Space truss based on piezoelectric vibration suppression and its working method

Abstract

The present invention discloses a space truss based on piezoelectric vibration suppression and a working method thereof. The space truss comprises 4N vibration suppression rods and N+1 connection frames; the connection frame is in the shape of a square frame; the vibration suppression rod comprises a preload beam, a support beam, a threaded rod, a positioning rod, a piezoelectric actuation module and a piezoelectric sensor; the threaded blind hole on the preload beam is threadedly connected to the threaded rod, and the positioning blind hole and the positioning rod are clearance-matched, so that the preload beam and the support beam press the piezoelectric actuation module; the N+1 connection frames are coaxially arranged, and two adjacent connection frames are connected by four vibration suppression rods, and the two ends of the four vibration suppression rods are respectively and vertically fixedly connected to the four corners of the two connection frames in a one-to-one correspondence. When working, the piezoelectric actuation module is controlled to generate vibrations that are consistent in phase with the disturbed vibration of the space truss and in the opposite direction to achieve active vibration suppression. The present invention can suppress vibrations of multiple modes of the space truss, is not limited by the order of the vibration mode, is simple to operate, has strong reliability, has a wide range of applications, and has good application prospects.

Description

Technical Field

[0001] The invention relates to the fields of piezoelectric actuation and mechanical vibration control, and in particular to a space truss based on piezoelectric vibration suppression and a working method thereof. Background Art

[0002] With the development and progress of aerospace technology, spacecraft are rapidly developing towards the trend of intelligence, large-scale, complex and lightweight. As a special space structure, large-flexure space trusses are increasingly widely used. In the space environment, space trusses will be subject to inevitable internal and external disturbances such as aircraft attitude adjustment and space debris impact, causing them to vibrate in different modes, and vibration control devices are needed to suppress the vibration.

[0003] At present, the vibration control of space trusses is mostly based on traditional passive vibration suppression technologies such as vibration isolators and vibration absorbers, and some attempts to develop active vibration suppression using piezoelectric materials have been made. However, the operating system is too complex, the structure is bulky, and the weight is large, which makes it difficult to meet the requirements of lightweight, fast response, and simple control of space trusses. In addition, the vibration control devices currently used are difficult to efficiently suppress vibration in different directions and different vibration types. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a space truss based on piezoelectric vibration suppression and a working method thereof in view of the defects involved in the background technology.

[0005] The present invention adopts the following technical solutions to solve the above technical problems:

[0006] A space truss based on piezoelectric vibration suppression, comprising 4N vibration suppression rods and N+1 connection frames, where N is a natural number greater than or equal to 2;

[0007] The connection frame is in the shape of a square frame;

[0008] The vibration suppression rod comprises a preload beam, a support beam, a threaded rod, a positioning rod, a piezoelectric actuation module and a piezoelectric sensor;

[0009] The support beam and the pre-tensioning beam are cylinders with the same cross-sectional shape;

[0010] The threaded rod, the positioning rod, and the support beam are coaxially fixedly connected in sequence, and the cross-sectional areas are increased in sequence;

[0011] A positioning blind hole for cooperating with the positioning rod is provided at the center of one end surface of the preload beam, and a threaded blind hole for cooperating with the threaded rod is provided at the center of the positioning blind hole;

[0012] The piezoelectric actuation module includes N piezoelectric actuation units;

[0013] The piezoelectric actuator unit comprises 8 single-partition piezoelectric ceramic sheets; the single-partition piezoelectric ceramic sheets are circular in shape with the same cross-section shape as the support beam, with a through hole in the center for the positioning rod to pass through, and are polarized along the thickness direction; the 8 single-partition piezoelectric ceramic sheets are stacked in sequence, and the polarization directions of adjacent single-partition piezoelectric ceramic sheets are opposite;

[0014] The N piezoelectric actuating units are stacked and sleeved on the positioning rod in sequence;

[0015] The threaded blind hole on the pre-tightening beam is threadably connected to the threaded rod, and the positioning blind hole and the positioning rod are clearance-matched, so that the pre-tightening beam and the supporting beam press each single-partition piezoelectric ceramic sheet of the N piezoelectric actuating units in the piezoelectric actuating module;

[0016] A mounting blind hole is provided on the side wall of the support beam close to one end of the piezoelectric actuation module;

[0017] The piezoelectric sensor is arranged in the mounting blind hole to sense the magnitude of the force at the location thereof;

[0018] The N+1 connection frames are coaxially arranged, and two adjacent connection frames are connected by four vibration-damping rods. The two ends of the four vibration-damping rods are respectively and vertically fixedly connected to the four corners of the two connection frames in a one-to-one correspondence, and the axes of the mounting blind holes on the four vibration-damping rods are all perpendicularly intersected with the axis of the connection frame.

[0019] The present invention also discloses a working method of the space truss based on piezoelectric vibration suppression, comprising the following steps:

[0020] For each piezoelectric actuator unit, the upper end surfaces of the first, third, fifth and seventh single-partition piezoelectric ceramic sheets are grounded, the lower end surfaces of the second, fourth, sixth and eighth single-partition piezoelectric ceramic sheets are grounded, the lower end surfaces of the first, third, fifth and seventh single-partition piezoelectric ceramic sheets are connected to the driving signal A, and the upper end surfaces of the second, fourth, sixth and eighth single-partition piezoelectric ceramic sheets are connected to the driving signal A; the driving signal A is an amplified signal of the induction signal emitted by the piezoelectric sensor on the same vibration suppression rod.

[0021] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0022] 1. The present invention adopts active vibration control technology, and the excitation signal is the gain electrical signal of the sensing signal generated by the piezoelectric sensor. The control system is simple, light, and resistant to electromagnetic interference, and is suitable for space environment;

[0023] 2. The present invention exerts a greater displacement and output force through the stacking of piezoelectric ceramic sheets, and uses the longitudinal vibration of the piezoelectric ceramic sheets to suppress the longitudinal vibration and different bending vibrations of the space truss, so that the present invention has a simple structure, multiple vibration suppression modes, obvious vibration suppression effect, and strong reliability;

[0024] 3. The present invention adopts a combination of piezoelectric actuation and piezoelectric sensing, making full use of the positive piezoelectric effect and the inverse piezoelectric effect of piezoelectric materials, so that the present invention has a compact structure and rich and powerful functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall appearance of the application of the present invention;

[0026] Figure 2 is a schematic diagram of the appearance of the vibration suppression rod of the present invention;

[0027] Figure 3 It is a structural schematic diagram of the prestressing beam in the present invention;

[0028] Figure 4 It is a structural schematic diagram of the threaded rod, the positioning rod, and the support beam in the present invention;

[0029] Figure 5 It is a schematic diagram of the structure, polarization direction and wiring method of the piezoelectric actuation module in the present invention;

[0030] Figure 6 It is a schematic diagram of the sensing signal generation process of the piezoelectric sensor in the present invention;

[0031] Figure 7 It is a schematic diagram of the actuation principle of the piezoelectric ceramic piece of the piezoelectric actuation module in the present invention when receiving an excitation signal;

[0032] Figure 8 It is a schematic diagram of the vibration suppression principle of the present invention in the longitudinal vibration mode;

[0033] Fig. 9 It is a schematic diagram of the vibration suppression principle of the present invention in the bending vibration mode;

[0034] In the figure, 1-preload beam, 2-support beam, 3-piezoelectric actuation module, 4-mounting blind hole on the support beam, 5-positioning blind hole, 6-threaded blind hole, 7-threaded rod, 8-positioning rod. DETAILED DESCRIPTION

[0035] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings:

[0036] The present invention can be implemented in many different forms and should not be considered to be limited to the embodiments described herein. On the contrary, these embodiments are provided to make this disclosure thorough and complete, and will fully express the scope of the present invention to those skilled in the art. In the accompanying drawings, components are enlarged for clarity.

[0037] like Figure 1As shown, a space truss based on piezoelectric vibration suppression is characterized in that it includes 4N vibration suppression rods and N+1 connection frames, where N is a natural number greater than or equal to 2;

[0038] The connection frame is in the shape of a square frame;

[0039] like Figure 2 As shown, the vibration suppression rod comprises a preload beam, a support beam, a threaded rod, a positioning rod, a piezoelectric actuation module and a piezoelectric sensor;

[0040] The support beam and the pre-tensioning beam are cylinders with the same cross-sectional shape;

[0041] like Figure 3 As shown, a positioning blind hole for cooperating with the positioning rod is provided at the center of one end surface of the preload beam, and a threaded blind hole for cooperating with the threaded rod is provided at the center of the positioning blind hole;

[0042] like Figure 4 As shown, the threaded rod, positioning rod, and support beam are coaxially fixedly connected in sequence, and the cross-sectional areas increase in sequence;

[0043] The piezoelectric actuation module includes N piezoelectric actuation units;

[0044] like Figure 5 As shown, the piezoelectric actuator unit includes 8 single-partition piezoelectric ceramic sheets; the single-partition piezoelectric ceramic sheets are circular in shape with the same cross-sectional shape as the support beam, with a through hole in the center for the positioning rod to pass through, and are polarized along the thickness direction; the 8 single-partition piezoelectric ceramic sheets are stacked in sequence, and the polarization directions of adjacent single-partition piezoelectric ceramic sheets are opposite;

[0045] The N piezoelectric actuating units are stacked and sleeved on the positioning rod in sequence;

[0046] The threaded blind hole on the pre-tightening beam is threadably connected to the threaded rod, and the positioning blind hole and the positioning rod are clearance-matched, so that the pre-tightening beam and the supporting beam press each single-partition piezoelectric ceramic sheet of the N piezoelectric actuating units in the piezoelectric actuating module;

[0047] A mounting blind hole is provided on the side wall of the support beam close to one end of the piezoelectric actuation module;

[0048] The piezoelectric sensor is arranged in the mounting blind hole to sense the magnitude of the force at the location thereof;

[0049] The N+1 connection frames are coaxially arranged, and two adjacent connection frames are connected by four vibration-damping rods. The two ends of the four vibration-damping rods are respectively and vertically fixedly connected to the four corners of the two connection frames in a one-to-one correspondence, and the axes of the mounting blind holes on the four vibration-damping rods are all perpendicularly intersected with the axis of the connection frame.

[0050] The present invention also discloses a working method of the space truss based on piezoelectric vibration suppression, comprising the following steps:

[0051] like Figure 5 As shown, for each piezoelectric actuator unit, the upper end surfaces of the first, third, fifth, and seventh single-partition piezoelectric ceramic sheets are grounded, the lower end surfaces of the second, fourth, sixth, and eighth single-partition piezoelectric ceramic sheets are grounded, the lower end surfaces of the first, third, fifth, and seventh single-partition piezoelectric ceramic sheets are connected to the driving signal A, and the upper end surfaces of the second, fourth, sixth, and eighth single-partition piezoelectric ceramic sheets are connected to the driving signal A; the driving signal A is an amplified signal of the induction signal emitted by the piezoelectric sensor on the same vibration suppression rod;

[0052] When the sensor sends different sensing signals, such as Figure 6 As shown in the figure, it indicates that the space truss is experiencing disturbed vibration. At this time, a driving signal is given to the piezoelectric actuator module. Under the excitation of the driving signal, the vibration suppression rod produces a vibration deformation opposite to the disturbed deformation, which effectively suppresses the disturbed vibration, as shown in the figure. Figure 7 As shown, the first round of vibration suppression is performed; the first round of vibration suppression ends with the end of the piezoelectric sensing signal, that is, when the excitation vibration and the disturbed vibration are completely offset, the vibration suppression rod reaches a force balance state, the first round of vibration suppression ends, the excitation signal is zero, and the piezoelectric actuation module has no excitation vibration;

[0053] If the piezoelectric sensor does not send out a sensing signal after the first round of vibration suppression, it means that the disturbed vibration of the structure disappears or is reduced to the point where it cannot generate a sensing signal after the first round of vibration suppression, and the vibration suppression is completed at this time;

[0054] If the piezoelectric sensor sends out a sensing signal again after the first round of vibration suppression, it means that the disturbance of the structure is still continuing and the structure is still experiencing disturbed vibration; at this time, a second round of vibration suppression is carried out and a driving signal is given respectively; the piezoelectric actuator module generates an excitation vibration again to suppress the disturbed vibration of the structure; when the piezoelectric sensing signal is zero again, the excitation signal is zero, the excitation vibration ends, and the second round of vibration suppression is completed; thereafter, whether to repeat the vibration suppression is determined based on whether the sensing signal occurs or not.

[0055] The space truss based on piezoelectric vibration suppression can suppress longitudinal vibration and bending vibration types, and is not limited by the order of the mode. The following takes any two adjacent connection frames and the four vibration suppression rods therebetween as a minimum unit to explain its specific vibration type in detail. The four vibration suppression rods are respectively called the first, second, third, and fourth vibration suppression rods in a clockwise direction, and the piezoelectric sensors on the first, second, third, and fourth vibration suppression rods are respectively called the first, second, third, and fourth piezoelectric sensors:

[0056] 1) When the induction signals emitted by the first, second, third and fourth piezoelectric sensors have equal frequencies, consistent phases, equal positive and negative values ​​and consistent peak values, it indicates that the space truss is in disturbed longitudinal vibration at this time; at this time, a driving signal is given to each piezoelectric actuation module; each piezoelectric actuation module is excited by the driving signal to generate an excited longitudinal vibration, and when the disturbed vibration of the first to fourth vibration suppression rods undergoes an elongation deformation, the excited longitudinal vibration produces a shortening deformation to suppress the disturbed deformation; and when the disturbed vibration of the first to fourth vibration suppression rods undergoes a shortening deformation, the excited longitudinal vibration produces an elongation deformation to suppress the disturbed longitudinal vibration, such as Figure 8 shown.

[0057] 2) When the sensing signals of the piezoelectric sensor are as follows, the sensing signals emitted by the first and second piezoelectric sensors are equal in positive and negative and have the same peak value, the sensing signals emitted by the third and fourth piezoelectric sensors are equal in positive and negative and have the same peak value, and the first and third sensing signals are opposite in positive and negative, it indicates that the space truss is in disturbed bending vibration at this time, and the vibration direction is the normal direction of the plane where the first and second vibration suppression rods are located; at this time, a driving signal is given to the piezoelectric actuator module; the piezoelectric actuator module is excited by the driving signal to generate excited longitudinal vibration; when the disturbed bending vibration causes the first and second vibration suppression rods to elongate and deform, and the third and fourth vibration suppression rods to shorten, the excited longitudinal vibration causes the first and second vibration suppression rods to shorten and the third and fourth vibration suppression rods to elongate, thereby suppressing the disturbed deformation; and when deformation occurs in the opposite direction, the same suppression effect is achieved.

[0058] Similarly, if the induction signals from the first and fourth piezoelectric sensors are equal in positive and negative and have the same peak value, and the induction signals from the second and third piezoelectric sensors are equal in positive and negative and have the same peak value, and the first and second sensing signals are opposite in positive and negative, it indicates that the space truss is in disturbed bending vibration at this time, and the vibration direction is the normal direction of the plane where the first and fourth vibration suppression rods are located; the same driving signal is given, and the bending vibration suppression effect is also achieved. Fig. 9 shown.

[0059] 3) When the sensing signals of the piezoelectric sensor are as follows, the sensing signals emitted by the first and third piezoelectric sensors are opposite in positive and negative and have the same peak value, and there is no obvious sensing signal from the second and fourth piezoelectric sensors, it indicates that the space truss is in disturbed bending vibration at this time, and the vibration direction is the direction of the center line connecting the first and third vibration suppression rods; at this time, a driving signal is given to the piezoelectric actuator module; the piezoelectric actuator module is excited by the driving signal to generate excited longitudinal vibration; when the disturbed bending vibration causes the first vibration suppression rod to elongate and the third vibration suppression rod to shorten, the excited longitudinal vibration causes the first vibration suppression rod to shorten and the third vibration suppression rod to elongate, thereby suppressing the disturbed deformation; and when deformation occurs in the opposite direction, the same suppression effect is achieved.

[0060] Similarly, if the induction signals from the second and fourth piezoelectric sensors are opposite in sign and have the same peak value, and there is no obvious induction signal from the first and third piezoelectric sensors, it indicates that the space truss is in disturbed bending vibration, and the vibration direction is the direction of the center line of the second and fourth vibration suppression rods; the same driving signal is given, and the bending vibration suppression effect is also achieved. Fig. 9 shown.

[0061] The present invention discloses a space truss based on piezoelectric vibration suppression and a working method thereof, which suppresses the bending vibration and longitudinal vibration that are most likely to be generated by the space truss. When the space truss is disturbed to generate bending vibration or longitudinal vibration, the piezoelectric sensor generates a sensing signal, and the piezoelectric actuator module is actively excited according to the feedback of the sensing signal. The excitation signal is a gain form of the sensing signal (amplification amplitude). The piezoelectric actuator module is subjected to the excitation signal to generate a vibration that is consistent with the phase and opposite to the disturbed vibration of the space truss, thereby realizing active control of piezoelectric vibration. The present invention adopts an active control method, and uses the gain signal of the sensing signal to excite the piezoelectric actuator module to suppress the bending vibration and longitudinal vibration that are most likely to be generated by the space truss, and is not limited by the order of the vibration mode. The present invention is simple to operate, has strong reliability, a wide range of applications, and has good application prospects.

[0062] It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as generally understood by those skilled in the art in the art to which the present invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with the meanings in the context of the prior art, and will not be interpreted with idealized or overly formal meanings unless defined as herein.

[0063] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A space truss based on piezoelectric vibration suppression, characterized in that: It includes 4N vibration-damping rods and N+1 connection frames, where N is a natural number greater than or equal to 2; The connection frame is in the shape of a square frame; The vibration suppression rod comprises a preload beam, a support beam, a threaded rod, a positioning rod, a piezoelectric actuation module and a piezoelectric sensor; The support beam and the pre-tensioning beam are cylinders with the same cross-sectional shape; The threaded rod, the positioning rod, and the support beam are coaxially fixedly connected in sequence, and the cross-sectional areas are increased in sequence; A positioning blind hole for cooperating with the positioning rod is provided at the center of one end surface of the preload beam, and a threaded blind hole for cooperating with the threaded rod is provided at the center of the positioning blind hole; The piezoelectric actuation module includes N piezoelectric actuation units; The piezoelectric actuator unit comprises 8 single-partition piezoelectric ceramic sheets; the single-partition piezoelectric ceramic sheets are circular in shape with the same cross-section shape as the support beam, with a through hole in the center for the positioning rod to pass through, and are polarized along the thickness direction; the 8 single-partition piezoelectric ceramic sheets are stacked in sequence, and the polarization directions of adjacent single-partition piezoelectric ceramic sheets are opposite; The N piezoelectric actuating units are stacked and sleeved on the positioning rod in sequence; The threaded blind hole on the pre-tightening beam is threadably connected to the threaded rod, and the positioning blind hole and the positioning rod are clearance-matched, so that the pre-tightening beam and the supporting beam press each single-partition piezoelectric ceramic sheet of the N piezoelectric actuating units in the piezoelectric actuating module; A mounting blind hole is provided on the side wall of the support beam close to one end of the piezoelectric actuation module; The piezoelectric sensor is arranged in the mounting blind hole to sense the magnitude of the force at the location thereof; The N+1 connection frames are coaxially arranged, and two adjacent connection frames are connected by four vibration-damping rods. The two ends of the four vibration-damping rods are respectively and vertically fixedly connected to the four corners of the two connection frames in a one-to-one correspondence, and the axes of the mounting blind holes on the four vibration-damping rods are all perpendicularly intersected with the axis of the connection frame.

2. The working method of the space truss based on piezoelectric vibration suppression according to claim 1, characterized in that: The following steps are involved: For each piezoelectric actuator unit, the upper end surfaces of the first, third, fifth and seventh single-partition piezoelectric ceramic sheets are grounded, the lower end surfaces of the second, fourth, sixth and eighth single-partition piezoelectric ceramic sheets are grounded, the lower end surfaces of the first, third, fifth and seventh single-partition piezoelectric ceramic sheets are connected to the driving signal A, and the upper end surfaces of the second, fourth, sixth and eighth single-partition piezoelectric ceramic sheets are connected to the driving signal A; the driving signal A is an amplified signal of the induction signal emitted by the piezoelectric sensor on the same vibration suppression rod.

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