Load constraint processing method in helicopter full-aircraft static test inertial load balancing

Abstract

The invention belongs to the field of aircraft test design, and relates to a load constraint processing method in helicopter full-aircraft static test inertial load balancing. The method comprises the following steps: establishing a nonlinear optimization model to optimize an inertia balancing loading load, wherein the constraint on a design variable comprises that the load on a loading joint does not exceed the bearing capacity of the loading joint on a static testing machine; on the basis of constraint on design variables, three constraint conditions are added: (1) a course bending moment loaded on a frame position is realized by more than two vertical loading joints applied to the bottom of a frame, and the value of the course bending moment is limited by the distance between the vertical loading joints and a vertical load; (2) in order to facilitate loading, the load of a part of loading points is limited by the size of another loading point under the limitation of an adjusting lever; and (3) when the value of the inertial load loading point is smaller than a given value, setting the value as 0.

Description

Technical Field

[0001] The invention belongs to the field of aircraft test design and relates to a load constraint processing method in inertia load balancing of a full-machine static test of a helicopter. Background Art

[0002] The full-aircraft static test is a major static strength test required for the development of new aircraft. During the preparation of the test task book, determining the balance load consumes a lot of time and energy of the designers. Summary of the Invention

[0003] Purpose of the invention: To propose a load constraint processing method for inertial load trimming during full helicopter static testing, which can complete the load trimming work in a short time, greatly improving work efficiency. At the same time, it can also improve the accuracy of the frame station bending moment matching.

[0004] Technical solution:

[0005] A method for processing load constraints in inertial load trimming during a full-helicopter static test is provided, comprising:

[0006] A nonlinear optimization model was established to optimize the inertial trim loading. The objective function was the sum of the absolute value of the bending moment at each frame station of the static testing machine and the calculated difference between the bending moments at each frame station. The equality constraint was to satisfy the load balance constraint equation. The constraints on the design variables included: the load on the loading joint did not exceed the load-bearing capacity of the loading joint on the static testing machine.

[0007] On the basis of the constraints on the design variables, three additional constraints are added: (1) The axial bending moment loaded on the frame station is realized by more than two vertical loading joints applied to the bottom of the frame, and the value of the axial bending moment is limited by the spacing between the vertical loading joints and the vertical load; (2) To facilitate loading, the load size of some loading points is limited by the size of another load loading point due to the restriction of the adjustment lever; (3) When the value of the inertial load loading point is less than the given value, the value needs to be set to 0.

[0008] Furthermore, the method further comprises:

[0009] According to the principle that the value of the heading bending moment is limited by the vertical loading joint spacing and the vertical load, the integral constraint conditions are determined as follows:

[0010]

[0011] Where x kp is the vertical inertia trim load applied to the frame station, p = 1…V. M kq is the heading torque on the frame station on the qth frame, q = 1...L; when the pth loading point is located on the qth frame, d qp It is the distance from the vertical loading point on the frame station to the frame station heading bending moment reference point.

[0012] Furthermore, when the pth loading point is not on the qth box, d qp is 0.

[0013] Furthermore, the method further comprises:

[0014] According to the load ratio limit caused by the test loading lever, the load at the loading point on one end of the lever is required to be no more than C times the load at the loading point on the other end of the lever. The loading point on one end of the lever and the loading point on the other end of the lever are located on both sides of the left and right symmetry planes of the helicopter respectively. The limit condition is expressed as:

[0015] And x i1 x i2 >0,

[0016] where i = 1…M, x i1 is the load at the loading point at one end of the i-th lever, x i2 is the load at the other end of the i-th lever, C i is the maximum allowable ratio of the i-th lever, and M is the number of levers, that is, the logarithm of the inertial balancing load.

[0017] Furthermore, the inequality constraints corresponding to the restriction conditions are:

[0018]

[0019] Where S i is a symbolic coefficient, when x i1 <0, S i =1, when x i1 >0; S i =-1, and all the terms except those near the diagonal are 0.

[0020] Furthermore, the method further comprises:

[0021] After calculating the inertia load applied to the loading joint of the static testing machine, take the minimum value of the inertia load {x i} min With the given minimum load L T Compare, if {x i} min <L T , the loading point with the smallest inertia load is removed from the design variable and its value is set to 0.

[0022] Furthermore, after setting its value to 0, the method further includes:

[0023] Solve the optimization model again and repeatedly remove the loading point with the smallest inertia load from the design variables until {xi} min >L T .

[0024] Beneficial effects: The load constraint processing method of the present invention can make the calculated inertial load more convenient for test implementation, reduce the number of required load actuators, and eliminate the need for high-precision small-load actuators, thereby reducing test costs. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the implementation of this application will be described in more detail below in combination with the implementation of this application. The same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The described implementation is a part of the implementation of this application, not all of the implementations. The reference embodiments below are illustrative and intended to be used to explain this application, and should not be understood as limitations on this application. Based on the implementation in this application, all other implementations obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The implementation of this application is described in detail below.

[0026] In the description of the present invention, it should be understood that the terms "center", "axial", "vertical", "up", "down", "upper end", "bottom end", "inside", "outside", etc., indicating orientation or positional relationships, are based on orientation or positional relationships and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present invention.

[0027] The present invention provides a load constraint processing method in inertia load trimming of a full-machine static test of a helicopter, comprising:

[0028] A nonlinear optimization model was established to optimize the inertial trim loading. The objective function was the sum of the absolute value of the bending moment at each frame station of the static testing machine and the calculated difference between the bending moments at each frame station. The equality constraint was to satisfy the load balance constraint equation. The constraints on the design variables included: the load on the loading joint did not exceed the load-bearing capacity of the loading joint on the static testing machine.

[0029] The objective function f(x) is calculated as follows:

[0030]

[0031] is the bending moment of each frame station on the static testing machine;

[0032]

[0033] are the heading, lateral and vertical coordinates of the lth inertial load loading joint respectively; The forces and moments in all directions of the inertial load applied to the loading joint of the static testing machine; are the moments of the kth external load respectively; are the heading, lateral and vertical coordinates of the kth external load loading joint, respectively; N is the total number of loading joints used to apply inertial loads; Q is the total number of external loads.

[0034] The load balance constraint equation is:

[0035]

[0036] The present invention uses a nonlinear optimization method to automatically optimize the load, complete the load balancing work in a short time, and greatly improve work efficiency. At the same time, it improves the accuracy of the frame station bending moment. Among them, the design variable is the inertial load applied to the loading joint of the static testing machine. The optimization goal is to make the bending moment of the frame station in each direction of the static test as close as possible to the theoretical calculated value. Constraint 1 is that the inertial balancing load is within the upper and lower limits, and constraint 2 is that the inertial balancing load is balanced with the applied external load.

[0037] On the basis of the constraints on the design variables, three additional constraints are added: (1) The axial bending moment loaded on the frame station is realized by more than two vertical loading joints applied to the bottom of the frame, and the value of the axial bending moment is limited by the spacing between the vertical loading joints and the vertical load; (2) To facilitate loading, the load size of some loading points is limited by the size of another load loading point due to the restriction of the adjustment lever; (3) When the value of the inertial load loading point is less than the given value, the value needs to be set to 0.

[0038] (1) Relationship between the frame station heading bending moment and vertical load

[0039] The heading bending moment loaded on the frame station is realized by more than two vertical loading joints applied to the bottom of the frame. Therefore, the value of the heading bending moment is limited by the spacing between the vertical loading joints and the vertical load.

[0040]

[0041] Where x kp (p=1…V) is the vertical inertia balancing load applied to the frame station, and there are V of them. kq (q=1…L) is the heading torque on the frame station on the qth frame, and there are L frames in total. When the pth loading point is located on the qth frame, d qp is the distance from the vertical loading point on the frame station to the frame station heading bending moment reference point. When the pth loading point is not on the qth frame, dqp is 0.

[0042] The above formula is used as the integral constraint condition of the optimization model.

[0043] (2) Load ratio limit

[0044] To facilitate loading, the load size of some inertial trim load loading points is limited by the size of other load loading points due to the adjustment lever. It is required that the load at one loading point is not greater than C times the load at another loading point. The restriction condition is expressed as And x i1 x i2 >0, where i=1…M. In the formula, x i1 and x i2 represents a pair of inertial trim loads subject to load ratio constraints. There are M such pairs of inertial trim loads. C i is the proportional coefficient.

[0045] The above requirements are transformed into the following inequality constraints.

[0046]

[0047] Where S i (i=1…M) is the symbol coefficient, when x i1 <0, S i =1, when x i1 >0, S i = -1. All the terms except those near the diagonal are 0.

[0048] The above equation is used as the inequality constraint of the optimization model.

[0049] (3) Load threshold limit

[0050] When the value of the inertia load loading point is too small, loading cannot be implemented due to limitations such as equipment loading accuracy, and the load of the loading point needs to be set to 0.

[0051] Therefore, after calculating the inertia load applied to the loading joint of the static testing machine, take the minimum value of the inertia load {x i} min With the given minimum load L T Compare, if {x i} min <L T , then the loading point with the smallest inertia load is removed from the design variables and its value is set to 0. Then, the optimization model is solved again, and the loading point with the smallest inertia load is repeatedly removed from the design variables until {x i} min >L T .

[0052] Other embodiments of the present disclosure will readily occur to those skilled in the art after considering the specification and practicing the disclosure herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include common knowledge or customary techniques in the art not disclosed herein. The description and examples are to be considered as exemplary only, with the true scope and spirit of the present disclosure being indicated by the following claims.

[0053] It should be understood that the present disclosure is not limited to the precise construction that has been described above and that various modifications and changes can be made without departing from the scope thereof. The scope of the present disclosure is limited only by the appended claims.

Claims

1. A method for processing load constraints in inertial load trimming during a full helicopter static test, characterized in that: include: A nonlinear optimization model was established to optimize the inertial trim loading. The objective function was the sum of the absolute value of the bending moment at each frame station of the static testing machine and the calculated difference between the bending moments at each frame station. The equality constraint was to satisfy the load balance constraint equation. The constraints on the design variables included: the load on the loading joint did not exceed the load-bearing capacity of the loading joint on the static testing machine. On the basis of the constraints on the design variables, three additional constraints are added: (1) The axial bending moment loaded on the frame station is realized by more than two vertical loading joints applied to the bottom of the frame, and the value of the axial bending moment is limited by the spacing between the vertical loading joints and the vertical load; (2) To facilitate loading, the load size of some loading points is limited by the size of another load loading point due to the restriction of the adjustment lever; (3) When the value of the inertial load loading point is less than the given value, the value of the inertial load loading point needs to be set to 0.

2. The method according to claim 1, characterized in that The method further comprises: According to the principle that the value of the heading bending moment is limited by the vertical loading joint spacing and the vertical load, the integral constraint conditions are determined as follows: Where x kp is the vertical inertia trim load applied to the frame station, p = 1…V; M kq is the heading torque on the frame station on the qth frame, q = 1...L; when the pth loading point is located on the qth frame, d qp It is the distance from the vertical loading point on the frame station to the frame station heading bending moment reference point.

3. The method according to claim 2, characterized in that When the pth loading point is not on the qth box, d qp is 0.

4. The method according to claim 1, wherein The method further comprises: According to the load ratio limit caused by the test loading lever, the load at the loading point on one end of the lever is required to be no more than C times the load at the loading point on the other end of the lever. The loading point on one end of the lever and the loading point on the other end of the lever are located on both sides of the left and right symmetry planes of the helicopter respectively. The limit condition is expressed as: And x i1 x i2 >0, where i = 1…M, x i1 is the load at the loading point at one end of the i-th lever, x i2 is the load at the other end of the i-th lever, C i is the maximum allowable ratio of the i-th lever, and M is the number of levers, that is, the logarithm of the inertial balancing load.

5. The method according to claim 4, characterized in that The inequality constraints corresponding to the restriction conditions are: Where S i is a symbolic coefficient, when x i1 <0, S i =1, when x i1 >0; S i =-1, and all the terms except those near the diagonal are 0.

6. The method according to claim 1, characterized in that The method further comprises: After calculating the inertia load applied to the loading joint of the static testing machine, take the minimum value of the inertia load {x i } min With the given minimum load L T Compare, if {x i } min <L T , the loading point with the smallest inertia load is removed from the design variable and its value is set to 0.

7. The method according to claim 6, characterized in that After setting its value to 0, the method further includes: Solve the optimization model again and repeatedly remove the loading point with the smallest inertia load from the design variables until {x i } min >L T .

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method according to any one of claims 1 to 7 is implemented.

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