CN116956503A - Dynamic equivalent structure design method for high-precision equipment - Google Patents

Abstract

The invention relates to the technical field of simulation of equivalent structures, in particular to a dynamic equivalent structure design method of high-precision equipment. Comprising the following steps: designing a high-precision equipment model to be simulated, and obtaining relevant parameter indexes of the high-precision equipment model to be simulated; selecting an interface design scheme which is the same as the actual structure of the high-precision equipment to be simulated, and designing a dynamic equivalent structure connection interface; designing and preparing a dynamic equivalent structure according to the structural outline size of actual high-precision equipment; acquiring actual data of related parameter indexes, and comparing the actual data with initial parameter index data; installing a weight plate according to actual conditions, wherein the installation plane of the weight plate is a known quantity, and establishing a constraint equation based on multiple targets through the known quantity; carrying out optimization calculation through constraint equations to obtain optimal solutions of all unknowns; and (3) carrying out manual optimization on the actual calculation result, and carrying out evaluation and detail adjustment on the error precision of the manual optimization. The advantage lies in the high-precision design of the equivalent structure.

Description

Dynamic equivalent structure design method for high-precision equipment

Technical field

The invention relates to the technical field of equivalent structure simulation, and in particular to a dynamic equivalent structure design method for high-precision equipment.

Background technique

During the initial design and field testing of mechanical structures, they are limited by the accuracy, value, and processing cycle of actual equipment. Many high-precision and high-value equipment will not actually be installed on the mechanical structure. Prevent damage to high-precision and high-value equipment due to insufficient structural design of the initial plan, under-consideration of simulation boundary conditions, and empirical reference values that do not meet the actual situation.

However, the actual dynamic response and measurement results during the field process are necessary conditions for evaluating the performance indicators of relevant mechanical structures, and the relevant test results are the prerequisite for judging whether high-precision and high-value equipment meets technical application requirements. In order to ensure and satisfy the authenticity of the actual dynamic response in the absence of high-value equipment, it is necessary to design relevant equivalent structures to replace the original high-precision, high-value equipment.

The simplest method of equivalent structure design is to re-process a set of equivalent equipment with reference to the original high-precision, high-value equipment. The accuracy of all parts in this equipment is several orders of magnitude lower than the technical indicators of the original parts. This set of equipment does not require installation and adjustment, it only needs to be installed at the required location. However, the advantage of the above scheme is that the dynamic equivalent is basically consistent with the original technical scheme, and the error is extremely small. The disadvantage is that it requires reprocessing a set of equivalent equipment, which requires a lot of time and money. This solution is acceptable for self-developed equipment, but is not feasible for purchased high-precision equipment.

The actual motion state of an object is motion with six degrees of freedom in space, including translational motion in three directions and rotational motion around three directions. For this purpose, its dynamic equivalent needs to meet the coordinate consistency of the center of mass in three directions, the consistency of the moment of inertia around the three axes, and the consistency of the mass, a total of seven parameter indicators.

The general method of equivalent structural design is to design equivalent tooling with reference to the original structural appearance and interfaces. For one-dimensional motion conditions such as a one-dimensional vibrating table, only the connection interface, center of mass position and other data need to be fitted to complete an equivalent structure design with high accuracy. The general equivalent structure design can only meet part of the fitting requirements of the seven parameter indicators. As for the simplest fitting method, although it can meet the fitting needs of seven parameter indicators, the time and funding costs will be high.

Contents of the invention

In order to solve the above problems, the present invention provides a dynamic equivalent structure design method for high-precision equipment.

The purpose of the present invention is to provide a dynamic equivalent structure design method for high-precision equipment, which includes the following steps:

S1. Design the high-precision equipment model to be simulated, and obtain the relevant parameter indicators of the high-precision equipment model to be simulated;

S2. Design the dynamic equivalent structure connection interface: Select the interface design scheme that is the same as the actual structure of the high-precision equipment to be simulated, and design the dynamic equivalent structure connection interface to ensure that the connection between the dynamic equivalent structure and the part to be connected is ensured. connectivity;

S3. Design and prepare a dynamic equivalent structure according to the actual structural outer contour dimensions of high-precision equipment;

S4. Obtain the actual data of relevant parameter indexes of the kinetic equivalent structure prepared in step S3, and compare this data with the parameter index data in step S1; if consistent, proceed to the next step; if any parameter index exceeds the parameters of step S1 If the value of the indicator data is invalid, return to step S3;

S5. According to the actual situation, install the counterweight plate on the outer frame of the dynamically equivalent structure. The installation plane of the counterweight plate is a known quantity. A multi-objective constraint equation based on the known quantity is established; carry out through the constraint equation Optimize calculations to obtain the optimal solution for each unknown quantity;

S6. Manual optimization adjustment: Perform manual optimization on the actual calculation results in step S5, and evaluate and adjust the details of the error accuracy of the manual optimization; if the requirements are met, the optimization design ends; if the requirements are not met, the redesign plan is returned.

Preferably, the parameter indicators include mass m ₀ , center of mass ( x ₀ , y ₀ , z ₀ ), and moment of inertia around the center of mass ( I _x0 , I _y0 , I _z0 ).

Preferably, the dynamically equivalent structure is a high-stiffness frame.

Preferably, the constraint equation in step S5 is as follows:

;

Among them, f ₁ ~ f ₇ correspond to 7 parameter indicators respectively; is the density,/> ,/> ,/> are the lengths in the three directions of xyz respectively,/> ,/> ,/> are the moments of inertia around the center of mass ( x ₀ , y ₀ , z ₀ ) respectively;

The corresponding optimization goal is .

Preferably, the optimization calculation algorithm in step S5 adopts the Monte Carlo algorithm idea to perform multiple calculations. The steps for a single calculation are as follows:

S501. Randomly generate the initial value of the unknown quantity;

S502. Calculate f ₁ ~ f ₇ , obtain the error value and calculate the 2-norm;

S503. Calculate the numerical gradient of all unknown quantities, that is, the change in the 2-norm when a certain unknown quantity changes ±δ;

S504. Take the direction of change where the 2-norm value becomes smaller;

S505. Repeat the operations of S502~S504 until the 2-norm value reaches the minimum.

Preferably, the unknown quantities in step S5 include the length, width, and height of the weight plate, as well as the installation position of the weight plate in the plane.

Preferably, the manual optimization in step S6 includes: rounding off the results in step S5 according to actual needs, or selecting models according to the size specifications of the plates, and modeling in three-dimensional design software to determine whether the relevant structural models are suitable. Interference occurs.

Preferably, the high-precision equipment model to be simulated in step S1 is passed through three-dimensional design software.

Compared with the existing technology, the present invention can achieve the following beneficial effects:

Through the design method of the present invention, in the early stage of field or laboratory testing, the original high-value and high-precision equipment can be replaced by an equivalent structure to realize the measurement of dynamics-related data. The advantage of the present invention is to realize high-precision design of equivalent structures, use equivalent structures to replace original high-value high-precision equipment, protect high-value equipment in the early stage, and ensure the accuracy of relevant dynamic data measurement results.

Description of the drawings

Figure 1 is a flow chart of a dynamic equivalent structure design method for high-precision equipment provided according to an embodiment of the present invention.

Detailed ways

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, the same modules are designated with the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, its detailed description will not be repeated.

In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention and do not constitute limitations of the present invention.

Example 1

Referring to Figure 1, the present invention provides a dynamic equivalent structure design method for high-precision equipment, which includes the following steps:

S1. Use three-dimensional design software to design the high-precision equipment model to be simulated, and obtain 7 parameter indicators of the high-precision equipment model to be simulated. The parameter indicators include mass m ₀ , center of mass ( x ₀ , y ₀ , z ₀ ) , the moment of inertia around the center of mass ( I _x0 , I _y0 , I _z0 ).

S2. Design the dynamic equivalent structure connection interface: Select the interface design scheme that is the same as the actual structure of the high-precision equipment to be simulated, and design the dynamic equivalent structure connection interface to ensure that the connection between the dynamic equivalent structure and the part to be connected is ensured. of connectivity.

S3. Design and prepare a high-stiffness frame, that is, a dynamic equivalent structure, according to the structural outer contour dimensions of the actual high-precision equipment.

S4. Obtain the actual data of 7 parameter indexes of the kinetic equivalent structure prepared in step S3, and compare this data with the parameter index data in step S1; if consistent, proceed to the next step; if any parameter index exceeds the parameter index in step S1 If the value of the parameter index data is determined, return to step S3.

S5. According to the actual situation, install the counterweight plate on the outer frame of the dynamically equivalent structure. The installation plane of the counterweight plate is a known quantity. A multi-objective constraint equation based on the known quantity is established; carry out through the constraint equation Optimize calculations to obtain the optimal solution for each unknown quantity;

The unknown quantities include the length, width, and height of the counterweight plate, as well as the installation position of the counterweight plate in the plane (the installation position in the plane includes the x- and y-axis coordinates located in the plane); a single counterweight plate contains 5 Unknown quantities, for n boards, it contains at most 5n unknown quantities;

The specific constraint equations are as follows ( f ₁ ~ f ₇ correspond to 7 parameter indicators respectively):

;

In the formula, is the density,/> ,/> ,/> are the lengths in the three directions of xyz respectively,/> , ,/> are the moments of inertia around the center of mass ( x ₀ , y ₀ , z ₀ ) respectively;

The corresponding optimization goal is ;

The optimization calculation algorithm adopts the Monte Carlo algorithm idea to perform multiple calculations. The steps for a single calculation are as follows:

S501. Randomly generate the initial value of the unknown quantity;

S502. Calculate f ₁ ~ f ₇ , obtain the error value and calculate the 2-norm;

S503. Calculate the numerical gradient of all unknown quantities, that is, the change in the 2-norm when a certain unknown quantity changes ±δ;

S504. Take the direction of change where the 2-norm value becomes smaller;

S505. Repeat the operations of S502~S504 until the 2-norm value reaches the minimum;

Principle: Since there is multi-objective optimization in the system, the difference between f ₁ ~ f ₇ and goal is regarded as the error value, and the 2-norm is taken for the error value vector to obtain the overall error evaluation of the multi-objective; for this error evaluation optimization, The goal is to have the lowest rating possible.

S6. Manual optimization adjustment: Perform manual optimization on the actual calculation results in step S5, and evaluate and adjust the error accuracy of the manual optimization; if the requirements are met, the optimization design ends; if the requirements are not met, the redesign plan is returned;

The manual optimization includes: rounding off the results in step S5 according to actual needs, or selecting models according to the size specifications of the plates, and modeling in three-dimensional design software to ensure that the relevant structural models do not interfere.

It should be understood that various forms of the process shown above may be used, with steps reordered, added or deleted. For example, each step described in the disclosure of the present invention can be executed in parallel, sequentially, or in a different order. As long as the desired results of the technical solution disclosed in the present invention can be achieved, there is no limitation here.

The above-mentioned specific embodiments do not constitute a limitation on the scope of the present invention. It will be understood by those skilled in the art that various modifications, combinations, sub-combinations and substitutions are possible depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims (8)

1. The dynamic equivalent structure design method of the high-precision equipment is characterized by comprising the following steps of:

s1, designing a high-precision equipment model to be simulated, and obtaining relevant parameter indexes of the high-precision equipment model to be simulated;

s2, designing a dynamic equivalent structure connection interface: selecting an interface design scheme which is the same as the actual structure of the high-precision equipment to be simulated, designing a dynamic equivalent structure connecting interface, and ensuring the connectivity between the dynamic equivalent structure and the connecting part of the part to be connected;

s3, designing and preparing a dynamic equivalent structure according to the structural outline size of the actual high-precision equipment;

s4, acquiring actual data of related parameter indexes of the dynamic equivalent structure prepared in the step S3, and comparing the actual data with the parameter index data in the step S1; if yes, entering the next step; if any parameter index exceeds the value of the parameter index data in the step S1, returning to the step S3;

s5, installing a weight plate on an outer frame of the dynamic equivalent structure according to actual conditions, wherein the installation plane of the weight plate is a known quantity, and establishing a constraint equation based on multiple targets through the known quantity; carrying out optimization calculation through constraint equations to obtain optimal solutions of all unknowns;

s6, manual optimization adjustment: performing manual optimization on the actual calculation result in the step S5, and performing evaluation and detail adjustment on the error precision of the manual optimization; if the requirements are met, the optimization design is finished; if the requirements are not met, returning to the redesign scheme.

2. The method for designing a dynamic equivalent structure of a high-precision apparatus according to claim 1, characterized in that: the parameter index includes qualitym ₀ Mass center [ (of mass.)x ₀ 、y ₀ 、z ₀ ) Moment of inertia about centroidI _x0 、I _y0 、I _z0 ）。

3. The method for designing a dynamic equivalent structure of a high-precision apparatus according to claim 2, characterized in that: the dynamic equivalent structure is a high-rigidity frame.

4. A method of designing a dynamic equivalent structure of a high-precision apparatus according to any one of claims 1 to 3, characterized in that: the constraint equation in the step S5 is specifically as follows:

；

wherein ,f ₁ ~f ₇ respectively corresponding to 7 parameter indexes;for density (I)>、/>、/>Respectively isxyzThe length in the three directions of the two-dimensional space,、/>、/>respectively winding the mass centerx ₀ 、y ₀ 、z ₀ ) Is a rotational inertia of (a);

the corresponding optimization targets are。

5. The method for designing a dynamic equivalent structure of a high-precision apparatus according to claim 4, characterized in that: the optimization calculation algorithm in the step S5 adopts the Monte Carlo algorithm idea to carry out multiple calculations, and the single calculation steps are as follows:

s501, randomly generating an unknown quantity initial value;

s502, calculatingf ₁ ~f ₇ Obtaining an error value and calculating a 2-norm;

s503, calculating the numerical gradients of all unknown quantities, namely, when a certain unknown quantity changes +/-delta, 2-norm changes;

s504, taking the value of the change direction of the 2-norm value becoming smaller;

s505, repeating the operations of S502-S504 until the 2-norm value reaches the minimum.

6. The method for designing a dynamic equivalent structure of a high-precision apparatus according to claim 5, characterized in that: the unknowns in step S5 include the length, width, height of the weight plate, and the installation position of the weight plate in the plane.

7. The method for designing a dynamic equivalent structure of a high-precision apparatus according to claim 6, wherein the manual optimization in step S6 includes: and (5) performing decimal place selection on the result in the step (S5) according to actual requirements, or performing model selection according to the size specification of the plate, modeling in three-dimensional design software, and determining that the related structural models do not interfere.

8. The method for designing a dynamic equivalent structure of a high-precision apparatus according to claim 7, characterized in that: the high-precision equipment model to be simulated in the step S1 passes through three-dimensional design software.