A method for engineering design of a dynamic vibration absorber for local vibration control of a helicopter

Abstract

The present application belongs to the field of helicopter vibration control, and relates to a power absorber engineering design method for local vibration control of a helicopter. The method comprises the following steps: determining an optimal installation position of the power absorber by carrying out power absorber and helicopter dynamics coupling analysis; determining an optimal effective mass of the power absorber in combination with overall design requirements of the power absorber; and carrying out power absorber structure design based on the effective mass of the power absorber.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of helicopter vibration control, and relates to an engineering design method of a dynamic vibration absorber for helicopter local vibration control. BACKGROUND

[0002] The dynamic vibration absorber is an effective means for helicopter local vibration control, and the vibration control effect of the dynamic vibration absorber depends on the installation position of the dynamic vibration absorber on the helicopter and the dynamic characteristics of the dynamic vibration absorber after being installed on the helicopter. The research on the design of the dynamic vibration absorber at home and abroad mainly focuses on the theoretical research on the dynamic parameters of the dynamic vibration absorber. The engineering design method which can be applied to engineering practice in the field of the dynamic vibration absorber installation position optimization and the dynamic vibration absorber effective mass optimization analysis through the dynamic vibration absorber and helicopter dynamics coupling analysis means is blank. SUMMARY

[0003] The application aims to make the installed dynamic vibration absorber play a good vibration control effect, and provides an engineering design method of a dynamic vibration absorber for helicopter local vibration control, which has great significance for the engineering design of the dynamic vibration absorber for helicopter local vibration control.

[0004] TECHNICAL SCHEME

[0005] The application provides an engineering design method of a dynamic vibration absorber for helicopter local vibration control, which comprises the following steps.

[0006] The optimal installation position of the dynamic vibration absorber is determined through the dynamic vibration absorber and helicopter dynamics coupling analysis, the optimal effective mass of the dynamic vibration absorber is determined in combination with the overall design requirements of the dynamic vibration absorber, and the structure design of the dynamic vibration absorber is carried out on the basis of the effective mass of the dynamic vibration absorber.

[0007] Further, the overall design requirements include the vibration control efficiency of the target position, the total weight requirement of the dynamic vibration absorber, the overall size of the dynamic vibration absorber, and the installation position with installation conditions.

[0008] Further, the optimal installation position of the dynamic vibration absorber is determined through the dynamic vibration absorber and helicopter dynamics coupling analysis, and the optimal installation position of the dynamic vibration absorber comprises the following steps.

[0009] The vibration control target position is determined, and the vibration frequency of the target position is determined.

[0010] The theoretical installation working frequency of the dynamic vibration absorber is determined through the vibration frequency of the target position.

[0011] The initial vibration response of the target position is obtained through the frequency domain response calculation method on the basis of the helicopter dynamics model.

[0012] The n mounting positions are selected from the n mounting positions on the helicopter structure, and n is a positive integer greater than 1;

[0013] The 1-m positions are selected from the n mounting positions to obtain a plurality of mounting position combinations; m is less than n;

[0014] The dynamic models of the dynamic absorbers with the same effective mass are established on the different mounting position combinations, the dynamic coupling analysis of the dynamic absorbers and the helicopter is carried out, and the vibration responses of the target position under the different mounting position combinations are obtained through the frequency domain response calculation method; wherein the sum of the effective masses of the dynamic absorbers in the different mounting position combinations is less than or equal to the total weight requirement of the dynamic absorber;

[0015] According to the initial vibration response of the target position and the vibration responses of the target position under the different mounting position combinations of the dynamic absorber, the vibration control efficiency of the target position under the different mounting position combinations of the dynamic absorber is calculated;

[0016] According to the vibration control efficiency of the target position under the different mounting position combinations of the dynamic absorber, the vibration control efficiency requirement of the target position, and the mounting positions with the installation conditions, the optimal combination of the dynamic absorber mounting positions meeting the requirements is selected.

[0017] Further, the optimal effective mass of the dynamic absorber is determined in combination with the overall design requirement of the dynamic absorber, including:

[0018] On the basis of the helicopter dynamic model, the dynamic models of the dynamic absorbers with different effective masses are established on the optimal combination, the dynamic coupling analysis of the dynamic absorbers and the helicopter is carried out, and the vibration responses of the target position under the different effective masses are obtained through the frequency domain response calculation method; the sum of the effective masses of the dynamic absorber dynamic models is less than or equal to the total weight requirement of the dynamic absorber;

[0019] According to the initial vibration response of the target position and the vibration responses of the target position under the different effective masses, the vibration control efficiency of the target position under the different effective masses is calculated;

[0020] According to the vibration control efficiency of the target position under the different effective masses, the vibration control efficiency requirement of the target position, the total weight requirement of the dynamic absorber, and the overall size requirement of the dynamic absorber, the optimal effective mass of the dynamic absorber meeting the requirements is selected.

[0021] Further, the dynamic absorber structure design is carried out based on the effective mass of the dynamic absorber, including:

[0022] According to the optimal effective mass of the dynamic absorber meeting the requirements, the total weight requirement of the dynamic absorber, and the overall size requirement of the dynamic absorber, the dynamic absorber structure design is carried out.

[0023] Further, the method further comprises:

[0024] According to the obtained installation position combination of the power absorber meeting the requirements, the power absorber is installed according to the power absorber structure design; and the installation working frequency is set;

[0025] Flight test is carried out;

[0026] The vibration control effect of the power absorber is verified through analyzing the flight test data;

[0027] If the vibration control effect of the power absorber does not meet the requirements, the effective mass of the power absorber is adjusted, the installation working frequency is re-set, flight test is carried out again until the vibration control effect of the power absorber meets the requirements.

[0028] Further, the working frequency of the power absorber dynamics model is consistent with the theoretical installation working frequency.

[0029] Beneficial effects:

[0030] The power absorber designed according to the engineering design method in the application has good vibration control effect, which proves that the engineering design method in the application provides an effective practical design method for local vibration control of a helicopter, and has high engineering application value. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 It is a flow chart of a power absorber engineering design method for local vibration control of a helicopter;

[0032] Figure 2 It is a schematic diagram of initial vibration response of a target position;

[0033] Figure 3 It is a schematic diagram of vibration response of a target position under different installation position combinations;

[0034] Figure 4 It is a schematic diagram of vibration control efficiency of a target position under different installation position combinations;

[0035] Figure 5 It is a schematic diagram of vibration response of a target position under different effective masses;

[0036] Figure 6 It is a schematic diagram of vibration control efficiency of a target position under different effective masses;

[0037] Figure 7 It is a power absorber for local vibration control of a helicopter;

[0038] Figure 8 It is a schematic diagram of installation frequency setting of a power absorber;

[0039] Figure 9 Figure of vibration control effect (flight test data) of the dynamic vibration absorber. DETAILED DESCRIPTION

[0040] The patent adopts a dynamic vibration absorber and helicopter dynamics coupling analysis method, and through dynamic vibration absorber installation position optimization and dynamic vibration absorber effective mass optimization analysis, an engineering design method which is in a blank field can be applied to engineering practice. In view of the actual vibration problem encountered by a certain type of helicopter, in order to reduce the local vibration of the helicopter pilot seat floor, an engineering design method of a dynamic vibration absorber for local vibration control of a helicopter is invented, and a dynamic vibration absorber is designed by using the engineering design method in the patent, and the dynamic vibration absorber is verified to have good vibration control effect on the helicopter through test flight, and the correctness and feasibility of the engineering design method in the patent are verified.

[0041] The following reasons lead to that the dynamic vibration absorber designed only through theoretical research on the dynamics parameters of the dynamic vibration absorber cannot achieve the optimal vibration control effect after installation.

[0042] 1. The dynamic vibration absorber has good vibration control effect within a certain range near the installation position, and has no vibration control effect or poor vibration control effect outside the range, that is, the vibration control range of the dynamic vibration absorber is limited and local;

[0043] 2. The range with good vibration control effect of the dynamic vibration absorber is directly related to the dynamics parameters of the dynamic vibration absorber, but after the dynamic vibration absorber is installed on the main system, the dynamics parameters of the dynamic vibration absorber are coupled with the structure stiffness and mass distribution near the dynamic vibration absorber, so that the local dynamic characteristics of the dynamic vibration absorber and the main system are changed, and therefore the dynamic vibration absorber and the main system dynamics coupling analysis need to be carried out when the dynamic vibration absorber is designed;

[0044] 3. The vibration control effect of the dynamic vibration absorber on the target position (hereinafter referred to as target position) depends on the installation position of the dynamic vibration absorber on the main system, that is, the transfer function from the installation position of the dynamic vibration absorber to the target position, different installation positions of the dynamic vibration absorber have different transfer functions, and therefore have different vibration control effects, so the installation position of the dynamic vibration absorber has an optimal installation position, and the installation position optimization of the dynamic vibration absorber needs to be carried out;

[0045] Based on the above discussion, in order to make the installed dynamic vibration absorber have good vibration control effect, an engineering design method of a dynamic vibration absorber for local vibration control of a helicopter is proposed, which has great significance for engineering design of a dynamic vibration absorber for local vibration control of a helicopter.

[0046] The application determines the optimal installation position of the dynamic absorber by carrying out dynamic absorber and helicopter dynamics coupling analysis, determines the optimal effective mass of the dynamic absorber in combination with the overall design requirements of the dynamic absorber (such as the vibration control efficiency of the target position, the total weight of the dynamic absorber, the overall size of the dynamic absorber, and the installation position with installation conditions), and carries out the structure design of the dynamic absorber based on the effective mass of the dynamic absorber. Figure 1 The specific steps are as follows:

[0047] [1] The target position of vibration control is determined, and the vibration frequency of the target position is determined.

[0048] [2] The theoretical installation working frequency of the dynamic absorber is determined through the vibration frequency of the target position.

[0049] [3] Based on the helicopter dynamics model, the initial vibration response of the target position is obtained through the frequency domain response calculation method.

[0050] [4] Based on the helicopter dynamics model, the dynamic absorber dynamics model with the same effective mass is established on different installation position combinations, the dynamic absorber and helicopter dynamics coupling analysis is carried out, and the vibration response of the target position under different dynamic absorber installation position combinations is obtained through the frequency domain response calculation method.

[0051] [5] The vibration control efficiency of the target position under different dynamic absorber installation position combinations is calculated according to the initial vibration response of the target position and the vibration response under different dynamic absorber installation position combinations.

[0052] [6] The dynamic absorber installation position combination meeting the requirements is optimized according to the vibration control efficiency of the target position under different dynamic absorber installation position combinations, the vibration control efficiency requirement of the target position, and the installation position with installation conditions.

[0053] [7] Based on the helicopter dynamics model, the dynamic absorber dynamics model with different effective masses is established on the same dynamic absorber installation position combination meeting the requirements, the dynamic absorber and helicopter dynamics coupling analysis is carried out, and the vibration response of the target position under different effective masses is obtained through the frequency domain response calculation method.

[0054] [8] The vibration control efficiency of the target position under different effective masses is calculated according to the initial vibration response of the target position and the vibration response under different effective masses.

[0055] [9] The dynamic absorber effective mass meeting the requirements is optimized according to the vibration control efficiency of the target position under different effective masses, the vibration control efficiency requirement of the target position, the total weight requirement of the dynamic absorber, and the overall size requirement of the dynamic absorber.

[0056]

[10] According to the obtained power absorber effective mass meeting the requirements, the total weight requirement of the power absorber, and the overall size requirement of the power absorber, the power absorber structure design is carried out;

[0057]

[11] According to the obtained power absorber installation position combination meeting the requirements, the power absorber is installed, and the installation working frequency is set.

[0058]

[12] The vibration control effect of the power absorber is verified by analyzing the flight test data.

[0059] Application example:

[0060] In order to prove the applicability and effectiveness of the present application, for the actual vibration problem encountered by a certain type of aircraft, in order to reduce the local vibration at the floor of the helicopter pilot seat, a power absorber is designed by applying the present application, and the power absorber is verified to have good vibration control effect through test flight. The specific implementation is as follows:

[0061] [1] As shown in Figure 1 , first of all, the floor of the pilot seat of a certain type of helicopter is defined as the target position for vibration control, and the vibration frequency is NΩ, wherein: N is the number of blades, and Ω is the rotor speed;

[0062] [2] According to the vibration frequency of the target position, the installation working frequency of the power absorber is determined as NΩ;

[0063] [3] On the basis of the dynamics model of a certain type of helicopter, the initial vibration response of the target position is obtained by the frequency domain response calculation method, as shown in Figure 2 ;

[0064] [4] On the basis of the dynamics model of a certain type of helicopter, the dynamics model of the power absorber with an effective mass of 5kg is established on different installation position combinations (combination 1-combination 6), the dynamics coupling analysis of the power absorber and the certain type of helicopter is carried out, and the vibration response of the target position under different power absorber installation position combinations is obtained by the frequency domain response calculation method, as shown in Figure 3 ;

[0065] [5] According to the initial vibration response of the target position and the vibration response under different power absorber installation position combinations, the vibration control efficiency of the target position under different power absorber installation position combinations is calculated, as shown in Figure 4 ;

[0066] [6] According to the vibration control efficiency of the target position under different combinations of the installation positions of the dynamic vibration absorber, the vibration control efficiency requirement of the target position, and the installation positions with installation conditions, the combination of the installation positions of the dynamic vibration absorber that meets the requirements is selected, including combination 3, combination 4 and combination 6;

[0067] [7] On the basis of the helicopter dynamics model, the combination 3 of the installation positions of the dynamic vibration absorber is selected, the dynamics model of the dynamic vibration absorber with different effective masses (5-20 kg) is established at the combination positions, the dynamics coupling analysis of the dynamic vibration absorber and the helicopter is carried out, and the vibration responses of the target position under different effective masses are obtained through the frequency domain response calculation method, as shown in Figure 5 ;

[0068] [8] According to the initial vibration response of the target position and the vibration responses under different effective masses, the vibration control efficiency of the target position under different effective masses is calculated, as shown in Figure 6 ;

[0069] [9] According to the vibration control efficiency of the target position under different effective masses, the vibration control efficiency requirement of the target position, the total weight requirement of the dynamic vibration absorber, and the overall size requirement of the dynamic vibration absorber, the effective mass of the dynamic vibration absorber that meets the requirements is selected, including 6 kg, 8 kg and 10 kg;

[0070]

[10] According to the effective mass of the dynamic vibration absorber that meets the requirements, the total weight requirement of the dynamic vibration absorber, and the overall size requirement of the dynamic vibration absorber, the structure of the dynamic vibration absorber is designed, as shown in Figure 7 ;

[0071]

[11] According to the combination of the installation positions of the dynamic vibration absorber that meets the requirements, the dynamic vibration absorber is installed, and the installation working frequency is set to NΩ, as shown in Figure 8 ;

[0072]

[12] Through the analysis of the flight test data, it is verified that the dynamic vibration absorber has good vibration control effect and meets the design requirements, as shown in Figure 9 .

Claims

1. A method of engineering design of a dynamic vibration absorber for local vibration control of a helicopter, characterized in that, The application relates to a method for determining the optimal installation position of a dynamic vibration absorber on a helicopter, and the optimal effective mass of the dynamic vibration absorber, and the structure design of the dynamic vibration absorber. The method comprises the following steps: Defining the vibration control target position and the vibration frequency of the target position; Determining the theoretical installation working frequency of the dynamic vibration absorber according to the vibration frequency of the target position; Obtaining the initial vibration response of the target position by a frequency domain response calculation method based on a helicopter dynamics model; Setting n installation positions of the dynamic vibration absorber on the helicopter structure, wherein n is a positive integer greater than 1; Selecting 1-m positions from the n installation positions to obtain a plurality of installation position combinations; m is less than n; Establishing dynamic vibration absorber dynamics models with the same effective mass on different installation position combinations, carrying out dynamic coupling analysis of the dynamic vibration absorber and the helicopter, and obtaining the vibration response of the target position under different installation position combinations by a frequency domain response calculation method; wherein the sum of the effective masses of the dynamic vibration absorbers under different installation position combinations is less than or equal to the total weight requirement of the dynamic vibration absorber; Calculating the vibration control efficiency of the target position under different installation position combinations according to the initial vibration response of the target position and the vibration response under different installation position combinations; Selecting the optimal combination of the installation position of the dynamic vibration absorber which meets the requirements according to the vibration control efficiency of the target position under different installation position combinations, the vibration control efficiency requirement of the target position and the installation positions with installation conditions; Determining the optimal effective mass of the dynamic vibration absorber according to the overall design requirements of the dynamic vibration absorber, which comprises the following steps: Establishing dynamic vibration absorber dynamics models with different effective masses on the optimal combination based on the helicopter dynamics model, carrying out dynamic coupling analysis of the dynamic vibration absorber and the helicopter, and obtaining the vibration response of the target position under different effective masses by a frequency domain response calculation method; the sum of the effective masses of the dynamic vibration absorber dynamics models is less than or equal to the total weight requirement of the dynamic vibration absorber; Calculating the vibration control efficiency of the target position under different effective masses according to the initial vibration response of the target position and the vibration response under different effective masses; Optimizing the effective mass of the dynamic vibration absorber which meets the requirements according to the vibration control efficiency of the target position under different effective masses, the vibration control efficiency requirement of the target position, the total weight requirement of the dynamic vibration absorber and the overall size requirement of the dynamic vibration absorber; Carrying out the structure design of the dynamic vibration absorber based on the effective mass of the dynamic vibration absorber, which comprises the following steps: Carrying out the structure design of the dynamic vibration absorber according to the effective mass of the dynamic vibration absorber which meets the requirements, the total weight requirement of the dynamic vibration absorber and the overall size requirement of the dynamic vibration absorber. The overall design requirements comprise the vibration control efficiency of the target position, the total weight requirement of the dynamic vibration absorber, the overall size of the dynamic vibration absorber and the installation positions with installation conditions.

2. The method of claim 1, wherein, ​ 3. The method of claim 1, wherein, The method further comprises: According to the obtained required power absorber installation position combination, installing the power absorber according to the power absorber structure design; and setting the installation working frequency; Performing a flight test; Verifying the vibration control effect of the power absorber by analyzing the flight test data; If the vibration control effect of the power absorber does not meet the requirements, adjusting the effective mass of the power absorber, resetting the installation working frequency, and performing a flight test again until the vibration control effect of the power absorber meets the requirements.

4. The method of claim 1, wherein, The working frequency of the power absorber dynamics model is consistent with the theoretical installation working frequency.

5. A computer-readable storage medium storing a computer program, characterized in that: The computer program is executed by a processor to implement the method of any one of claims 1-4.

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