Angular rate sensor

Abstract

To provide an angular velocity sensor capable of performing offset correction with high accuracy.SOLUTION: An angular velocity sensor 1 comprises an angular velocity detection element 11 and a control circuit 100. The angular velocity detection element 11 outputs an angular velocity signal. The control circuit 100 includes an angular velocity averaging section 111, a determination processing section 130, an offset amount calculation section 141, and an angular velocity correction section 142. The angular velocity averaging section 111 time-averages the angular velocity signal to generate an angular velocity average signal. The determination processing section 130 determines whether the sensor is in a state where an angular velocity is applied. The offset amount calculation section 141 outputs an offset correction amount for the angular velocity average signal as an angular velocity correction signal. The angular velocity correction section 142 applies the angular velocity correction signal to the angular velocity average signal. The offset amount calculation section 141 calculates the angular velocity correction signal in a first period where the sensor is in the applied state on the basis of the angular velocity signal in a second period where the sensor is not in the applied state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an angular velocity sensor, and more particularly to an angular velocity sensor that measures angular velocity. [Background technology]

[0002] Conventionally, offset (bias) correction has been performed in angular velocity sensors that measure angular velocity. Conventional offset correction methods use a static offset amount, a dynamic offset amount, and a transition offset amount, as disclosed in Patent Document 1, for example. In Patent Document 1, the static offset amount is a static average that is an average of sensor output while stationary. In Patent Document 1, the dynamic offset amount is a dynamic average that is an average of sensor output while moving. In Patent Document 1, the transition offset amount is calculated from the dynamic average and the static average. The angular velocity sensor disclosed in Patent Document 1 performs offset correction using the dynamic offset amount while moving, and the static offset amount or transition offset amount while stationary. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2016-512328 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the offset amount of the angular velocity sensor may change due to aging of the angular velocity sensor, etc. Therefore, the accuracy of the offset correction may not be sufficiently high when using a conventional method for calculating the correction amount for offset correction in an angular velocity sensor.

[0005] The present disclosure has been made in consideration of the above-described problems, and aims to provide an angular velocity sensor that can perform offset correction with high accuracy. [Means for solving the problem]

[0006] An angular velocity sensor according to one aspect of the present disclosure includes an angular velocity detection element and a control circuit. The angular velocity detection element detects an angular velocity around a detection axis and outputs an angular velocity signal. The control circuit processes the angular velocity signal. The control circuit includes an angular velocity averaging unit, a determination processing unit, an offset amount calculation unit, and an angular velocity correction unit. The angular velocity averaging unit time-averages the angular velocity signal to generate an angular velocity average signal. The determination processing unit determines whether the angular velocity is applied to the angular velocity detection element. The offset amount calculation unit calculates an offset correction amount for the angular velocity average signal and outputs it as an angular velocity correction signal. The angular velocity correction unit applies the angular velocity correction signal to the angular velocity average signal and outputs a corrected angular velocity signal. The offset amount calculation unit calculates the angular velocity correction signal for a first period during which the determination processing unit determines the angular velocity is applied, based on the angular velocity signal for a second period during which the determination processing unit determines the angular velocity is not applied. The determination processing unit further determines whether or not an impact has been applied to the angular velocity detection element. During a third period in which the determination processing unit determines that the angular velocity detection element is not in an impact applied state, the angular velocity averaging unit outputs an average of the angular velocity signals over a fifth period as the angular velocity average signal. During a fourth period in which the determination processing unit determines that the angular velocity detection element is in an impact applied state, the angular velocity averaging unit outputs an average of the angular velocity signals over a sixth period that is longer than the fifth period as the angular velocity average signal. [Effects of the Invention]

[0007] According to an angular velocity sensor according to an aspect of the present disclosure, angular velocity information can be corrected with high accuracy by performing offset correction using an angular velocity signal when the angular velocity sensor is not in a voltage-applied state. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a functional block diagram showing the logical configuration of the angular velocity sensor according to the first embodiment. [Figure 2] FIG. 2 is a functional block diagram showing a logical configuration of a determination processing unit in the angular velocity sensor. [Figure 3] FIG. 3 is a flowchart showing the operation of the control circuit in the angular velocity sensor. [Figure 4] FIG. 4 is a flowchart showing the operation of the control circuit in the applied state. [Figure 5]FIG. 5 is a flowchart showing the operation of the control circuit in the non-energized state. [Figure 6] Fig. 6A is a graph showing time-series changes in the angular velocity signal and the offset amount, and Fig. 6B is an enlarged view of a region in Fig. 6A where the angular velocity is near 0. [Figure 7] FIG. 7 is a functional block diagram showing a logical configuration of a determination processing unit in the angular velocity sensor according to the first modification. [Figure 8] FIG. 8 is a functional block diagram showing the logical configuration of the angular velocity sensor according to the second embodiment. [Figure 9] FIG. 9 is a functional block diagram showing a logical configuration of a determination processing unit in the angular velocity sensor. [Figure 10] Fig. 10A is a functional block diagram showing the logical configuration of an angular velocity averaging unit in the angular velocity sensor according to the second modification, and Fig. 10B is a functional block diagram showing the logical configuration of an angular velocity averaging unit in the angular velocity sensor according to the second modification. [Figure 11] FIG. 11 is a graph showing time-series changes in the angular velocity signal and the average angular velocity signal. [Figure 12] FIG. 12 is a functional block diagram showing the logical configuration of an angular velocity sensor according to another modified example 1. In FIG. [Figure 13] FIG. 13 is a functional block diagram showing the logical configuration of an angular velocity sensor according to another modified example 2. In FIG. [Figure 14] FIG. 14 is a functional block diagram showing the logical configuration of a determination processing unit according to another modified example 4. In FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] (Embodiment 1) The angular velocity sensor 1 according to the present disclosure will be described below with reference to the drawings.

[0010] (1) Angular velocity sensor 1 is a block diagram showing the logical configuration of an angular velocity sensor 1 according to embodiment 1. The angular velocity sensor 1 according to embodiment 1 includes an angular velocity detection element 11 and a control circuit 100.

[0011] (2) Angular velocity detection element The angular velocity detection element 11 is a uniaxial gyro sensor. The angular velocity detection element 11 detects an angular velocity around a detection axis. The angular velocity detection element 11 is, for example, a so-called MEMS (Micro Electro Mechanical Systems) gyro sensor. The angular velocity detection element 11 includes, for example, a vibrating electrode and a detection electrode. The vibrating electrode vibrates in a first direction perpendicular to the detection axis. The detection electrode detects the movement of the vibrating electrode in a second direction perpendicular to both the detection axis and the first direction using electrostatic capacitance. Note that the structure of the angular velocity detection element 11 is not limited to the above-described structure, and any structure may be used as long as it is capable of detecting an angular velocity around the detection axis.

[0012] The angular velocity detection element 11 outputs an angular velocity signal ωr indicating the angular velocity to the control circuit 100. The angular velocity signal ωr is output, for example, as a voltage value. The absolute value of the angular velocity signal ωr is the absolute value of the amplitude of the angular velocity signal ωr, and indicates the magnitude of the angular velocity. The sign of the angular velocity signal ωr indicates the direction of rotation. The unit of the angular velocity is, for example, deg / sec (hereinafter referred to as "dps"). Note that the unit of the angular velocity may be another unit indicating the angular velocity, such as rad / sec.

[0013] (3) Control circuit (3.1) Overview of the control circuit The control circuit 100 acquires the angular velocity signal ωr from the angular velocity detection element 11. Then, the control circuit 100 corrects the angular velocity signal ωr.

[0014] As shown in FIG. 1, the control circuit 100 includes an angular velocity averaging unit 111, a determination processing unit 130, an offset amount calculation unit 141, and an angular velocity correction unit 142.

[0015] The control circuit 100 is, for example, a single ASIC (Application Specific Integrated Circuit). Note that the control circuit 100 is not limited to a single ASIC, and may be a circuit including one or more ICs, or may be a microcomputer.

[0016] (3.2) Angular velocity average part The angular velocity averaging unit 111 performs time averaging of the angular velocity signal ωr.

[0017] The angular velocity averaging unit 111 repeatedly outputs the average value of the angular velocity signal ωr per unit time. The unit time is, for example, 100 ms. That is, the angular velocity averaging unit 111 calculates the average value of the angular velocity signal ωr per 100 ms every 100 ms and outputs it as the average angular velocity signal ω0.

[0018] (3.3) Judgment processing unit The determination processing unit 130 is a circuit that determines whether or not an angular velocity is applied to the angular velocity sensor 1.

[0019] 2 is a block diagram of the determination processing unit 130. The determination processing unit 130 includes an angular velocity change amount calculation unit 131 and an application state determination unit 132, as shown in FIG.

[0020] (3.3.1) Angular velocity change calculation unit The angular velocity change amount calculation unit 131 calculates an angular velocity parameter indicating whether or not an angular velocity is applied to the angular velocity sensor 1. The angular velocity parameter is, for example, the amount of change in the angular velocity signal ωr over time. The amount of change in the angular velocity signal ωr over time is a value obtained by dividing the amount of change in the angular velocity signal ωr per unit time by the unit time. For example, if the unit time is 3 ms, the angular velocity change amount calculation unit 131 acquires the angular velocity signal ωr every 3 ms. For example, the angular velocity change amount calculation unit 131 divides the amount of change in the angular velocity signal ωr relative to the angular velocity signal ωr 3 ms prior by 3 ms, and stores the result as the amount of change in the angular velocity signal ωr over time. For example, if the unit of the angular velocity signal ωr is dps, the unit of the amount of change in the angular velocity signal ωr over time is, for example, dps / s. The angular velocity change amount calculation unit 131 calculates, for example, the absolute value of the amount of change in the angular velocity signal ωr over time as the angular velocity parameter.

[0021] (3.3.2) Voltage application status determination unit The voltage application state determination unit 132 determines whether or not an angular velocity is applied to the angular velocity sensor 1.

[0022] Specifically, based on the angular velocity parameter, the application state determination unit 132 determines whether or not an angular velocity is applied to the angular velocity sensor 1. Hereinafter, the state in which an angular velocity is applied to the angular velocity detection element 11 of the angular velocity sensor 1 will be referred to as the "application state."

[0023] The application state determination unit 132 determines that a state in which the angular velocity parameter exceeds the change amount threshold is an application state. In other words, the application state determination unit 132 determines that a state in which the angular velocity parameter is equal to or less than the change amount threshold is not an application state. The change amount threshold is, for example, 0.01 dps / s.

[0024] The voltage application state determination unit 132 repeatedly determines whether or not the angular velocity sensor 1 is in an applied state at a predetermined cycle. The predetermined cycle is, for example, 3 ms. The voltage application state determination unit 132 also outputs the determination result as an application state signal St1 at the predetermined cycle. The application state signal St1 is a signal that indicates whether the angular velocity sensor 1 is in an applied state or not.

[0025] Hereinafter, a period during which the application state determination unit 132 determines that the angular velocity sensor 1 is in an applied state will be referred to as a first period. Furthermore, a period during which the application state determination unit 132 determines that the angular velocity sensor 1 is not in an applied state will be referred to as a second period. For example, when no angular velocity is applied to the angular velocity sensor 1, the application state determination unit 132 determines that the angular velocity sensor 1 is not in an applied state. This period during which the angular velocity sensor 1 is not in an applied state is the second period. Furthermore, when an angular velocity is subsequently applied to the angular velocity sensor 1, the application state determination unit 132 determines that the angular velocity sensor 1 is in an applied state. That is, when the angular velocity applied to the angular velocity sensor 1 is no longer zero, the second period ends and the first period begins. Furthermore, when the angular velocity applied to the angular velocity sensor 1 becomes zero, the application state determination unit 132 determines that the angular velocity sensor 1 is not in an applied state. That is, when the angular velocity applied to the angular velocity sensor 1 becomes zero, the application state determination unit 132 determines that the angular velocity sensor 1 is not in an applied state.

[0026] (3.4) Offset calculation unit The offset amount calculation unit 141 outputs an angular velocity correction signal ωc for offset-correcting the angular velocity average signal ω0 based on the application-state signal St1 output by the determination processing unit 130. The angular velocity correction signal ωc indicates the offset amount relative to the angular velocity average signal ω0.

[0027] The offset amount calculation unit 141 acquires the angular velocity signal ωr from the angular velocity detection element 11. The offset amount calculation unit 141 also acquires the angular velocity average signal ω0 from the angular velocity averaging unit 111.

[0028] If the application state signal St1 indicates that the angular velocity sensor 1 is not in an application state, the offset amount calculation unit 141 outputs the angular velocity average signal ω0 as the angular velocity correction signal ωc. If the determination processing unit 130 determines that the angular velocity sensor 1 is not in an application state, no angular velocity is applied to the angular velocity sensor 1. Therefore, the angular velocity average signal ω0 is used as is as the angular velocity correction signal ωc. As a result, the angular velocity average signal ω0 is offset-corrected by the angular velocity average signal ω0, and the angular velocity after the offset correction becomes 0.

[0029] Furthermore, the offset amount calculation unit 141 calculates the time average of the angular velocity signal ωr during the second period and stores the calculated time average as the on-voltage offset amount ωd. When the content indicated by the application state signal St1 changes from a non-applied state to an applied state, the offset amount calculation unit 141 outputs the on-voltage offset amount ωd calculated during the immediately preceding second period as the angular velocity correction signal ωc during the started first period. That is, when the determination processing unit 130 determines that the angular velocity sensor 1 is in the applied state, the offset amount calculation unit 141 outputs the angular velocity correction signal ωc with the average of the angular velocity signal ωr during the immediately preceding second period as the offset amount.

[0030] For example, the offset amount calculation unit 141 holds the angular velocity signal ωr during the second period. Then, when the content indicated by the application state signal St1 changes from a non-application state to an application state, the offset amount calculation unit 141 calculates the time average of the held angular velocity signal ωr during the second period, and sets the calculated value as the angular velocity correction signal ωc.

[0031] When the content indicated by the application state signal St1 changes from the applied state to the non-applied state, the offset amount calculation unit 141 initializes the applied offset amount ωd that it has been holding, and outputs the average angular velocity signal ω0 as the angular velocity correction signal ωc. Then, the time average of the angular velocity signal ωr in the new second period is held as the applied offset amount ωd. This process ensures that the angular velocity correction signal ωc in the first period is output based on the angular velocity signal ωr in the immediately preceding second period, even if fluctuations in the offset amount occur due to environmental changes such as temperature changes, or aging, etc. Therefore, the offset amount calculation unit 141 can always output an appropriate angular velocity correction signal ωc.

[0032] (3.5) Angular velocity correction section Angular velocity correction section 142 applies angular velocity correction signal ωc output by offset amount calculation section 141 to angular velocity average signal ω0 output by angular velocity averaging section 111 to generate corrected angular velocity signal ωa.

[0033] The angular velocity correction unit 142 subtracts the angular velocity correction signal ωc from the angular velocity average signal ω0 to generate a corrected angular velocity signal ωa.

[0034] (4) Operation FIG. 3 is a flowchart showing the operation of the control circuit 100 according to the first embodiment.

[0035] The determination processing unit 130 of the control circuit 100 determines whether the angular velocity sensor 1 is in an applied state (step S1). As described above, the determination processing unit 130 determines that the angular velocity sensor 1 is in an applied state if the amount of change in the angular velocity over time exceeds the change amount threshold. Furthermore, the determination processing unit 130 determines that the angular velocity sensor 1 is not in an applied state if the amount of change in the angular velocity over time is equal to or less than the change amount threshold.

[0036] When the determination processing unit 130 determines that the angular velocity sensor 1 is in the applied state ("Yes" in step S1), the control circuit 100 executes step S2, which is the applied state operation, as follows: Fig. 4 is a flowchart showing the operation of the control circuit 100 when the angular velocity sensor 1 is in the applied state.

[0037] The angular velocity averaging unit 111 of the control circuit 100 performs time averaging processing on the angular velocity signal ωr output by the angular velocity detection element 11 to output the angular velocity average signal ω0 (step S11). The angular velocity averaging unit 111 calculates the time average of the angular velocity signal ωr as the angular velocity average signal ω0.

[0038] The offset amount calculation unit 141 of the control circuit 100 outputs the on-voltage offset amount ωd generated and held during the immediately preceding second period as the angular velocity correction signal ωc (step S12). The process of generating and holding the on-voltage offset amount ωd will be described later.

[0039] The angular velocity correction unit 142 of the control circuit 100 applies the angular velocity correction signal ωc to the average angular velocity signal ω0, and outputs the corrected angular velocity signal ωa (step S13).

[0040] With the above operations, step S2 is completed.

[0041] Returning to FIG. 3, the explanation continues. Next, the determination processing unit 130 of the control circuit 100 again determines whether the angular velocity sensor 1 is in an applied state (step S4). Details are the same as those of step S1, so they are omitted. If the determination processing unit 130 determines that the angular velocity sensor 1 is in an applied state ("Yes" in step S4), the first period is considered to be continuing, and the control circuit 100 performs step S2 again. On the other hand, if the determination processing unit 130 determines that the angular velocity sensor 1 is not in an applied state ("No" in step S4), the first period is considered to have ended and the second period has begun, and the control circuit 100 initializes the applied offset amount ωd (step S5). After step S5, the control circuit 100 starts step S3, which is the operation when the angular velocity sensor 1 is not in an applied state.

[0042] The following describes step S3, which is the operation of the control circuit 100 when no voltage is applied. Fig. 5 is a flowchart showing the operation of the control circuit 100 when the angular velocity sensor 1 is not in a voltage-applied state.

[0043] The angular velocity averaging unit 111 of the control circuit 100 performs time averaging processing on the angular velocity signal ωr output by the angular velocity detecting element 11, and outputs the angular velocity average signal ω0 (step S11).

[0044] The offset amount calculation unit 141 of the control circuit 100 outputs the angular velocity average signal ω0 as the angular velocity correction signal ωc (step S21).

[0045] The offset amount calculation unit 141 of the control circuit 100 calculates the average of the angular velocity signal ωr during the second period and stores it as the upon-application offset amount ωd (step S22). For example, the offset amount calculation unit 141 stores all of the angular velocity signals ωr during the second period in a buffer memory, calculates the time average, and stores it as the upon-application offset amount ωd. For example, the offset amount calculation unit 141 additionally stores the angular velocity signal ωr in the buffer memory every time the angular velocity signal ωr is output from the angular velocity detection element 11. The offset amount calculation unit 141 also recalculates the time average of the angular velocity signal ωr from the start of the second period to the present, and updates and stores the upon-application offset amount ωd.

[0046] Alternatively, the operation of the offset amount calculation unit 141 in step S22 may be as follows. The offset amount calculation unit 141 holds, for example, the length of the second period and the upon-voltage offset amount ωd, which is the time average of the angular velocity signal ωr since the start of the second period. Every time the angular velocity signal ωr is output from the angular velocity detection element 11, the offset amount calculation unit 141 updates the length of the second period and the upon-voltage offset amount ωd to their latest values ​​based on the length of the second period, the upon-voltage offset amount ωd, and the angular velocity signal ωr.

[0047] Alternatively, the operation of the offset amount calculation unit 141 in step S22 may be as follows. During the second period, the offset amount calculation unit 141 calculates the time average of the angular velocity signal ωr for a predetermined time length going back from the current time and stores it as the upon-application offset amount ωd. The predetermined time length is, for example, three seconds. In this case, during the second period, for example, every time the angular velocity signal ωr is output from the angular velocity detection element 11, the offset amount calculation unit 141 calculates the time average of the angular velocity signal ωr for the most recent three seconds and updates and stores the upon-application offset amount ωd.

[0048] The angular velocity correction unit 142 of the control circuit 100 applies the angular velocity correction signal ωc to the average angular velocity signal ω0, and outputs the corrected angular velocity signal ωa (step S13).

[0049] With the above operations, step S3 is completed.

[0050] Returning to FIG. 3, the explanation continues. Next, the determination processing unit 130 of the control circuit 100 again determines whether the angular velocity sensor 1 is in an applied state (step S6). Details are the same as those of step S1, so they are omitted. If the determination processing unit 130 determines that the angular velocity sensor 1 is not in an applied state ("No" in step S6), the second period is considered to be continuing, and the control circuit 100 performs step S3 again. On the other hand, if the determination processing unit 130 determines that the angular velocity sensor 1 is in an applied state ("Yes" in step S6), the control circuit 100 starts step S2 from the beginning.

[0051] (5) Offset correction example Fig. 6A is a graph showing time-series changes in the angular velocity signal ωr and the offset amount. Fig. 6B is a partial graph showing an enlarged vertical axis of region 200 in Fig. 6. In Figs. 6A and 6B, the angular velocity signal ωr is represented by data 201, and the offset amount is represented by data 202.

[0052] 6B, in each of the second periods P2a, P2b, and P2c, the angular velocity signal ωr is not 0, but fluctuates in a range of about ±0.2 dps. Since no angular velocity is applied to the angular velocity sensor 1 in the second periods, the angular velocity signal ωr in the second periods includes noise due to environmental factors such as heat and an error due to a deviation of the angular velocity signal ωr from 0 caused by aging or the like.

[0053] In the angular velocity sensor 1 according to the first embodiment, the attitude of the angular velocity sensor 1 is calculated using the angular velocity average signal ω0, which is the time average of the angular velocity signal ωr, rather than the angular velocity signal ωr itself. This reduces noise through time averaging. However, the time averaging process does not reduce the deviation of the zero point in the angular velocity signal ωr. Therefore, in the angular velocity sensor 1 according to the first embodiment, the angular velocity average signal ω0 is used as an offset amount in each of the second periods P2a, P2b, and P2c. This ensures that the corrected angular velocity signal ωa is always zero in each of the second periods P2a, P2b, and P2c. Therefore, in the second period P2a, the value obtained by integrating the corrected angular velocity signal ωa over the second period P2a is zero. In other words, the angular change of the angular velocity sensor 1 in the second period P2a is zero. Similarly, the angular change of the angular velocity sensor 1 in each of the second periods P2b and P2c is also zero. In other words, when the angular velocity sensor 1 is not rotating, it is possible to prevent the calculated attitude from rotating due to the accumulation of errors.

[0054] Furthermore, in the angular velocity sensor 1, the time average of the angular velocity signal ωr in the second period P2a, which is the immediately preceding second period, is used as the offset amount in the first period P1a. Because the first period P1a is continuous with the second period P2a on the time axis, the influence of noise and errors due to a shift in the zero of the angular velocity signal ωr on the angular velocity signal ωr is similar in the first period P1a and the second period P2a. Therefore, in the angular velocity sensor 1, by offset-correcting the average angular velocity signal ω0 in the first period P1a with the time average of the angular velocity signal ωr in the second period P2a, it is possible to remove noise and errors with high precision.

[0055] In addition, in the angular velocity sensor 1, the time average of the angular velocity signal ωr in the second period P2b, which is the immediately preceding second period, is used as the offset amount in the first period P1b. Because the first period P1b is continuous with the second period P2b on the time axis, the effects of noise and errors due to a shift in the zero of the angular velocity signal ωr on the angular velocity signal ωr are similar in the first period P1b and the second period P2b. Therefore, in the angular velocity sensor 1, noise and errors can be removed with high precision by offset correcting the average angular velocity signal ω0 in the first period P1b using the time average of the angular velocity signal ωr in the second period P2b. In addition, in the angular velocity sensor 1, the angular velocity signal ωr in the second period P2a is not used to calculate the offset amount in the first period P1b. Therefore, for example, even if the average value of the error is not the same between the second period P2a and the second period P2b, the offset correction in the first period P1b can be performed using the error in the second period P2b that is considered to be closest to the error in the first period P1b. In other words, even if the average value of the error in the angular velocity signal ωr changes over time, the angular velocity sensor 1 can remove the error with high precision by performing the offset correction using the time average of the angular velocity signal ωr in the most recent second period.

[0056] In the first embodiment, the offset amount for the first period P1b is the time average of the angular velocity signal ωr during the second period P2b, which is the immediately preceding second period. However, for example, the offset amount for the first period P1b may be the time average of the angular velocity signal ωr during a portion of the second period P2b, which is the immediately preceding second period. The period P2B is, for example, a period excluding a 500 ms period from the start time of the second period P2b and a 500 ms period from the end time of the second period P2b. Even if the determination processing unit 130 determines that the angular velocity sensor 1 is not in an applied state near the start time and end time of the second period, an angular velocity may be applied to the angular velocity sensor 1. Therefore, by excluding the periods near the start time and end time of the second period from the calculation of the time average of the angular velocity signal ωr, the accuracy of the offset amount can be further improved.

[0057] Alternatively, for example, the offset amount for the first period P1b may be the time average of the angular velocity signal ωr for a portion of the second period P2b, which is the immediately preceding second period. The portion of the second period P2b may be, for example, a period of 3 seconds prior to the end of the second period P2b. Even with this method, the offset amount for the first period P1b is based on the angular velocity signal ωr for the portion of the second period P2b, which is the immediately preceding second period, and therefore, errors in the angular velocity signal ωr for the first period P1b can be removed with high accuracy.

[0058] (6) Effects The angular velocity sensor 1 according to the first embodiment performs offset correction on the average angular velocity signal ωo for the first period based on the angular velocity signal ωr output by the angular velocity sensing element 11 for the second period. Because the angular velocity applied to the angular velocity sensor 1 for the second period is zero, the average value of the angular velocity signal ωr output by the angular velocity sensing element 11 for the second period is the average of noise and errors resulting from deviation of the angular velocity signal ωr from zero. Therefore, by using the time average of the angular velocity signal ωr output by the angular velocity sensing element 11 for the second period as the offset amount, noise and errors can be removed from the average angular velocity signal ωo with high accuracy. That is, the angular velocity sensor 1 according to the first embodiment can improve the accuracy of the corrected angular velocity signal ωa.

[0059] Furthermore, in the angular velocity sensor 1 according to the first embodiment, the angular velocity signal ωr in the first period is not used as data for calculating the offset amount in the first period. With this configuration, the angular velocity applied to the angular velocity sensor 1 is not reflected in the offset amount. Therefore, the accuracy of the corrected angular velocity signal ωa can be improved.

[0060] Furthermore, in the angular velocity sensor 1 according to the first embodiment, the determination processing unit 130 determines whether or not an angular velocity is being applied to the angular velocity sensor 1 based on the change over time in the angular velocity signal ωr. Therefore, based on whether or not a change has occurred in the angular velocity applied to the angular velocity sensor 1, it is possible to accurately determine whether or not an angular velocity has been applied to the angular velocity sensor 1.

[0061] Furthermore, in the angular velocity sensor 1 according to the first embodiment, when the angular velocity sensor 1 is not in an applied state, the average angular velocity signal ω0 is used as the angular velocity correction signal ωc. That is, when no angular velocity is applied to the angular velocity sensor 1, the corrected angular velocity signal ωa is 0. Therefore, the calculated rotational movement amount of the angular velocity sensor 1 in the first period is necessarily 0. That is, in the first period, an error in the attitude of the angular velocity sensor 1 due to an accumulation of an error between the angular velocity signal ωr and the angular velocity applied to the angular velocity sensor 1 can be suppressed.

[0062] (Variation 1) The angular velocity sensor 1 according to the first modification differs from the angular velocity sensor 1 according to the first embodiment in that the method of determining whether the angular velocity sensor 1 is in an applied state is different.

[0063] The angular velocity sensor 1 according to the first modification includes a determination processing unit 130a instead of the determination processing unit 130. Fig. 7 is a functional block diagram of the determination processing unit 130a. As shown in Fig. 7, the determination processing unit 130a includes an angular velocity average value calculation unit 133 and an application state determination unit 132a.

[0064] The angular velocity average value calculation unit 133 calculates the angular velocity average value ω1 by performing time averaging processing on the angular velocity signal ωr output by the angular velocity detection element 11. The angular velocity average value calculation unit 133 calculates the time average value of the angular velocity signal ωr as the angular velocity average value ω1.

[0065] The application state determination unit 132a uses the average angular velocity value ω1 to determine whether the angular velocity sensor 1 is in an applied state. The application state determination unit 132a stores an average threshold value corresponding to the average angular velocity value ω1 in advance. The application state determination unit 132a compares the average angular velocity value ω1 with the average threshold value. If the average angular velocity value ω1 is greater than the average threshold value, the application state determination unit 132a determines that the angular velocity sensor 1 is in an applied state. In other words, if the average angular velocity value ω1 is equal to or less than the average threshold value, the application state determination unit 132a determines that the angular velocity sensor 1 is not in an applied state. The average threshold value is, for example, 0.01 dps. Note that the above threshold value is just an example, and the threshold value may be determined arbitrarily depending on the application of the angular velocity sensor 1.

[0066] The angular velocity sensor 1 according to Modification 1 also achieves the same effects as the angular velocity sensor 1 according to Embodiment 1. That is, the angular velocity sensor 1 according to Modification 1 can also perform offset correction on the angular velocity signal ωr with high accuracy.

[0067] (Embodiment 2) Angular velocity sensor 1b according to the second embodiment differs from angular velocity sensor 1 according to the first embodiment in that determination processing unit 130b further determines whether or not angular velocity sensor 1b is in an impact applied state in which an impact has been applied, and in that the processing of angular velocity averaging unit 111b differs depending on whether or not angular velocity sensor 1b is in an impact applied state.

[0068] (1) Composition (1.1) Control circuit 8 is a functional block diagram of angular velocity sensor 1b according to embodiment 2. Angular velocity sensor 1b includes control circuit 100b instead of control circuit 100. Control circuit 100b differs from control circuit 100 in that it includes angular velocity averaging unit 111b and determination processing unit 130b. The remaining configuration is the same as that of angular velocity sensor 1 according to embodiment 1, and therefore description thereof will be omitted.

[0069] (1.2) Judgment processing unit As shown in FIG. 9, the determination processing unit 130b includes an angular velocity change amount calculation unit 131, an application state determination unit 132, and an impact determination unit .

[0070] The impact determination unit 134 determines whether the angular velocity sensor 1b is in an impact-applied state. The impact-applied state refers to a state in which an impact is applied to the angular velocity sensor 1b, causing noise due to the impact to be added to the angular velocity signal ωr. When the angular velocity sensor 1b is not in an impact-applied state, the impact determination unit 134 determines whether the angular velocity sensor 1b is in an impact-applied state based on the angular velocity signal ωr. The impact determination unit 134 stores a first angular velocity threshold in advance. The impact determination unit 134 compares the magnitude of the angular velocity signal ωr with the first angular velocity threshold. The impact determination unit 134 determines that the angular velocity sensor 1b is in an impact-applied state when the magnitude of the angular velocity signal ωr is greater than the first angular velocity threshold. In other words, when the angular velocity sensor 1b is not in an impact-applied state, if the magnitude of the angular velocity signal ωr is equal to or less than the first angular velocity threshold, the impact determination unit 134 determines that the angular velocity sensor 1b continues not to be in an impact-applied state. The first angular velocity threshold is, for example, 1 dps. The above threshold value is just an example, and the threshold value may be determined arbitrarily depending on the application of the angular velocity sensor 1b.

[0071] Furthermore, when the angular velocity sensor 1b is in the shock-applied state, the shock determination unit 134 determines whether the angular velocity sensor 1b has transitioned to a shock-free state based on the angular velocity signal ωr. The shock determination unit 134 stores a second angular velocity threshold in advance. The shock determination unit 134 determines that the angular velocity sensor 1b has transitioned to a shock-free state when the magnitude of the angular velocity signal ωr remains below the second angular velocity threshold for a predetermined period of time. In other words, when the angular velocity sensor 1b is in the shock-applied state, if the magnitude of the angular velocity signal ωr exceeds the second angular velocity threshold, the shock determination unit 134 determines that the angular velocity sensor 1b remains in the shock-applied state. Furthermore, when the angular velocity sensor 1b is in the shock-applied state, if the magnitude of the angular velocity signal ωr falls below the second angular velocity threshold and then exceeds the second angular velocity threshold before a predetermined period of time has elapsed, the shock determination unit 134 determines that the angular velocity sensor 1b remains in the shock-applied state. The angular velocity threshold is, for example, 0.01 dps. The predetermined time is, for example, 100 ms. Note that the above threshold is just an example, and the threshold may be determined arbitrarily depending on the application of the angular velocity sensor 1b.

[0072] The impact determination unit 134 outputs an impact state signal St2 indicating whether or not the angular velocity sensor 1b is in an impact applied state.

[0073] Hereinafter, the period from the time when the shock determination unit 134 determines that the angular velocity sensor 1b is in an impact-applied state to the time when the shock determination unit 134 determines that the angular velocity sensor 1b has transitioned to a non-impact-applied state will be referred to as the third period. Each consecutive period other than the third period will be referred to as the fourth period. That is, the fourth period is the period during which no impact is applied to the angular velocity sensor 1b and no impact-related noise is generated. The third period is the period from when an impact is applied to the angular velocity sensor 1b until the impact-related noise disappears. The fourth period is the period after an impact is applied to the angular velocity sensor 1b and after the impact-related noise disappears.

[0074] (1.3) Angular velocity average part FIG. 10A is a functional block diagram showing the configuration of angular velocity averaging section 111b.

[0075] The angular velocity averaging unit 111b includes a first averaging circuit 121, a second averaging circuit 122, and a selection unit 123.

[0076] The first averaging circuit 121 performs time averaging of the angular velocity signal ωr in a fifth period. The second averaging circuit 122 performs time averaging of the angular velocity signal ωr in a sixth period. The sixth period is longer than the fifth period. The fifth period is, for example, 100 ms. The sixth period is, for example, 1 s. That is, the first averaging circuit 121 outputs a 100 ms average of the angular velocity signal ωr every 100 ms. The second averaging circuit 122 outputs a 1 s average of the angular velocity signal ωr every 1 s. The sixth period may be, for example, 500 ms or 2 s.

[0077] The selection unit 123 selects either the output of the first averaging circuit 121 or the output of the second averaging circuit 122 as the angular velocity average signal ω0. If the shock state signal St2 indicates that the angular velocity sensor 1b is not in a shock state, the selection unit 123 selects the output of the first averaging circuit 121 as the angular velocity average signal ω0. In other words, if the angular velocity sensor 1b is not in a shock state, the angular velocity average signal ω0 is the average of the angular velocity signal ωr over a fifth period. On the other hand, if the shock state signal St2 indicates that the angular velocity sensor 1b is in a shock state, the selection unit 123 selects the output of the second averaging circuit 122 as the angular velocity average signal ω0. In other words, if the angular velocity sensor 1b is in a shock state, the angular velocity average signal ω0 is the average of the angular velocity signal ωr over a sixth period.

[0078] (2) Angular velocity averaging The angular velocity averaging process will be described in detail below.

[0079] FIG. 11 is a graph showing time series changes in the angular velocity signal ωr and the long-term average signal ω2 of the angular velocity. The long-term average signal ω2 is the average of the angular velocity signal ωr over the sixth period. In other words, the long-term average signal ω2 is the output of the second averaging circuit 122. In FIG. 11, the angular velocity signal ωr is represented by data 221. Also in FIG. 11, the average of the angular velocity signal ωr over the sixth period is represented by data 222 as the long-term average signal ω2.

[0080] When an impact is applied to angular velocity sensor 1b, large noise due to the impact may be mixed into angular velocity signal ωr. For example, when an impact is applied to angular velocity sensing element 11 in a direction perpendicular to the detection axis of angular velocity sensing element 11, the impact may cause a displacement inside angular velocity sensing element 11 similar to that caused when an angular velocity is applied to angular velocity sensing element 11 due to the impact. In such a case, noise due to the impact temporarily mixes into angular velocity signal ωr.

[0081] As shown in FIG. 11, the effect of noise due to an impact continues for several seconds after the impact is applied. The impact determination unit 134 detects an impact applied state at time t1 when an impact is applied to the angular velocity sensor 1b. The impact determination unit 134 also detects that an impact is no longer applied at time t2 when the impact noise in the angular velocity signal ωr has become sufficiently weak. The period between time t1 and time t2 is the third period P3. The period before time t1 is the fourth period P4a. The period after time t2 is the fourth period P4b. As shown in FIG. 11, large noise occurs in the angular velocity signal ωr during the third period P3.

[0082] The noise in the angular velocity signal ωr during the third period P3 can be reduced by lengthening the averaging period when generating the average angular velocity signal ω0 by time-averaging the angular velocity signal ωr. As shown by data 222 in FIG. 11, using the average angular velocity signal ω0 during the sixth period reduces the noise by averaging it. However, if the period for calculating the average angular velocity signal ω0 is always extended, it becomes difficult to detect short-term changes in the angular velocity signal ωr. Furthermore, the average time difference between the angular velocity signal ωr and the average angular velocity signal ω0 increases, reducing the responsiveness of the angular velocity sensor 1b. Therefore, in the angular velocity sensor 1b, the period for generating the average angular velocity signal ω0 is lengthened when an impact is applied, and the period for generating the average angular velocity signal ω0 is shortened in other cases.

[0083] (3) Effects According to the angular velocity sensor 1b of the second embodiment, when an impact is applied to the angular velocity sensor 1b, the period during which the angular velocity signal ωr is averaged to calculate the average angular velocity signal ω0 is set longer than when there is no impact. Therefore, even if noise occurs in the angular velocity signal ωr output by the angular velocity detecting element 11 due to the application of an impact to the angular velocity sensor 1b, the influence of the noise on the average angular velocity signal ω0 can be reduced. Furthermore, when there is no impact, the angular velocity sensor 1b sets the period during which the angular velocity signal ωr is averaged to calculate the average angular velocity signal ω0 shorter than when there is no impact. Therefore, when there is no impact, the angular velocity sensor 1b can improve its responsiveness.

[0084] Furthermore, according to angular velocity sensor 1b of embodiment 2, even when no shock is applied, second averaging circuit 122 calculates angular velocity average signal ω0 to be used in the shock applied state. Therefore, when a shock is applied to angular velocity sensor 1b, angular velocity averaging unit 111b can quickly change the averaging period for calculating angular velocity average signal ω0 by changing the averaging circuit selected by selection unit 123.

[0085] (Variation 2) Angular velocity sensor 1b according to Modification 2 differs from angular velocity sensor 1b according to Embodiment 2 in that angular velocity averaging section 111c does not have a selection section, but has a single averaging circuit.

[0086] 10B, the angular velocity averaging unit 111c according to the second modification includes a single averaging circuit 124. The averaging circuit 124 calculates the time average of the angular velocity signal ωr for at least two different periods. When the shock state signal St2 indicates that the shock state is not present, the averaging circuit 124 calculates the time average of the angular velocity signal ωr for a fifth period.

[0087] Furthermore, when the shock state signal St2 indicates the shock applied state, the averaging circuit 124 calculates the time average of the angular velocity signal ωr in the sixth period.

[0088] The averaging circuit 124 includes, for example, a buffer that holds the angular velocity signal ωr output by the angular velocity detecting element 11. When the shock state signal St2 indicates an impact state and the angular velocity signal ωr output during a sixth period is held in the buffer, the averaging circuit 124 calculates and outputs the time average of the angular velocity signal ωr during the sixth period and clears the buffer. When the shock state signal St2 indicates no impact state and the angular velocity signal ωr output during a fifth period is held in the buffer, the averaging circuit 124 calculates and outputs the time average of the angular velocity signal ωr during the fifth period and clears the buffer.

[0089] In the angular velocity sensor 1b according to the second modification, the period for averaging the angular velocity signal ωr to calculate the average angular velocity signal ω0 is set longer when the angular velocity sensor 1b is in an impact state than when the angular velocity sensor 1b is not in an impact state. Therefore, even if noise occurs in the angular velocity signal ωr output by the angular velocity detecting element 11 due to the application of an impact to the angular velocity sensor 1b, the effect of the noise on the average angular velocity signal ω0 can be reduced.

[0090] Furthermore, in angular velocity sensor 1b according to Modification 2, angular velocity averaging section 111c calculates angular velocity average signal ω0 using the same averaging circuit 124 regardless of whether an impact is applied or not. Therefore, angular velocity averaging section 111c according to Modification 2 can be realized with a circuit smaller in size than angular velocity averaging section 111b of embodiment 2.

[0091] (Another modified example of the embodiment) (Another variation 1) In the first to third embodiments and each modification, the offset amount calculation unit 141 calculates the average value of the angular velocity signal ωr in the second period as the on-voltage offset amount ωd, and outputs the on-voltage offset amount ωd as the angular velocity correction signal ωc in the first period.

[0092] However, for example, the voltage application offset amount ωd may be calculated using the average angular velocity signal ω0 in the second period.

[0093] 12 is a functional block diagram of an angular velocity sensor 1d according to another modification 1. A control circuit 100d of the angular velocity sensor 1d differs from the control circuit 100 according to the first embodiment in that it includes an offset amount calculation unit 141d.

[0094] During the second period when the application status signal St1 indicates that the sensor is not in the applied state, the offset amount calculation unit 141d outputs the angular velocity average signal ω0 as the angular velocity correction signal ωc.The offset amount calculation unit 141d then calculates the time average of the angular velocity average signal ω0 during the second period and stores this as the application offset amount ωd.When the application status signal St1 indicates the application state, the offset amount calculation unit 141d outputs the application offset amount ωd as the angular velocity correction signal ωc.

[0095] Even with the above configuration, the application offset amount ωd, which is the average value of the angular velocity average signal ω0 in the second period, is used as the offset amount in the first period, so that the angular velocity average signal ω0 can be offset corrected with high accuracy.

[0096] (Another variation 2) In the first to third embodiments and each modification, when the application state signal St1 indicates that the motor is not in the application state, the offset amount calculation unit 141 outputs the angular velocity average signal ω0 as the angular velocity correction signal ωc.

[0097] However, for example, when the application state signal St1 indicates that the motor is not in the application state, the offset amount calculation unit 141e may generate and output the angular velocity correction signal ωc based on the angular velocity signal ωr.

[0098] 13 is a functional block diagram of an angular velocity sensor 1e according to another modification 2. A control circuit 100e of the angular velocity sensor 1e differs from the control circuit 100 according to the first embodiment in that it includes an offset amount calculation unit 141e.

[0099] The offset amount calculation unit 141e holds the time average of the angular velocity signal ωr during the second period when the application status signal St1 indicates the non-application status as the application offset amount ωd. When the application status signal St1 indicates the application status, the offset amount calculation unit 141e outputs the application offset amount ωd as the angular velocity correction signal ωc.

[0100] Furthermore, if the application status signal St1 indicates that the motor is not applied, the offset amount calculation unit 141e outputs the angular velocity signal ωr as the angular velocity correction signal ωc. Alternatively, for example, if the application status signal St1 indicates that the motor is not applied, the offset amount calculation unit 141e outputs a short-term average of the angular velocity signal ωr as the angular velocity correction signal ωc. The short-term average of the angular velocity signal ωr is, for example, an average of the angular velocity signal ωr per 100 ms.

[0101] Even with the above configuration, the offset amount in the second period is calculated based on the angular velocity signal ωr in the second period, so that the angular velocity average signal ω0 can be offset-corrected with high precision in the second period.

[0102] (Other Variation 3) In the first embodiment, the angular velocity change amount calculation unit 131 calculates the amount of change over time of the angular velocity signal ωr as an angular velocity parameter. Furthermore, the application state determination unit 132 determines that the angular velocity sensor 1 is in an application state when the angular velocity parameter exceeds the change amount threshold.

[0103] In the first modification, the angular velocity average value calculation unit 133 calculates the time average value of the angular velocity signal ωr as the angular velocity average value ω1. The applied state determination unit 132a compares the angular velocity average value ω1 with an average value threshold. If the angular velocity average value ω1 is greater than the average value threshold, the applied state determination unit 132a determines that the angular velocity sensor 1 is in an applied state.

[0104] However, the method for determining the voltage application state is not limited to the above example.

[0105] For example, the application state may be determined as follows. The angular velocity change amount calculation unit 131 calculates the square of the time change amount of the angular velocity signal ωr as the angular velocity parameter. The application state determination unit 132 determines that the angular velocity sensor 1 is in the application state when the angular velocity parameter exceeds the corresponding threshold. In other words, the application state determination unit 132 determines that the angular velocity sensor 1 is not in the application state when the angular velocity parameter is equal to or less than the corresponding threshold. The threshold may be, for example, 0.0001 (dps / s). 2 is.

[0106] The method for determining the voltage application state may be a combination of two or more of the above-described methods.

[0107] For example, the determination processing unit 130 further includes an angular velocity average value calculation unit 133. The application state determination unit 132 determines that the applied state is not present when the angular velocity parameter is equal to or less than the corresponding threshold value and the angular velocity average value ω1 is equal to or less than the average value threshold value. In other words, the application state determination unit 132 determines that the applied state is present both when the angular velocity parameter exceeds the corresponding threshold value and when the angular velocity average value ω1 is greater than the average value threshold value. Alternatively, for example, the application state determination unit 132 may determine that the applied state is present when the angular velocity parameter exceeds the corresponding threshold value and when the angular velocity average value ω1 is greater than the average value threshold value. In other words, the application state determination unit 132 determines that the applied state is not present both when the angular velocity parameter is equal to or less than the corresponding threshold value and when the angular velocity average value ω1 is equal to or less than the average value threshold value.

[0108] Furthermore, for example, when the difference between the average angular velocity value ω1 and the offset amount ωd upon application exceeds a threshold, the determination processing unit 130 may determine that an angular velocity is being applied to the angular velocity sensor 1. In other words, when the difference between the average angular velocity value ω1 and the offset amount ωd upon application is equal to or smaller than the threshold, the determination processing unit 130 determines that an angular velocity is not being applied to the angular velocity sensor 1.

[0109] (Other Variation 4) In the second embodiment, the impact determination unit 134 determines that the state has transitioned to a state where no impact is applied when the angular velocity signal ωr is continuously below the second angular velocity threshold for a predetermined time in the impact applied state.

[0110] However, the shock determination unit 134 may determine that the state has transitioned from the shock applied state to the shock non-applied state based on other determination criteria.

[0111] For example, as shown in FIG. 14, the determination processing unit 130f further includes an average angular velocity calculation unit 133 and an impact determination unit 134f. The impact determination unit 134f compares the average angular velocity value ω1 with a second angular velocity threshold. The impact determination unit 134f determines that the state has transitioned to a state where the impact has not been applied if the average angular velocity value ω1 is below the second angular velocity threshold for a predetermined period of time. In other words, the impact determination unit 134f determines that the impact state continues if the average angular velocity value ω1 exceeds the second angular velocity threshold in the impact state. Furthermore, the impact determination unit 134f determines that the impact state continues if the average angular velocity value ω1 exceeds the second angular velocity threshold before a predetermined period of time has elapsed after the average angular velocity value ω1 falls below the second angular velocity threshold in the impact state. Note that the second angular velocity threshold may be different from the second angular velocity threshold in the second embodiment.

[0112] Alternatively, for example, the impact determination unit 134f determines that the state has transitioned to a shock-free state when the average angular velocity ω1 falls below the corresponding threshold. In other words, the impact determination unit 134f determines that the shock state continues when the average angular velocity ω1 exceeds the second angular velocity threshold in the shock state. Note that the threshold corresponding to the average angular velocity ω1 may be different from the second angular velocity threshold in the second embodiment.

[0113] (summary) An angular velocity sensor (1; 1b; 1d; 1e) according to a first aspect includes an angular velocity detection element (11) and a control circuit (100; 100b; 100d; 100e). The angular velocity detection element (11) detects an angular velocity around a detection axis and outputs an angular velocity signal (ωr). The control circuit (100; 100b; 100d; 100e) processes the angular velocity signal (ωr). The control circuit (100; 100b; 100d; 100e) includes an angular velocity averaging unit (111; 111b; 111c), a determination processing unit (130; 130a; 130b; 130f), an offset amount calculation unit (141; 141d; 141e), and an angular velocity correction unit (142). The angular velocity averaging units (111; 111b; 111c) time-average the angular velocity signal (ωr) to generate an angular velocity average signal (ω0). The determination processing units (130; 130a; 130b; 130f) determine whether or not an angular velocity is being applied to the angular velocity detection element (11). The offset amount calculation units (141; 141d; 141e) calculate an offset correction amount for the angular velocity average signal (ω0) and output it as an angular velocity correction signal (ωc). The angular velocity correction unit (142) applies the angular velocity correction signal (ωc) to the angular velocity average signal (ω0) and outputs a corrected angular velocity signal (ωa). The offset amount calculation unit (141; 141d; 141e) calculates the angular velocity correction signal (ωc) for the first period, which is a period determined by the judgment processing unit (130; 130a; 130b; 130f) to be in an applied state, based on the angular velocity signal (ωr) for the second period, which is a period determined by the judgment processing unit (130; 130a; 130b; 130f) to be in an applied state.

[0114] According to the angular velocity sensor (1; 1b; 1d; 1e) of the first aspect, the average angular velocity signal (ω0) is corrected based on the angular velocity signal (ωr) in the second period in which no angular velocity is applied to the angular velocity sensor (1; 1b; 1d; 1e). Therefore, the accuracy of the angular velocity correction signal (ωc) can be improved.

[0115] In the angular velocity sensor (1:1b:1e) according to the second aspect, in the first aspect, the offset amount calculation unit (141; 141e) time-averages the angular velocity signal (ωr) output from the angular velocity detection element (11) in the second period, and outputs the time-averaged signal as the angular velocity correction signal (ωc) for the first period.

[0116] According to the angular velocity sensor (1; 1b; 1e) of the second aspect, the angular velocity correction signal (ωc) is calculated using the angular velocity signal (ωr) output from the angular velocity detection element (11). Therefore, the accuracy of the angular velocity correction signal (ωc) can be improved.

[0117] In the angular velocity sensor (1d) according to the third aspect, in the first aspect, the offset amount calculation unit (141d) time-averages the angular velocity average signal (ω0) generated by the angular velocity averaging unit (111; 111b; 111c) in the second period, and calculates the time-averaged signal as the offset correction amount (ωc) for the first period.

[0118] According to the angular velocity sensor (1d) of the third aspect, the angular velocity correction signal (ωc) is calculated using the angular velocity average signal (ω0) generated by the angular velocity averaging section (111; 111b; 111c), thereby reducing the amount of calculation in the offset amount calculation section (141d).

[0119] In the angular velocity sensor (1; 1b; 1d; 1e) according to the fourth aspect, in any of the first to third aspects, the determination processing unit (130; 130b; 130f) includes an angular velocity change amount calculation unit (131) and an application state determination unit (132). The angular velocity change amount calculation unit (131) calculates an angular velocity change amount, which is the amount of change per time of the angular velocity signal (ωr). The application state determination unit (132) determines whether or not the application state is in progress based on the angular velocity change amount. If the angular velocity change amount is equal to or less than a change amount threshold, the application state determination unit (132) determines that the application state is not in progress, and if the angular velocity change amount exceeds the change amount threshold, the application state is in progress.

[0120] According to the angular velocity sensor (1; 1b; 1d; 1e) of the fourth aspect, it is possible to accurately determine whether or not an angular velocity is applied to the angular velocity sensor (1; 1b; 1d; 1e) based on the change over time of the angular velocity signal (ωr).

[0121] In the angular velocity sensor (1) according to a fifth aspect, in any of the first to third aspects, the determination processing unit (130a) includes an angular velocity average value calculation unit (133) and an application state determination unit (132a). The angular velocity average value calculation unit (133) calculates an angular velocity average value (ω1) which is a time average of the angular velocity signal (ωr). The application state determination unit (132a) determines whether or not the application state is established based on the angular velocity average value (ω1). The application state determination unit (132a) determines that the application state is not established if the angular velocity average value (ω1) is equal to or less than the average value threshold, and determines that the application state is established if the angular velocity average value (ω1) exceeds the average value threshold.

[0122] According to the angular velocity sensor (1) of the fifth aspect, it is possible to accurately determine whether or not an angular velocity is applied to the angular velocity sensor (1) based on the time average of the angular velocity signal (ωr).

[0123] In the angular velocity sensor (1) according to a sixth aspect, in any of the first to third aspects, the determination processing unit (130) includes an angular velocity change amount calculation unit (131), an angular velocity average value calculation unit (133), and an application state determination unit (132). The angular velocity change amount calculation unit (131) calculates an angular velocity change amount, which is the amount of change per time of the angular velocity signal (ωr). The angular velocity average value calculation unit (133) calculates an angular velocity average value (ω1), which is the time average of the angular velocity signal (ωr). The application state determination unit (132) determines whether or not the application state is in progress based on the angular velocity change amount and the angular velocity average value (ω1). If the angular velocity change amount is equal to or less than the change amount threshold and the angular velocity average value (ω1) is equal to or less than the average value threshold, the application state determination unit (132) determines that the application state is not in progress if the angular velocity change amount is equal to or less than the change amount threshold or the angular velocity average value (ω1) is equal to or less than the average value threshold. If the angular velocity change amount exceeds the change amount threshold or the angular velocity average value (ω1) exceeds the average value threshold, the application state determination unit (132) determines that the application state is in progress.

[0124] According to the angular velocity sensor (1) of the sixth aspect, it is possible to accurately determine whether or not an angular velocity is applied to the angular velocity sensor (1) based on the time change and time average of the angular velocity signal (ωr).

[0125] In the angular velocity sensor (1b) according to the seventh aspect, in any of the first to sixth aspects, the determination processing unit (130b; 130f) further determines whether or not an impact has been applied to the angular velocity detection element (11). During a third period in which the determination processing unit (130b; 130f) determines that the angular velocity detection element (11) is not in an impact applied state, the angular velocity averaging unit (111b) outputs an average of the angular velocity signals (ωr) during a fifth period as the angular velocity average signal (ω0), and during a fourth period in which the determination processing unit (130b; 130f) determines that the angular velocity detection element (11) is in an impact applied state, the angular velocity averaging unit (111b) outputs an average of the angular velocity signals (ωr) during a sixth period longer than the fifth period as the angular velocity average signal (ω0).

[0126] According to the angular velocity sensor (1b) of the seventh aspect, the period for calculating the angular velocity average signal (ω0) in the third period in which the impact is applied to the angular velocity sensor (1b) is set longer than the period for calculating the angular velocity average signal (ω0) in the fourth period, thereby averaging out noise in the angular velocity signal (ωr) caused by the impact and reducing its influence.

[0127] In an angular velocity sensor (1b) according to an eighth aspect, in the seventh aspect, the angular velocity averaging unit (111b) includes a first averaging circuit (121), a second averaging circuit (122), and a selection unit (123). The first averaging circuit (121) calculates the average of the angular velocity signal (ωr) in a fifth period. The second averaging circuit (122) calculates the average of the angular velocity signal (ωr) in a sixth period. The selection unit (123) selects the first averaging circuit (121) as a circuit that outputs the angular velocity average signal (ω0) in a fourth period, and selects the second averaging circuit (122) as a circuit that outputs the angular velocity average signal (ω0) in a third period.

[0128] According to the angular velocity sensor (1b) of the eighth aspect, both the angular velocity average signal (ω0) when an impact is applied and the angular velocity average signal (ω0) when no impact is applied are calculated, regardless of whether an impact is applied or not. Therefore, when an impact is applied to the angular velocity sensor (1b), the angular velocity average signal (ω0) when an impact is applied can be used immediately.

[0129] In an angular velocity sensor (1b) according to a ninth aspect, in the seventh aspect, the angular velocity averaging unit (111c) further includes an averaging circuit (124). In the fourth period, the averaging circuit (124) outputs an average of the angular velocity signals (ωr) in the fifth period as an angular velocity average signal (ω0), and in the third period, outputs an average of the angular velocity signals (ωr) in the sixth period as an angular velocity average signal (ω0).

[0130] In the angular velocity sensor (1b) according to the ninth aspect, the angular velocity averaging section (111c) calculates the angular velocity average signal (ω0) using the same averaging circuit (124) regardless of whether or not an impact is applied. Therefore, the angular velocity averaging section (111c) can be realized with a small-scale circuit.

[0131] In the angular velocity sensor (1b) according to a tenth aspect, in any one of the seventh to ninth aspects, the determination processing unit (130b) further includes an impact determination unit (134; 134f). The impact determination unit (134) determines whether or not an impact has been applied. When the value of the angular velocity signal (ωr) exceeds a first angular velocity threshold when the impact has not been applied, the impact determination unit (134; 134f) determines that the impact has been applied.

[0132] According to the angular velocity sensor (1b) of the tenth aspect, it is possible to determine with high accuracy whether or not an impact has been applied to the angular velocity sensor (1b) based on the value of the angular velocity signal (ωr).

[0133] In the angular velocity sensor (1b) according to the eleventh aspect, in the tenth aspect, the impact determination unit (134; 134f) determines that an impact has been applied, and then determines that an impact has not been applied if at least one of the value of the angular velocity signal (ωr) and the time average (ω1) of the value of the angular velocity signal (ωr) is equal to or less than the second angular velocity threshold value for a predetermined period of time, and determines that an impact has been applied in any other case.

[0134] According to the angular velocity sensor (1b) of the eleventh aspect, when at least one of the angular velocity signal (ωr) and the time average (ω1) of the value of the angular velocity signal (ωr) remains sufficiently small for a predetermined time, it is determined that the impact state is not present. Therefore, it is possible to end the processing in the impact state after the effect of the impact on the angular velocity signal (ωr) becomes sufficiently small.

[0135] In the angular velocity sensor (1b) according to the twelfth aspect, in the tenth aspect, the impact determination unit (134f) determines that an impact has been applied, and then determines that an impact has not been applied if the time average (ω1) of the value of the angular velocity signal (ωr) is equal to or less than the second angular velocity threshold value, and determines that the impact has continued in any other cases.

[0136] According to the angular velocity sensor (1b) of the twelfth aspect, when the time average (ω1) of the value of the angular velocity signal (ωr) becomes sufficiently small, it is determined that the shock is not being applied. Therefore, it is possible to end the processing in the shock application state after the influence of the shock on the angular velocity signal (ωr) becomes sufficiently small. [Explanation of symbols]

[0137] 1, 1b, 1d, 1e Angular rate sensors 11 Angular velocity detection element 100, 100b, 100d, 100e control circuit 111, 111b, 111c Angular velocity average part 121 1st average circuit 122 Second average circuit 123 Selection Section 124 Average circuit 130, 130a, 130b, 130f Determination processing unit 131 Angular velocity change amount calculation unit 132, 132a Application state determination unit 133 Angular velocity average value calculation unit 134, 134f Impact judgment section 141, 141d, 141e offset amount calculation unit 142 Angular velocity correction section ωr Angular velocity signal ω0 Average angular velocity signal ωc Angular velocity correction signal ωa Corrected angular velocity signal ω1 Angular velocity average value

Claims

1. an angular velocity detection element that detects an angular velocity around a detection axis and outputs an angular velocity signal; a control circuit for processing the angular velocity signal; The control circuit an angular velocity averaging unit that time-averages the angular velocity signal to generate an average angular velocity signal; a determination processing unit that determines whether the angular velocity is applied to the angular velocity detection element; an offset amount calculation unit that calculates an offset correction amount for the angular velocity average signal and outputs the calculated offset correction amount as an angular velocity correction signal; an angular velocity correction unit that applies the angular velocity correction signal to the average angular velocity signal and outputs a corrected angular velocity signal; and the offset amount calculation unit calculates the angular velocity correction signal for a first period, which is a period during which the determination processing unit determines that the voltage is applied, based on the angular velocity signal for a second period, which is a period during which the determination processing unit determines that the voltage is not applied; the determination processing unit further determines whether or not an impact has been applied to the angular velocity detection element; The angular velocity averaging unit During a third period in which the determination processing unit determines that the shock is not being applied, an average of the angular velocity signals during a fifth period is output as the angular velocity average signal; During a fourth period in which the determination processing unit determines that the shock has been applied, an average of the angular velocity signals during a sixth period longer than the fifth period is output as the angular velocity average signal. Angular velocity sensor.

2. The angular velocity averaging unit a first averaging circuit that calculates an average of the angular velocity signal during the fifth period; a second averaging circuit that calculates an average of the angular velocity signal during the sixth period; a selection unit; The selection unit during the fourth period, the first averaging circuit is selected as a circuit for outputting the angular velocity average signal; In the third period, the second averaging circuit is selected as a circuit that outputs the angular velocity average signal.

2. The angular velocity sensor according to claim 1.

3. The angular velocity averaging unit further includes an averaging circuit, The averaging circuit In the fourth period, an average of the angular velocity signals in the fifth period is output as the average angular velocity signal; In the third period, an average of the angular velocity signals in the sixth period is output as the average angular velocity signal.

2. The angular velocity sensor according to claim 1.

4. The determination processing unit further includes an impact determination unit that determines whether or not the impact is applied, the impact determination unit determines that the impact is applied when the value of the angular velocity signal exceeds a first angular velocity threshold value when the impact is not applied; 4. The angular velocity sensor according to claim 1.

5. After determining that the impact is applied, the impact determination unit determines that the impact is not applied if at least one of the value of the angular velocity signal and the time average of the value of the angular velocity signal remains below a second angular velocity threshold for a predetermined period of time, and otherwise determines that the impact is applied.

5. The angular velocity sensor according to claim 4.

6. After determining that the impact is applied, the impact determination unit determines that the impact is not applied if the time average of the value of the angular velocity signal is equal to or less than a second angular velocity threshold value, and determines that the impact is still applied in any other case.

5. The angular velocity sensor according to claim 4.

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