WO2011111180A1 - Capteur de quantité physique et procédé de mesure de quantité physique - Google Patents

Capteur de quantité physique et procédé de mesure de quantité physique Download PDF

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Publication number
WO2011111180A1
WO2011111180A1 PCT/JP2010/053966 JP2010053966W WO2011111180A1 WO 2011111180 A1 WO2011111180 A1 WO 2011111180A1 JP 2010053966 W JP2010053966 W JP 2010053966W WO 2011111180 A1 WO2011111180 A1 WO 2011111180A1
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Prior art keywords
period
physical quantity
oscillation
semiconductor laser
interference
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PCT/JP2010/053966
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English (en)
Japanese (ja)
Inventor
達也 上野
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株式会社山武
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Priority to PCT/JP2010/053966 priority Critical patent/WO2011111180A1/fr
Publication of WO2011111180A1 publication Critical patent/WO2011111180A1/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/491—Details of non-pulse systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G01S17/08—Systems determining position data of a target for measuring distance only
    • G01S17/32—Systems determining position data of a target for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated
    • G01S17/34—Systems determining position data of a target for measuring distance only using transmission of continuous waves, whether amplitude-, frequency-, or phase-modulated, or unmodulated using transmission of continuous, frequency-modulated waves while heterodyning the received signal, or a signal derived therefrom, with a locally-generated signal related to the contemporaneously transmitted signal
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/50—Systems of measurement based on relative movement of target
    • G01S17/58—Velocity or trajectory determination systems; Sense-of-movement determination systems
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/491—Details of non-pulse systems
    • G01S7/4912—Receivers
    • G01S7/4916—Receivers using self-mixing in the laser cavity

Definitions

  • the present invention relates to a physical quantity sensor and a physical quantity measurement method for measuring a physical quantity such as a distance to an object and a speed of an object from information on interference caused by a self-coupling effect between laser light emitted from a semiconductor laser and return light from the object. Is.
  • FIG. 11 shows a composite resonator model of an FP type (Fabry-Perot type) semiconductor laser.
  • FP type Fabry-Perot type
  • FIG. 12 is a diagram showing the relationship between the oscillation wavelength and the output waveform of the photodiode 103 when the oscillation wavelength of the semiconductor laser is changed at a certain rate.
  • MHP is a phenomenon different from the mode hopping phenomenon. For example, if the number of MHPs is 10 when the distance to the measurement object 104 is L1, the number of MHPs is 5 at half the distance L2. That is, when the oscillation wavelength of the semiconductor laser is changed for a certain time, the number of MHPs changes in proportion to the measurement distance. Therefore, if the MHP is detected by the photodiode 103 and the frequency of the MHP is measured, the distance can be easily measured.
  • conventional interferometric instruments including self-coupled instruments, have the problem that they can measure the distance to a stationary measurement object, but cannot measure the distance of a measurement object with speed. .
  • the distance / speed meter of FIG. 13 condenses the light from the semiconductor laser 201 that emits laser light to the object to be measured, the photodiode 202 that converts the optical output of the semiconductor laser 201 into an electrical signal, and the light from the semiconductor laser 201.
  • a lens 203 that irradiates the measurement target 210 and collects return light from the measurement target 210 and makes it incident on the semiconductor laser 201.
  • a laser driver 204 that alternately repeats a second oscillation period in which the current continuously decreases, a current-voltage conversion amplifier 205 that converts and amplifies the output current of the photodiode 202 into a voltage, and a current-voltage conversion amplifier 205
  • Signal extraction circuit 206 that differentiates the output voltage of the signal twice and a counting circuit that counts the number of MHPs included in the output voltage of the signal extraction circuit 206 With a 07, a calculation unit 208 for calculating the distance and speed of the measurement target 210 to the measurement target 210, and a display device 209 for displaying the calculation result of the arithmetic unit 208.
  • the laser driver 204 supplies a triangular wave drive current that repeatedly increases and decreases at a constant change rate with respect to time to the semiconductor laser 201 as an injection current. Accordingly, the semiconductor laser 201 alternately repeats the first oscillation period in which the oscillation wavelength continuously increases at a constant change rate and the second oscillation period in which the oscillation wavelength continuously decreases at a constant change rate.
  • FIG. 14 is a diagram showing the change over time of the oscillation wavelength of the semiconductor laser 201.
  • P1 is the first oscillation period
  • P2 is the second oscillation period
  • ⁇ a is the minimum value of the oscillation wavelength in each period
  • ⁇ b is the maximum value of the oscillation wavelength in each period
  • Tt is the period of the triangular wave.
  • the laser light emitted from the semiconductor laser 201 is collected by the lens 203 and enters the measurement object 210.
  • the light reflected by the measurement object 210 is collected by the lens 203 and enters the semiconductor laser 201.
  • the photodiode 202 converts the optical output of the semiconductor laser 201 into a current.
  • the current-voltage conversion amplifier 205 converts the output current of the photodiode 202 into a voltage and amplifies it, and the signal extraction circuit 206 differentiates the output voltage of the current-voltage conversion amplifier 205 twice.
  • the counting circuit 207 counts the number of MHPs included in the output voltage of the signal extraction circuit 206 for each of the first oscillation period P1 and the second oscillation period P2.
  • the arithmetic unit 208 determines the distance from the measurement object 210 based on the minimum oscillation wavelength ⁇ a and the maximum oscillation wavelength ⁇ b of the semiconductor laser 1, the number of MHPs in the first oscillation period P1, and the number of MHPs in the second oscillation period P2. And the speed of the measuring object 210 is calculated.
  • FIG. 15 is a diagram for explaining a problem of the conventional self-coupled laser measuring instrument, and is a diagram showing a change over time in the counting result of the counting circuit 207.
  • Nu is the counting result of the first oscillation period P1
  • Nd is the counting result of the second oscillation period P2.
  • the time change of the counting result Nu becomes a shape in which the negative waveform shown by 150 in FIG.
  • the time change of the counting result Nd takes a form in which the negative waveform indicated by 151 in FIG. 15 is folded back to the positive side.
  • an error may occur in the counting result, and a physical quantity such as a distance or a speed may be erroneously calculated.
  • the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a physical quantity sensor and a physical quantity measuring method capable of reducing the possibility of erroneous calculation of physical quantities.
  • the physical quantity sensor of the present invention includes at least a semiconductor laser that emits laser light to a measurement target, a first oscillation period that includes at least a period in which the oscillation wavelength continuously increases monotonously, and a period in which the oscillation wavelength continuously decreases monotonously.
  • Oscillation wavelength modulation means for operating the semiconductor laser so that the second oscillation period including it alternately exists, and a self-coupling effect between the laser light emitted from the semiconductor laser and the return light from the measurement target
  • Detection means for detecting an electrical signal including an interference waveform, measurement means for measuring the physical quantity of the measurement target from information on the interference waveform included in the output signal of the detection means, and a carrier wave for modulation of oscillation wavelength of the semiconductor laser
  • an adjusting means capable of adjusting the amplitude or frequency.
  • the measurement unit may calculate the number of the interference waveforms included in the output signal of the detection unit for each of the first oscillation period and the second oscillation period.
  • At least the distance from the measurement object and the speed of the measurement object from the signal extraction means to count, the minimum oscillation wavelength and the maximum oscillation wavelength in the period of counting the number of interference waveforms by the signal extraction means, and the counting result of the signal extraction means It is characterized by comprising computing means for calculating one of them.
  • the adjustment unit may be an average of a period of the interference waveform when the measurement object is stationary or a period of a predetermined number of interference waveforms measured immediately before the adjustment. Is characterized by adjusting the amplitude or frequency of the carrier wave so as to have a predetermined period. Further, in one configuration example of the physical quantity sensor of the present invention, the adjustment unit is configured such that the number of the interference waveforms in the first oscillation period and the number of the interference waveforms in the second oscillation period are substantially the same. The amplitude or frequency of the carrier wave is adjusted so that the period of the interference waveform at this time becomes a predetermined period.
  • the adjusting means calculates the average value of the number of interference waveforms, thereby calculating the number of interference waveforms proportional to the average distance between the semiconductor laser and the measurement target.
  • a distance proportional number calculating means for obtaining a certain distance proportional number, a period calculating means for calculating the period of the interference waveform from the distance proportional number, and a period calculated by the period calculating means to be a predetermined period. It comprises carrier wave adjusting means for adjusting the amplitude or frequency of the carrier wave.
  • the predetermined period is a period corresponding to a value that is 1 ⁇ 2 of the maximum frequency of the interference waveform that can be processed by the physical quantity sensor. It is what.
  • the first oscillation period including at least a period in which the oscillation wavelength continuously increases monotonously and the second oscillation period including at least a period in which the oscillation wavelength continuously decreases monotonically are alternated.
  • An oscillation procedure for operating the semiconductor laser to exist in a detection procedure, and a detection procedure for detecting an electrical signal including an interference waveform caused by a self-coupling effect between the laser light emitted from the semiconductor laser and the return light from the measurement object From the interference waveform information contained in the output signal obtained by this detection procedure, it is possible to adjust the measurement procedure for measuring the physical quantity of the measurement target and the amplitude or frequency of the oscillation wavelength modulation carrier wave of the semiconductor laser And an adjustment procedure.
  • an adjustment means capable of adjusting the amplitude or frequency of the carrier wave of the oscillation wavelength modulation of the semiconductor laser, it is possible to reduce the possibility that the interference waveform count result will be folded, The possibility of miscalculating physical quantities such as distance and speed can be reduced.
  • FIG. 4 is a waveform diagram schematically showing an output voltage waveform of a current-voltage conversion amplification unit and an output voltage waveform of a filter unit in the first embodiment of the present invention. It is a block diagram which shows an example of a structure of the calculating part in the 1st Embodiment of this invention. It is a flowchart which shows operation
  • FIG. 1 is a block diagram showing a configuration of a physical quantity sensor according to the first embodiment of the present invention.
  • the physical quantity sensor in FIG. 1 condenses the light from the semiconductor laser 1 that emits laser light to the object 10 to be measured, the photodiode 2 that converts the light output of the semiconductor laser 1 into an electrical signal, and the light from the semiconductor laser 1.
  • the lens 3 that collects the return light from the object 10 and makes it incident on the semiconductor laser 1, the laser driver 4 that serves as an oscillation wavelength modulation means for driving the semiconductor laser 1, and the output current of the photodiode 2
  • a current-voltage conversion amplification unit 5 that converts and amplifies the voltage
  • a filter unit 6 that removes a carrier wave from the output voltage of the current-voltage conversion amplification unit 5, and a self-coupled signal included in the output voltage of the filter unit 6
  • a signal extraction unit 7 that counts the number of mode hop pulses (hereinafter referred to as MHP), a calculation unit 8 that calculates the distance to the object 10 and the speed of the object 10 from the number of MHPs, and a calculation unit 8
  • a calculation result display unit 9 for displaying, and an adjustment section 11 capable of adjusting the amplitude or frequency of the oscillation wavelength modulation of a carrier of the semiconductor laser 1.
  • the photodiode 2 and the current-voltage conversion amplification unit 5 constitute detection means, and the signal extraction unit 7 and the calculation unit 8 constitute measurement means.
  • a semiconductor laser 1 of a type that does not have a mode hopping phenomenon VCSEL type, DFB laser type
  • the laser driver 4 supplies the semiconductor laser 1 with a triangular wave drive current that repeatedly increases and decreases at a constant rate of change as an injection current.
  • the semiconductor laser 1 has a first oscillation period P1 in which the oscillation wavelength continuously increases at a constant change rate in proportion to the magnitude of the injection current, and the oscillation wavelength continuously decreases at a constant change rate. It is driven to alternately repeat the second oscillation period P2.
  • the time change of the oscillation wavelength of the semiconductor laser 1 at this time is as shown in FIG.
  • the maximum value ⁇ b of the oscillation wavelength and the minimum value ⁇ a of the oscillation wavelength are always constant, and the difference ⁇ b ⁇ a is also always constant.
  • the laser light emitted from the semiconductor laser 1 is condensed by the lens 3 and enters the object 10.
  • the light reflected by the object 10 is collected by the lens 3 and enters the semiconductor laser 1.
  • condensing by the lens 3 is not essential.
  • the photodiode 2 is disposed in the semiconductor laser 1 or in the vicinity thereof, and converts the optical output of the semiconductor laser 1 into a current.
  • the current-voltage conversion amplification unit 5 converts the output current of the photodiode 2 into a voltage and amplifies it.
  • the filter unit 6 has a function of extracting a superimposed signal from the modulated wave.
  • FIG. 2A is a diagram schematically showing an output voltage waveform of the current-voltage conversion amplification unit 5
  • FIG. 2B is a diagram schematically showing an output voltage waveform of the filter unit 6.
  • the signal extraction unit 7 counts the number of MHPs included in the output of the filter unit 6 for each of the first oscillation period P1 and the second oscillation period P2.
  • the signal extraction unit 7 may use a counter composed of logic gates, or may measure the frequency of MHP (that is, the number of MHPs per unit time) using FFT (Fast Fourier Transform).
  • the calculation unit 8 calculates the distance to the object 10 and the speed of the object 10 based on the minimum oscillation wavelength ⁇ a and the maximum oscillation wavelength ⁇ b of the semiconductor laser 1 and the number of MHPs counted by the signal extraction unit 7.
  • FIG. 3 is a block diagram showing an example of the configuration of the calculation unit 8
  • FIG. 4 is a flowchart showing the operation of the calculation unit 8.
  • the calculation unit 8 calculates a distance / speed calculation unit that calculates a candidate value for the distance to the object 10 and a candidate value for the speed of the object 10 based on the minimum oscillation wavelength ⁇ a, the maximum oscillation wavelength ⁇ b, and the number of MHPs of the semiconductor laser 1.
  • a history displacement calculation unit 81 that calculates a history displacement that is a difference between the distance candidate value calculated by the distance / speed calculation unit 80 and the distance candidate value calculated immediately before, and a distance / speed calculation unit 80
  • a storage unit 82 that stores the calculation results of the history displacement calculation unit 81
  • a state determination unit 83 that determines the state of the object 10 based on the calculation results of the distance / speed calculation unit 80 and the history displacement calculation unit 81
  • the distance / speed determination unit 84 determines the distance to the object 10 and the speed of the object 10 based on the determination result of the unit 83.
  • the state of the object 10 is either a minute displacement state that satisfies a predetermined condition or a displacement state that moves more than the minute displacement state.
  • the minute displacement state is a state satisfying ( ⁇ b ⁇ a) / ⁇ b> V / Lb (where Lb is time (distance at time t), the displacement state is a state satisfying ( ⁇ b ⁇ a) / ⁇ b ⁇ V / Lb.
  • the distance / speed calculation unit 80 of the calculation unit 8 calculates the distance candidate values L ⁇ (t) and L ⁇ (t) and the speed candidate values V ⁇ (t) and V ⁇ (t) at the current time t as follows: And stored in the storage unit 82 (step S10 in FIG. 4).
  • MHP (t) is the number of MHPs calculated at the current time t
  • MHP (t ⁇ 1) is the number of MHPs calculated one time before MHP (t). is there.
  • MHP (t) is the counting result of the first oscillation period P1
  • MHP (t ⁇ 1) is the counting result of the second oscillation period P2
  • MHP (t) is the second counting period. If the result is the counting result of the oscillation period P2, the MHP (t ⁇ 1) is the counting result of the first oscillation period P1.
  • the candidate values L ⁇ (t) and V ⁇ (t) are values calculated on the assumption that the object 10 is in a minute displacement state, and the candidate values L ⁇ (t) and V ⁇ (t) are obtained when the object 10 is in a displacement state. This is a calculated value.
  • the calculation unit 8 performs calculations of Expressions (2) to (5) at each time (every oscillation period) when the number of MHPs is measured by the signal extraction unit 7.
  • the history displacement calculation unit 81 of the calculation unit 8 for each of the minute displacement state and the displacement state, the distance candidate value at the current time t and the distance candidate value at the previous time stored in the storage unit 82 is calculated as follows and stored in the storage unit 82 (step S11 in FIG. 4).
  • the candidate distance values calculated one time before the current time t are L ⁇ (t ⁇ 1) and L ⁇ (t ⁇ 1).
  • the history displacement Vcal ⁇ (t) is a value calculated on the assumption that the object 10 is in a minute displacement state
  • the history displacement Vcal ⁇ (t) is a value calculated on the assumption that the object 10 is in a displacement state.
  • the calculation unit 8 performs the calculations of Expressions (6) to (7) at each time when the number of MHPs is measured by the signal extraction unit 7. In the equations (4) to (7), the direction in which the object 10 approaches the distance / velocity meter of this embodiment is defined as a positive velocity, and the direction in which the object 10 moves away is defined as a negative velocity.
  • the state determination unit 83 of the calculation unit 8 determines the state of the object 10 using the calculation results of the expressions (2) to (7) stored in the storage unit 82 (step S12 in FIG. 4).
  • the state determination unit 83 has a constant sign of the history displacement Vcal ⁇ (t) calculated on the assumption that the object 10 is in a minute displacement state, and the object 10 is in a minute displacement state. If the velocity candidate value V ⁇ (t) calculated on the assumption that the velocity is equal to the average value of the absolute values of the history displacement Vcal ⁇ (t) is equal, it is determined that the object 10 is moving at a constant velocity in a minute displacement state. .
  • the state determination unit 83 has a constant sign of the history displacement Vcal ⁇ (t) calculated on the assumption that the object 10 is in the displacement state, and the object 10 is in the displacement state. If the velocity candidate value V ⁇ (t) calculated on the assumption that the average displacement is equal to the absolute value of the absolute value of the history displacement Vcal ⁇ (t), it is determined that the object 10 is moving at a constant velocity in the displacement state.
  • the state determination unit 83 measures the number of MHPs with the sign of the history displacement Vcal ⁇ (t) calculated on the assumption that the object 10 is in a minute displacement state.
  • the object 10 is It is determined that a movement other than a constant speed movement is performed in a minute displacement state.
  • the state determination unit 83 assumes that the absolute value of the velocity candidate value V ⁇ (t) calculated on the assumption that the object 10 is in the displacement state is equal to the wavelength change rate, and that the object 10 is in the minute displacement state. If the velocity candidate value V ⁇ (t) calculated in this way and the average value of the absolute values of the history displacement Vcal ⁇ (t) do not match, it is determined that the object 10 is moving in a minute displacement state other than the constant velocity motion. May be.
  • the state determination unit 83 calculates the number of MHPs at which the sign of the history displacement Vcal ⁇ (t) calculated on the assumption that the object 10 is in the displacement state is measured.
  • the velocity candidate value V ⁇ (t) calculated on the assumption that the object 10 is in the displacement state does not match the average value of the absolute values of the history displacement Vcal ⁇ (t)
  • the object 10 is in the displacement state. It is determined that the person is exercising other than the uniform speed movement.
  • the state determination unit 83 assumes that the absolute value of the velocity candidate value V ⁇ (t) calculated on the assumption that the object 10 is in the minute displacement state is equal to the wavelength change rate, and that the object 10 is in the displacement state. If the calculated velocity candidate value V ⁇ (t) and the average value of the history displacement Vcal ⁇ (t) do not coincide with each other, it is determined that the object 10 is moving in a displaced state other than the uniform velocity motion. May be.
  • the distance / speed determination unit 84 of the calculation unit 8 determines the speed of the object 10 and the distance to the object 10 based on the determination result of the state determination unit 83 (step S13 in FIG. 4). That is, when it is determined that the object 10 is moving at a constant speed in a minute displacement state, the distance / speed determining unit 84 sets the speed candidate value V ⁇ (t) as the speed of the object 10 and uses the distance candidate value L ⁇ ( t) is a distance from the object 10, and when it is determined that the object 10 is moving at a constant speed in a displaced state, the velocity candidate value V ⁇ (t) is the velocity of the object 10, and the distance candidate value L ⁇ (t ) Is the distance to the object 10.
  • the distance / speed determination unit 84 determines that the object 10 is moving in a minute displacement state other than the constant speed movement, the distance / speed determination unit 84 sets the speed candidate value V ⁇ (t) as the speed of the object 10 and sets the distance
  • the candidate value L ⁇ (t) is set as the distance from the object 10.
  • the actual distance is an average value of the distance candidate values L ⁇ (t).
  • the distance / speed determination unit 84 sets the speed candidate value V ⁇ (t) as the speed of the object 10 and uses the distance candidate.
  • the value L ⁇ (t) is the distance from the object 10.
  • the actual distance is an average value of the distance candidate values L ⁇ (t).
  • V ⁇ (t) is always a positive value and V ⁇ (t) is either a positive value or a negative value due to the magnitude relationship between MHP (t ⁇ 1) and MHP (t). It is not a representation of 10 speed directions.
  • the speed of the object 10 is positive (direction approaching the laser).
  • the calculation unit 8 performs the processing of steps S10 to S13 at every time (every oscillation period) when the number of MHPs is measured by the signal extraction unit 7.
  • the display unit 9 displays the distance to the object 10 and the speed of the object 10 calculated by the calculation unit 8 in real time.
  • FIG. 5 is a block diagram illustrating a configuration example of the adjustment unit 11.
  • the adjustment unit 11 includes a binarization unit 110, a period measurement unit 111, and a carrier wave adjustment unit 112.
  • FIGS. 6A to 6D are diagrams for explaining the operation of the adjusting unit 11, and FIG. 6A schematically shows the waveform of the output voltage of the filter unit 6, that is, the waveform of MHP.
  • 6B is a diagram illustrating an output of the binarization unit 110 corresponding to FIG. 6A
  • FIG. 6C is a diagram illustrating a sampling clock CLK input to the adjustment unit 11
  • FIG. 6D is a diagram illustrating a measurement result of the period measurement unit 111 corresponding to FIG.
  • the binarization unit 110 of the adjustment unit 11 determines whether the output voltage of the filter unit 6 illustrated in FIG. 6A is a high level (H) or a low level (L), and the binarization unit 110 illustrated in FIG. Such a determination result is output. At this time, the binarizing unit 110 determines that the output voltage of the filter unit 6 is high level when the output voltage of the filter unit 6 increases to be equal to or higher than the threshold value TH1, and the output voltage of the filter unit 6 decreases to decrease the threshold value TH2. By determining that the level is low when (TH2 ⁇ TH1) or less, the output of the filter unit 6 is binarized.
  • the cycle measuring unit 111 measures the cycle of the rising edge of the output of the binarizing unit 110 (that is, the MHP cycle) every time a rising edge occurs. At this time, the period measuring unit 111 measures the MHP period with the period of the sampling clock CLK shown in FIG. 6C as one unit. In the example of FIG. 6D, the period measurement unit 111 sequentially measures T ⁇ , T ⁇ , and T ⁇ as the MHP period. As is apparent from FIGS. 6C and 6D, the sizes of the periods T ⁇ , T ⁇ , and T ⁇ are 5 [samplings], 4 [samplings], and 2 [samplings], respectively. The frequency of the sampling clock CLK is assumed to be sufficiently higher than the highest frequency that the MHP can take.
  • the carrier wave adjustment unit 112 at the time of initial setting when the object 10 is stationary, for example, according to a carrier wave adjustment instruction signal input from an operator, the period T0 in which the MHP cycle T measured by the cycle measurement unit 111 is defined in advance.
  • the amplitude of the triangular wave drive current (the amplitude of the carrier wave) is adjusted through the laser driver 4.
  • the maximum frequency fmax of the MHP that can be processed by the physical quantity sensor is determined by a circuit of the physical quantity sensor (for example, an operational amplifier included in the current-voltage conversion amplification unit 5).
  • FIG. 7 is a diagram for explaining a method of adjusting the amplitude of the triangular wave drive current supplied from the laser driver 4 to the semiconductor laser 1.
  • the laser driver 4 drives the maximum drive current while fixing the maximum value to a constant value (in the example of FIG. 7, the upper limit CL of the drive current defined by the semiconductor laser 1).
  • the amplitude AMP of the drive current is adjusted by increasing or decreasing the minimum value of the current. In this way, the amplitude of the drive current can be adjusted.
  • the measurement dynamic range related to the speed of the object 10 can be maximized by setting the cycle of the measured MHP to a predetermined cycle T0, and the signal extraction unit 7
  • the possibility that aliasing will occur in the counting result can be reduced, and the possibility of miscalculating physical quantities such as distance and speed can be reduced.
  • the carrier wave adjustment unit 112 adjusts the frequency of the triangular wave drive current (carrier wave frequency) through the laser driver 4 so that the MHP cycle T measured by the cycle measurement unit 111 becomes a predetermined cycle T0. Good.
  • the period T of the MHP used for adjustment is the period when the object 10 is stationary.
  • the present invention is not limited to this, and a predetermined number of MHPs measured immediately before the adjustment are used.
  • the amplitude or frequency of the carrier wave may be adjusted using the moving average of the period as the period T. According to this method, even in the case of the object 10 that cannot be stationary, the amplitude or frequency of the carrier wave can be adjusted.
  • the adjustment unit 11 may determine whether the object 10 is stationary based on the count result of the signal extraction unit 7. That is, the carrier wave adjustment unit 112 is configured such that the number of MHPs in the first oscillation period P1 in which the oscillation wavelength of the semiconductor laser 1 increases is substantially the same as the number of MHPs in the second oscillation period P2 in which the oscillation wavelength decreases. It is determined that the object 10 is stationary, and the amplitude or frequency of the triangular wave drive current is adjusted through the laser driver 4 so that the MHP period T measured by the period measurement unit 111 at this time becomes a predetermined period T0. May be. Moreover, in this Embodiment, although both the distance with the object 10 and the speed of the object 10 are measured, it cannot be overemphasized that either one may be measured.
  • FIG. 8 is a block diagram illustrating a configuration example of the adjustment unit 11 according to the present embodiment.
  • the adjustment unit 11 calculates the average value of the count results of the carrier extraction unit 112a, the count result of the signal extraction unit 7, and the count result of the signal extraction unit 7, so that the semiconductor laser 1 and the object 10
  • the distance proportional number calculation unit 114 for obtaining the number of MHPs proportional to the average distance (hereinafter referred to as distance proportional number) NL, the count result of the signal extraction unit 7 one time before, and a past count result from this count result
  • the sign adding unit 115 for adding a positive or negative sign to the latest count result of the signal extraction unit 7 in accordance with the magnitude relationship with the double of the distance proportional number NL calculated by using the distance proportional number NL and the period of MHP from the distance proportional number NL
  • a cycle calculating unit 116 for calculating
  • the count result of the signal extraction unit 7 is stored in the storage unit 113 of the adjustment unit 11.
  • the distance proportional number calculation unit 114 of the adjustment unit 11 obtains the distance proportional number NL from the count result of the signal extraction unit 7.
  • FIG. 9 is a diagram for explaining the operation of the distance proportional number calculation unit 114, and is a diagram illustrating the time change of the counting result of the signal extraction unit 7.
  • Nu is the counting result of the first oscillation period P1
  • Nd is the counting result of the second oscillation period P2.
  • the counting results Nu and Nd are the sum or difference of the distance proportional number NL and the number of MHPs proportional to the displacement of the object 10 (hereinafter referred to as the displacement proportional number) NV.
  • the distance proportional number NL corresponds to the average value of the sine waveform shown in FIG.
  • the difference between the counting result Nu or Nd and the distance proportional number NL corresponds to the displacement proportional number NV.
  • the distance proportional number calculation unit 114 calculates the distance proportional number NL by calculating the average value of the counting results for the even number of times measured up to two times before the current time t as shown in the following equation.
  • N (t-2) represents the number N of MHPs measured two times before the current time t
  • N (t-3) is measured three times before the current time t. This indicates that the number of MHPs is N.
  • the count result N (t) at the current time t is the count result Nu of the first oscillation period P1
  • the count result N (t-2) two times before is also the count result Nu of the first oscillation period P1.
  • the count result N (t ⁇ 3) three times before is the count result Nd in the second oscillation period P2.
  • the count result N (t-2) two times before is also the count result of the second oscillation period P2.
  • Nd, and the count result N (t ⁇ 3) is the count result Nu in the first oscillation period P1.
  • Expression (8) is an expression when the distance proportional number NL is obtained from the count results for two times. However, when the count result of 2m (m is a positive integer) is used, the distance proportional number calculation unit 114 uses the following formula. The distance proportional number NL is calculated as follows.
  • Expressions (8) and (9) are expressions used at the beginning of measurement of the distance to the object 10 and the speed of the object 10, and from the middle, a signed count result described later is used instead of Expression (8).
  • the distance proportional number NL is calculated from the equation.
  • N ′ (t ⁇ 2) is a count result with a sign obtained after performing a later-described code addition process on the count result N (t ⁇ 2) two times before
  • N ′ (t ⁇ 3) is a count result three times before. This is a signed count result after applying a sign providing process to N (t ⁇ 3).
  • Expression (10) is used after the count result N (t) at the current time t becomes the seventh count result from the start of the measurement of the number of MHPs.
  • the distance proportional number NL is calculated by the following equation using a signed count result instead of the equation (9) from the middle.
  • Expression (11) is used after the count result N (t) at the current time t becomes the (2m ⁇ 2 + 3) th count result from the start of the measurement of the number of MHPs.
  • the distance proportional number NL is stored in the storage unit 113.
  • the distance proportional number calculation unit 114 performs the calculation process of the distance proportional number NL as described above at each time (every oscillation period) when the number of MHPs is measured by the signal extraction unit 7.
  • the distance proportional number NL may be calculated from the odd number of count results.
  • the code assigning unit 115 counts the signal extraction unit 7 according to the magnitude relationship between the count result N (t ⁇ 1) measured one time before the current time t and the multiple 2NL of the distance proportional number NL. A positive or negative sign is assigned to the result N (t). Specifically, the sign assigning unit 115 executes the following expression.
  • the time change of the counting result Nu is that the negative waveform indicated by 150 in FIG.
  • the time change of the counting result Nd becomes a shape in which the negative waveform indicated by 151 in FIG. 15 is folded back to the positive side.
  • the state of the object 10 in the portion where the counting result is folded is defined as the displacement state.
  • the state of the object 10 in the portion where the counting result is not folded is the above-described minute displacement state.
  • Expressions (12) and (13) are expressions for determining whether the object 10 is in a displacement state or a minute displacement state.
  • N (t ⁇ 1) ⁇ 2NL is established in the displacement state in which the counting result is folded. Therefore, as shown in Expression (12), when N (t ⁇ 1) ⁇ 2NL is established, the count result N (t) of the current time t of the signal extraction unit 7 is given a negative sign.
  • the signed count result is N ′ (t).
  • N (t ⁇ 1) ⁇ 2NL is established in the minute displacement state where the counting result is not folded in FIGS. 9 and 15. Therefore, as shown in Equation (13), when N (t ⁇ 1) ⁇ 2NL is satisfied, the count result N (t) at the current time t of the signal extraction unit 7 is given a positive sign.
  • the signed count result is N ′ (t).
  • the signed count result N ′ (t) is stored in the storage unit 113.
  • the code assigning unit 115 performs the above-described code assigning process at each time (every oscillation period) when the number of MHPs is measured by the signal extracting unit 7. It should be noted that the condition for establishing equation (12) may be N (t ⁇ 1)> 2NL, and the condition for establishing equation (13) may be N (t ⁇ 1) ⁇ 2NL.
  • the period calculation unit 116 calculates the MHP period T from the distance proportional number NL as in the following equation.
  • T C / (2 ⁇ f ⁇ NL) (14)
  • f is the frequency of the triangular wave
  • C is the speed of light.
  • the carrier wave adjustment unit 112a may adjust the amplitude or frequency of the triangular wave drive current through the laser driver 4 so that the MHP cycle T calculated by the cycle calculation unit 116 becomes a predetermined cycle T0.
  • the amplitude or frequency of the carrier wave can be adjusted even in the case of the object 10 that cannot be stationary.
  • the present embodiment is effective when the vibration period of the vibrating object 10 is sufficiently slower than the frequency of the carrier wave (for example, 1/10).
  • FIG. 10 is a block diagram showing a configuration of a physical quantity sensor according to the third embodiment of the present invention. The same reference numerals are given to the same configurations as those in FIG.
  • the physical quantity sensor according to the present embodiment uses a voltage detection unit 12 as detection means instead of the photodiode 2 and the current-voltage conversion amplification unit 5 according to the first and second embodiments.
  • the voltage detector 12 detects and amplifies the voltage between the terminals of the semiconductor laser 1, that is, the anode-cathode voltage.
  • the anode-cathode voltage When interference occurs between the laser light emitted from the semiconductor laser 1 and the return light from the object 10, an MHP waveform appears in the voltage between the terminals of the semiconductor laser 1. Therefore, it is possible to extract the MHP waveform from the voltage between the terminals of the semiconductor laser 1.
  • the filter unit 6 removes the carrier wave from the output voltage of the voltage detection unit 12.
  • Other configurations of the physical quantity sensor are the same as those in the first and second embodiments.
  • an MHP waveform can be extracted without using a photodiode, and the physical quantity sensor components can be reduced as compared with the first and second embodiments. The cost can be reduced.
  • no photodiode since no photodiode is used, the influence of disturbance light can be eliminated.
  • At least the signal extraction unit 7, the calculation unit 8, and the adjustment unit 11 are realized by, for example, a computer having a CPU, a memory, and an interface, and a program for controlling these hardware resources. can do.
  • the CPU executes the processes described in the first to third embodiments according to the program stored in the memory.
  • the present invention can be applied to a technique for measuring a physical quantity of an object from information on interference caused by a self-coupling effect between laser light emitted from a semiconductor laser and return light from the object.
  • SYMBOLS 1 Semiconductor laser, 2 ... Photodiode, 3 ... Lens, 4 ... Laser driver, 5 ... Current-voltage conversion amplification part, 6 ... Filter part, 7 ... Signal extraction part, 8 ... Calculation part, 9 ... Display part, 10 ... object, 11 ... adjustment part, 12 ... voltage detection part, 80 ... distance / speed calculation part, 81 ... history displacement calculation part, 82 ... storage part, 83 ... state determination part, 84 ... distance / speed determination part, 110 ... Binarization unit, 111... Period measurement unit, 112, 112a ... carrier wave adjustment unit, 113 ... storage unit, 114 ... distance proportional number calculation unit, 115 ... sign addition unit, 116 ... cycle calculation unit.

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  • Computer Networks & Wireless Communication (AREA)
  • General Physics & Mathematics (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Optical Radar Systems And Details Thereof (AREA)
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Abstract

La présente invention concerne un capteur de quantité physique permettant de diminuer les possibilités de calcul erroné d'une quantité physique, comprenant : un laser à semi-conducteur (1), destiné à irradier un objet (10) avec un faisceau laser; un étage laser (4), destiné à faire fonctionner le laser à semi-conducteur (1) de manière à ce qu'une première période d'oscillation pendant laquelle la longueur d'onde d'oscillation augmente et qu'une seconde période d'oscillation pendant laquelle la longueur d'onde d'oscillation diminue soient alternativement présentes; une photodiode (2) et une unité d'amplification de conversion courant-tension (5), destinées toutes les deux à la détection d'un signal électrique contenant une forme d'onde d'interférence formée par l'effet d'auto-couplage entre le faisceau laser émis depuis le laser à semi-conducteur (1) et le faisceau lumineux renvoyé par l'objet (10); une unité d'extraction de signal (7), destinée au comptage du nombre de formes d'onde d'interférence contenues dans le signal de sortie provenant de l'unité d'amplification de conversion courant-tension (5); une unité de calcul (8), destinée au calcul de la distance de l'objet (10) et de la vitesse de l'objet (10) à partir du nombre de formes d'onde d'interférence; et une unité de réglage (11), capable de régler l'amplitude ou la fréquence de la porteuse pour la modulation de la longueur d'onde d'oscillation du laser à semi-conducteur (1).
PCT/JP2010/053966 2010-03-10 2010-03-10 Capteur de quantité physique et procédé de mesure de quantité physique WO2011111180A1 (fr)

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Publication number Priority date Publication date Assignee Title
US10835607B2 (en) 2015-07-23 2020-11-17 Inimmune Corporation Monoclonal antibody and vaccine targeting filamentous bacteriophage

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JPH1090396A (ja) * 1996-09-20 1998-04-10 Tech Res & Dev Inst Of Japan Def Agency 距離測定方法及び距離測定装置
JPH11326504A (ja) * 1998-05-08 1999-11-26 Toyota Motor Corp Ｆｍ−ｃｗレーダ装置
JP2006313080A (ja) * 2005-05-06 2006-11-16 Yamatake Corp 距離・速度計および距離・速度計測方法
JP2008175602A (ja) * 2007-01-17 2008-07-31 Yamatake Corp 距離計および距離計測方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH1090396A (ja) * 1996-09-20 1998-04-10 Tech Res & Dev Inst Of Japan Def Agency 距離測定方法及び距離測定装置
JPH11326504A (ja) * 1998-05-08 1999-11-26 Toyota Motor Corp Ｆｍ−ｃｗレーダ装置
JP2006313080A (ja) * 2005-05-06 2006-11-16 Yamatake Corp 距離・速度計および距離・速度計測方法
JP2008175602A (ja) * 2007-01-17 2008-07-31 Yamatake Corp 距離計および距離計測方法

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10835607B2 (en) 2015-07-23 2020-11-17 Inimmune Corporation Monoclonal antibody and vaccine targeting filamentous bacteriophage
US11911472B2 (en) 2015-07-23 2024-02-27 Inimmune Corporation Monoclonal antibody and vaccine targeting filamentous bacteriophage

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