A patch type piezoelectric vibration suppression structure and control method thereof

Abstract

The present invention discloses a patch-type piezoelectric vibration suppression structure and a control method thereof. The patch-type piezoelectric vibration suppression structure includes a plurality of vibration suppression units arranged on a vibration suppression object; the vibration suppression unit includes a piezoelectric body, a piezoelectric sensor and a control module; the piezoelectric body and the piezoelectric sensor are both made of piezoelectric material and are symmetrically arranged on both sides of the vibration suppression object; the control module includes an N-type MOS tube, an NPN-type transistor, a P-type MOS tube, a PNP-type transistor, a first diode, a second diode and an adjustment resistor. The present invention achieves the purpose of reducing the vibration amplitude by changing the stiffness of the system, and does not require energy input and control outside the system. It adopts a passive control method, so that the structure is simple, the reliability is strong, and the environment is environmentally friendly. It has great application prospects in the fields of aerospace and the like and in the fields of high vibration.

Description

Technical Field

[0001] The present invention relates to the fields of piezoelectric sensing and mechanical vibration control, and in particular to a patch-type piezoelectric vibration suppression structure and a control method thereof. Background Art

[0002] In the fields of machinery, aerospace, vehicles and ships, vibration has a serious impact on work and even causes danger. At present, passive methods for vibration control mainly rely on vibration absorption and vibration isolation, which have low vibration suppression effects, large weight, complex structure, high maintenance costs, etc., and are difficult to meet the growing scientific and technological needs.

[0003] The present invention discloses a patch-type piezoelectric vibration suppression structure and a control method thereof, which can suppress the longitudinal vibration or bending vibration of a vibrating body; utilizing the difference in resonant frequency between an electrical boundary short circuit and an open circuit of a piezoelectric composite structure, the present invention suppresses vibration by consuming vibration mechanical energy through the equivalent stiffness of a switching system, and does not require energy input and control outside the system. A passive control method is adopted, which makes the structure simple, reliable, and environmentally friendly, etc., and has great application prospects in fields such as aerospace and fields with high vibration incidence. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a piezoelectric self-sensing passive vibration suppression control circuit and method based on switching stiffness 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 patch-type piezoelectric vibration suppression structure, comprising a plurality of vibration suppression units arranged on a vibration suppression object;

[0007] The vibration suppression unit includes a piezoelectric body, a piezoelectric sensor and a control module;

[0008] The piezoelectric body and the piezoelectric sensor are both made of piezoelectric material, symmetrically arranged on both sides of the vibration suppression object, and are polarized along the thickness direction. When the longitudinal vibration of the vibration suppression object needs to be suppressed, the polarization directions of the piezoelectric body and the piezoelectric sensor are opposite; when the bending vibration of the vibration suppression object needs to be suppressed, the polarization directions of the piezoelectric body and the piezoelectric sensor are the same;

[0009] The control module includes an N-type MOS tube, an NPN-type transistor, a P-type MOS tube, a PNP-type transistor, a first diode, a second diode and an adjusting resistor;

[0010] The source of the N-type MOS tube is respectively connected to the source of the P-type MOS tube and the side of the piezoelectric body close to the vibration suppression object and then grounded;

[0011] The side of the piezoelectric body away from the vibration suppression object is respectively connected to the drain of the N-type MOS tube and the drain of the P-type MOS tube;

[0012] The emitter of the NPN transistor is connected to the gate of the P-type MOS transistor, the collector of the NPN transistor is respectively connected to the side of the piezoelectric sensor close to the vibration suppression object and the collector of the PNP transistor and then grounded, and the base of the NPN transistor is connected to the cathode of the first diode;

[0013] The emitter of the PNP transistor is connected to the gate of the N-type MOS transistor, and the base of the PNP transistor is connected to the anode of the second diode;

[0014] The anode of the first diode is connected to the cathode of the second diode and one end of the adjusting resistor respectively;

[0015] The other end of the adjustment resistor is connected to a side of the piezoelectric sensor away from the vibration suppression object.

[0016] The present invention also discloses a vibration suppression method of the patch-type piezoelectric vibration suppression structure, which comprises the following process:

[0017] Let the N-type MOS tube be a negative threshold switch, the P-type MOS tube be a positive threshold switch, the NPN transistor and the first diode form a positive threshold comparator, and the PNP transistor and the second diode form a negative threshold comparator. When the vibration suppression object is disturbed and vibrates, the piezoelectric sensor generates a sensing signal due to the positive piezoelectric effect caused by deformation. The sensing signal affects the components of the control module to undergo the following periodic changes:

[0018] Step 1), when the sensing signal of the piezoelectric sensor is positive and reaches the threshold of the positive threshold comparator, the NPN transistor is turned on, the positive threshold switch is closed, the electrical boundary of the piezoelectric body is switched from an open circuit to a short circuit state, and the equivalent stiffness of the entire structure is also switched from a high stiffness to a low stiffness;

[0019] Step 2), the sensing signal of the piezoelectric sensor begins to decrease after reaching the positive peak value. When the sensing signal is positive and lower than the threshold set by the positive threshold comparator, the positive threshold switch is disconnected, the electrical boundary of the piezoelectric body is switched from a short circuit to an open circuit state, and the equivalent stiffness of the entire structure is switched from a low stiffness to a high stiffness;

[0020] Step 3), the sensing signal of the piezoelectric sensor continues to decrease after dropping to zero. When the sensing signal is negative and reaches the threshold of the negative threshold comparator, the PNP transistor is turned on, the negative threshold switch is closed, the electrical boundary of the piezoelectric body is switched from an open circuit to a short circuit state, and the equivalent stiffness of the entire structure is switched from high stiffness to low stiffness;

[0021] Step 4), the sensing signal of the piezoelectric sensor starts to rise after reaching the negative peak value. When the sensing signal is negative and the absolute value is less than the threshold of the negative threshold comparator, the negative threshold switch is disconnected, the electrical boundary of the piezoelectric body is switched from a short circuit to an open circuit state, and the equivalent stiffness of the entire structure is also switched from low stiffness to high stiffness.

[0022] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0023] 1. The present invention utilizes the difference in resonant frequency between the short circuit and the open circuit of the electrical boundary of the piezoelectric composite structure, switches the equivalent stiffness of the system through the control module, consumes the vibration mechanical energy to suppress the vibration, has strong reliability, high stability and wide application;

[0024] 2. The present invention does not require energy input from outside the system, belongs to passive vibration suppression technology, and can achieve vibration suppression by using piezoelectric materials and control circuits. It is particularly suitable for aerospace and other fields, and meets the development needs of lightweight, portability, self-adaptation, environmental protection and energy saving;

[0025] 3. Compared with active control, the present invention does not require cumbersome and complicated control algorithms, is more flexible and lightweight than other passive controls, and has greater application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of module coordination of the present invention;

[0027] Figure 2 is a circuit diagram of a control module in the present invention;

[0028] Figure 3 It is a schematic diagram of switching electrical signals of the piezoelectric body in the open circuit and short circuit states in the present invention;

[0029] Figure 4 It is a comparison between the open circuit and short circuit of the piezoelectric body in the present invention and the vibration amplitude-frequency curve of the present invention;

[0030] Figure 5 It is a schematic diagram of the change of the electrical signals of the piezoelectric sensor and the piezoelectric body during bending vibration of the present invention;

[0031] Figure 6 It is a schematic diagram of the change of electrical signals of the piezoelectric sensor and the piezoelectric body during longitudinal vibration of the present invention. DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings:

[0033] 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.

[0034] like Figure 1 As shown, the present invention discloses a patch-type piezoelectric vibration suppression structure, comprising a plurality of vibration suppression units arranged on a vibration suppression object;

[0035] The vibration suppression unit includes a piezoelectric body, a piezoelectric sensor and a control module;

[0036] The piezoelectric body and the piezoelectric sensor are both made of piezoelectric material, symmetrically arranged on both sides of the vibration suppression object, and are polarized along the thickness direction. When the longitudinal vibration of the vibration suppression object needs to be suppressed, the polarization directions of the piezoelectric body and the piezoelectric sensor are opposite; when the bending vibration of the vibration suppression object needs to be suppressed, the polarization directions of the piezoelectric body and the piezoelectric sensor are the same;

[0037] like Figure 2 As shown, the control module includes an N-type MOS tube, an NPN-type transistor, a P-type MOS tube, a PNP-type transistor, a first diode, a second diode and an adjusting resistor;

[0038] The source of the N-type MOS tube is respectively connected to the source of the P-type MOS tube and the side of the piezoelectric body close to the vibration suppression object and then grounded;

[0039] The side of the piezoelectric body away from the vibration suppression object is respectively connected to the drain of the N-type MOS tube and the drain of the P-type MOS tube;

[0040] The emitter of the NPN transistor is connected to the gate of the P-type MOS transistor, the collector of the NPN transistor is respectively connected to the side of the piezoelectric sensor close to the vibration suppression object and the collector of the PNP transistor and then grounded, and the base of the NPN transistor is connected to the cathode of the first diode;

[0041] The emitter of the PNP transistor is connected to the gate of the N-type MOS transistor, and the base of the PNP transistor is connected to the anode of the second diode;

[0042] The anode of the first diode is connected to the cathode of the second diode and one end of the adjusting resistor respectively;

[0043] The other end of the adjustment resistor is connected to the side of the piezoelectric sensor away from the vibration suppression object. The triode in the vibration suppression unit can also be replaced by a MOS tube, and the MOS tube can also be replaced by a triode. The MOS tube compares the voltage threshold and the triode compares the current threshold.

[0044] In the entire control module, the N-type MOS tube is used as a negative threshold switch, the P-type MOS tube is used as a positive threshold switch, the NPN transistor and the first diode constitute a positive threshold comparator, and the PNP transistor and the second diode constitute a negative threshold comparator; the positive threshold comparator is used to control the conduction of the positive threshold switch, and the negative threshold comparator is used to control the conduction of the negative threshold switch. The comparison thresholds of the positive threshold comparator and the negative threshold comparator are adjusted by adjusting the resistance value of the resistor.

[0045] The short circuit of the electrical boundary of the piezoelectric body reduces the equivalent stiffness of the system, and the open circuit of its electrical boundary increases the equivalent stiffness of the system. This is caused by the characteristics of the piezoelectric material. The difference in its stiffness is related to the electromechanical coupling coefficient of the piezoelectric body. The control module closes and opens the positive threshold switch and the negative threshold switch, so that the electrical boundary of the piezoelectric body is short-circuited when the electrical signal of the piezoelectric sensor reaches the threshold; the electrical boundary of the piezoelectric body is open-circuited when the electrical signal of the piezoelectric sensor does not reach the threshold. The equivalent stiffness of the system also switches between short circuit and open circuit accordingly.

[0046] The present invention also discloses a control method for a patch-type piezoelectric vibration suppression structure, which is characterized by comprising the following steps:

[0047] When the vibration suppression object is disturbed and vibrates, the piezoelectric sensor generates a sensing signal due to the positive piezoelectric effect caused by deformation, and the sensing signal affects the change of the components of the control module, such as Figure 3 As shown:

[0048] Step 1), when the sensing signal of the piezoelectric sensor is positive and reaches the threshold of the positive threshold comparator, the NPN transistor is turned on, the positive threshold switch is closed, the electrical boundary of the piezoelectric body is switched from an open circuit to a short circuit state, and the equivalent stiffness of the entire structure is also switched from a high stiffness to a low stiffness;

[0049] Step 2), the sensing signal of the piezoelectric sensor begins to decrease after reaching the positive peak value. When the sensing signal is positive and lower than the threshold set by the positive threshold comparator, the positive threshold switch is disconnected, the electrical boundary of the piezoelectric body is switched from a short circuit to an open circuit state, and the equivalent stiffness of the entire structure is switched from a low stiffness to a high stiffness;

[0050] Step 3), the sensing signal of the piezoelectric sensor continues to decrease after dropping to zero. When the sensing signal is negative and reaches the threshold of the negative threshold comparator, the PNP transistor is turned on, the negative threshold switch is closed, the electrical boundary of the piezoelectric body is switched from an open circuit to a short circuit state, and the equivalent stiffness of the entire structure is switched from high stiffness to low stiffness;

[0051] Step 4), the sensing signal of the piezoelectric sensor starts to rise after reaching the negative peak value. When the sensing signal is negative and the absolute value is less than the threshold of the negative threshold comparator, the negative threshold switch is disconnected, the electrical boundary of the piezoelectric body is switched from a short circuit to an open circuit state, and the equivalent stiffness of the entire structure is also switched from low stiffness to high stiffness.

[0052] The present invention utilizes the difference in resonant frequency between the short circuit and the open circuit of the electrical boundary of the piezoelectric composite structure, and consumes the vibration mechanical energy by switching the equivalent stiffness of the system to suppress the vibration. Figure 4 As shown. In addition, the present invention can suppress the longitudinal vibration or bending vibration of the vibrating body, such as Figure 5 and Figure 6 shown.

[0053] 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.

[0054] 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 patch-type piezoelectric vibration suppression structure, characterized in that: It includes a plurality of vibration suppression units arranged on the vibration suppression object; The vibration suppression unit includes a piezoelectric body, a piezoelectric sensor and a control module; The piezoelectric body and the piezoelectric sensor are both made of piezoelectric material, symmetrically arranged on both sides of the vibration suppression object, and are polarized along the thickness direction. When the longitudinal vibration of the vibration suppression object needs to be suppressed, the polarization directions of the piezoelectric body and the piezoelectric sensor are opposite; when the bending vibration of the vibration suppression object needs to be suppressed, the polarization directions of the piezoelectric body and the piezoelectric sensor are the same; The control module includes an N-type MOS tube, an NPN-type transistor, a P-type MOS tube, a PNP-type transistor, a first diode, a second diode and an adjusting resistor; The source of the N-type MOS tube is respectively connected to the source of the P-type MOS tube and the side of the piezoelectric body close to the vibration suppression object and then grounded; The side of the piezoelectric body away from the vibration suppression object is respectively connected to the drain of the N-type MOS tube and the drain of the P-type MOS tube; The emitter of the NPN transistor is connected to the gate of the P-type MOS transistor, the collector of the NPN transistor is respectively connected to the side of the piezoelectric sensor close to the vibration suppression object and the collector of the PNP transistor and then grounded, and the base of the NPN transistor is connected to the cathode of the first diode; The emitter of the PNP transistor is connected to the gate of the N-type MOS transistor, and the base of the PNP transistor is connected to the anode of the second diode; The anode of the first diode is connected to the cathode of the second diode and one end of the adjusting resistor respectively; The other end of the adjustment resistor is connected to a side of the piezoelectric sensor away from the vibration suppression object.

2. The vibration suppression method based on the patch-type piezoelectric vibration suppression structure according to claim 1 is characterized in that: The following procedures are included: Let the N-type MOS tube be a negative threshold switch, the P-type MOS tube be a positive threshold switch, the NPN transistor and the first diode form a positive threshold comparator, and the PNP transistor and the second diode form a negative threshold comparator. When the vibration suppression object is disturbed and vibrates, the piezoelectric sensor generates a sensing signal due to the positive piezoelectric effect caused by deformation. The sensing signal affects the components of the control module to undergo the following periodic changes: Step 1), when the sensing signal of the piezoelectric sensor is positive and reaches the threshold of the positive threshold comparator, the NPN transistor is turned on, the positive threshold switch is closed, the electrical boundary of the piezoelectric body is switched from an open circuit to a short circuit state, and the equivalent stiffness of the entire structure is also switched from a high stiffness to a low stiffness; Step 2), the sensing signal of the piezoelectric sensor begins to decrease after reaching the positive peak value. When the sensing signal is positive and lower than the threshold set by the positive threshold comparator, the positive threshold switch is disconnected, the electrical boundary of the piezoelectric body is switched from a short circuit to an open circuit state, and the equivalent stiffness of the entire structure is switched from a low stiffness to a high stiffness; Step 3), the sensing signal of the piezoelectric sensor continues to decrease after dropping to zero. When the sensing signal is negative and reaches the threshold of the negative threshold comparator, the PNP transistor is turned on, the negative threshold switch is closed, the electrical boundary of the piezoelectric body is switched from an open circuit to a short circuit state, and the equivalent stiffness of the entire structure is switched from high stiffness to low stiffness; Step 4), the sensing signal of the piezoelectric sensor starts to rise after reaching the negative peak value. When the sensing signal is negative and the absolute value is less than the threshold of the negative threshold comparator, the negative threshold switch is disconnected, the electrical boundary of the piezoelectric body is switched from a short circuit to an open circuit state, and the equivalent stiffness of the entire structure is also switched from low stiffness to high stiffness.

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