Research On Coordination Between Hoisting And Luffing Of Heavy-load Long-boom All-terrain Crane

The box-type telescopic boom is the main load-bearing component of al-terrain crane during hoisting.With the rapid development of slender and lightweight of al-terrain crane boom and the increasing hoisting weight,the nonlinear deformation of the boom during hoisting is particularly obvious.When the weight is just lifted to completely leave the contact surface,the excessive nonlinear deformation of the main boom directly causes the boom tip to extend forward and the working range to increase.At the moment when the load leaves the contact surface,there is a positive deflection angle between the hoisting wire rope and the vertical direction,which causes the weight to swing forward.In the falling stage of the boom unloading,the nonlinear deformation of the boom gradually recovers,which causes the boom tip to move backward,and the wire rope has a negative deflection angle with the vertical direction,which may cause the weight to move backward in the process of contacting the ground.In practical engineering,in order to avoid this phenomenon,it is often necessary for the operator to adjust the luffing oil cylinder and hoisting at the same time,so that the hoisting weight can be vertically off the ground and landing.In this paper,a 500 t al-terrain crane is taken as the research weight,and the main research around the nonlinear deformation of the telescopic boom is as follows:(1)This paper introduces the research on the nonlinear deformation of al-terrain crane when hoisting the weight,and expounds the reasons for the deflection and movement of the load in the process of hoisting and landing.(2)In this paper,the analytical expression of nonlinear deformation displacement of boxtype telescopic boom is studied.Considering the influence of the second-order effect of the axial load on the deformation,the relationship between the deflection deformation of the single boom and the load is described mathematically,and the transcendental equation in the analytic a l formula is expanded by Taylor,which greatly simplifies the complexity of the analytic a l formula.After that,the relationship between deflection deformation and load of complete boom is studied by coordinate transformation method,and the accuracy of the conclusion is verified by finite element simulation.(3)Furthermore,the influence of nonlinear deformation on the working range of al-terrain crane is discussed,and two compensation strategies are put forward.One is to set the extension length of luffing oil cylinder in advance and lift it directly,the other is to set the angle between steel wire rope and vertical direction in advance.In this paper,the critical condition of the sliding of the heavy load during the loading and unloading of the boom is deduced.(4)Aiming at the expansion length of luffing cylinder and the prior deflection angle of wire rope in the coordination strategy,a prediction model based on BP neural network is established.The experimental results show that the neural network model proposed in this paper has high prediction accuracy and fast calculation speed,which provides a new method for the vertical hoisting and landing of the load in practical engineering.