Piezoelectric self-sensing passive vibration suppression control circuit and method based on switching stiffness

Abstract

The present invention discloses a piezoelectric self-sensing passive vibration suppression control circuit and method based on switching stiffness, which includes a piezoelectric module, a bridge balance circuit, and a control circuit. The piezoelectric module comprises two piezoelectric units symmetrically arranged on both sides of the vibration suppression object, and each piezoelectric unit contains N piezoelectric bodies connected in parallel; the bridge balance circuit separates the electrical signals generated by the piezoelectric bodies into self-sensing signals for monitoring the electrical state and vibration state of the piezoelectric bodies and control signals for controlling the electrical boundary conditions of the piezoelectric bodies, and the control circuit is used to switch the system stiffness. The present invention achieves the vibration suppression effect by switching the equivalent system stiffness, which belongs to the passive vibration suppression method and does not require external energy input to the system. It has the advantages of environmental protection, convenience, wide application range, strong reliability, and real-time monitoring, and has good application prospects.

Description

Technical Field

[0001] The present invention relates to the fields of piezoelectric sensing and mechanical vibration control, and particularly to a piezoelectric self-sensing passive vibration suppression control circuit and method based on switched stiffness. Background Art

[0002] Vibration commonly occurs in fields such as aerospace, wind turbines, and tower structures, causing adverse effects. Therefore, it is very important to suppress the vibration of vibrating bodies. Currently, vibration control is divided into active control, semi-active control, and passive control. Active control using piezoelectric materials often has a complex system and relies on algorithms for vibration control. The need for a large amount of energy outside the system and unreliability limit the application of active control. Semi-active control requires external energy to change system characteristics such as stiffness or damping to control vibration. The system is complex and cumbersome, and at the same time, the stability is poor. However, traditional passive control cannot be adjusted according to actual vibration, and the vibration control effect is not good.

[0003] At present, applications such as wind turbines, helicopter rotors, and satellite solar panels still use traditional passive control technologies, which are difficult to meet the requirements of vibration control. The present invention achieves vibration suppression by switching the equivalent stiffness of the system, and belongs to a passive vibration suppression method. It does not require external energy input, has advantages such as environmental protection, convenience, wide application range, strong reliability, and real-time monitoring, and has good application prospects. 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 switched stiffness for the defects involved in the background art.

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

[0006] A piezoelectric self-sensing passive vibration suppression control circuit based on switched stiffness includes a piezoelectric module, a resistor R1, a resistor R2, a capacitor Cr, an N-type MOS transistor, an NPN-type bipolar transistor, a P-type MOS transistor, a PNP-type bipolar transistor, a first diode, a second diode, and a resistor Rc;

[0007] The piezoelectric module includes a first to a second piezoelectric unit; the first to the second piezoelectric units have the same structure and each includes N piezoelectric bodies connected in parallel, where N is a natural number greater than or equal to 1; the piezoelectric bodies are made of piezoelectric materials and are used to convert mechanical energy into electrical energy through the piezoelectric effect;

[0008] The first and second piezoelectric units are symmetrically arranged on both sides of the vibration suppression object. When the vibration suppression object vibrates, the piezoelectric bodies in the first and second piezoelectric units generate corresponding deformations;

[0009] The first piezoelectric unit is respectively connected to one end of the resistor R1 and one end of the resistor Rc, and the second piezoelectric unit is respectively connected to one end of the capacitor Cr, the drain of the N-type MOS transistor, and the drain of the P-type MOS transistor;

[0010] The other end of the resistor R1 is respectively connected to one end of the resistor R2, the source of the N-type MOS transistor, and the source of the P-type MOS transistor;

[0011] The other end of the capacitor Cr is respectively connected to the other end of the resistor R2, the collector of the NPN-type triode, and the collector of the PNP-type triode;

[0012] The emitter of the NPN-type triode is connected to the gate of the P-type MOS transistor, and the base is connected to the negative electrode of the first diode;

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

[0014] The positive electrode of the first diode is respectively connected to the other end of the resistor Rc and the negative electrode of the second diode;

[0015] Let the equivalent capacitance of the piezoelectric module be Cp, R1*Cp = R2*Cr, and the piezoelectric module, capacitor Cr, resistor R1, and resistor R2 form a bridge balance circuit.

[0016] As a further optimized scheme of the piezoelectric self-sensing passive vibration suppression control circuit based on switching stiffness of the present invention, the resistor R1 is replaced by a capacitor C1, the resistor R2 is replaced by a capacitor C2, C2*Cp = C1*Cr, and the piezoelectric module, capacitor Cr, capacitor C1, and capacitor C2 form a bridge balance circuit.

[0017] The present invention also discloses a vibration suppression method for the piezoelectric self-sensing passive vibration suppression control circuit based on switching stiffness, comprising the following steps:

[0018] The N-type MOS transistor, NPN-type triode, P-type MOS transistor, PNP-type triode, first diode, second diode, and resistor Rc form a control circuit. Among them, the N-type MOS transistor is a negative threshold switch, the P-type MOS transistor is a positive threshold switch, the NPN triode and the first diode form a positive threshold comparator, and the PNP triode 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 the deformation, and the sensing signal affects the components of the control module to perform the following periodic changes:

[0019] Step 1), when the vibration suppression object vibrates, the piezoelectric module generates deformation and undergoes the positive piezoelectric effect, and a voltage difference appears at the electrical boundary of the corresponding piezoelectric body;

[0020] Step 2), the bridge balance circuit separates the electrical signal generated by the piezoelectric body into a self-sensing signal for monitoring the electrical state and vibration state of the piezoelectric body and a control signal for controlling the electrical boundary conditions of the piezoelectric body.

[0021] Step 3), the self-sensing signal increases as the vibration deformation of the vibration suppression object increases. When its voltage reaches the preset positive threshold, the positive threshold comparator is turned on, the positive threshold switch is closed, and the control signal controls the electrical boundary conditions of the piezoelectric body to change to a short circuit, and the charge accumulated at the electrical boundary of the piezoelectric body is neutralized to dissipate electrical energy.

[0022] Step 4), when the vibration positive direction deformation of the vibration suppression object reaches the maximum and then begins to decrease, the self-sensing signal decreases accordingly. When its voltage drops below the preset positive threshold, the positive threshold comparator is turned off, the positive threshold switch is turned off, and the control signal controls the electrical boundary conditions of the piezoelectric body to change to an open circuit, the overall structure stiffness increases, the ability to resist deformation is enhanced, and the vibration displacement is reduced.

[0023] Step 5), as the vibration deformation of the vibration suppression object continues to decrease, the self-sensing signal decreases accordingly. When its voltage drops below the preset negative threshold, the negative threshold comparator is turned on, the negative threshold switch is closed, and the control signal controls the electrical boundary conditions of the piezoelectric body to change to a short circuit, and the charge accumulated at the electrical boundary of the piezoelectric body is neutralized to dissipate electrical energy, and the overall structure stiffness becomes smaller.

[0024] Step 6), when the vibration negative direction deformation of the vibration suppression object reaches the maximum and then begins to decrease, the self-sensing signal increases accordingly. When its voltage rises above the preset negative threshold, the negative threshold comparator is turned off, the negative threshold switch is turned off, and the control signal controls the electrical boundary conditions of the piezoelectric body to change to an open circuit, the overall structure stiffness increases, the ability to resist elastic deformation is strong, and the vibration displacement is reduced.

[0025] Compared with the prior art, the present invention adopts the above technical solutions and has the following technical effects:

[0026] 1. The passive control technology of the present invention does not require energy input from outside the system, has great development prospects in fields such as spacecraft and aircraft, and has the advantages of environmental protection, energy conservation, and wide application.

[0027] 2. The present invention can separate the self-sensing signal through the self-induction circuit module for real-time monitoring of the system state, facilitating the identification of vibration states and monitoring of faults, etc., which is convenient, efficient, and highly reliable.

[0028] 3. The present invention realizes the switching of the equivalent stiffness of the system by controlling the on-off of the switch through the control circuit, achieving a reliable and efficient passive vibration suppression effect, with a simple structure, strong functionality, and meeting the development requirements of lightweight. Description of the Drawings

[0029] Figure 1 is a structural schematic diagram of the present invention;

[0030] Figure 2 is a connection schematic diagram of the piezoelectric module in the present invention;

[0031] Figure 3 is a circuit schematic diagram when a capacitance-resistance type bridge is adopted in the present invention;

[0032] Figure 4 is a comparison schematic diagram of the capacitance-resistance type bridge and the capacitance-capacitance type bridge in the present invention;

[0033] Figure 5 is a circuit schematic diagram of the control circuit module in the present invention;

[0034] Figure 6 is a switching schematic diagram of the piezoelectric body open-circuit state electrical signal in the present invention;

[0035] Figure 7 is a comparison schematic diagram of the self-sensing signal and the vibration displacement in the present invention. Detailed implementation manners

[0036] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings:

[0037] The present invention can be implemented in many different forms and should not be considered limited to the embodiments described herein. On the contrary, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present invention to those skilled in the art. In the drawings, components are enlarged for clarity.

[0038] As Figure 1 shown, the present invention discloses a piezoelectric self-sensing passive vibration suppression control circuit based on switching stiffness, which includes a piezoelectric module, a resistor R1, a resistor R2, a capacitor Cr, an N-type MOS transistor, an NPN-type triode, a P-type MOS transistor, a PNP-type triode, a first diode, a second diode, and a resistor Rc;

[0039] As Figure 2 shown, the piezoelectric module body includes first to second piezoelectric units; the first to second piezoelectric units have the same structure and each includes N piezoelectric bodies connected in parallel, where N is a natural number greater than or equal to 1; the piezoelectric body is made of a piezoelectric material and is used to convert mechanical energy into electrical energy through the piezoelectric effect;

[0040] The first and second piezoelectric units are symmetrically arranged on both sides of the vibration suppression object. When the vibration suppression object vibrates, the piezoelectric bodies in the first and second piezoelectric units generate corresponding deformations;

[0041] As Figure 3As shown, one end of the first piezoelectric unit is respectively connected to one end of the resistor R1 and one end of the resistor Rc, and one end of the second piezoelectric unit is respectively connected to one end of the capacitor Cr, the drain of the N-type MOS transistor, and the drain of the P-type MOS transistor;

[0042] The other end of the resistor R1 is respectively connected to one end of the resistor R2, the source of the N-type MOS transistor, and the source of the P-type MOS transistor;

[0043] The other end of the capacitor Cr is respectively connected to the other end of the resistor R2, the collector of the NPN-type triode, and the collector of the PNP-type triode;

[0044] The emitter of the NPN-type triode is connected to the gate of the P-type MOS transistor, and the base is connected to the negative electrode of the first diode;

[0045] The emitter of the PNP-type triode is connected to the gate of the N-type MOS transistor, and the base is connected to the positive electrode of the second diode;

[0046] The positive electrode of the first diode is respectively connected to the other end of the resistor Rc and the negative electrode of the second diode;

[0047] Let the equivalent capacitance of the piezoelectric module be Cp, R1*Cp = R2*Cr, and the piezoelectric module, capacitor Cr, resistor R1, and resistor R2 form a bridge balance circuit.

[0048] As Figure 4 shown, the bridge balance circuit adopted here is a capacitance-resistance type bridge. This bridge balance circuit can also adopt a capacitance-capacitance type bridge, specifically as follows: the resistor R1 is replaced by a capacitor C1, the resistor R2 is replaced by a capacitor C2, C2*Cp = C1*Cr, and the piezoelectric module, capacitor Cr, capacitor C1, and capacitor C2 form a bridge balance circuit.

[0049] In practical applications, since it is difficult to achieve bridge balance with a capacitance-capacitance type bridge, a capacitance-resistance type bridge is recommended here.

[0050] The bridge balance circuit outputs a self-sensing signal and a control signal; the self-sensing signal is proportional to the induction signal of the piezoelectric body and also proportional to the piezoelectric induction charge. According to the piezoelectric equation, the induction signal and the induction charge are proportional to the strain of the piezoelectric material. Therefore, the self-sensing signal can be used to monitor the state of the piezoelectric body; while the control signal is used to control the electrical boundary conditions of the piezoelectric body.

[0051] As Figure 5As shown, an N-type MOS transistor, an NPN-type bipolar transistor, a P-type MOS transistor, a PNP-type bipolar transistor, a first diode, a second diode, and a resistor Rc form a control circuit. Among them, the N-type MOS transistor serves as a negative threshold switch, the P-type MOS transistor serves as a positive threshold switch, the NPN bipolar transistor and the first diode form a positive threshold comparator, and the PNP bipolar transistor and the second diode form 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 both the positive threshold comparator and the negative threshold comparator are adjusted by the resistance value of the resistor Rc.

[0052] The present invention also discloses a vibration suppression method for the piezoelectric self-sensing passive vibration suppression control circuit based on switching stiffness, which includes the following steps:

[0053] When the vibration suppression object is disturbed and vibrates, the piezoelectric sensor generates a sensing signal due to the piezoelectric effect caused by deformation. The sensing signal affects the components of the control module to undergo the following periodic changes, as Figure 7 shown:

[0054] Step 1), when the vibration suppression object vibrates, the piezoelectric module deforms and the piezoelectric effect occurs, and a voltage difference appears at the electrical boundary of the corresponding piezoelectric body. As Figure 6 shown, when the voltage difference reaches the corresponding threshold, the circuit state (switching stiffness) is changed;

[0055] Step 2), the bridge balance circuit separates the electrical signal generated by the piezoelectric body into a self-sensing signal for monitoring the electrical state and vibration state of the piezoelectric body and a control signal for controlling the electrical boundary conditions of the piezoelectric body;

[0056] Step 3), the self-sensing signal increases as the vibration deformation of the vibration suppression object increases. When its voltage reaches the preset positive threshold, the positive threshold comparator is turned on, the positive threshold switch is closed, and the control signal controls the electrical boundary conditions of the piezoelectric body to change to a short circuit, and the charge accumulated at the electrical boundary of the piezoelectric body is neutralized to dissipate electrical energy;

[0057] Step 4), when the vibration of the vibration suppression object reaches the maximum in the positive direction of deformation and then the deformation begins to decrease, the self-sensing signal decreases accordingly. When its voltage drops below the preset positive threshold, the positive threshold comparator is turned off, the positive threshold switch is turned off, and the control signal controls the electrical boundary conditions of the piezoelectric body to change to an open circuit, the overall structural stiffness increases, the ability to resist deformation is enhanced, and the vibration displacement is reduced;

[0058] Step 5), the vibration deformation of the vibration suppression object continues to decrease, and the self-sensing signal decreases accordingly. When its voltage drops below the preset negative threshold, the negative threshold comparator is turned on, the negative threshold switch is closed, and the control signal controls the electrical boundary condition of the piezoelectric body to change to a short circuit. The charges accumulated at the electrical boundary of the piezoelectric body are neutralized to dissipate electrical energy, and the stiffness of the entire structure becomes smaller;

[0059] Step 6), when the negative-direction deformation of the vibration suppression object reaches the maximum and then begins to decrease, the self-sensing signal increases accordingly. When its voltage rises above the preset negative threshold, the negative threshold comparator is turned off, the negative threshold switch is turned off, and the control signal controls the electrical boundary condition of the piezoelectric body to change to an open circuit. The stiffness of the entire structure becomes larger, the ability to resist elastic deformation is strong, and the vibration displacement is reduced.

[0060] The present invention achieves the vibration suppression effect by switching the equivalent stiffness of the system, and belongs to a passive vibration suppression method. It does not require an external energy input to the system, and has advantages such as environmental protection, convenience, wide application range, strong reliability, and real-time monitoring, and has good application prospects.

[0061] Those skilled in the art of the present technology can understand that, unless otherwise defined, all terms (including technical terms and scientific terms) used here have the same meaning as the general understanding of those of ordinary skill in the art in the field to which the present invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless defined as here.

[0062] The specific embodiments described above have further elaborated on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A piezoelectric self-sensing passive vibration suppression control circuit based on switching stiffness, characterized in that It includes a piezoelectric module, resistor R1, resistor R2, capacitor Cr, N-type MOS transistor, NPN-type triode, P-type MOS transistor, PNP-type triode, first diode, second diode and resistor Rc; The piezoelectric module includes first to second piezoelectric units; the first to second piezoelectric units have the same structure and each includes N piezoelectric bodies connected in parallel, where N is a natural number greater than or equal to 1; the piezoelectric bodies are made of piezoelectric materials and are used to convert mechanical energy into electrical energy through the piezoelectric effect; The first and second piezoelectric units are symmetrically arranged on both sides of the vibration suppression object. When the vibration suppression object vibrates, the piezoelectric bodies in the first and second piezoelectric units generate corresponding deformations; One end of the first piezoelectric unit is respectively connected to one end of resistor R1 and one end of resistor Rc, and one end of the second piezoelectric unit is respectively connected to one end of capacitor Cr, the drain of the N-type MOS transistor, and the drain of the P-type MOS transistor; The other end of resistor R1 is respectively connected to one end of resistor R2, the source of the N-type MOS transistor, and the source of the P-type MOS transistor; The other end of capacitor Cr is respectively connected to the other end of resistor R2, the collector of the NPN-type triode, and the collector of the PNP-type triode; The emitter of the NPN-type triode is connected to the gate of the P-type MOS transistor, and the base is connected to the negative electrode of the first diode; The emitter of the PNP-type triode is connected to the gate of the N-type MOS transistor, and the base is connected to the positive electrode of the second diode; The positive electrode of the first diode is respectively connected to the other end of resistor Rc and the negative electrode of the second diode; Let the equivalent capacitance of the piezoelectric module be Cp, and R1*Cp = R2*Cr. The piezoelectric module, capacitor Cr, resistor R1, and resistor R2 form a balanced bridge circuit.

2. The piezoelectric self-sensing passive vibration suppression control circuit based on switching stiffness according to claim 1, wherein Resistor R1 is replaced by capacitor C1, and resistor R2 is replaced by capacitor C2. C2*Cp = C1*Cr. The piezoelectric module, capacitor Cr, capacitor C1, and capacitor C2 form a balanced bridge circuit.

3. The vibration suppression method of the piezoelectric self-sensing passive vibration suppression control circuit based on switching stiffness according to claim 1 or 2, characterized in that It includes the following steps: The N-type MOS transistor, NPN-type triode, P-type MOS transistor, PNP-type triode, first diode, second diode, and resistor Rc form a control circuit. Among them, the N-type MOS transistor is a negative threshold switch, the P-type MOS transistor is a positive threshold switch, the NPN triode and the first diode form a positive threshold comparator, and the PNP triode 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 the deformation. The sensing signal affects the components of the control module to perform the following periodic changes: Step 1), when the vibration suppression object vibrates, the piezoelectric module generates a deformation and undergoes the positive piezoelectric effect, and a voltage difference appears at the electrical boundary of the corresponding piezoelectric body; Step 2), the balanced bridge circuit separates the electrical signal generated by the piezoelectric body into a self-sensing signal for monitoring the electrical state and vibration state of the piezoelectric body and a control signal for controlling the electrical boundary conditions of the piezoelectric body; Step 3), the self-sensing signal increases as the vibration deformation of the vibration suppression object increases. When its voltage reaches the preset positive threshold, the positive threshold comparator is turned on, the positive threshold switch is closed, and the control signal controls the electrical boundary condition of the piezoelectric body to change to a short circuit, and the charges accumulated at the electrical boundary of the piezoelectric body are neutralized to dissipate electrical energy; Step 4), when the vibration positive direction deformation of the vibration suppression object reaches the maximum and then begins to decrease, the self-sensing signal decreases accordingly. When its voltage drops below the preset positive threshold, the positive threshold comparator is turned off, the positive threshold switch is turned off, and the control signal controls the electrical boundary condition of the piezoelectric body to change to an open circuit. The overall structure stiffness increases, the ability to resist deformation enhances, and the vibration displacement is reduced; Step 5), the vibration deformation of the vibration suppression object continues to decrease, and the self-sensing signal decreases accordingly. When its voltage drops below the preset negative threshold, the negative threshold comparator is turned on, the negative threshold switch is closed, and the control signal controls the electrical boundary condition of the piezoelectric body to change to a short circuit, and the charges accumulated at the electrical boundary of the piezoelectric body are neutralized to dissipate electrical energy, and the overall structure stiffness becomes smaller; Step 6), when the vibration negative direction deformation of the vibration suppression object reaches the maximum and then begins to decrease, the self-sensing signal increases accordingly. When its voltage rises above the preset negative threshold, the negative threshold comparator is turned off, the negative threshold switch is turned off, and the control signal controls the electrical boundary condition of the piezoelectric body to change to an open circuit. The overall structure stiffness increases, the ability to resist elastic deformation is strong, and the vibration displacement is reduced.

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