Design method of high-stability electromechanical servo turntable

Abstract

The invention discloses a high-stability electromechanical servo turntable design method which comprises the following steps: determining input conditions according to turntable design requirements; selecting a motor, a driver and a speed reducer according to the torque and the rotating speed; determining a motor flange connection mode and a torque transmission mode; determining the model selection and circuit connection design of electronic devices such as a controller, a power supply and an encoder; designing a bearing structural member; performing modal analysis by applying a finite element technology to obtain an inherent frequency and a vibration mode; building type selection and combination of a passive shock absorber and an active shock absorber; determining the connection structure design of the shock absorber and the rotary table; a general vibration test bench is used for verification; and determining whether to modify the design of the bearing structural member or not according to whether the verification result meets the GJB150 vibration test or load characteristic requirements or has no formant, and repeating the subsequent steps until the requirements are met.

Description

Technical Field

[0001] The present invention relates to the technical field of electromechanical servo turntable structures, and in particular to a design method for a high-stability electromechanical servo turntable combining finite element modal analysis and active and passive vibration reduction technologies. Background Art

[0002] The present invention relates to the military field of high-stability electromechanical servo turntables carrying large inertia loads, and specifically to a design method for high-stability electromechanical servo turntables combining finite element modal analysis and active and passive vibration reduction technology. Electromechanical servo turntables (including single-axis, two-axis, and three-axis) are widely used in radar systems, laser weapon systems, optoelectronic systems, and measurement and control systems and play a key role. With the development of weapon equipment technology, the military field urgently needs high-stability electromechanical servo turntables that can carry large inertia loads.

[0003] For electromechanical servo turntables carrying equipment with large inertia and heavy weight, such as radar servo turntables, laser weapon servo turntables, etc., their rigidity and stability are often poor, and the first three natural frequencies are generally low. When the load structure size is large, the first order natural frequency may even be lower than 10Hz. On the other hand, according to Part 16 of GJB150 "Military Equipment Laboratory Environmental Test Methods", the vibration frequency of the working environment of shipborne equipment is generally 1-60Hz, the vibration frequency of the working environment of vehicle-borne equipment is generally 5-500Hz, and the vibration frequency of the working environment of airborne equipment is generally 3-500Hz. Therefore, in the working environment of a large-load electromechanical servo turntable, it is easy for the external vibration frequency to be close to or equal to the natural frequency, causing the turntable to vibrate significantly, which has a significant negative impact on the normal operation of the equipment it carries, and accelerates fatigue damage to the turntable structure, and even strength damage.

[0004] At present, in the field of high-end equipment, there is an urgent need for a high-stability electromechanical servo turntable design method to improve the rigidity, stability and reliability of the turntable in a wide-band vibration environment to meet the needs of the rapid development of weapons and equipment in the military industry.

[0005] At present, the research on electromechanical servo turntables is mostly focused on control accuracy, control strategy, dynamics, and unilateral analysis of structural static and dynamic characteristics. There is no literature report on combining finite element modal analysis with active and passive vibration reduction technology to improve the stability and reliability of servo turntables. Summary of the invention

[0006] The purpose of the present invention is to provide a design method for a high-stability electromechanical servo turntable that combines finite element modal analysis and active and passive vibration reduction technology, which can improve its working stability and reliability in a wide-band vibration environment.

[0007] The object of the present invention is achieved through the following technical solution: A method for designing a high-stability electromechanical servo turntable comprises the following steps:

[0008] S1: Determine the input conditions,

[0009] S2: Select the motor and driver model;

[0010] S3: Determine the motor flange connection method and torque transmission method;

[0011] S4: Determine the selection of electronic components such as controller, power supply, encoder, etc.;

[0012] S5: Establish a load-bearing structural component model;

[0013] S6: Establish a finite element analysis model and obtain finite element analysis results;

[0014] S7: Selection and combination of passive and active vibration absorbers;

[0015] S8: Determine the design of the connection structure between the shock absorber and the turntable according to the shock absorber results;

[0016] S9: Use a general vibration test bench for test verification;

[0017] S10: Verify whether the GJB150 vibration test or load characteristic requirements are met or there is no resonance peak. If not, adjust the load-bearing structure model and conduct test verification again;

[0018] The high-stability electromechanical servo turntable design method is characterized in that in step S1, the input condition is determined by the rotation requirement of the servo turntable, and step S1 includes:

[0019] S101: two-axis rotation, azimuth and pitch;

[0020] S102: Rotation range: azimuth ±180°; pitch ±30°

[0021] S103: Speed: Maximum azimuth rotation speed 40° / s; Maximum pitch rotation speed 30° / s

[0022] S104: Acceleration: Maximum azimuth rotation acceleration 40° / s 2 ; Maximum pitch acceleration 30° / s 2

[0023] S105: Load weight: 60kg

[0024] S106: Moment of inertia: 5kgm2

[0025] S107: Installation interface: φ630 circumferentially uniform 10-M12 screws

[0026] S108: Electrical interface: three-phase 220±5VAC

[0027] S109: Determine the mechanical interface and turntable peripheral dimension requirements

[0028] The high-stability electromechanical servo turntable design method is characterized in that in step S2, the motor and driver models are determined by kinematic and dynamic formulas, and step S2 includes:

[0029] S209: Direct drive torque motors are used for both azimuth and pitch rotations, and the drivers are provided by the motor manufacturer;

[0030] The high-stability electromechanical servo turntable design method is characterized in that in step S3, the output shaft of the direct-drive torque motor is connected to the load through a cylindrical pin and a screw, and the cylindrical pin transfers the torque; the mounting flange of the direct-drive torque motor is also connected to the base through a cylindrical pin and a screw, and the cylindrical pin transfers the reverse torque;

[0031] The high-stability electromechanical servo turntable design method is characterized in that in step S5, the bearing structure includes three parts, a pitch axis part-U-shaped structure, an azimuth axis part-base structure 1, and an electrical component mounting part-base structure 2;

[0032] The high-stability electromechanical servo turntable design method is characterized in that, in step S6, the finite element modal analysis includes the first six natural frequencies and vibration mode analysis;

[0033] The high-stability electromechanical servo turntable design method is characterized in that step S7 comprises:

[0034] S701: Passive vibration absorber selection: Select wire rope rubber vibration absorber to isolate vibration in three directions of XYZ;

[0035] S702: Vibration transmissibility calculation formula for passive vibration isolators:

[0036]

[0037] Where: T is the ratio of the amplitude of the isolated object to the basic amplitude;

[0038] f is the external excitation frequency;

[0039] f 0 is the natural frequency of the system;

[0040] ξ is the relative damping coefficient.

[0041] S703: Stewart platform is used as active vibration isolation. The six legs of the Stewart platform are linear actuators based on piezoelectric ceramics or linear actuators based on electromagnetic principles;

[0042] S704: The active vibration absorber and the passive vibration absorber are rigidly connected by screws, the upper plane of the passive vibration absorber and the lower platform of the active vibration absorber are connected by screws, and the passive vibration absorbers are evenly arranged in the circumferential direction;

[0043] The high-stability electromechanical servo turntable design method is characterized in that, in step S8, the upper platform of the shock absorber is rigidly connected to the bottom surface of the turntable by screws, and the screws are evenly distributed along the circumference, and step S8 includes:

[0044] S801: turntable load structure, pitch brake and encoder assembly, pitch motor assembly, U-shaped structure, azimuth motor and brake encoder assembly, base structure 1, base structure 2, Stewart active vibration reduction assembly, electrical components, passive vibration reduction assembly, turntable base;

[0045] The high-stability electromechanical servo turntable design method, in step S9, the upper platform of the shock absorber is rigidly connected to the bottom surface of the turntable by screws, and the screws are evenly arranged along the circumference;

[0046] The high stability electromechanical servo turntable design method is characterized in that in step S10, the test verification is verified by a general vibration test bench. The test content includes: sine sweep vibration, random vibration, and standing frequency vibration. The test results should have no strength damage, no resonance peak, and meet the characteristics of the GJB150 vibration test and turntable load requirements;

[0047] The present invention has the following beneficial effects:

[0048] In order to solve the problems that large-inertia and large-load electromechanical servo turntables are prone to large-amplitude vibration, fatigue damage, and strength destruction in a wide-band vibration environment, the present invention proposes a high-stability electromechanical servo turntable design method, which comprehensively applies finite element modal analysis, passive vibration reduction and active vibration reduction technology to improve its stability and reliability in a wide-band vibration environment, reduce fatigue damage to the turntable structure, avoid strength destruction, and significantly reduce the impact of resonance peaks on the load, thereby ensuring the normal operation of high-end and high-precision loads (laser weapons, optoelectronic components, radars, etc.) in complex environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic diagram of the process flow for designing a high stability electromechanical servo turntable of the present invention;

[0050] Figure 2 Diagram of the servo turntable without vibration damper built for this embodiment;

[0051] Figure 3 A schematic diagram of the appearance of the steel wire rope rubber vibration isolator used in this embodiment;

[0052] Figure 4 A schematic diagram of the Stewart platform structure established for this embodiment;

[0053] Figure 5 This is a schematic diagram of the electromechanical servo turntable structure established in this embodiment. DETAILED DESCRIPTION

[0054] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0055] A high stability electromechanical servo turntable design method of the present invention is as follows: Figure 1 As shown, the following steps are included:

[0056] S1: Determine input conditions;

[0057] The input condition of the high stability electromechanical servo turntable design method is determined by the rotation requirement of the servo turntable, and step S1 includes:

[0058] S101: two-axis rotation, azimuth and pitch;

[0059] S102: Rotation range: azimuth ±180°; pitch ±30°

[0060] S103: Speed: Maximum azimuth rotation speed 40° / s; Maximum pitch rotation speed 30° / s

[0061] S104: Acceleration: Maximum azimuth rotation acceleration 40° / s 2 ; Maximum pitch acceleration 30° / s 2

[0062] S105: Load weight: 60kg

[0063] S106: Moment of inertia: 5kgm2

[0064] S107: Installation interface: φ630 circumferentially uniform 10-M12 screws

[0065] S108: Electrical interface: three-phase 220±5VAC

[0066] S109: Determine the mechanical interface and turntable peripheral dimension requirements

[0067] S2: Select the motor and driver model;

[0068] The motor and driver models are determined by kinematic and dynamic formulas, and step S2 includes:

[0069] Direct-drive torque motors are selected for both azimuth and pitch rotations. The key parameters are shown in the following table. The drivers are provided by the motor manufacturers.

[0070]

[0071]

[0072] S3: Determine the motor flange connection method and torque transmission method;

[0073] In step S3, the output shaft of the direct-drive torque motor is connected to the load through cylindrical pins and screws, and the cylindrical pins transfer torque; the mounting flange of the direct-drive torque motor is also connected to the base through cylindrical pins and screws, and the cylindrical pins transfer reverse torque.

[0074] S4: Determine the selection of electronic components such as controller, power supply, encoder, etc.;

[0075] The step S4 comprises:

[0076] S401: The controller uses a mature product on the market with STM32 as the main control chip;

[0077] S402: Power supply selection power 1000W, three-phase 220±5VAC input, 48VDC, 24VDC two-way output;

[0078] S403: The encoder selects an absolute photoelectric encoder with a precision of 23 bits and a communication interface of Biss-C.

[0079] S5: Establish a load-bearing structural component model;

[0080] The load-bearing structure in step S5 includes three parts: a pitch axis part—a U-shaped structure, an azimuth axis part—a base structure 1, and an electrical component mounting part—a base structure 2. Figure 2 .

[0081] S6: Establish a finite element analysis model and obtain finite element analysis results;

[0082] The finite element analysis model is established by using Ansys software, and step S6 comprises:

[0083] The 3D model is saved as a general format file and imported into the Ansys Workbench software. Finite element analysis is performed in the software according to the modal analysis process. Finally, the first six natural frequencies and vibration modes are obtained. The frequency values ​​are shown in the following table.

[0084] Degree Frequency value (Hz) 1 18.1 2 19.3 3 47.6 4 59.6 5 67.1 6 89.5

[0085] From the modal analysis, it can be seen that the turntable will resonate near the lowest frequency of 18.1Hz, so it is necessary to isolate external vibrations with frequencies of 18.1Hz and above.

[0086] S7: Selection and combination of passive and active vibration absorbers;

[0087] The step S7 comprises:

[0088] S701: Passive vibration damper selection

[0089] The passive vibration absorber is a wire rope rubber vibration absorber, which isolates the vibration in the three directions of XYZ. Its appearance is shown as follows Figure 3 shown.

[0090] The vibration transmissibility calculation formula of the passive vibration isolator is:

[0091]

[0092] Where: T is the ratio of the amplitude of the isolated object to the basic amplitude;

[0093] f is the external excitation frequency;

[0094] f 0 is the natural frequency of the system;

[0095] ξ is the relative damping coefficient.

[0096] From the above formula, we can see that when The vibration isolation effect is achieved only when the ratio is 2.5 to 4.5. Here, f / f 0 =3, from step 6 we know f = 18.1Hz, then f 0 =f / 3=18.1 / 3≈6Hz. Therefore, a wire rope rubber vibration damper with a natural frequency of 6Hz is selected. Vibrations above this value have a vibration reduction effect.

[0097] S702: Active shock absorber selection:

[0098] The inherent defect of passive vibration absorbers is that they cannot isolate low-frequency vibrations. From equation (1), we know that the passive vibration absorber Vibrations with a frequency of and above have a vibration reduction effect, that is, the vibration transmission rate T < 1; The following vibrations have an amplifying effect, that is, the transmission rate T>1, and the amplification effect is most obvious around 6Hz, where T reaches its peak value.

[0099] Therefore, an active vibration absorber is required to isolate the external frequency. Because the passive vibration isolator Although the transmission rate T is less than 1, it is still relatively large. Therefore, when selecting an active shock absorber, its ability to isolate external vibrations of 1 to 15 Hz should be considered.

[0100] Stewart platform is used as active vibration isolation. Figure 4 The six legs of the Stewart platform are linear actuators based on piezoelectric ceramics or electromagnetic principles.

[0101] S702: Active and passive shock absorber combination:

[0102] The active vibration absorber and the passive vibration absorber are rigidly connected by screws, the upper plane of the passive vibration absorber is connected to the lower platform of the active vibration absorber by screws, the passive vibration absorbers are evenly arranged in the circumferential direction, the number can be 3 to 8, and 6 are taken here. The lower plane of the passive vibration absorber is rigidly connected to the mounting base by screws.

[0103] S8: Determine the design of the connection structure between the shock absorber and the turntable according to the shock absorber results;

[0104] The step S8 comprises:

[0105] The upper platform of the shock absorber is rigidly connected to the bottom surface of the turntable by screws, and the screws are evenly arranged along the circumference, such as Figure 5 shown.

[0106] S9: Use a general vibration test bench for test verification;

[0107] The step S9 comprises:

[0108] Verification shall be conducted using a general vibration test bench. Test contents include: sine frequency sweep vibration, random vibration, and standing frequency vibration. The test results shall show no strength damage, no resonance peak, and meet the requirements of GJB150 vibration test and turntable load characteristics.

[0109] S10: Verify whether the GJB150 vibration test or load characteristic requirements are met or there is no resonance peak. If not, adjust the load-bearing structure model and conduct test verification again;

[0110] The step S10 comprises:

[0111] S1002: The test verification shall be conducted on a general vibration test bench. The test contents include: sine frequency sweep vibration, random vibration, and standing frequency vibration. The test results shall have no strength damage, no resonance peak, and meet the characteristics requirements of GJB150 vibration test and turntable load;

[0112] S1002: If the test results do not meet the requirements, it is necessary to return to step S5 to improve the design of the load-bearing structure and repeat the subsequent steps until the test results have no strength damage, no resonance peak and meet the characteristics requirements of the GJB150 vibration test and turntable load.

[0113] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for designing a high-stability electromechanical servo turntable, characterized in that: The steps include: S1: Determine input conditions; S2: Select the motor and driver model; S3: Determine the motor flange connection method and torque transmission method; S4: Determine the selection of electronic components such as controller, power supply, encoder, etc.; S5: Establish a load-bearing structural component model; S6: Establish a finite element analysis model and obtain finite element analysis results; S7: Selection and combination of passive and active vibration absorbers; S8: Determine the design of the connection structure between the shock absorber and the turntable according to the shock absorber results; S9: Use a general vibration test bench for test verification; S10: Verify whether the GJB150 vibration test or load characteristic requirements are met or there is no resonance peak. If not, adjust the load-bearing structure model and conduct test verification again.

2. The high stability electromechanical servo turntable design method according to claim 1, characterized in that: In step S1, the input condition is determined by the rotation requirement of the servo turntable, and step S1 includes: S101: two-axis rotation, azimuth and pitch; S102: Determine the mechanical interface and turntable peripheral dimension requirements.

3. The high stability electromechanical servo turntable design method according to claim 1, characterized in that: In step S2, the motor and driver models are determined by kinematic and dynamic formulas, and step S2 includes: S201: Direct-drive torque motors are selected for both azimuth and pitch rotations, and the drivers are provided by the motor manufacturer.

4. The high stability electromechanical servo turntable design method according to claim 1, characterized in that: In step S3, the output shaft of the direct-drive torque motor is connected to the load through cylindrical pins and screws, and the cylindrical pins transfer torque; the mounting flange of the direct-drive torque motor is also connected to the base through cylindrical pins and screws, and the cylindrical pins transfer reverse torque.

5. The high stability electromechanical servo turntable design method according to claim 1, characterized in that: In step S5, the bearing structure includes three parts: a pitch axis part-U-shaped structure, an azimuth axis part-base structure 1, and an electrical component mounting part-base structure 2.

6. The high stability electromechanical servo turntable design method according to claim 1, characterized in that: In step S6, the finite element modal analysis includes the first six order natural frequencies and vibration mode analysis.

7. The high stability electromechanical servo turntable design method according to claim 1, characterized in that: The step S7 comprises: S701: Passive vibration absorber selection: Select wire rope rubber vibration absorber to isolate vibration in three directions of XYZ; S702: Stewart platform is used as active vibration isolation. The six legs of the Stewart platform are linear actuators based on piezoelectric ceramics or electromagnetic principles; S703: The active vibration absorber and the passive vibration absorber are rigidly connected by screws, the upper plane of the passive vibration absorber and the lower platform of the active vibration absorber are connected by screws, and the passive vibration absorber is evenly arranged in the circumferential direction.

8. The high stability electromechanical servo turntable design method according to claim 1 is characterized in that: In the step S8, the upper platform of the shock absorber is rigidly connected to the bottom surface of the turntable by screws, and the screws are evenly distributed along the circumference. The step S8 includes: S801: turntable load structure, pitch brake and encoder assembly, pitch motor assembly, U-shaped structure, azimuth motor and brake encoder assembly, base structure 1, base structure 2, Stewart active vibration reduction assembly, electrical components, passive vibration reduction assembly, turntable base.

9. The high-stability electromechanical servo turntable design method according to claim 1, wherein in step S9, the upper platform of the shock absorber is rigidly connected to the bottom surface of the turntable by screws, and the screws are evenly arranged along the circumference.

10. The high stability electromechanical servo turntable design method according to claim 1 is characterized in that: In step S10, the test verification is verified by a general vibration test bench. The test contents include: sine frequency sweep vibration, random vibration, and standing frequency vibration. The test results should have no strength damage, no resonance peak, and meet the characteristics requirements of GJB150 vibration test and turntable load.

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