Angular velocity sensor calibration device and angular velocity sensor calibration method

Abstract

To make it possible to synchronize the start and end timing of measurements for the calibration of an angular velocity sensor and a standard angular sensor.SOLUTION: An angular velocity sensor calibration device includes a synchronous signal generation unit, a start time acquisition unit, an end time acquisition unit, a time standard acquisition unit, an angle standard calculation unit, an angular velocity standard calculation unit, a calibrated angular velocity acquisition unit, and a deviation amount calculation unit. The start time acquisition unit acquires the time indicated by a time measurement unit as the start time of measurement when the sensor, among the calibrated angular velocity sensor or the standard angular sensor that detected the voltage signal at the start of measurement, which detected the voltage signal later, detects the voltage signal. The end time acquisition unit acquires the time indicated by the time measurement unit as the end time of measurement when the sensor, among the calibrated angular velocity sensor or the standard angular sensor that detected the voltage signal at the end of measurement, which detected the voltage signal earlier, detects the voltage signal. The deviation amount calculation unit calculates the deviation of the calibrated angular velocity sensor from the angular velocity standard.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to an angular velocity sensor calibration device and an angular velocity sensor calibration method, and more particularly to an angular velocity sensor calibration device and an angular velocity sensor calibration method that enable highly accurate calibration. [Background technology]

[0002] An angular velocity sensor is a sensor that uses the Coriolis force to detect the rotation and change in direction of an object as an angular velocity and outputs an electrical signal. Examples of applications of angular velocity sensors include automatic driving of automobiles, car navigation systems and skid prevention devices, image stabilization functions of digital cameras, attitude control and autonomous navigation of airplanes, ships, rockets, etc., and motion sensors of robots and game controllers.

[0003] In recent years, there has been a demand for angular velocity sensors to measure with higher accuracy and resolution, and it has become necessary to calibrate angular velocity sensors with high accuracy. Calibration of angular velocity sensors refers to clarifying the relationship, which involves uncertainty, between the indication of the angular velocity sensor to be calibrated (hereinafter referred to as the calibrated angular velocity sensor) and the standard angular velocity (hereinafter referred to as the angular velocity standard). An example of a calibration device for an angular velocity sensor is disclosed in Patent Document 1.

[0004] The angular velocity standard is the value obtained by dividing the change in angle standard during a time standard by the time standard. A time standard is a time measured by an atomic clock, a cesium frequency standard, a rubidium frequency standard, or a frequency oscillator with equivalent accuracy, which is used as a specific secondary standard or a regular reference standard, and refers to the period during which measurements for calibration are conducted. An angle standard refers to an angle measured by an angle measuring sensor (hereinafter referred to as a standard angle sensor) used as a specific secondary standard or a common reference standard.

[0005] When comparing the indication of the calibrated angular velocity sensor with the angular velocity standard, it is necessary to compare them in the same interval, i.e., the start of the measurement of the calibrated angular velocity sensor needs to coincide with the start point of the time standard, and the end of the measurement of the calibrated angular velocity sensor needs to coincide with the end point of the time standard.

[0006] Even if voltage signals indicating the start and end of the period for performing calibration measurements are input simultaneously to the calibrated angular velocity sensor and the standard angle sensor, if the delay time when the calibrated angular velocity sensor and the standard angle sensor detect the voltage signals differs between the calibrated angular velocity sensor and the standard angle sensor, the timing at which the voltage signals indicating the start and end of the calibration measurements are detected differs between the calibrated angular velocity sensor and the standard angle sensor, resulting in a problem that the start and end of the period for performing calibration measurements for the calibrated angular velocity sensor and the standard angle sensor cannot be made to match. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 6-100615 Summary of the Invention [Problem to be solved by the invention]

[0008] Therefore, an object of the present invention is to provide an angular velocity sensor calibration device and an angular velocity sensor calibration method that can match the start and end of the period during which calibration measurements are performed in the calibrated angular velocity sensor and the standard angle sensor even if the delay times in detecting input signals from the calibrated angular velocity sensor and the standard angle sensor are different. [Means for solving the problem]

[0009] That is, the angular velocity sensor calibration device according to the first aspect is an angular velocity sensor calibration device that calibrates the angular velocity sensor to be calibrated, comprising a tilt angle generating unit that changes the tilt of a tilt table on which a calibrated angular velocity sensor to be calibrated is placed, a standard angle sensor that measures an angle standard that serves as a standard for calibration, and a time measuring unit that measures time based on a reference time, and that calibrates the angular velocity sensor to be calibrated, and includes a synchronization signal generating unit that generates a voltage signal at the start and end of measurement of the tilt when the tilt of the tilt table is increased at a constant speed to perform calibration, a start time acquiring unit that acquires as the start time of measurement the time indicated by the time measuring unit when the sensor that detected the voltage signal at the start of the measurement is the later of the calibrated angular velocity sensors or the standard angle sensors that detected the voltage signal at the end of the measurement, and the time standard acquisition unit acquires the period between the start time acquired by the start time acquisition unit and the end time acquired by the end time acquisition unit as a time standard; an angle standard calculation unit acquires the difference between the indication value of the standard angle sensor at the start time and the indication value of the standard angle sensor at the end time as an angle standard; an angular velocity standard calculation unit calculates an angular velocity standard by dividing the angle standard calculated by the angle standard calculation unit by the time standard acquired by the time standard acquisition unit; a calibrated angular velocity acquisition unit acquires the indication value of the calibrated angular velocity sensor at the start time and the indication value of the calibrated angular velocity sensor at the end time; and a deviation amount calculation unit calculates the deviation amount of the calibrated angular velocity sensor from the angular velocity standard based on the angular velocity standard calculated by the angular velocity standard calculation unit, the indication values ​​of the calibrated angular velocity sensor at the start time and the end time acquired by the calibrated angular velocity acquisition unit, and the time standard acquired by the time standard acquisition unit.

[0010] In a second aspect, in the angular velocity sensor calibration device according to the first aspect, the deviation calculation unit may determine the deviation as a value obtained by dividing the difference between the angular velocity standard and an average value of the indication value of the angular velocity sensor to be calibrated at the start time and the indication value of the angular velocity sensor to be calibrated at the end time by the time standard.

[0011] In a third aspect, in the angular velocity sensor calibration device according to the first aspect, the deviation calculation unit may determine the deviation as a value obtained by dividing the difference between the angular velocity standard and an average value of the indication value of the angular velocity sensor to be calibrated at the start time and the indication value of the angular velocity sensor to be calibrated at the end time by the angular velocity standard.

[0012] As a fourth aspect, in the angular velocity sensor calibration device according to the first aspect, an output unit that outputs the angular velocity standard calculated by the angular velocity standard calculation unit may be further provided.

[0013] According to a fifth aspect, in the angular velocity sensor calibration device according to the first aspect, the standard angle sensor may be a self-calibrating encoder.

[0014] As a sixth aspect, in the angular velocity sensor calibration device according to the first aspect, the standard angle sensor may include a scale using a diffraction grating, and a sensor head that irradiates the scale with laser light to read the number of scale marks.

[0015] A seventh aspect of the angular velocity sensor calibration method is an angular velocity sensor calibration method for calibrating a calibrated angular velocity sensor using a tilt angle generating unit that changes the tilt of a tilt table on which a calibrated angular velocity sensor to be calibrated is placed, a standard angle sensor that measures an angle standard that serves as a calibration standard, and a time measuring unit that measures time based on a reference time, the method including a synchronization signal generating step of generating voltage signals at the start and end of measurement of the tilt of the tilt table in a state in which the tilt of the tilt table is increased at a constant speed to perform the calibration, a start time acquiring step of acquiring, as the start time of the measurement, the time indicated by the time measuring unit when the sensor that detected the voltage signal at the start of the measurement is the later of the calibrated angular velocity sensor or the standard angle sensor that detected the voltage signal at the start of the measurement, and an end time acquiring step of acquiring, as the end time of the measurement, the time indicated by the time measuring unit when the sensor that detected the voltage signal at the end of the measurement is the earlier of the calibrated angular velocity sensor or the standard angle sensor that detected the voltage signal at the end of the measurement, the time standard acquisition step of acquiring the period between the start time acquired in the start time acquisition step and the end time acquired in the end time acquisition step as a time standard; an angle standard calculation step of acquiring the difference between the indication value of the standard angle sensor at the start time and the indication value of the standard angle sensor at the end time as an angle standard; an angular velocity standard calculation step of calculating an angular velocity standard by dividing the angle standard calculated in the angle standard calculation step by the time standard acquired in the time standard acquisition step; a calibrated angular velocity acquisition step of acquiring the indication value of the calibrated angular velocity sensor at the start time and the indication value of the calibrated angular velocity sensor at the end time; and a deviation amount calculation step of calculating the deviation amount of the calibrated angular velocity sensor from the angular velocity standard based on the angular velocity standard calculated in the angular velocity standard calculation step, the indication values ​​of the calibrated angular velocity sensor at the start time and the end time acquired in the calibrated angular velocity acquisition step, and the time standard acquired in the time standard acquisition step. Effect of the Invention

[0016] The angular velocity sensor calibration device according to the present invention is an angular velocity sensor calibration device for calibrating an angular velocity sensor to be calibrated, the device comprising: a tilt angle generating unit for changing the tilt of a tilt table on which a calibrated angular velocity sensor to be calibrated is placed; a standard angle sensor for measuring an angle standard that serves as a standard for calibration; and a time measuring unit for measuring time based on a reference time, the angular velocity sensor calibration device for calibrating an angular velocity sensor to be calibrated, the angular velocity sensor calibration device comprising: a synchronization signal generating unit for generating voltage signals at the start and end of measurement of the tilt when the tilt of the tilt table is increased at a constant speed in order to perform calibration; a start time acquiring unit for acquiring, as the start time of measurement, the time indicated by the time measuring unit when the sensor that detected the voltage signal at the start of the measurement is the later of the calibrated angular velocity sensors or the standard angle sensors that detected the voltage signal at the start of the measurement; an end time acquiring unit for acquiring, as the end time of measurement, the time indicated by the time measuring unit when the sensor that detected the voltage signal at the end of the measurement is the earlier of the calibrated angular velocity sensors or the standard angle sensors that detected the voltage signal at the end of the measurement; a time standard acquisition unit that acquires, as a time standard, the period between the time and the end time acquired by the end time acquisition unit; an angle standard calculation unit that acquires, as an angle standard, the difference between the indication value of the standard angle sensor at the start time and the indication value of the standard angle sensor at the end time; an angular velocity standard calculation unit that calculates an angular velocity standard by dividing the angle standard calculated by the angle standard calculation unit by the time standard acquired by the time standard acquisition unit; a calibrated angular velocity acquisition unit that acquires the indication value of the calibrated angular velocity sensor at the start time and the indication value of the calibrated angular velocity sensor at the end time; and a deviation amount calculation unit that calculates the deviation amount of the calibrated angular velocity sensor from the angular velocity standard based on the angular velocity standard calculated by the angular velocity standard calculation unit, the indication values ​​of the calibrated angular velocity sensor at the start time and the end time acquired by the calibrated angular velocity acquisition unit, and the time standard acquired by the time standard acquisition unit. [Brief description of the drawings]

[0017] [Figure 1]FIG. 1 is a diagram for explaining an overview of an angular velocity sensor calibration device according to this embodiment. [Diagram 2] FIG. 2 is a diagram for explaining the change in the inclination angle θ applied to the calibration target acceleration sensor according to this embodiment. [Diagram 3] FIG. 3 is a diagram for explaining the configuration of the angular velocity sensor calibration device according to this embodiment. [Figure 4] FIG. 4 is a diagram for explaining the functional configuration of the angular velocity sensor calibration device according to this embodiment. [Diagram 5] FIG. 5 is a diagram for explaining a voltage signal generated by the synchronization signal generating unit according to the present embodiment. [Figure 6] FIG. 6 is a diagram for explaining the time standard according to this embodiment. [Figure 7] FIG. 7 is a flowchart of the angular velocity sensor calibration method according to this embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] (Overview of the angular velocity sensor calibration device 10) An angular velocity sensor calibration device 10 according to one embodiment of the present invention will be described with reference to FIGS. First, an overview of an angular velocity sensor calibration device 10 will be described with reference to FIGS. The angular velocity sensor calibration device 10 calibrates an angular velocity sensor to be calibrated (hereinafter referred to as a calibrated angular velocity sensor 12) by comparing it with a standard angular velocity (hereinafter referred to as an angular velocity standard). The calibrated angular velocity sensor 12 of this embodiment is attached to an object to be measured so that its rotation and orientation change integrally with the object, and measures the changes in rotation and orientation of the object.

[0019] The angular velocity standard is the value obtained by dividing the movement angle measured in the angle standard by the time standard. A time standard refers to the time at which calibration measurements are made, measured by a high-precision oscillator used as a specific secondary standard or a regular reference standard. In this embodiment, an oven controlled crystal oscillator (OCXO), which will be described later, is used as a regular reference standard.

[0020] The angle standard refers to an angle measured by an angle measuring sensor (hereinafter referred to as the standard angle sensor 13) used as a specific secondary standard or a common reference standard. In this embodiment, a self-calibrating encoder, which will be described later, is used as the standard angle sensor 13.

[0021] The angular velocity sensor calibration device 10 applies the same change in tilt angle θ to the calibrated angular velocity sensor 12 and the standard angle sensor 13, and compares the change over time in the tilt angle θ measured by the calibrated angular velocity sensor 12 with an angular velocity standard calculated based on the angle standard and time standard measured by the standard angle sensor 13.

[0022] Calibration, as defined in JIS Z8103 (2019), refers to an operation in which, under specified conditions, in the first step, a relationship with uncertainty is established between the value of a quantity with uncertainty provided by a measurement standard and its corresponding indication value, and in the second step, this information is used to establish a relationship for obtaining a measurement result from the indication value.

[0023] The angular velocity sensor calibration device 10 according to this embodiment is mainly responsible for the first stage of the above calibration, in which the indication value of the calibrated angular velocity sensor 12 is compared with the angular velocity standard calculated based on the angle standard and time standard measured by the standard angle sensor 13, and the relationship therebetween is grasped and clarified.

[0024] Angular velocity sensors, also known as gyro sensors, are sensors that use the Coriolis force to detect the rotation and change in direction of an object as angular velocity and output it as an electrical signal. Angular velocity sensors are classified into mechanical, optical and vibration types, with the most common being the vibration type acceleration sensor, which has a piezoelectric type and a capacitance type as its mechanism. Angular velocity refers to the angle of rotation per unit time, and is calculated by dividing the change in angle by time, and is expressed in units of "deg / sec" (degrees per second) (see Figure 2).

[0025] The angular velocity sensor calibration device 10 according to this embodiment applies a vertical rotation to the angular velocity sensor 12 to be calibrated by changing the tilt angle θ of the tilt table 11a of the tilt angle generating unit 11 (see Figs. 1 and 3).The angular velocity sensor calibration device 10 compares a value (indicated value) detected and displayed by the angular velocity sensor 12 to be calibrated of the change in the tilt angle θ with an angular velocity standard calculated based on an angle standard and a time standard detected by a standard angle sensor 13, and calculates how much the indicated value of the angular velocity sensor 12 to be calibrated deviates from the angular velocity standard (deviation amount).

[0026] As shown in FIGS. 1 and 3, the angular velocity sensor calibration device 10 applies a change in the vertical direction to the angular velocity sensor 12 to be calibrated as a change in the inclination angle θ of the angular velocity sensor 12 to be calibrated. The tilt angle θ refers to the angle between a tilt table 11a on which the calibration target angular velocity sensor 12 is placed and a horizontal line 11b (see FIGS. 1 and 3). As shown in FIG. 1, the angular velocity sensor calibration device 10 rotates the tilt table 11a in a rotation direction 15 to increase the tilt angle θ, thereby changing the orientation of the tilt table 11a in the vertical direction.

[0027] With reference to Fig. 2, the manner in which an inclination is applied to the calibration target angular velocity sensor 12 will be described. Fig. 2 is a diagram for explaining the change in the inclination angle θ applied to the calibration target acceleration sensor according to this embodiment. The vertical axis of Fig. 2 is angular velocity (deg / sec), and the horizontal axis is inclination angle θ (deg).

[0028] The angular velocity sensor calibration device 10 controls the tilt angle generating unit 11 described later to increase the tilt angle θ of the tilt table 11a. As shown in FIG. 2, in the initial state 14a of the tilt angle θ, the angular velocity is 0 (deg / sec) and the tilt angle θ is 0 (degree). The tilt angle θ increases with an increase in angular velocity due to a constant angular acceleration until it reaches a predetermined first tilt angle 14b from the initial state 14a. Next, the tilt angle θ increases with a constant angular velocity until it reaches a next predetermined second tilt angle 14c. Next, the tilt angle θ increases with a decrease in angular velocity due to a constant angular acceleration until it reaches a next predetermined third tilt angle 14d. Then, the tilt angle θ reaches the third tilt angle 14d, and the angular velocity becomes 0.

[0029] The angular velocity sensor calibration device 10 receives an external operation to start measurement (start operation 41) at any time during a period of constant angular velocity from the first tilt angle 14b to the second tilt angle 14c, and generates a voltage signal 33 for starting measurement of the angular velocity from a synchronization signal generating unit 22 described later, and receives an external operation to end measurement (end operation 42) to generate a voltage signal 33 for ending measurement of the angular velocity from the synchronization signal generating unit 22 (see Figs. 5 and 6). Each functional unit of the angular velocity sensor calibration device 10 described later operates in synchronization with the voltage signal 33 generated from the synchronization signal generating unit 22. The configuration and each functional unit of the angular velocity sensor calibration device 10 will be described below.

[0030] (Configuration of the angular velocity sensor calibration device 10) The configuration of the angular velocity sensor calibration device 10 according to this embodiment will be described with reference to Fig. 3 and Fig. 4. Fig. 3 is a diagram for explaining the configuration of the angular velocity sensor calibration device 10 according to this embodiment, and Fig. 4 is a diagram for explaining the functional configuration of the angular velocity sensor calibration device 10.

[0031] The angular velocity sensor calibration device 10 includes a tilt angle generating unit 11 that changes the tilt of a tilt table 11a on which a calibrated angular velocity sensor 12 to be calibrated is placed, a standard angle sensor 13 that measures an angle standard that serves as a standard for calibration, and a time measuring unit 21 that measures the time based on a reference time (see FIG. 3). 3 shows the inside of the tilt angle generating unit 11. The tilt angle generating unit 11 includes a tilt table 11a. The calibrated angular velocity sensor 12 is fixed to the upper surface of the tilt table 11a. The calibrated angular velocity sensor 12 is securely fixed to the tilt table 11a so as not to shift or float. The tilt angle generating unit 11 changes the tilt of the calibrated angular velocity sensor 12 by changing the tilt angle θ of the tilt table 11a within a predetermined range.

[0032] Standard angle sensor 13 is a self-calibrating encoder. A self-calibrating encoder is a type of rotary encoder and angle detector that can detect and correct angle errors by itself. A self-calibrating encoder attaches a scale unit with graduations engraved on it to the rotating shaft of the device to be measured, and uses multiple sensors to detect the number of graduations that rotate with the rotating shaft, making it possible to calculate angle error factors such as scale error and shaft eccentricity error with high precision. Standard angle sensor 13 is a sensor that has the above-mentioned self-calibration function and outputs an electrical signal. The standard angle sensor 13 is not limited to a rotary encoder, but may be an angular velocity sensor of the same type as the calibrated angular velocity sensor 12. Specifically, the standard angle sensor 13 may be attached to the calibrated angular velocity sensor 12 or the tilt table 11a so that its rotation and orientation change integrally with the calibrated angular velocity sensor 12, and measure the changes in rotation and orientation of the calibrated angular velocity sensor 12.

[0033] The self-calibrating encoder used in the standard angle sensor 13 of this embodiment employs a sensor head that irradiates semiconductor laser light onto a high-resolution scale made of a diffraction grating to read the number of graduations (scale marks), thereby achieving an angle accuracy of ±0.1 arc seconds, a resolution of 0.0012 arc seconds, and a sampling rate of 50 μsec.

[0034] The scale plate (scale unit) (not shown) of the standard angle sensor 13 according to this embodiment is attached to the end face of a rotation shaft that is attached to the tilt table 11a and tilts the tilt table 11a. The standard angle sensor 13 measures the trajectory of the rotation angle of the rotation shaft of the tilt angle generating unit 11, i.e., the change in the rotation angle over time. In addition, the tilt angle θ in this embodiment refers to the angle between a horizontal line 11b and a tilt table 11a on the drawings, as shown in FIG.

[0035] The time measurement unit 21 measures the time based on the reference time. In this embodiment, time measurement unit 21 measures time using a highly accurate and stable frequency generated by an oven-controlled crystal oscillator as a time reference (reference time). An oven-controlled crystal oscillator is a high-precision oscillator that uses a thermostatic oven to keep the temperature of the crystal oscillator constant, minimizing changes in output frequency caused by changes in the ambient temperature.

[0036] The accuracy of an oven-controlled crystal oscillator depends on the frequency-temperature characteristics and long-term frequency stability, but it has the highest accuracy of all crystal oscillators, second only to atomic oscillators. The characteristics of an oven-controlled crystal oscillator are that the frequency deviation in response to ambient temperature changes (ambient temperature -40°C to +85°C) ranges from a few ppb (parts per billion) to several tens of ppb (frequency-temperature characteristics), and the frequency deviation over time ranges from a few tenths of ppb / day to several ppb / day (long-term frequency stability), and low near-field phase noise can be expected due to irregular fluctuations in the phase of the output signal (phase noise).

[0037] The time measurement unit 21 of this embodiment is built into the angular velocity sensor calibration device 10 and used as one of its functional units, but is not limited thereto and may be prepared as a unit independent of the angular velocity sensor calibration device 10. For example, an oven-controlled crystal oscillator built into a commercially available frequency counter may be used as the time measurement unit 21. A frequency counter is a measuring instrument that can display various frequencies generated in electronic circuits as numbers and measure the frequency of AC signals.

[0038] (Functional Configuration of Angular Velocity Sensor Calibration Device 10) Next, the functional configuration of the angular velocity sensor calibration device 10 will be described with reference to FIG. The angular velocity sensor calibration device 10 is an information processing device (computer) such as a personal computer (hereinafter referred to as a PC), a notebook PC, or a tablet PC, or a control device equipped with an information processing device, and includes, as functional units, a synchronization signal generating unit 22, a start time acquiring unit 23, an end time acquiring unit 24, a time standard acquiring unit 25, an angle standard calculating unit 26, an angular velocity standard calculating unit 27, a calibrated angular velocity acquiring unit 28, a deviation amount calculating unit 29, and an output unit 30.

[0039] The synchronization signal generating unit 22 generates a voltage signal 33 at the start and end of measurement of the tilt while the tilt of the tilt table 11a is being increased at a constant speed for calibration (FIGS. 5 and 6). The synchronization signal generating unit 22 generates a voltage signal 33 based on an external operation. This voltage signal 33 is input as a synchronization signal to the calibrated angular velocity sensor 12, the standard angle sensor 13, and the time measuring unit 21. The calibrated angular velocity sensor 12, the standard angle sensor 13, and the time measuring unit 21 perform predetermined operations based on the detection of the voltage signal 33.

[0040] The voltage signal 33 generated by the synchronization signal generating section 22 will be described with reference to Fig. 5. Fig. 5 is a diagram for explaining the voltage signal 33 generated by the synchronization signal generating section 22 according to this embodiment.

[0041] The voltage signal 33 is one or more square waves. A square wave is an AC wave whose magnitude changes over time, and is a waveform that takes two values, for example, 0 (V) and 5 (V) (see FIG. 5(a)), and -5 (V) and 5 (V) (see FIG. 5(b)). In this embodiment, the voltage signal 33 is a square wave as shown in FIG. 5(a). The calibrated angular velocity sensor 12, the standard angle sensor 13, and the time measurement unit 21 have different threshold levels (voltages) for detecting input signals, and the time required for detecting the input signals is different, so that the delay times from when the synchronization signal generating unit 22 generates the voltage signal 33 until it is detected may differ. The threshold levels (voltages) vary depending on the ICs (integrated circuits) used in the terminals that receive the input signals of the calibrated angular velocity sensor 12, the standard angle sensor 13, and the time measurement unit 21. For this reason, for example, even if the calibrated angular velocity sensor 12 is the same, the threshold levels (voltages) are different, and the delay times when detecting the input signals are different.

[0042] The high-level voltage 34 of the voltage signal 33 is set to a voltage value that is reliably recognized as a high level by the calibrated angular velocity sensor 12, the standard angle sensor 13, and the time measurement unit 21, and the high-level voltage 34 of the voltage signal 33 used in this embodiment is 5 (V). Note that the voltage signal 33 is not limited to a square wave, and may be a pulse wave, a sine wave, or a step wave other than a square wave as long as it has high and low voltage values.

[0043] The start time acquisition unit 23 acquires as the start time 23a of the measurement of the tilt of the tilt table 11a the time indicated by the time measurement unit 21 when the sensor to be calibrated 12 or the standard angle sensor 13 that detected the voltage signal 33 at the start of the measurement of the tilt when the tilt of the tilt table 11a is increased at a constant speed for calibration detects the voltage signal 33 later. The measurement start time 23a refers to the time point at which the measurement for performing the calibration starts, and is the starting point of the time standard.

[0044] The acquisition of the measurement start time 23a by the start time acquiring section 23 will be described with reference to Fig. 6. Fig. 6 is a diagram for explaining the time standard according to this embodiment. As shown in Fig. 6, the voltage signal 33 at the start of measurement generated by the synchronization signal generating unit 22 is detected by the calibrated angular velocity sensor 12, the standard angle sensor 13, and the time measuring unit 21 after each having a different delay time. In the example of Fig. 6, the voltage signal 33 at the start of measurement is first detected by the time measuring unit 21, then detected by the standard angle sensor 13, and finally detected by the calibrated angular velocity sensor 12. The order shown in Fig. 6 is one example, and the order of detection may change, and it is also assumed that the voltage signal 33 at the start of measurement is first detected by the time measuring unit 21, then detected by the calibrated angular velocity sensor 12, and finally detected by the standard angle sensor 13.

[0045] 6, the start time acquiring unit 23 acquires as the start time of the measurement the time (start time 23a) indicated by the time measuring unit 21 at the detection time of the voltage signal 33 of the later calibrated angular velocity sensor 12 of the calibrated angular velocity sensor 12 or the standard angle sensor 13 which detected the voltage signal 33 at the start of the measurement of the tilt of the tilt table 11a. Note that, if the detection of the voltage signal 33 at the start of the measurement of the tilt of the tilt table 11a is later for the standard angle sensor 13 than for the calibrated angular velocity sensor 12, the start time acquiring unit 23 acquires as the start time of the measurement the time (start time 23a) indicated by the time measuring unit 21 at the detection time of the voltage signal 33 of the later standard angle sensor 13.

[0046] The end time acquisition unit 24 acquires, as the end time of the measurement of the tilt of the tilt table 11a, the time (end time 24a) indicated by the time measurement unit 21 when the sensor to be calibrated 12 or the standard angle sensor 13 that detected the voltage signal 33 at the end of the measurement of the tilt of the tilt table 11a earlier, out of the calibrated angular velocity sensor 12 or the standard angle sensor 13 that detected the voltage signal 33 at the end of the measurement of the tilt of the tilt table 11a when the tilt of the tilt table 11a is increased at a constant speed for calibration, detects the voltage signal 33. The measurement end time 24a refers to the time point at which the measurement for performing calibration ends, and is the end point of the time standard.

[0047] With reference to Fig. 6, the acquisition of the measurement end time 24a by the end time acquisition unit 24 will be described. As shown in Fig. 6, the voltage signal 33 at the end of the measurement generated by the synchronization signal generation unit 22 is detected by the calibrated angular velocity sensor 12, the standard angle sensor 13, and the time measurement unit 21 after each having a different delay time. In the example of Fig. 6, the voltage signal 33 at the end of the measurement is first detected by the time measurement unit 21, then detected by the standard angle sensor 13, and finally detected by the calibrated angular velocity sensor 12. The order shown in Fig. 6 is an example, and the order of detection may change as in the case of the detection of the voltage signal 33 at the start of the measurement, and it is also assumed that the voltage signal 33 at the end of the measurement is first detected by the time measurement unit 21, then detected by the calibrated angular velocity sensor 12, and finally detected by the standard angle sensor 13.

[0048] 6, the end time acquisition unit 24 acquires, as the end time of the measurement, the time (end time 24a) indicated by the time measurement unit 21 at the detection time of the voltage signal 33 of the later calibrated angular velocity sensor 12 out of the calibrated angular velocity sensor 12 or the standard angle sensor 13 that detected the voltage signal 33 at the end of the measurement of the tilt of the tilt table 11a. Note that, if the detection of the voltage signal 33 at the end of the measurement of the tilt of the tilt table 11a is later for the standard angle sensor 13 than for the calibrated angular velocity sensor 12, the end time acquisition unit 24 acquires, as the end time of the measurement, the time (end time 24a) indicated by the time measurement unit 21 at the detection time of the voltage signal 33 of the later standard angle sensor 13.

[0049] The time standard acquisition section 25 acquires the period between the start time 23a acquired by the start time acquisition section 23 and the end time 24a acquired by the end time acquisition section 24 as a time standard 25a. The time standard 25a is the period to be calibrated, and calibration is performed by comparing the indication of the calibrated angular velocity sensor 12 during this period with the angular velocity standard.

[0050] The angle standard calculation unit 26 obtains the difference between the indication value of the standard angle sensor 13 at the start time 23a and the indication value of the standard angle sensor 13 at the end time 24a as the angle standard.

[0051] The angular velocity standard calculation unit 27 divides the angle standard calculated by the angle standard calculation unit 26 by the time standard acquired by the time standard acquisition unit 25 to calculate the angular velocity standard. The angular velocity standard is calculated based on the angle standard and the time standard, and therefore can be said to meet the calibration standard.

[0052] The calibration target angular velocity acquisition unit 28 acquires the indication value of the calibration target angular velocity sensor 12 at the start time 23a and the indication value of the calibration target angular velocity sensor 12 at the end time 24a.

[0053] The deviation amount calculation unit 29 calculates the deviation amount of the calibrated angular velocity sensor 12 from the angular velocity standard based on the angular velocity standard calculated by the angular velocity standard calculation unit 27, the indication values ​​of the calibrated angular velocity sensor 12 at the start time 23a and end time 24a acquired by the calibrated angular velocity acquisition unit 28, and the time standard 25a acquired by the time standard acquisition unit 25. The deviation amount is the difference between the measurement value of the calibrated angular velocity sensor 12 at the time standard 25a and the angular velocity standard.

[0054] The deviation calculation unit 29 may determine the deviation as a value obtained by dividing the difference between the average value of the indication value of the calibrated angular velocity sensor 12 at the start time 23a and the indication value of the calibrated angular velocity sensor 12 at the end time 24a and the angular velocity standard by the time standard 25a.

[0055] The deviation calculation unit 29 may also determine the deviation as a value obtained by dividing the difference between the average value of the indication value of the calibrated angular velocity sensor 12 at the start time 23a and the indication value of the calibrated angular velocity sensor 12 at the end time 24a and the angular velocity standard by the angular velocity standard. The deviation means the proportion of the difference to the angular velocity standard.

[0056] The output unit 30 outputs the angular velocity standard calculated by the angular velocity standard calculation unit 27 . In addition, the output unit 30 may further output the time standard acquired by the time standard acquisition unit 25, the angle standard calculated by the angle standard calculation unit 26, and the indication value of the calibrated angular velocity sensor 12 at the start time 23a and the indication value of the calibrated angular velocity sensor 12 at the end time 24a acquired by the calibrated angular velocity acquisition unit 28. The output unit 30 can output the above-mentioned values ​​to a display device (not shown) such as a monitor of the angular velocity sensor calibration device 10, and display them to the user.

[0057] (How to calibrate the angular velocity sensor) Next, a method for calibrating the angular velocity sensor will be described with reference to Fig. 7. Fig. 7 is a flowchart of the method for calibrating the angular velocity sensor according to this embodiment. The angular velocity sensor calibration method calibrates the calibrated angular velocity sensor 12 using a tilt angle generating unit 11 that changes the tilt of a tilt table 11a on which the calibrated angular velocity sensor 12 to be calibrated is placed, a standard angle sensor 13 that measures an angle standard that serves as the calibration standard, and a time measuring unit 21 that measures the time based on a reference time.

[0058] The angular velocity sensor calibration method includes a synchronization signal generating step S22, a start time acquiring step S23, an end time acquiring step S24, a time standard acquiring step S25, an angle standard calculating step S26, an angular velocity standard calculating step S27, a calibrated angular velocity acquiring step S28, a deviation amount calculating step S29, and an output step S30.

[0059] The angular velocity sensor calibration method is performed in the order shown in the flowchart of Fig. 7, but the order can be changed as appropriate. Note that each step overlaps with the description of the various functional parts of the angular velocity sensor calibration device 10 described above, so detailed description thereof will be omitted.

[0060] In the synchronization signal generating step S22, a voltage signal 33 is generated at the start and end of measurement of the tilt in a state in which the tilt of the tilt table 11a is increased at a constant speed for calibration (synchronization signal generating unit 22).

[0061] In the start time acquisition step S23, the time (start time 23a) indicated by the time measurement unit 21 when the sensor to be calibrated 12 or the standard angle sensor 13 that detected the voltage signal 33 at the start of the measurement of the tilt of the tilt table 11a when the tilt of the tilt table 11a is increased at a constant speed for calibration is detected by the sensor that detected the voltage signal 33 later, is acquired as the start time of the measurement of the tilt of the tilt table 11a (start time acquisition unit 23).

[0062] In the end time acquisition step S24, the time (end time 24a) indicated by the time measurement unit 21 when the sensor to be calibrated 12 or the standard angle sensor 13 that detected the voltage signal 33 at the end of the measurement of the tilt of the tilt table 11a earlier than the other sensor that detected the voltage signal 33 at the end of the measurement of the tilt of the tilt table 11a when the tilt of the tilt table 11a is increased at a constant speed for calibration is acquired as the end time of the measurement of the tilt of the tilt table 11a (end time acquisition unit 24).

[0063] In the time standard acquisition step S25, the period between the start time 23a acquired in the start time acquisition step S23 and the end time 24a acquired in the end time acquisition step S24 is acquired as a time standard 25a (time standard acquisition unit 25).

[0064] In the angle standard calculation step S26, the difference between the indication value of the standard angle sensor 13 at the start time 23a and the indication value of the standard angle sensor 13 at the end time 24a is acquired as the angle standard (angle standard calculation unit 26).

[0065] In angular velocity standard calculation step S27, the angle standard calculated in angle standard calculation step S26 is divided by the time standard 25a acquired in time standard acquisition step S25 to calculate an angular velocity standard (angular velocity standard calculation unit 27).

[0066] In the calibrated angular velocity acquisition step S28, the indication value of the calibrated angular velocity sensor 12 at the start time 23a and the indication value of the calibrated angular velocity sensor 12 at the end time 24a are acquired (calibrated angular velocity acquisition unit 28).

[0067] In deviation calculation step S29, the deviation of the calibrated angular velocity sensor 12 from the angular velocity standard is calculated based on the angular velocity standard calculated in angular velocity standard calculation step S27, the indication value of the calibrated angular velocity sensor 12 at the start time 23a and end time 24a acquired in calibrated angular velocity acquisition step S28, and the time standard 25a acquired in time standard acquisition step S25 (deviation calculation unit 29).

[0068] In the output step S30, the angular velocity standard calculated in the angular velocity standard calculation step S27 is output (output unit 30). In addition, in the output step S30, it is also possible to output the time standard 25a acquired in the time standard acquisition step S25, the angle standard calculated in the angle standard calculation step S26, and the indication value of the calibrated angular velocity sensor 12 at the start time 23a and the indication value of the calibrated angular velocity sensor 12 at the end time 24a acquired in the calibrated angular velocity acquisition step S28.

[0069] According to the angular velocity sensor calibration device 10 of the above embodiment, even if the delay times for detection by the calibrated angular velocity sensor 12 and the standard angle sensor 13 are different in response to an external operation to start measurement and an operation to end measurement, the timing of measurements for the purpose of calibrating the calibrated angular velocity sensor 12 and the standard angle sensor 13 can be matched.

[0070] The present invention is not limited to the angular velocity sensor calibration device 10 and the angular velocity sensor calibration method according to the above-described embodiment, and may be embodied in various other modified or applied examples without departing from the gist of the present invention as set forth in the claims. [Explanation of symbols]

[0071] 10 Angular rate sensor calibration device 11 Tilt angle generating section 11a Tilting table 11b Horizontal line 12 Angular velocity sensor to be calibrated 13 Standard Angle Sensor 14a Initial state 14b 1st inclination angle 14c 2nd tilt angle 14d 3rd inclination angle 15 Rotation direction 21 Time measurement section 22 Synchronization signal generator 23 Start time acquisition part 23a Start time 24 End time acquisition section 24a End time 25 Time Standard Acquisition Department 25a time standard 26 Angle standard calculation unit 27 Angular velocity standard calculation section 28 Angular velocity acquisition section to be calibrated 29 Displacement calculation unit 30 Output section 33 Voltage Signal 34 High Level Voltage 41 Startup operations 42 End-of-life operations θ Tilt angle

Claims

1. An angular velocity sensor calibration device for calibrating an angular velocity sensor to be calibrated, comprising: a tilt angle generating unit for changing the tilt of a tilt table on which a calibration target angular velocity sensor to be calibrated is placed; a standard angle sensor for measuring an angle standard that serves as a calibration standard; and a time measuring unit for measuring time based on a reference time, the device comprising: a synchronization signal generating unit that generates a voltage signal at the start and end of measurement of the tilt in a state in which the tilt of the tilt table is increased at a constant speed in order to perform the calibration; a start time acquisition unit that acquires, as a start time of the measurement, a time indicated by the time measurement unit when a voltage signal is detected by the sensor that detects the voltage signal at the start of the measurement later, out of the calibrated angular velocity sensor or the standard angular sensor that detects the voltage signal at the start of the measurement; an end time acquisition unit that acquires, as an end time of the measurement, a time indicated by the time measurement unit when a voltage signal is detected by the sensor that detects the end voltage signal earlier, of the calibrated angular velocity sensor or the standard angle sensor that detects the end voltage signal; a time standard acquisition unit that acquires, as a time standard, a period between the start time acquired by the start time acquisition unit and the end time acquired by the end time acquisition unit; an angle standard calculation unit that acquires, as the angle standard, a difference between an indication value of the standard angle sensor at the start time and an indication value of the standard angle sensor at the end time; an angular velocity standard calculation unit that calculates an angular velocity standard by dividing the angle standard calculated by the angle standard calculation unit by the time standard acquired by the time standard acquisition unit; a calibrated angular velocity acquisition unit that acquires an indication value of the calibrated angular velocity sensor at the start time and an indication value of the calibrated angular velocity sensor at the end time; a deviation amount calculation unit that calculates a deviation amount of the calibrated angular velocity sensor from the angular velocity standard based on the angular velocity standard calculated by the angular velocity standard calculation unit, the indication values ​​of the calibrated angular velocity sensor at the start time and the end time acquired by the calibrated angular velocity acquisition unit, and the time standard acquired by the time standard acquisition unit; An angular velocity sensor calibration device comprising:

2. The deviation amount calculation unit calculates the deviation amount by 2. The angular velocity sensor calibration device according to claim 1, wherein the difference between the average value of the indication value of the calibrated angular velocity sensor at the start time and the indication value of the calibrated angular velocity sensor at the end time and the angular velocity standard is divided by the time standard to obtain a value.

3. The deviation amount calculation unit calculates the deviation amount by 2. The angular velocity sensor calibration device according to claim 1, wherein the difference between the average value of the indication value of the calibrated angular velocity sensor at the start time and the indication value of the calibrated angular velocity sensor at the end time and the angular velocity standard is divided by the angular velocity standard to obtain a value.

4. 2. The angular velocity sensor calibration device according to claim 1, further comprising an output unit that outputs the angular velocity standard calculated by the angular velocity standard calculation unit.

5. The standard angle sensor is a self-calibrating encoder.

2. The angular velocity sensor calibration device according to claim 1.

6. The standard angle sensor is 2. The angular velocity sensor calibration device according to claim 1, further comprising: a scale formed by a diffraction grating; and a sensor head for irradiating the scale with laser light to read the number of the scale marks.

7. A method for calibrating an angular velocity sensor to be calibrated, comprising: a tilt angle generating unit that changes the tilt of a tilt table on which a calibration target angular velocity sensor to be calibrated is placed; a standard angle sensor that measures an angle standard that is a calibration standard; and a time measuring unit that measures time based on a reference time, the method comprising: a synchronization signal generating step of generating a voltage signal at the start and end of measurement of the tilt while the tilt of the tilt table is being increased at a constant rate for performing the calibration; a start time acquisition step of acquiring, as a start time of the measurement, a time indicated by the time measurement unit when a voltage signal is detected by the sensor that detects the voltage signal at the start of the measurement later, out of the calibrated angular velocity sensor or the standard angle sensor that detects the voltage signal at the start of the measurement; an end time acquisition step of acquiring, as an end time of the measurement, a time indicated by the time measurement unit when a voltage signal is detected by the sensor that detects the end voltage signal earlier, out of the calibrated angular velocity sensor or the standard angle sensor that detects the end voltage signal; a time standard acquisition step of acquiring, as a time standard, a period between the start time acquired in the start time acquisition step and the end time acquired in the end time acquisition step; an angle standard calculation step of acquiring, as the angle standard, a difference between an indication value of the standard angle sensor at the start time and an indication value of the standard angle sensor at the end time; an angular velocity standard calculation step of calculating an angular velocity standard by dividing the angle standard calculated in the angle standard calculation step by the time standard acquired in the time standard acquisition step; a calibrated angular velocity acquisition step of acquiring an indication value of the calibrated angular velocity sensor at the start time and an indication value of the calibrated angular velocity sensor at the end time; a deviation amount calculation step of calculating a deviation amount of the calibrated angular velocity sensor from the angular velocity standard based on the angular velocity standard calculated in the angular velocity standard calculation step, the indication values ​​of the calibrated angular velocity sensor at the start time and the end time acquired in the calibrated angular velocity acquisition step, and the time standard acquired in the time standard acquisition step; Angular velocity sensor calibration method comprising:

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