Inertial sensor
An inertial sensor according to the embodiment includes a first sensor, a first detection circuit, a second sensor, a second detection circuit, and a range setting unit. The first sensor detects a first physical quantity on a first axis. The first detection circuit outputs first detection information based on a first sensor signal from the first sensor. The second sensor detects a second physical quantity on a second axis. The second detection circuit outputs second detection information based on a second sensor signal from the second sensor. The range setting unit performs range setting processing of setting a detection range of the first physical quantity in the first detection circuit based on the first detection information and the second detection information.
1 . An inertial sensor comprising:
a first sensor configured to detect a first physical quantity only on a first axis;
a first detection circuit configured to perform detection processing of the first physical quantity based on a first sensor signal from the first sensor, and output first detection information;
a second sensor configured to detect a second physical quantity only on a second axis, the second axis being different than the first axis;
a second detection circuit configured to perform the detection processing of the second physical quantity based on a second sensor signal from the second sensor including determining whether the second physical quantity exceeds a threshold value, and output second detection information that includes an indication of whether the second physical quantity exceeds the threshold value; and
a range setting unit configured to perform range setting processing,
wherein the range setting unit is configured to perform the range setting processing of adjusting a detection range of the first physical quantity in the first detection circuit based on both the first detection information and the second detection information including the indication of whether the second physical quantity exceeds the threshold value, such that the detection range of the first physical quantity is adjusted in response to the second physical quantity exceeding the threshold value as detected by the second detection circuit on the second axis that is different from the first axis.
2 . The inertial sensor according to claim 1 , wherein
the first axis is an X axis or a Y axis,
the first physical quantity is an X-axis angular velocity which is an angular velocity around the X axis or a Y-axis angular velocity which is an angular velocity around the Y axis,
the second axis is a Z axis, and
the second physical quantity is a Z-axis angular velocity which is an angular velocity around the Z axis.
3 . The inertial sensor according to claim 2 , wherein
the range setting unit is configured to set, when the Z-axis angular velocity exceeds the threshold value, a detection range of the X-axis angular velocity or the Y-axis angular velocity to be small.
4 . The inertial sensor according to claim 1 , wherein
the first axis is a Z axis,
the first physical quantity is a Z-axis angular velocity which is an angular velocity around the Z axis,
the second axis is an X axis or a Y axis, and
the second physical quantity is an X-axis acceleration which is an acceleration in an X-axis direction or a Y-axis acceleration which is an acceleration in a Y-axis direction.
5 . The inertial sensor according to claim 4 , wherein
the range setting unit is configured to set, when the X-axis acceleration or the Y-axis acceleration exceeds the threshold value, a detection range of the Z-axis angular velocity to be large.
6 . The inertial sensor according to claim 1 , further comprising:
an attitude calculation unit configured to obtain attitude information of a measurement target based on the first detection information and the second detection information, wherein
the range setting unit is configured to perform the range setting processing based on the attitude information obtained by the attitude calculation unit.
7 . The inertial sensor according to claim 6 , wherein
the first axis is an X axis or a Y axis,
the first physical quantity is an X-axis angular velocity which is an angular velocity around the X axis or a Y-axis angular velocity which is an angular velocity around the Y axis,
the attitude calculation unit is configured to obtain, as the attitude information, a roll angle which is a rotation angle around the X axis or a pitch angle which is a rotation angle around the Y axis, and
the range setting unit is configured to set, when the roll angle or the pitch angle exceeds a threshold value, a detection range of the X-axis angular velocity or the Y-axis angular velocity to be small.
8 . The inertial sensor according to claim 1 , wherein
the first axis is an X axis or a Y axis,
the first physical quantity is an X-axis angular velocity which is an angular velocity around the X axis or a Y-axis angular velocity which is an angular velocity around the Y axis,
the second axis is a Z axis,
the second physical quantity is a Z-axis angular velocity which is an angular velocity around the Z axis, and
the range setting unit is configured to set, in an initial setting, a detection range of the Z-axis angular velocity to a magnitude equal to or smaller than a detection range of the X-axis angular velocity or the Y-axis angular velocity.
9 . The inertial sensor according to claim 1 , wherein
the first axis is an X axis or a Y axis,
the first physical quantity is an X-axis acceleration which is an acceleration in an X-axis direction or a Y-axis acceleration which is an acceleration in a Y-axis direction,
the second axis is a Z axis,
the second physical quantity is a Z-axis acceleration which is an acceleration in a Z-axis direction, and
the range setting unit is configured to set, in an initial setting, a detection range of the Z-axis acceleration to a magnitude equal to or larger than a detection range of the X-axis acceleration or the Y-axis acceleration.
10 . The inertial sensor according to claim 1 , further comprising:
a third sensor configured to detect a third physical quantity on a third axis; and
a third detection circuit configured to perform the detection processing of the third physical quantity based on a third sensor signal from the third sensor, and output third detection information, wherein
the range setting unit is configured to perform the range setting processing of setting a detection range of the first physical quantity based on the first detection information, the second detection information, and the third detection information.
11 . The inertial sensor according to claim 10 , further comprising:
an attitude calculation unit configured to obtain attitude information of a measurement target based on the first detection information, the second detection information, and the third detection information, wherein
the range setting unit is configured to perform the range setting processing based on the attitude information obtained by the attitude calculation unit.
12 . The inertial sensor according to claim 1 , wherein
the range setting unit is configured to set, when a detection value of the first detection information exceeds a first threshold value in a first detection range while the first detection circuit is performing the detection processing of the first physical quantity in the first detection range, the detection range of the first physical quantity to a second detection range larger than the first detection range.
13 . The inertial sensor according to claim 1 , wherein the range setting unit is configured to:
maintain a first detection range for the first physical quantity when the second physical quantity does not exceed the threshold value; and
switch to a second detection range for the first physical quantity when the second physical quantity exceeds the threshold value, wherein the second detection range is different from the first detection range.
14 . The inertial sensor according to claim 1 , wherein:
the second detection circuit is configured to compare the second sensor signal to the threshold value and generate the indication based on the comparison; and
the range setting unit receives the indication from the second detection circuit and uses the indication as a trigger for adjusting the detection range of the first physical quantity.
15 . The inertial sensor according to claim 1 , wherein the detection range of the first physical quantity is adjusted based on a cross-axis relationship between the first axis and the second axis, such that detection characteristics on the second axis control the detection range on the first axis.