CN100465651C

CN100465651C - Resonant sensor control system with intermittent operation mode

Info

Publication number: CN100465651C
Application number: CNB200710063638XA
Authority: CN
Inventors: 樊尚春; 蔡晨光; 邢维巍
Original assignee: Beihang University
Current assignee: Beihang University
Priority date: 2007-02-07
Filing date: 2007-02-07
Publication date: 2009-03-04
Anticipated expiration: 2027-02-07
Also published as: CN101034115A

Abstract

This invention relates to a resonator transducer/sensor control system adopting intermittent service way. The invention includes preamplifier, frequency detector, controller and pumping signal generator. Pick-up component output signal transit preamplifier for magnifying, and by frequency detector to measure the frequency. Controller control pumping signal generator to create pumping signal; pumping signal adopts chirp signal; sensitivity structural resonator vibrate under stimulation of chirp signal, while controller control pumping signal disconnection, resonator get in free vibration state, and its vibration frequency is inherent rate of resonator. while pumping signal disconnection, controller control frequency detector to detect output signal frequency of pick-up component, thereby realize measuring of measured signal. The stimulating element in sensitivity structure and pick-up component could be one same component. This invention solves the problem that output signal of resonator transducer/sensor sensitivity structure is rather faint while adopting singleness frequency signal as stimulation.

Description

Adopt the resonant sensor control system of intermittent duty

Technical field

The present invention relates to resonant sensor control system, particularly a kind of resonant sensor control system that adopts intermittent duty.

Background technology

Resonant transducer is under measured effect, and the natural frequency of the resonator of its sensitive structure changes, and can record measured value by the natural frequency of measuring resonator.Performance index such as the repeatability of resonant transducer, resolving power and stability are suitable for the measurement as multiple parameters such as pressure, acceleration, power, density.

Usually the sensitive structure of resonant transducer needs and closed-loop system are in conjunction with working, common closed-loop system comprises amplitude controlling unit and phase shift link, amplitude controller is used for regulating the gain of whole closed loop, to satisfy the amplitude conditions of resonant transducer self-excitation closed loop, the phase shift link is used for regulating the phase shift of whole closed loop, to satisfy the phase condition of resonant transducer self-excitation closed loop.

Thereby the pick-up signal of resonant transducer can be subjected to the signal to noise ratio (S/N ratio) step-down that the interference of its pumping signal makes its pick-up signal, make that the pick-up signal is difficult for measuring, ' having proposed a kind of " Burst " technology among " Burst " Technology with Feedback-Loop Control for CapacitiveDetection and Electrostatic Excitation of Resonant Silicon Sensors ' is used for addressing this problem at article for people such as Thierry Corman 1999, employing timesharing excitation, the method that timesharing detects realizes the closed loop of resonant transducer, in this scheme, adopt single-frequency signals to come stimulus sensor, the problem of this method is that the intensity of sensitive structure output signal will be very faint when the natural frequency of the resonator of excitation frequency off-resonance formula transducer sensitive structure is too many.The theoretic frequency characteristic of resonator as shown in Figure 2, from the amplitude versus frequency characte of resonator as can be seen, when the natural frequency of pumping signal off-resonance device was too many, the gain of resonator was much lower with respect to the gain of its natural frequency correspondence.When the intensity of resonator output signal is very faint, testing circuit can't record the output signal of resonator.

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome the deficiencies in the prior art, a kind of resonant sensor control system that adopts intermittent duty is provided, when having solved the excitation of employing single-frequency signals, the problem that the resonant transducer sensitive structure output signal is fainter.

Technical solution of the present invention: the resonant sensor control system that adopts intermittent duty, its characteristics are: comprise prime amplifier, frequency detector, controller and excitation signal generator, controller control excitation signal generator produces pumping signal, pumping signal adopts linear FM signal, the excitation of the resonator Linear Frequency Modulation signal of sensitive structure is vibration down, after controller control pumping signal disconnects, resonator is in the free vibration state, its vibration frequency is the natural frequency of resonator, after pumping signal disconnects certain hour, controller controlled frequency detecting device detects through the pick-up element output signal frequency after the prime amplifier amplification, record the natural frequency of resonator, thereby realize measurement measured signal.

Principle of the present invention: the present invention has adopted the pumping signal of linear FM signal as resonant transducer sensitive structure.Linear FM signal concentrates on its initial frequency comparatively uniformly and stops the signal in the frequency band between the frequency at a kind of power, under the excitation of the resonator Linear Frequency Modulation signal of resonant transducer sensitive structure, the power of resonator vibrates also concentrates in this frequency band.When comprising the natural frequency of resonator in the frequency band as the linear FM signal of pumping signal, the vibration signal of resonator also comprises the component of signal on its natural frequency point, the vibration signal of resonator is also stronger, and when departing from single-frequency signals with the resonator natural frequency as pumping signal, the vibration signal of resonator a little less than.After the pumping signal that acts on resonant transducer sensitive structure disconnects, resonator will be done free vibration with its natural frequency, by measuring the vibration signal frequency under the resonator free vibration state, can record the natural frequency of resonator, thereby realize measured measurement.

The present invention's advantage compared with prior art: because the present invention has adopted the pumping signal of linear FM signal as resonant transducer sensitive structure, relatively and the single-frequency signals of the resonator of off-resonance formula transducer sensitive structure as pumping signal, effectively raise the intensity of resonant transducer sensitive structure output signal.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Fig. 2 is the theoretic frequency performance diagram of resonant transducer of the present invention, and wherein Fig. 2 a is amplitude-versus-frequency curve figure, and Fig. 2 b is the phase-frequency characteristic curve map;

The structural representation of the sensory-control system when Fig. 3 is same element for the exciting element in the sensitive structure of the present invention and pick-up element.

Embodiment

As shown in Figure 1, the sensory-control system 2 of the discontinuous operation method of resonant transducer is by prime amplifier 6, frequency detector 5, controller 4 and excitation signal generator 3 are formed, the signal of pick-up element 7 outputs of sensitive structure 1 amplifies through prime amplifier 6, record pick-up element 7 output signal frequency by frequency detector 5, controller 4 control excitation signal generators 3 produce pumping signal, pumping signal adopts linear FM signal, the excitation of the resonator 8 Linear Frequency Modulation signals of sensitive structure 1 is vibration down, after controller 4 control pumping signals disconnect, resonator 8 is in the free vibration state, its vibration frequency is the natural frequency of resonator, after pumping signal disconnects, controller 4 controlled frequency detecting devices 5 detect pick-up element 7 output signal frequency, record the natural frequency of resonator 8.

As shown in Figure 3, when exciting element 9 in the sensitive structure 1 and pick-up element 7 are same element, when promptly encouraging pick-up element 10, adopt change-over switch 11 to switch, when needs encourage the sensitive structure 1 of resonant transducer, controller 4 control its switch 11 are connected excitation signal generator 3, and the signal of excitation signal generator 3 outputs is through the excitation pick-up element 10 in the change-over switch 11 excitation sensitive structures 1; After pumping signal was finished, controller 4 control its switch 11 were connected prime amplifier 6, and the signal of excitation pick-up element 10 outputs is detected by frequency detector 5 behind prime amplifier 6, records the natural frequency of resonator 8.

Above-mentioned excitation signal generator 3 is realized that by the DDS chip DDS chip can adopt the serial DDS chip of ADI company, as AD9852 etc.

Frequency detector 5 can be realized by analog-digital converter or microprocessor, and for example: the AD7671 that analog-digital converter can ADI company, processor can adopt single-chip microcomputer C8051F120 or digital signal processor TMS3206713.

Controller 4 can be selected digital signal processor DSP or chip microcontroller for use, for example: processors such as TMS3206713, C8051F120.

Change-over switch 11 can adopt analog switch or relay to realize.

Prime amplifier 6 is by the characteristics design according to the pick-up element 7 of sensitive structure 1 or excitation pick-up element 10.When pick-up element 7, when excitation pick-up element 10 is resistance, can realize by operational amplifier, the selection of operational amplifier will be considered the own noise of bandwidth, operational amplifier and the direct current biasing of sensor vibration signal, assurance can be good the feeble signal of realization sensor output and the amplification of the pumping signal that sensor needs, specifically can select operational amplifiers such as OPA627, OPA228, LT1028 for use.

Claims

1, adopt the resonant sensor control system of intermittent duty, it is characterized in that: comprise prime amplifier (6), frequency detector (5), controller (4) and excitation signal generator (3), the signal of pick-up element (7) output of sensitive structure (1) amplifies through prime amplifier (6), record pick-up element (7) output signal frequency by frequency detector (5), controller (4) control excitation signal generator (3) produces pumping signal, pumping signal adopts linear FM signal, the excitation of resonator (8) the Linear Frequency Modulation signal of sensitive structure (1) is vibration down, after controller (4) control pumping signal disconnects, resonator (8) is in the free vibration state, its vibration frequency is the natural frequency of resonator, after pumping signal disconnects, controller (4) controlled frequency detecting device (5) detects pick-up element (7) output signal frequency, records the natural frequency of resonator (8).

2, the resonant sensor control system of employing intermittent duty according to claim 1, it is characterized in that: exciting element (9) in the described sensitive structure (1) and pick-up element (7) are during for same element, when promptly encouraging pick-up element (10), adopt change-over switch (11) to switch, when needs encourage the sensitive structure (11) of resonant transducer, controller (4) control is changed switch (11) and is connected excitation signal generator (3), and the signal of excitation signal generator (3) output is through the excitation pick-up element (10) in change-over switch (11) the excitation sensitive structure (1); After pumping signal was finished, controller (4) control was changed switch (9) and is connected prime amplifier (6), and the signal of excitation pick-up element (10) output is detected by frequency detector (5) behind prime amplifier (6), records the natural frequency of resonator (8).