JP2013104707A - Angular velocity sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an angular velocity sensor that can accurately output output signals even when clock frequency of the angular velocity sensor and clock frequency of a master computer are different.SOLUTION: In synchronization with data update signals output from an INT output control circuit 76, response signals comprising angular velocity signals are input from an output terminal 66 in a communication control circuit 63 to an input terminal 71 in a master computer 68.

Description

  The present invention particularly relates to an angular velocity sensor that can be used for posture control and navigation of a moving body such as a camera with a camera shake correction function, an aircraft, an automobile, a robot, a ship, and a vehicle.

  Conventionally, this type of angular velocity sensor has a configuration as shown in FIG.

  Hereinafter, a conventional angular velocity sensor will be described with reference to the drawings.

  FIG. 5 is a circuit block diagram of a conventional angular velocity sensor.

  In FIG. 5, reference numeral 1 denotes a quartz crystal vibrator composed of an H-shaped tuning fork. The vibrator 1 includes a pair of drive units 2 and a pair of detection units 3 disposed on opposite sides of the pair of drive units 2. The detection unit 3 is provided with an angular velocity detection electrode (not shown). In addition, a drive electrode 4 is provided on one side of the drive unit 2 of the vibrator 1, and a drive detection electrode 5 is provided on the other side of the drive unit 2. Reference numeral 6 denotes a drive circuit. The drive circuit 6 is electrically connected to the drive electrode 4 and the drive detection electrode 5 in the vibrator 1, and controls the vibrator 1 to have a constant amplitude. . The drive circuit 6 is provided with an EEPROM 6a, and the drive signal is corrected by data stored in the EEPROM 6a.

  Next, the operation of the conventional angular velocity sensor configured as described above will be described.

  When an AC voltage is applied to the drive electrode 4 of the vibrator 1, the vibrator 1 resonates, and a charge corresponding to the vibration amplitude of the vibrator 1 is generated on the drive detection electrode 5 of the vibrator 1. The electric charge is amplified and adjusted by the drive circuit 6 and then input to the drive electrode 4 to control the vibrator 1 to vibrate with a constant amplitude. Further, when the amplitude deviates from a predetermined value due to variations in the vibrator 1, the amplitude is finely adjusted by rewriting the data of the EEPROM 6a in the drive circuit 6.

  When the angular velocity ω is applied to the vibrator 1, electric charges are generated in the angular velocity detection electrodes (not shown) provided in the pair of detection units 3. Then, the electric charge generated in the electrode for detecting angular velocity (not shown) is converted into an output voltage by the detection circuit 10 and input to the counterpart computer (not shown) or the like as an angular velocity signal from the input / output terminal 11. The angular velocity is detected.

  Here, as shown in FIG. 6, as the digital processing technology advances, the counterpart computer is set as the master computer 12, and the first angular velocity sensor 13, as the slave side controlled by the master computer 12, Consider a case in which the second angular velocity sensor 14, the acceleration sensor 15 and the rotation speed sensor 16 are controlled. In such a case, the chip select terminal 17 is provided in the master computer 12, and the chip select terminal 18 is provided in all of the first angular velocity sensor 13, the second angular velocity sensor 14, the acceleration sensor 15, and the rotation speed sensor 16. .

  The master computer 12 is provided with an output terminal 19, and an input terminal 20 corresponding to the output terminal 19 is connected to all of the first angular velocity sensor 13, the second angular velocity sensor 14, the acceleration sensor 15, and the rotation speed sensor 16. Provide. The first angular velocity sensor 13, the second angular velocity sensor 14, the acceleration sensor 15, and the rotation speed sensor 16 are all provided with an output terminal 21, and an input terminal 22 corresponding to the output terminal 21 is provided in the master computer 12. . Here, for example, considering the case where the first angular velocity sensor 13 is operated, a signal is output from the chip select terminal 17 in the master computer 12 to the chip select terminal 18 in the first angular velocity sensor 13. Then, a command signal composed of an 8-bit signal is transmitted from the output terminal 19 of the master computer 12 to the input terminal 20 of the first angular velocity sensor 13, and 8-bit data corresponding to the command signal is output to the output terminal of the first angular velocity sensor 13. 21 to the input terminal 22 in the master computer 12. Examples of the command signal include output of angular velocity information from the first angular velocity sensor 13, writing of data to the EEPROM 6a of the driving circuit 6 in the first angular velocity sensor 13, and reading of data from the EEPROM 6a.

  As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.

JP 2002-174521 A

  However, in the above conventional configuration, when the clock frequency of the angular velocity sensor 13 and the clock frequency of the master computer 12 are different, a signal is sent from the chip select terminal 17 in the master computer 12 to the chip select terminal 18 in the angular velocity sensor 13. By outputting the angular velocity information from the angular velocity sensor 13 to the input terminal 22 in the master computer 12 from the output terminal 21, due to the phase shift of the clock frequency between the angular velocity sensor 13 and the master computer 12, There has been a problem that the output signal fluctuates by the amount of phase shift.

  The present invention solves the above-mentioned conventional problems, and provides an angular velocity sensor capable of outputting an accurate output signal even when the clock frequency of the angular velocity sensor and the clock frequency of the master computer are different. It is for the purpose.

  To achieve the above object, the present invention detects a vibrator, a drive circuit that vibrates the vibrator, and an electric charge generated by Coriolis force when an angular velocity is applied to the vibrator as an output signal of an analog signal. Detection circuit, an A / D converter that converts an analog signal from the detection circuit into a digital signal, an oscillator that controls the operation timing of the A / D converter, and a rectangular wave output from the oscillator. An INT output control circuit for converting to a data update signal via a peripheral, storage means for storing the digital signal converted by the A / D converter, an external master computer, a chip select terminal, a clock terminal, A communication control circuit electrically connected via an input terminal and an output terminal, and synchronized with a data update signal output from the INT output control circuit The response signal comprising the angular velocity signal is input from the output terminal of the communication control circuit to the input terminal of the master computer. According to this configuration, the clock frequency of the angular velocity sensor and the clock frequency of the master computer are Even in a different case, a response signal composed of an angular velocity signal is input from the output terminal of the communication control circuit to the input terminal of the master computer in synchronization with the data update signal output from the INT output control circuit. The angular velocity signal can be output without being influenced by the clock frequency in the computer, and there is an effect that the output fluctuation due to the phase shift of the clock signal between the angular velocity sensor and the master computer is eliminated.

  An angular velocity sensor according to the present invention includes a vibrator, a drive circuit that vibrates the vibrator, a detection circuit that detects an electric charge generated by Coriolis force when an angular velocity is added to the vibrator as an output signal of an analog signal, and An A / D converter that converts an analog signal from the detection circuit into a digital signal, an oscillator that controls the operation timing of the A / D converter, and a rectangular wave output from the oscillator via a frequency divider An INT output control circuit for converting into a data update signal, a storage means for storing the digital signal converted by the A / D converter, an external master computer, a chip select terminal, a clock terminal, an input terminal and an output A communication control circuit electrically connected via a terminal, and an angular velocity synchronized with a data update signal output from the INT output control circuit. The response signal consisting of a signal is input from the output terminal of the communication control circuit to the input terminal of the master computer. According to this configuration, the clock frequency of the angular velocity sensor and the clock frequency of the master computer are different. However, in response to the data update signal output from the INT output control circuit, the response signal including the angular velocity signal is input from the output terminal of the communication control circuit to the input terminal of the master computer. It is possible to provide an angular velocity sensor with improved characteristics that can output an angular velocity signal without being affected by the clock frequency and does not cause output fluctuation due to a phase shift of the clock signal between the angular velocity sensor and the master computer. it can It is those having the effect of say.

The block diagram which shows the detection circuit of the angular velocity sensor in one embodiment of this invention The figure which shows the output signal in the operating state of the same angular velocity sensor The figure which shows the data update signal output from the INT output control circuit of the angular velocity sensor in one embodiment of this invention The figure which shows the state which outputs angular velocity information by the command from the master computer to the angular velocity sensor Circuit block diagram of conventional angular velocity sensor The figure which shows the state which connects the conventional angular velocity sensor with a master computer

  Hereinafter, an angular velocity sensor according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a detection circuit of an angular velocity sensor according to an embodiment of the present invention.

  In FIG. 1, reference numeral 31 denotes a vibrator, and the vibrator 31 includes a pair of drive units 32 and a pair of detection units 33 disposed at respective tips of the pair of drive units 32. In addition, a drive electrode 34 is provided on one side of the drive unit 32 of the vibrator 31, and a drive detection electrode 35 is provided on the other side of the drive unit 32. In addition, an angular velocity detection electrode 36 is provided on the pair of detection units 33 in the vibrator 31. Reference numeral 37 denotes a monitor circuit. The monitor circuit 37 includes a current amplifier 38 for inputting the electric charge of the drive detection electrode 35 of the vibrator 31, a bandpass filter 39 for inputting an output signal of the current amplifier 38, and the bandpass. A rectifier 40 for inputting the output signal of the filter 39 and a smoothing circuit 41 for inputting the output signal of the rectifier 40 are configured. Reference numeral 42 denotes an AGC circuit. The AGC circuit 42 inputs the output signal of the smoothing circuit 41 in the monitor circuit 37 and amplifies or attenuates the output signal of the band-pass filter 39 in the monitor circuit 37. Reference numeral 43 denotes a control circuit. The control circuit 43 inputs an output signal of the AGC circuit 42 and inputs a drive signal to the drive electrode 34 of the vibrator 31. The monitor circuit 37, the AGC circuit 42, and the control circuit 43 constitute a drive circuit 44.

  Reference numeral 45 denotes a current amplifier. The current amplifier 45 converts electric charges generated by the Coriolis force on the pair of angular velocity detection electrodes 36 in the vibrator 31 into a voltage. A detection circuit 46 includes a differential amplifier 47 that receives the output signal of the current amplifier 45, a synchronous detector 48 that receives the output signal of the differential amplifier 47, and the synchronous detector 48. The smoothing circuit 49 inputs the output signal and the DC amplifier 50 which inputs the output signal of the smoothing circuit 49 and amplifies and outputs the angular velocity signal. Reference numeral 60 denotes an A / D converter. The A / D converter 60 converts an analog output signal output from the DC amplifier 50 in the detection circuit 46 into a digital signal. Reference numeral 62 denotes a register, which stores an output signal as angular velocity information, correction data of the drive circuit 44, and the like as data.

  Reference numeral 63 denotes a communication control circuit corresponding to a slave in three-wire serial communication. This communication control circuit 63 exchanges data with the register 62, and also includes a chip select terminal 64, an input terminal 65, an output terminal 66, and a clock terminal 67. Provided. Reference numeral 68 denotes an external master computer that controls communication in the three-wire serial communication system. The master computer 68 is connected to the chip select terminal 64 of the angular velocity sensor and the input of the angular velocity sensor. An output terminal 70 connected to the terminal 65, an input terminal 71 connected to the output terminal 66 in the angular velocity sensor, a clock terminal 72 connected to the clock terminal 67 in the angular velocity sensor, and an INT terminal 73 are provided. The master computer 68 is provided with a timing circuit 68a. 74 is an oscillator, and this oscillator 74 outputs a rectangular waveform. Reference numeral 75 denotes a frequency divider, and this frequency divider 75 converts the output signal from the oscillator 74 into a rectangular wave of 13.3 KHz and outputs it. An INT output control circuit 76 converts the rectangular wave output from the frequency divider 75 into a data update signal and outputs it. The data update signal is input to the timing circuit 68 a via the INT terminal 73 in the master computer 68. The output signal output from the timing circuit 68a is input as a low signal to the chip select terminal 64 in the communication control circuit 63 of the angular velocity sensor via the chip select terminal 69 in the master computer 68.

  Next, the operation of the angular velocity sensor according to one embodiment of the present invention configured as described above will be described.

  When an AC voltage is applied to the drive electrode 34 of the vibrator 31, the vibrator 31 resonates and charges are generated at the drive detection electrode 35 of the vibrator 31. The electric charge generated in the drive detection electrode 35 is input to the current amplifier 38 in the drive circuit 44 and converted into a sine waveform output voltage. Then, the output voltage of the current amplifier 38 is input to a band pass filter 39 in the monitor circuit 37, and only the resonance frequency of the vibrator 31 is extracted, and a sine waveform as shown in FIG. Output. Further, the output signal of the bandpass filter 39 in the monitor circuit 37 is input to the rectifier 40 to convert the negative voltage component into a positive voltage and then input to the smoothing circuit 41 to be converted into a DC voltage signal. . When the DC voltage signal of the smoothing circuit 41 is large, the AGC circuit 42 attenuates the output signal of the band-pass filter 39 in the monitor circuit 37, while the DC voltage signal of the smoothing circuit 41 If it is small, a signal that amplifies the output signal of the bandpass filter 39 in the monitor circuit 37 is input to the control circuit 43, and the vibration of the vibrator 31 is adjusted to have a constant amplitude. When the vibrator 31 rotates at an angular velocity ω around the longitudinal center axis of the vibrator 31 in a state where the drive unit 32 of the vibrator 31 is bending-vibrated at a speed V in the driving direction, the vibrator 31 is rotated. A Coriolis force of F = 2 mV × ω is generated in the detector 33. Due to this Coriolis force, electric charges are generated in the pair of angular velocity detection electrodes 36 in the detection section 33 as shown in FIGS. 2B and 2C. Since the electric charge generated in the angular velocity detection electrode 36 is generated by the Coriolis force, the phase is advanced by 90 degrees from the signal generated in the drive detection electrode 35. Further, by superimposing the output signals generated on the pair of angular velocity detection electrodes 36, a charge signal as shown in FIG. 2D is obtained. Further, the current amplifier 45 converts the output voltage as shown in FIG. At this time, the current amplifier 45 is provided with a capacitor (not shown), and further advances the output of the angular velocity detection electrode 36 by 90 degrees. Then, the output signal of the current amplifier 45 is branched into two output signals, and only one of the branched output signals is extracted by the differential amplifier 47 in the detection circuit 46, and the noise component is extracted. At the same time, the output of the differential amplifier 47 is input to the synchronous detector 48, phase detection is performed at the period of vibration of the bandpass filter 39 in the monitor circuit 37, and the negative voltage of the power voltage of the differential amplifier 47 is detected. The component is converted into a positive voltage to obtain an output signal as shown in FIG. The output voltage of the synchronous detector 48 is smoothed and amplified by the smoothing circuit 49 and the DC amplifier 50 to obtain an output signal as shown in FIG. The output signal of the DC amplifier 50 in the detection circuit 46 is input to the A / D converter 60 as analog angular velocity information. The A / D converter 60 converts the analog output information output from the DC amplifier 50 into a digital output signal.

  Here, as a normal operation state, a case where the angular velocity sensor outputs angular velocity information composed of a digital signal according to a command from the master computer 68 is considered. As angular velocity information consisting of 10 bits, the stationary state of the angular velocity sensor, that is, 0 [degree / second] is (1000000000), the maximum angular velocity 511 [degree / second] of the measurement range is (1111111111), and the minimum angular velocity of the measurement range is −511. Define [degrees / second] as (0000000000).

  Then, the output signal from the oscillator 74 is converted into a rectangular wave signal by the frequency divider 75, and a data update signal of 78 μsec is output from the INT output control circuit 76 as shown in FIG. This data update signal is input to the INT terminal 73 in the master computer 68. By inputting a low signal from the chip select terminal 69 to the chip select terminal 64 in the communication control circuit 63 in the angular velocity sensor via the timing circuit 68a in the master computer 68, as shown in FIG. The angular velocity sensor according to the embodiment of the present invention is selected as a target to receive the command.

  Thereafter, the clock signal shown in FIG. 4C is input from the clock terminal 72 in the master computer 68 to the clock terminal 67 in the communication control circuit 63, and the angular velocity information shown in FIG. The first command 77 is input from the output terminal 70 of the master computer 68 to the input terminal 65 of the communication control circuit 63. Then, in response to the fall of the clock signal in FIG. 4C, a response signal 77 composed of an angular velocity signal is sent from the output terminal 66 in the communication control circuit 63 to the input terminal 71 in the master computer 68 as shown in FIG. To enter.

  That is, in the angular velocity sensor according to the embodiment of the present invention, even when the update time 78 μsec possessed by the angular velocity sensor and the update time 125 μsec possessed by the master computer are different, the data update signal output from the INT output control circuit 76 Since the response signal composed of the angular velocity signal is input to the input terminal 71 of the master computer 68 from the output terminal 66 of the communication control circuit 63 in synchronization with each other, the master computer 68 is not affected by the clock frequency of about 8 KHz. Thus, the angular velocity signal can be output, and the output fluctuation due to the phase shift of the clock signal between the angular velocity sensor and the master computer is eliminated.

  The response signal 78 made up of this angular velocity signal is composed of 4-wire, SPI communication, and 16-bit angular velocity data.

  In response to the command requesting the upper byte of the angular velocity information as the first command 77, a response signal 78 comprising an angular velocity signal including the upper byte signal as shown in FIG. 5A is sent from the communication control circuit 63 to the master computer. Output to 68. Next, in response to a command that requests the lower byte of the angular velocity information that is the second command 79, a response signal 80 including an angular velocity signal including a lower byte signal as shown in FIG. To the master computer 68. Then, the master computer 68 combines the response signal 78 made up of the angular velocity signal of the upper byte and the response signal 80 made up of the angular velocity signal of the lower byte, thereby receiving 10-bit angular velocity information.

  The angular velocity sensor according to the present invention has an effect of providing an angular velocity sensor capable of outputting an accurate output signal even when the clock frequency of the angular velocity sensor and the clock frequency of the master computer are different. It is useful as an angular velocity sensor that can be used for posture control and navigation of a moving body such as a camera with a camera shake correction function, an aircraft, an automobile, a robot, a ship, and a vehicle.

31 vibrator 44 drive circuit 46 detection circuit 60 A / D converter 62 register 63 communication control circuit 64 chip select terminal 65 input terminal 66 output terminal 67 clock terminal 68 master computer 75 frequency divider 76 INT output control circuit

Claims (1)

A vibrator, a drive circuit that vibrates the vibrator, a detection circuit that detects an electric charge generated by Coriolis force when an angular velocity is applied to the vibrator, and an analog signal output from the detection circuit; An A / D converter that converts a signal into a digital signal, an oscillator that controls the operation timing of the A / D converter, and a rectangular wave output from the oscillator is converted into a data update signal via a frequency divider. An INT output control circuit, storage means for storing the digital signal converted by the A / D converter, an external master computer, a chip select terminal, a clock terminal, an input terminal, and an output terminal electrically A communication control circuit connected thereto, and a response signal including an angular velocity signal is transmitted in synchronization with a data update signal output from the INT output control circuit. An angular velocity sensor that is configured to input from the output terminal of the control circuit to the input terminal of the master computer.

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