virtual work; highaltitude platform