Damping adaptive structure and control method of acceleration sensor

Abstract

The application relates to a damping self-adaptive structure and control method of an acceleration sensor, belonging to the technical field of fuzes. Two opposite electrode plates are additionally arranged between a mass block of the acceleration sensor and a lower supporting silicon base to realize the effect of variable damping. When the output of the sensor is greater than a trigger threshold value, a certain current is passed through the electrode plates to generate an acting force between the two electrode plates, thereby generating damping for limiting the movement of the sensor, enabling the acceleration sensor to return to the initial stable state more quickly and reducing the oscillation time; when the output of the sensor is less than a termination threshold value, it is determined that the sensor has returned to the initial stable state, the feedback control is turned off, the acting force between the two electrode plates disappears, and the sensor normally works again. The application is suitable for the field of acceleration sensors, enables the acceleration sensor to have better dynamic performance, can return to a stable value more quickly when subjected to a pulse signal, increases the detectable bandwidth of the sensor, and improves the controllability of the damping self-adaptive structure of the acceleration sensor.

Description

TECHNICAL FIELD

[0001] The application relates to a damping self-adaptive structure and a control method of an acceleration sensor, and belongs to the technical field of fuzes. BACKGROUND

[0002] The hardening and undergrounding of important military targets make the development of penetration weapons particularly rapid. Important military equipment, command centers and the like are hidden in the underground or multi-layer protective buildings, and the environment is generally relatively hard. In order to achieve the destruction of them, it is necessary to require the hard target penetration weapon to explode after multiple high-speed impacts, so as to achieve the maximum damage to the target. The penetration fuze is the key to realize the accurate control of the explosion point.

[0003] The penetration fuze is developed from the traditional timing fuze to the current multi-functional intelligent fuze such as layer counting, depth counting, medium recognition and the like along the direction of high precision and high intelligence. The layer counting fuze technology is the main initiation control mode of the current hard target penetration fuze, which calculates, identifies and accumulates the number of layers penetrated by the projectile through the layer counting algorithm and according to the penetration sensitive signal. However, when the projectile is long and the projectile speed is high, the response decay of the projectile structure is slow, causing the measurement signals of the sensors to be mutually adhered when penetrating the layer, and the layers cannot be effectively identified, the warhead cannot be initiated as expected, and thus the damage efficiency is greatly reduced.

[0004] At present, the solutions to the signal adhesion problem when penetrating the multi-layer hard target mainly include two aspects of sensor design and layer counting algorithm design. Changing the response signal of the sensor through design is a solution to the signal adhesion, and with the development and maturity of the micro-electro-mechanical system (MEMS) technology, designing a unique micro sensor, controller and actuator structure to optimize the output signal and improve the signal adhesion phenomenon of the penetration weapon when penetrating the layer is considered as a high-reliability solution. The MEMS acceleration sensor widely used in the penetration fuze at the present stage is the focus of improvement. However, the open-loop system of the MEMS acceleration sensor has no feedback link, the stability of the system is poor, and the response time is long. When the MEMS acceleration sensor is subjected to high external impact signals in a short time when the warhead penetrates the hard target and the multi-layer target, the system cannot automatically adjust its output, the rising time of the output acceleration signal is long, and the adhesion phenomenon is easy to occur, which is not conducive to the layer initiation.

[0005] The layer counting algorithm design is another scheme for solving signal sticking, however, the layer counting algorithm design often relies on the signal feature extraction, including threshold extraction, spectrum feature analysis, multi-sensor signal convolution, etc.For the complex penetration signal extraction algorithm, the processor needs to spend too much time on signal processing to extract the layer number, and the layer counting algorithm requires high real-time performance, if the time is too long, even if the layer number can be accurately extracted, the projectile has penetrated the predetermined layer, therefore, the layer counting algorithm design has its limitations. SUMMARY

[0006] In view of the technical problems that the dynamic performance of the high overload acceleration sensor in the fuze is difficult to adapt to high-speed attack, and signal sticking is prone to occur, the main purpose of the application is to provide a damping adaptive structure and control method of an acceleration sensor, an electrostatic driving mode is adopted, electrode plates are added to the back and lower silicon substrate surface of the acceleration sensor, and the electrode plates are connected with the damping controller through wires, when the damping controller controls the two electrode plates to pass through the same current, repulsive electrostatic force is generated, the size of the electrostatic force is controlled by controlling the size of the current, and controllable damping is generated, the sticking degree of the signal is reduced by controlling the damping, and the accuracy of the burst point is improved.

[0007] The purpose of the application is realized through the following technical schemes.

[0008] The damping adaptive structure of the acceleration sensor disclosed by the application comprises a damping controller, a piezoresistor, an acceleration sensor mass block, a mass block back electrode plate, an acceleration sensor support, a lower support silicon substrate and a lower silicon substrate surface electrode plate. The mass block back electrode plate and the lower silicon substrate surface electrode plate are respectively located between the acceleration sensor mass block and the lower support silicon substrate, are opposite to each other, and are connected with the damping controller by wires respectively; the piezoresistor is arranged at the root of the cantilever beam of the acceleration sensor support; and the acceleration sensor support and the lower support silicon substrate are connected in a bonding mode.

[0009] The damping controller cooperates with the damping adaptive control method proposed by the application to control the damping force size generated between the electrode plates;

[0010] The piezoresistor is a signal collection element of the acceleration sensor, and is used for detecting acceleration;

[0011] The acceleration sensor mass block is a sensitive element of the acceleration sensor, and is used for amplifying the input signal of the sensor, facilitating the detection of the sensor;

[0012] The acceleration sensor support and the lower support silicon substrate are a support part in an integral structure, and are used for structural support;

[0013] The mass back electrode plate and the lower silicon substrate surface electrode plate are low resistivity original elements, are located opposite to each other between the sensitive element of the acceleration sensor and the substrate, and jointly constitute a damping generation device of the damping self-adaptive control structure, and are used for limiting the movement of the sensitive element and shortening the response time.

[0014] The application discloses a damping self-adaptive control method of an acceleration sensor.

[0015] Step 1, the output electric signal of the sensor is set as x and is introduced into the damping controller.

[0016] Step 2, the algorithm is initialized, the application scene is identified, the trigger threshold a and the event termination threshold b are determined according to the event.

[0017] Step 3, when the output signal x of the acceleration sensor is greater than a, the control trigger is set to 1 at this time, and when the output signal x of the acceleration sensor is not greater than a, the next determination process is entered without processing.

[0018] Step 4, when the output signal x of the acceleration sensor is less than b, the control trigger is set to 0 at this time, and when the output signal x of the acceleration sensor is not less than b, the next determination process is entered without processing.

[0019] Step 5, whether the control trigger is set to 1 is determined, the feedback control is started when the control trigger is set to 1, the damping controller output signal controls the relative electrode plate on the acceleration sensor to generate the damping force, the sensor returns to the initial state, the control is not performed when the control trigger is not set to 1, and the sensor returns to the initial state after the control process is completed.

[0020] Beneficial effects:

[0021] 1. The damping self-adaptive structure of the acceleration sensor disclosed by the application adds two electrode plates between the sensitive element of the acceleration sensor and the substrate, generates the force on the electrode plates through the electric current, generates the damping for limiting the movement of the sensor, makes the acceleration sensor return to the initial stable state more quickly, shortens the oscillation time, improves the signal sticking phenomenon, and improves the accuracy of the burst point.

[0022] 2, The application discloses a damping self-adaptive structure and control method of an acceleration sensor, when the sensor output is greater than a trigger threshold, an acting force is generated between two polar plates, so that the acceleration sensor quickly returns to an initial state; when the sensor output is less than a termination threshold, it is determined that the sensor has returned to the initial stable state, the feedback control is closed, the acting force between the two polar plates disappears at this time, and the sensor can work normally again; the acceleration sensor has better dynamic performance, can return to a stable value more quickly when subjected to a pulse signal, the detectable bandwidth of the sensor is increased, and the controllability of the damping self-adaptive structure of the acceleration sensor is improved.

[0023] 3, The application discloses a damping self-adaptive structure and control method of an acceleration sensor, variable damping control is performed on a PID feedback control method, compared with open-loop control, the damping self-adaptive structure has higher stability and shorter response time. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a schematic diagram of the damping self-adaptive structure of the acceleration sensor disclosed by the application;

[0025] Figure 2 It is a principle schematic diagram of the damping self-adaptive structure and control method of the acceleration sensor disclosed by the application;

[0026] Figure 3 It is a PID feedback control flowchart of event triggering;

[0027] Figure 4 It is a flow schematic diagram of the damping self-adaptive control method of the acceleration sensor disclosed by the application;

[0028] Figure 5 It is a structural schematic diagram of the acceleration sensor with an added electrode plate at the back in the embodiment;

[0029] Figure 6 It is a structural schematic diagram of the bottom support base in the embodiment;

[0030] Figure 7 It is a PID control result based on event triggering in the embodiment;

[0031] Wherein the reference signs are:

[0032] 1-damping controller, 2-pressure sensitive resistor, 3-acceleration sensor mass block, 4-mass block back electrode plate, 5-acceleration sensor support, 6-lower support silicon base, 7-lower silicon base surface electrode plate. DETAILED DESCRIPTION

[0033] The application will be described in detail below with reference to the accompanying drawings and examples. The technical problems solved by the technical solutions of the application and the beneficial effects are also described. It should be pointed out that the described examples are only intended to facilitate the understanding of the application and do not limit the application in any way.

[0034] As shown in the accompanying drawings and examples, the technical solutions of the application solve the technical problems and have the beneficial effects. Figure 1 The damping self-adaptive structure of the acceleration sensor disclosed by the present embodiment comprises a damping controller 1, a piezoresistor 2, an acceleration sensor mass 3, a mass back electrode plate 4, an acceleration sensor support 5, a lower support silicon substrate 6 and a lower silicon substrate surface electrode plate 7. The mass back electrode plate 4 and the lower silicon substrate surface electrode plate 7 are respectively located between the acceleration sensor mass 3 and the lower support silicon substrate 6, and are respectively connected to the damping controller 1 by wires. The piezoresistor 2 is arranged at the root of the cantilever beam of the acceleration sensor support 5. When the acceleration sensor is subjected to acceleration and deformed, the root of the cantilever beam will be deformed, thereby causing the piezoresistor to change, and the resistance change of the piezoresistor can be measured to obtain the corresponding acceleration. The acceleration sensor support 5 and the lower support silicon substrate 6 are connected by bonding. The piezoresistor 2 and the acceleration sensor mass 3 act as sensitive elements and signal collection elements of the acceleration sensor to detect acceleration. The mass back electrode plate 4 and the lower silicon substrate surface electrode plate together constitute a damping generation device of the damping self-adaptive control structure, which limits the movement of the sensitive element and shortens the response time. The acceleration sensor support 5 and the lower support silicon substrate 6 have a whole supporting effect. The damping controller 1 cooperates with the damping self-adaptive control method to achieve the damping control effect and the purpose of controllable damping change.

[0035] A pair of opposite mass back electrode plates 4 and lower silicon substrate surface electrode plates 7 are made on the back of the acceleration sensor mass 3 and the recessed center surface of the lower supporting silicon substrate 6. The material of the pair of metal electrode plates is gold, which has a low resistivity, so that the electric signal is in a well-controlled range. When they are supplied with the same current, electrostatic forces are generated to repel each other, and a driving force f is generated, so that the acceleration sensor is prevented from moving. The size of the driving force f is related to the size of the current supplied between the upper and lower electrode plates. The upper and lower electrode plates are connected to the 1 damping controller 1 through wires, and are driven by electrostatic forces. The two electrode plates repel each other by the same current, and generate a damping force to limit the sensitive element. The damping controller 1 controls the force between the two electrode plates by controlling the size of the current, and controls the size of the current by the damping self-adaptive control method, so as to control the size of the electrostatic force, and achieve the purpose of controllable damping change. In this way, the acceleration sensor can switch between the initial state and the final stable state at a faster speed, reduce the time in the intermediate state, shorten the oscillation time, and improve the signal sticking phenomenon.

[0036] The structural dimensions are shown in the following table:

[0037]

[0038] The length of the upper and lower electrode plates is 600 μm, and the width is 600 μm.

[0039] As Figure 5 and Figure 6 The mass back electrode plates 4 and the lower silicon substrate surface electrode plates 7 are made by the lift-off process, and the lower supporting silicon substrate 6 is made by the photolithography and etching process. The manufacturing process of the mass back electrode plates 4 and the lower silicon substrate surface electrode plates 7 is to spin the photoresist on the corresponding surface, expose the photoresist to light with the required pattern by the photolithography process, and then remove the exposed photoresist together with the unnecessary metal film part to realize the patterning of the electrode plates. The manufacturing process of the lower supporting silicon substrate 6 is to spin the photoresist on the surface, expose the photoresist to light with the required pattern by the photolithography process, remove the surface exposed photoresist to realize the patterning, and then realize the manufacturing of the recess by the etching process. Finally, all the photoresist is removed to realize the structure manufacturing of the lower supporting silicon substrate 6. The acceleration sensor support 5 and the lower supporting silicon substrate 6 are connected by bonding.

[0040] The embodiment adopts a piezoresistance type acceleration sensor, and the piezoresistive 2 is arranged at the root of the cantilever beam of the acceleration sensor support 5. When the acceleration sensor mass 3 is deformed by acceleration, the root of the cantilever beam is deformed to change the piezoresistive, and the resistance change of the piezoresistive is measured, so that the corresponding acceleration is obtained.

[0041] As Figure 2 shown in the principle diagram of the acceleration sensor for the fuze. The high-g MEMS acceleration sensor is a typical single-degree-of-freedom second-order system, and the open-loop system has no feedback link, the stability of the system is not high, and the response time is relatively long. When the warhead penetrates hard targets and multi-layer targets, the high-g MEMS accelerometer is affected by an external impact signal of up to 100000g in a short time (microsecond level), the system cannot automatically adjust its output, the rising time of the output acceleration signal is long, and the sticking phenomenon is easy to occur, which is not conducive to layer initiation. Through the event-triggered closed-loop feedback control of the high-g MEMS, the high-g MEMS accelerometer system can be quickly stabilized when receiving the external impact signal. The high-g MEMS accelerometer is structurally modified, and a damping controller is added to the mass block. During the penetration of the warhead into the multi-layer target, the accelerometer system is quickly stabilized in real time by generating an active control signal through electromagnetic force, and accurate layering is realized.

[0042] The adaptive control method is analyzed, and the mechanical equation of the high-g MEMS acceleration sensor after adding the damping controller is shown in formula (1):

[0043]

[0044] Among them, is the acceleration sensor mass velocity, is the acceleration of the acceleration sensor mass, x is the displacement of the acceleration sensor mass, ω is the noise of the system in the impact process, d is the structural response signal of the projectile system when impacting, f(·) is the acceleration sensor system equation, and u is the control input generated by the electromagnetic force. By applying a damping force to the acceleration sensor mass, the acceleration of the acceleration sensor mass is changed to achieve the purpose of controllable damping change.

[0045] As Figure 4As shown, in order to more accurately realize the penetration metering, the PID feedback control cannot be directly designed to the control input, but an event triggering mechanism needs to be introduced to the feedback control. According to the event triggering threshold a and the event termination threshold b of the expert knowledge base, when the accelerometer signal is greater than a, the closed-loop feedback control is triggered to control the accelerometer signal, and when the accelerometer signal is less than b, the closed-loop feedback control is turned off, the signal converges to 0 quickly, the signal sticking phenomenon caused by multiple warhead impacts on the multi-layer obstacle is reduced, the precise metering is realized, and the event triggering feedback control process is as shown in Figure 2 The event triggering process algorithm is as shown below.

[0046]

[0047] The feedback control in the event triggering feedback control process adopts a PID control algorithm, and the controller form is as shown in formula (2):

[0048]

[0049] Wherein, u(t) is the control input, x(t) is the displacement of the accelerometer mass block, the purpose of the control is to make the displacement of the mass block after penetration return to zero as soon as possible, k p is a proportional coefficient, T d is a differential time, and T i is an integral time.

[0050] The action of the MEMS acceleration sensor on the input displacement can be equivalent to a second-order system, and the open-loop transfer function equation of the MEMS acceleration sensor is derived as shown in formula (3):

[0051]

[0052] Wherein, c is a damping coefficient, m is the mass of the accelerometer mass block, and k is a stiffness coefficient of the acceleration sensor, and the overall material of the sensor is silicon material.

[0053] The PID controller block diagram based on the event triggering is as shown in Figure 3 The whole forms a closed-loop feedback, and the output value of the sensor is closed-loop controlled according to the above damping self-adaptive control method of the acceleration sensor.

[0054] When the acceleration sensor works, if the input quantity is a high-amplitude impact signal, the signal rise time is long, and the signal sticking phenomenon is easy to occur. The method of the present application proposes to add a variable damping driving force generating device to the mass part of the acceleration sensor to reduce the influence of signal sticking. After the signal input, the current size between the electrode plates is controlled by the damping controller to adjust the size of the driving force, so that the damping is increased, and the oscillation caused by the pulse signal input is weakened.

[0055] When the warhead penetrates the multi-layer target, the acceleration of 100000g can be reached within several microseconds, and when the damping ratio is 0.6, the amplitude-frequency characteristic of the system is in the best state, in the critical damping state, and the working bandwidth is maximum. The length of the rectangular plate in the x direction is B (B=a2), and the length in the y direction is L (L=b2). The mass block of the sensor is rectangular. The size of the sensor is shown in the following table:

[0056]

[0057] For the structure size of the acceleration sensor, ω n =1.67*10 5 Hz, the damping is c=0.1104N·s / m, the damping ratio is ξ=0.6902. The mass block is made of silicon, and the density is m=a2*b2*h2*p=4.47*10 -7 kg, k=1.5625*10 -5 kg.

[0058] The stiffness coefficient of the acceleration sensor is:

[0059]

[0060] Since the acceleration sensor is made of silicon material, the elastic coefficient is E=190GPa.

[0061] The calculated open-loop transfer function is:

[0062]

[0063] PID feedback control is performed on the acceleration sensor, and the event trigger module is set. When the warhead penetrates the multi-layer target, the amplitude of the external impact signal can reach 170000g, the event trigger threshold is set to 120000g, the signal amplitude is greater than 120000g, the PID control is started, the signal amplitude is less than 50000g, and the PID control is closed. The simulation result is shown in Figure 7 The blue curve in the figure is the open-loop response of the accelerometer, and the red curve is the signal after the PID feedback control of the event trigger is added. Under the action of the feedback control based on the event trigger, the signal rapidly decays, the interlayer adhesion degree of the accelerometer signal is greatly reduced, and the accurate layer counting in the warhead penetration process is effectively realized.

[0064] The damping self-adaptive control method and structure of the acceleration sensor according to the embodiment of the application can realize controllable change of the current size, so as to control the size of the electrostatic force, achieve the purpose of controllable change of the damping, realize reduction of the signal adhesion degree, and be beneficial to accurate layer counting in the warhead penetration process and improve the accuracy of the burst point.

[0065] The above detailed description of the specific embodiments of the present application makes further explanation of the purpose, technical solutions and beneficial effects of the present application, and it should be understood that the above description is only for specific embodiments of the present application and is not used to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of adaptive structure control with damping for an acceleration sensor, characterized by: The damping self-adaptive structure of the acceleration sensor comprises a damping controller, a piezoresistor, an acceleration sensor mass block, a mass block back electrode plate, an acceleration sensor support, a lower support silicon substrate and a lower silicon substrate surface electrode plate; The mass block back electrode plate and the lower silicon substrate surface electrode plate are respectively located between the acceleration sensor mass block and the lower support silicon substrate, face each other and are connected with the damping controller by wires respectively; the piezoresistor is arranged at the root of the cantilever beam of the acceleration sensor support; and the acceleration sensor support and the lower support silicon substrate are connected by bonding. The damping self-adaptive control method of the acceleration sensor comprises the following steps, Step 1: setting the output electrical signal of the sensor as x and introducing it into the damping controller; Step 2: initializing the algorithm, identifying the application scenario and determining the trigger threshold a and the event termination threshold b according to the event; Step 3: when the output signal x of the acceleration sensor is greater than a, the control trigger is set to 1 at this time, and when it is not greater than a, it is not processed and the next determination process is entered; Step 4: when the output signal x of the acceleration sensor is less than b, the control trigger is set to 0 at this time, and when it is not less than b, it is not processed and the next determination process is entered; Step 5: determining whether the control trigger is set to 1, and when it is set to 1, the feedback control is started, the damping controller output signal controls the relative electrode plate on the acceleration sensor to generate damping force, so that the sensor returns to the initial state, and when it is not set to 1, the control is not performed, and after the control process is completed, the sensor returns to the initial state, reduces the signal sticking when multiple impacts occur, realizes accurate layer counting and improves the accuracy of the burst point.

2. The method of claim 1, wherein: The damping controller controls the size of the damping force generated between the electrode plates in cooperation with the damping self-adaptive control method.

3. A method of adaptive damping structure control of an acceleration sensor as claimed in claim 2, characterized in that: The piezoresistor is a signal collection element of the acceleration sensor and is used for detecting acceleration.

4. A method of adaptive damping structure control of an acceleration sensor as claimed in claim 3, characterized in that: The acceleration sensor mass block is a sensitive element of the acceleration sensor and is used for amplifying the input signal of the sensor to facilitate the detection of the sensor.

5. A method of adaptive damping structure control of an acceleration sensor as claimed in claim 4, characterized in that: The acceleration sensor support and the lower support silicon substrate are a support part of an integral structure and are used for structural support.

6. A method of adaptive damping structure control of an acceleration sensor as claimed in claim 5, characterized in that: The mass block back electrode plate and the lower silicon substrate surface electrode plate are low-resistivity elements, are located between the sensitive element and the substrate of the acceleration sensor, face each other and jointly constitute a damping generation device of the damping self-adaptive control structure, and are used for limiting the movement of the sensitive element and shortening the response time.

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