JP2009168542A - Angular velocity sensor - Google Patents

Abstract

An object of the present invention is to provide an angular velocity sensor capable of accurately detecting an angular velocity even in an environment where the ambient temperature of the angular velocity sensor rapidly changes.
An angular velocity sensor according to the present invention is provided with an outer temperature sensor that measures an ambient temperature outside a case, and an inner temperature sensor that measures a temperature inside the case. Further, a temperature variable element 57 is provided inside the case 30.
[Selection] Figure 2

Description

  The present invention particularly relates to an angular velocity sensor used for posture control of a moving body such as an aircraft, an automobile, a robot, a ship, and a vehicle.

  A conventional angular velocity sensor of this type has a configuration as shown in FIG.

  FIG. 8 is a perspective view of a conventional angular velocity sensor. In FIG. 8, 1 is a vibrator, and the vibrator 1 is housed in a case 2. A temperature sensor 3 is housed inside the case 2 and detects the temperature in the vicinity of the vibrator 1. Reference numeral 4 denotes a Peltier element. The Peltier element 4 is provided on the upper surface of the case 2. Reference numeral 5 denotes a temperature control means. The temperature control means 5 controls the direction and amount of the current flowing through the Peltier element 4 based on the output signal from the temperature sensor 3 so that the temperature in the case 2 becomes a constant value. It is something to control.

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

  When an alternating voltage is applied to the vibrator 1, the vibrator 1 is oscillated symmetrically in the Y-axis direction, and the vibrator 1 is rotated at an angular velocity ω around the Z axis while maintaining the vibration state. Coriolis force is generated. The angular velocity is detected by converting the electric charge generated in the vibrator 1 by this Coriolis force into an output voltage.

  Here, considering the case where the temperature around the angular velocity sensor is changed, in the conventional angular velocity sensor, the temperature sensor 3 detects the temperature in the case 2 and the temperature control means 5 By controlling the direction and amount of current applied to the Peltier element 4, the temperature in the case 1 is controlled to a predetermined value, thereby preventing fluctuations in the output signal caused by temperature changes.

As prior art document information relating to the invention of this application, for example, Patent Document 1 is known.
JP-A-5-18762

  However, in the above-described conventional configuration, the heat transfer is attenuated by the case 2 because the temperature sensor 3 is provided inside the case 2 in an environment where the temperature around the angular velocity sensor rapidly changes. As a result, the temperature around the angular velocity sensor cannot be accurately detected. Therefore, even if the temperature around the vibrator 1 is controlled by the Peltier element 4, the temperature cannot be accurately controlled. There was a problem that the angular velocity could not be detected.

  The present invention solves the above-described conventional problems, and an object thereof is to provide an angular velocity sensor that can accurately detect an angular velocity even in an environment where the temperature around the angular velocity sensor changes rapidly. is there.

  In order to achieve the above object, the present invention has the following configuration.

  According to a first aspect of the present invention, there is provided a vibrator, a case that houses the vibrator, a drive circuit that is provided inside the case and that drives the vibrator, An IC provided with a detection circuit for processing the output signal, a storage means provided with correction data for correcting the output signal output from the detection circuit, and an outer temperature provided outside the case and measuring the ambient temperature A sensor and an inner temperature sensor that is provided inside the case and measures a temperature inside the case, a temperature variable element is provided inside the case, and a temperature measurement from the temperature sensor is performed by the temperature variable element. It is configured to change the temperature inside the case to a predetermined temperature based on the data. According to this configuration, the outside that measures the ambient temperature outside the case A temperature sensor is provided, an inner temperature sensor for measuring the temperature inside the case is provided inside the case, and a temperature variable element is provided inside the case, so that the temperature around the angular velocity sensor changes rapidly. Under the environment, the temperature controlled by the temperature variable element can be changed according to the difference in measured temperature between the outer temperature sensor and the inner temperature sensor, and the temperature around the angular velocity sensor changes rapidly. Even in this case, there is an effect that the temperature around the vibrator can be stabilized instantaneously.

  According to the second aspect of the present invention, the temperature variable element is particularly provided in the vicinity of the vibrator. According to this configuration, the temperature variable element is provided in the vicinity of the vibrator. Therefore, it is possible to accurately control the temperature around the vibrator, thereby having the effect of stabilizing the output signal.

  In the invention according to claim 3 of the present invention, in particular, the temperature variable element is configured by a Peltier element. According to this configuration, the temperature variable element is configured by a Peltier element. It has an effect that the temperature can be adjusted to a wide temperature range.

  As described above, the angular velocity sensor according to the present invention includes a vibrator, a case that houses the vibrator, a drive circuit that is provided inside the case and drives the vibrator, and outputs from the vibrator. IC provided with a detection circuit for processing a signal, storage means provided with correction data for correcting an output signal output from the detection circuit, and an outer temperature sensor provided outside the case and measuring the ambient temperature And an inner temperature sensor that is provided inside the case and measures the temperature inside the case, a temperature variable element is provided inside the case, and temperature measurement data from the temperature sensor is provided by the temperature variable element. Based on this, the temperature inside the case is changed to a predetermined temperature, and an outside temperature sensor that measures the ambient temperature is installed outside the case. In addition, an internal temperature sensor that measures the temperature inside the case is provided inside the case, and a temperature variable element is provided inside the case, so that the environment around the angular velocity sensor changes rapidly. The temperature controlled by the temperature variable element can be changed according to the difference in measured temperature between the outer temperature sensor and the inner temperature sensor, so that even when the temperature around the angular velocity sensor changes suddenly Since the temperature around the vibrator can be instantly stabilized, the angular velocity can be accurately detected.

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

  1 is an exploded perspective view of an angular velocity sensor according to an embodiment of the present invention, FIG. 2 is a side sectional view of the angular velocity sensor, FIG. 3 is a perspective view of a vibrator in the angular velocity sensor, and FIG. 4 is a circuit of the angular velocity sensor. FIG.

  1 to 4, reference numeral 21 denotes a tuning-fork-shaped vibrator. The vibrator 21 has a quadrangular columnar crystal detection electrode vibrating body 22 and a parallel to the detection electrode vibrating body 22 as shown in FIG. 3. The drive electrode vibrating body 23 is made of quartz, and the connection portion 24 made of crystal that connects one end of the detection electrode vibration body 22 and one end of the drive electrode vibration body 23 is provided. The drive electrode vibrating body 23 in the vibrator 21 is provided with a first drive electrode 25 and a second drive electrode 26 made of gold on four side surfaces. In addition, a monitor electrode 27 made of gold is provided on the front and back surfaces of the detection electrode vibrating body 22 in the vibrator 21, and a gold electrode 28 made of gold is provided on the inner side surface of the detection electrode vibrating body 22. On the outer side surface, a first detection electrode 29a and a second detection electrode 29b made of gold are provided.

  Reference numeral 30 denotes a case made of ceramic. The case 30 is provided with a multilayer circuit board 31 having a layer structure of ceramic and a wiring conductor from the inner bottom surface to the outer bottom surface. A wiring electrode 32 is provided. An IC 35 electrically connected to the first wiring electrode 32 by a wire wire (not shown) made of gold or aluminum is provided on the upper surface of the multilayer circuit board 31. The IC 35 is housed inside the case 30 and processes output signals output from the first detection electrode 29a and the second detection electrode 29b in the vibrator 21. Further, the IC 35 includes a drive circuit 36 and a detection circuit 37 as shown in FIG. The drive circuit 36 in the IC 35 includes an amplifier 39 for inputting the charge of one monitor electrode 27 of the vibrator 21, a bandpass filter (BPF) 40 for inputting an output signal of the amplifier 39, and the bandpass filter. A rectifier 41 for inputting the output signal of (BPF) 40 and a smoothing circuit 42 for inputting the output signal of the rectifier 41 are configured. Reference numeral 43 denotes an AGC circuit. The AGC circuit 43 inputs the output signal of the smoothing circuit 42 in the drive circuit 36 and amplifies or attenuates the output signal of the band pass filter (BPF) 40. Reference numeral 44 denotes a drive control circuit. The drive control circuit 44 inputs an output signal of the AGC circuit 43 and inputs a drive signal to the first drive electrode 25 and the second drive electrode 26 in the vibrator 21. .

  Reference numeral 45 denotes an inverting amplifier. The inverting amplifier 45 inputs the output signal of the drive control circuit 44 and also outputs a drive signal obtained by inverting the output signal of the drive control circuit 44 to the first drive electrode 25 in the vibrator 21. Input. The detection circuit 37 converts the charge generated by the Coriolis force at one detection electrode 29a of the vibrator 21 into a voltage, and the charge generated by the Coriolis force at the other detection electrode 29b as a voltage. A second amplifier 47 for conversion; a differential amplifier 48 for inputting the output signals of the first amplifier 46 and the second amplifier 47; a phase shifter 49 for inputting an output signal of the differential amplifier 48; A synchronous detector 50 to which the output signal of the phase shifter 49 is input, a smoothing circuit 51 to which the output signal of the synchronous detector 50 is input, and an output signal of the smoothing circuit 51 are input and amplified to output an angular velocity signal. And a direct current amplifier 52. Further, the IC 35 is provided with an adder 53, and the adder 53 adds correction data to the angular velocity signal from the DC amplifier 52 in the detection circuit 37. A side wall 54 made of ceramic is provided on the upper surface of the multilayer circuit board 31 over the outer periphery. Further, as shown in FIG. 1, a stepped portion 55 is provided on the inner bottom surface of the case 30, and the connecting portion 24 of the vibrator 21 shown in FIG. A third wiring electrode 56 is provided on both sides to which the connecting portion 24 is fixed, and the third wiring electrode 56 is connected to the first wiring in the vibrator 21 via a wire line (not shown). The drive electrode 25, the second drive electrode 26, the detection electrode 29, the monitor electrode 27 and the GND electrode 28 are electrically connected. Reference numeral 57 denotes a temperature variable element composed of a Peltier element. The temperature variable element 57 is integrally attached to the upper surface of the IC 35, and controls the temperature around the vibrator 21 to a predetermined temperature.

  In the embodiment of the present invention, since the temperature variable element 57 is provided in the vicinity of the vibrator 21, the temperature around the vibrator 21 can be accurately controlled. The effect that the signal is stabilized is obtained.

  Further, since the temperature variable element 57 is composed of a Peltier element, an effect that the temperature in the vicinity of the vibrator 21 can be adjusted in a wide temperature range can be obtained.

  Reference numeral 58 denotes an inner temperature sensor. The inner temperature sensor 58 is provided inside the case 30 and measures the temperature inside the case 30. 59 is a metal lid, and this lid 59 seals the opening of the case 30 so that the inside of the case 30 is in a vacuum atmosphere. Reference numeral 60 denotes an outer temperature sensor. The outer temperature sensor 60 is provided outside the case 30 and detects the temperature outside the angular velocity sensor. Reference numeral 61 denotes an A / D converter. The A / D converter 61 converts an analog output signal from the outside temperature sensor 60 into a digital output signal. Further, the angular velocity sensor is provided with a storage means 62 composed of an EEPROM, and the storage means 62 stores correction data for correcting an error in the output signal output from the DC amplifier 52 in the detection circuit 37.

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

  When an AC voltage is applied to the first drive electrode 25 and the second drive electrode 26 of the vibrator 21, the vibrator 21 resonates and charges are generated at the monitor electrode 27 of the vibrator 21. The electric charges generated on the monitor electrode 27 are input to the amplifier 39 in the drive circuit 36 and output as a sinusoidal output voltage. Then, the output voltage of the amplifier 39 is input to a band pass filter (BPF) 40, and only the resonance frequency of the vibrator 21 is extracted and the noise component is removed to output a sine waveform as shown in FIG. To do. Further, the negative voltage component is converted into a positive voltage by inputting the output signal of the bandpass filter (BPF) 40 to the rectifier 41, and then converted into a DC voltage signal by inputting it into the smoothing circuit 42. When the DC voltage signal of the smoothing circuit 42 is large, the AGC circuit 43 reduces the signal that attenuates the output signal of the bandpass filter (BPF) 40, and the DC voltage signal of the smoothing circuit 42 is small. In this case, a signal that amplifies the output signal of the bandpass filter (BPF) 40 is input to the drive control circuit 44, and the vibration of the vibrator 21 is adjusted to have a constant amplitude. Here, when the vibrator 21 rotates at an angular velocity ω around the central axis in the longitudinal direction of the vibrator 21 in a state in which the drive electrode vibrating body 23 of the vibrator 21 is bent and vibrated at a speed v in the vibration direction, this vibration is generated. A Coriolis force of F = 2 mV × ω is generated in the detection electrode vibrating body 22 of the child 21. The Coriolis force generates charges as shown in FIG. 5B on the first detection electrode 29a of the pair of detection electrodes provided on the detection electrode vibrating body 22, and the second detection electrode 29b has FIG. Electric charges as shown in (c) are generated. Then, the first amplifier 46 converts the electric charge generated from one detection electrode 29a into an output voltage as shown in FIG. The second amplifier 47 inverts and amplifies the charge generated from the other detection electrode 29b and converts it into an output voltage as shown in FIG. Further, the differential amplifier 48 takes the differential of the output signals of the first amplifier 46 and the second amplifier 47, and further delays the phase of the output signal of the differential amplifier 48 by 90 degrees by the phase shifter 49. The output voltage is converted to the output voltage shown in 5 (f). Then, the output signal of the phase shifter 49 is input to the synchronous detector 50 and phase detection is performed at the vibration period of the band pass filter (BPF) 40 in the drive circuit 36, and the negative voltage component of the output voltage of the phase shifter 49 is Conversion to a positive voltage results in an output signal as shown in FIG. Then, the output voltage of the synchronous detector 50 is smoothed and amplified by the smoothing circuit 51 and the DC amplifier 52 to obtain an output signal as shown in FIG. Then, the output signal of the DC amplifier 52 of the detection circuit 37 is input to the adder 53 as an angular velocity signal.

  Here, consider the case where an angular velocity sensor is installed in the engine room of an automobile and the temperature in the vicinity of the angular velocity sensor changes from −55 ° C. to 150 ° C.

  First, as shown in FIG. 6, the angular velocity sensor is assembled to the inspection device 64 provided in the temperature chamber 63, and the temperature in the vicinity of the angular velocity sensor is set to −55 so that the conditions are the same as those in the engine room of the automobile. Change from 0 to 150 ° C. Then, an output signal from the outer temperature sensor 60 at the angular temperature is input to the CPU 65 in the inspection device 64 via the A / D converter 61, and at the same time, an output signal from the angular velocity sensor in a state where no angular velocity is applied is input to the CPU 65. Then, the CPU 65 in the inspection device 64 calculates correction data for each temperature such that the output signal of the angular velocity sensor for each temperature is already zero, and stores it in the storage means 62 such as an EEPROM, EPROM or flash memory. .

  When an angular velocity is applied to the automobile, an angular velocity signal is output from the detection circuit 37 in the angular velocity sensor. In this case, as shown in FIG. 7, the correction signal calculated by the CPU 67 is converted into an analog signal by the D / A converter 68 based on the correction data stored in the storage means 62 by the control means 66. The analog signal is added to the angular velocity signal output from the detection circuit 37 by the adder 53, thereby correcting the output signal from the detection circuit 37, that is, the angular velocity signal.

  Here, considering the case where the ambient temperature of the angular velocity sensor changes abruptly, in the angular velocity sensor according to the embodiment of the present invention, the outer temperature sensor 60 that measures the ambient temperature is provided outside the case 30. In addition, since the inner temperature sensor 58 for measuring the temperature inside the case 30 is provided inside the case 30 and the temperature variable element 57 is provided inside the case 30, the temperature around the angular velocity sensor suddenly increases. Under a changing environment, the temperature controlled by the Peltier element 57 can be changed in accordance with the difference in measured temperature between the outer temperature sensor 60 and the inner temperature sensor 58, so that the temperature around the angular velocity sensor can be changed. Even in the case of a sudden change, the temperature around the vibrator 21 can be instantly stabilized, so the angular velocity is accurately detected. Those having the effect of bets can be.

  The angular velocity sensor according to the present invention has an effect that the angular velocity can be accurately detected even in an environment where the temperature around the angular velocity sensor changes, and in particular, an aircraft, an automobile, a robot, a ship, and an automobile. It is useful as an angular velocity sensor used for attitude control of both moving bodies.

1 is an exploded perspective view of an angular velocity sensor according to an embodiment of the present invention. Side sectional view of the same angular velocity sensor Perspective view of transducer in same angular velocity sensor Circuit diagram of the same angular velocity sensor (A)-(h) Waveform diagram which shows the output signal of the angular velocity sensor in one embodiment of this invention Block diagram showing the state of inspecting the output characteristics of the angular velocity sensor Block diagram showing the state of correcting the output signal from the same angular velocity sensor A perspective view of a conventional angular velocity sensor

Explanation of symbols

21 vibrator 30 case 35 IC
36 drive circuit 37 detection circuit 57 temperature variable element 58 inner temperature sensor 60 outer temperature sensor 62 storage means

Claims (3)

A vibrator, a case for housing the vibrator, an IC provided inside the case, provided with a drive circuit for driving the vibrator, and provided with a detection circuit for processing an output signal from the vibrator; Storage means provided with correction data for correcting the output signal output from the detection circuit, an outer temperature sensor provided outside the case and measuring ambient temperature, and provided inside the case An internal temperature sensor for measuring the temperature inside the case, a temperature variable element is provided inside the case, and the temperature inside the case is set to a predetermined temperature based on temperature measurement data from the temperature sensor by the temperature variable element. Angular velocity sensor configured to change to temperature. The angular velocity sensor according to claim 1, wherein the temperature variable element is provided in the vicinity of the vibrator. The angular velocity sensor according to claim 1, wherein the temperature variable element is a Peltier element.

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