Method for measuring the forced deflection angle of the boom during the luffing process of a tower crane

Abstract

The present invention discloses a method for measuring the forced deflection angle of a boom during a luffing process of a tower crane, which comprises first obtaining basic parameters of the tower crane, then obtaining operating state parameters of the tower crane when performing luffing motion, analyzing the system kinetic energy and potential energy of the tower crane, and constructing the Lagrange equation of the system according to the law of conservation of energy, solving the Lagrange equation and simplifying it, and then performing Laplace transformation, and solving to obtain the forced deflection angle of the boom. The present invention can quickly and in real time measure the forced deflection angle of the boom during the luffing motion by obtaining the basic parameters of the tower crane and the operating state parameters of the tower crane when performing luffing motion, without the need for additional measuring instruments; and lays a foundation for the subsequent tower crane to quickly eliminate the forced deflection angle of the boom.

Description

Technical Field

[0001] The invention relates to the field of tower cranes, in particular to a method for measuring the forced deflection angle of a lifting arm during the luffing process of a tower crane. Background Art

[0002] Since the luffing trolley and the load are connected by multiple ropes, during the entire luffing process of the tower crane, the swing state of the load is not just a simple pendulum swing along the boom, but exists in a form similar to a conical pendulum; if the swing angle of the load deviates too much from the boom, it will cause mechanical sprain of the boom and reduce the service life of the tower crane; and it is easy to cause resonance of the tower crane, and in severe cases it will drag the entire tower crane, posing a serious safety hazard; therefore, in order to solve the above problems, how to better and quickly calculate the real-time forced deflection angle of the boom is an issue that urgently needs to be solved in this field. Summary of the invention

[0003] The purpose of the present invention is to provide a method for measuring the forced deflection angle of a boom during the luffing process of a tower crane. The present invention has the advantage of being able to quickly measure the forced deflection angle of a boom during the luffing process without the need for equipment measurement.

[0004] The technical solution of the present invention is a method for measuring the forced deflection angle of a boom during a tower crane luffing process, comprising the following steps:

[0005] a. Obtain the basic parameters of the tower crane, including the mass M and moment of inertia J0 of the luffing trolley;

[0006] b. Obtaining the operating state parameters of the tower crane when performing luffing motion, the operating state parameters include the mass m of the load, the length l of the rope connecting the luffing trolley and the load, and the vertical distance x between the luffing trolley and the central axis of the tower crane;

[0007] c. Assume that the load swing angle is θ, which can be decomposed into θ1 and θ2, where θ1 is the angle between the load and the Z axis on the XZ plane, and θ2 is the angle between the load and the rope length on the XZ plane;

[0008] d. Consider the load as a point mass, and ignore the rope mass, elasticity and other factors. Assume that the generalized coordinates of the tower crane are q = (x, γ, θ1, θ2), where γ is the angular displacement of the boom rotation. Then the kinetic energy of the entire system is:

[0009]

[0010] Taking the horizontal plane where the tower crane boom is located as the zero potential energy surface, the potential energy of the system is:

[0011] V=-mglcosθ1cosθ2

[0012] According to the law of conservation of energy, the Lagrange equation of the system is constructed:

[0013] L=TV

[0014]

[0015] L is the Lagrangian, F x is the force on the luffing trolley in the X direction, D x is the damping component of the luffing trolley along the X direction, T γ is the swing torque of the boom;

[0016] e. Solve the Lagrange equation in step d and get

[0017]

[0018] f. When only considering the effect of load on boom deflection during the luffing process, θ1 = 0, step e can be simplified and solved to

[0019]

[0020] According to the Laplace transform, we can get

[0021]

[0022] The forced deflection angle of the crane arm is obtained as

[0023]

[0024] Compared with the prior art, the present invention can quickly and in real time calculate the forced deflection angle of the boom during the luffing movement by acquiring the basic parameters of the tower crane and the operating status parameters of the tower crane during the luffing movement, without the need for additional measuring instruments; this lays the foundation for subsequent tower cranes to quickly eliminate the forced deflection angle of the boom. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural diagram of a tower crane. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings and embodiments, but they are not intended to limit the present invention.

[0027] Embodiment. A method for measuring the forced deflection angle of a boom during a luffing process of a tower crane, wherein the tower crane is Figure 1 As shown, the following steps are included:

[0028] a. Obtain the basic parameters of the tower crane, including the mass M and moment of inertia J0 of the luffing trolley;

[0029] b. Obtaining the operating state parameters of the tower crane when performing luffing motion, the operating state parameters include the mass m of the load, the length l of the rope connecting the luffing trolley and the load, and the vertical distance x between the luffing trolley and the central axis of the tower crane;

[0030] c. Assume that the load swing angle is θ, which can be decomposed into θ1 and θ2, where θ1 is the angle between the load and the Z axis on the XZ plane, and θ2 is the angle between the load and the rope length on the XZ plane;

[0031] d. Consider the load as a point mass, and ignore the rope mass, elasticity and other factors. Assume that the generalized coordinates of the tower crane are q = (x, γ, θ1, θ2), where γ is the angular displacement of the boom rotation. Then the kinetic energy of the entire system is:

[0032]

[0033] Taking the horizontal plane where the tower crane boom is located as the zero potential energy surface, the potential energy of the system is:

[0034] V=-mglcosθ1cosθ2

[0035] According to the law of conservation of energy, the Lagrange equation of the system is constructed:

[0036] L=TV

[0037]

[0038] L is the Lagrangian, F x is the force on the luffing trolley in the X direction, D x is the damping component of the luffing trolley along the X direction, T γ is the swing torque of the boom;

[0039] e. Solve the Lagrange equation in step d and get

[0040]

[0041] f. When only considering the effect of load on boom deflection during the luffing process, θ1 = 0, step e can be simplified and solved to

[0042]

[0043] According to the Laplace transform, we can get

[0044]

[0045] The forced deflection angle of the crane arm is obtained as

[0046]

Claims

1. A method for measuring the forced deflection angle of a boom during a tower crane luffing process, characterized in that: The following steps are involved: a. Obtain the basic parameters of the tower crane, including the mass M and moment of inertia J0 of the luffing trolley; b. Obtaining the operating state parameters of the tower crane when performing luffing motion, the operating state parameters include the mass m of the load, the length l of the rope connecting the luffing trolley and the load, and the vertical distance x between the luffing trolley and the central axis of the tower crane; c. Assume that the load swing angle is θ, which can be decomposed into θ1 and θ2, where θ1 is the angle between the load and the Z axis on the XZ plane, and θ2 is the angle between the load and the rope length on the XZ plane; d. Consider the load as a point mass, and ignore the rope mass, elasticity and other factors. Assume that the generalized coordinates of the tower crane are q = (x, γ, θ1, θ2), where γ is the angular displacement of the boom rotation. Then the kinetic energy of the entire system is: Taking the horizontal plane where the tower crane boom is located as the zero potential energy surface, the potential energy of the system is: V=-mglcosθ1cosθ2 According to the law of conservation of energy, the Lagrange equation of the system is constructed: L=TV L is the Lagrangian, F x is the force on the luffing trolley in the X direction, D x is the damping component of the luffing trolley along the X direction, T γ is the swing torque of the boom; e. Solve the Lagrange equation in step d and get f. When only considering the effect of load on boom deflection during the luffing process, θ1 = 0, step e can be simplified and solved to According to the Laplace transform, we can get The forced deflection angle of the crane arm is obtained as

Images