Angular velocity sensor and angular velocity sensor system

An angular velocity sensor system configured to detect an angular velocity, the angular velocity sensor system comprising

• an angular velocity sensor;
• and
• a controller configured to execute predetermined processing, wherein:
• the angular velocity sensor includes
• a movable part including
• a drive spring,
• a detection spring,
• a mass part supported via the drive spring and the detection spring, configured to vibrate in a first direction by deformation of the drive spring, and configured to vibrate in a second direction orthogonal to the first direction by deformation of the detection spring due to a Coriolis force when an angular velocity is applied while vibrating in the first direction,
• a movable part drive electrode,
• a movable part detection electrode, and
• a movable part detection excitation electrode, and
• a fixed part including
• a fixed part drive electrode facing the movable part drive electrode,
• a fixed part detection electrode facing the movable part detection electrode, and
• a fixed part detection excitation electrode facing the movable part detection excitation electrode,
• the angular velocity sensor includes
• a drive spring adjustment part configured to change a spring constant of the drive spring, and
• a detection spring adjustment part configured to change a spring constant of the detection spring, and
• the controller is configured to
• vibrate the movable part in the second direction by applying a predetermined voltage to the fixed part detection excitation electrode and simultaneously vibrate the movable part in the first direction by applying a predetermined voltage to the fixed part drive electrode,
• acquire a first resonance frequency of the movable part, which is in a direction along the first direction, and a second resonance frequency of the movable part, which is in a direction along the second direction,
• adjust the spring constant of the drive spring by controlling the drive spring adjustment part, such that the first resonance frequency is maintained at a constant value,
• adjust the spring constant of the detection spring by controlling the detection spring adjustment part, such that the second resonance frequency is maintained at a constant value, and
• detect the angular velocity on a basis of a result of synchronously detecting a signal from the fixed part detection electrode with the first resonance frequency,
• the movable part has, as the second resonance frequency, a detection resonance frequency and a non-detection resonance frequency, which is different from the detection resonance frequency and the first resonance frequency, and
• the controller is configured to
• acquire, as the second resonance frequency, the non-detection resonance frequency,
• estimate the detection resonance frequency from the non-detection resonance frequency, and
• adjust the spring constant of the detection spring by controlling the detection spring adjustment part, such that the estimated detection resonance frequency is maintained at the constant value.

An angular velocity sensor configured to detect an angular velocity, the angular velocity sensor comprising:

• a movable part including
• a drive spring,
• a detection spring,
• a mass part, which is supported via the drive spring and the detection spring, configured to vibrate in a first direction by deformation of the drive spring, and configured to vibrate in a second direction orthogonal to the first direction by deformation of the detection spring due to a Coriolis force when an angular velocity is applied while vibrating in the first direction,
• a movable part drive electrode,
• a movable part detection electrode, and
• a movable part detection excitation electrode;
• and
• a fixed part including
• a fixed part drive electrode facing the movable part drive electrode,
• a fixed part detection electrode facing the movable part detection electrode, and
• a fixed part detection excitation electrode facing the movable part detection excitation electrode;
• a drive spring adjustment part configured to change a spring constant of the drive spring;
• and
• a detection spring adjustment part configured to change a spring constant of the detection spring, wherein:
• the movable part is configured to vibrate in the second direction when a predetermined voltage is applied to the fixed part detection excitation electrode and simultaneously vibrate in the first direction when a predetermined voltage is applied to the fixed part drive electrode,
• the spring constant of the drive spring is configured to be adjusted by controlling the drive spring adjustment part, such that a first resonance frequency of the movable part in a direction along the first direction is maintained at a constant value,
• the spring constant of the detection spring is configured to be adjusted by controlling the detection spring adjustment part, such that a second resonance frequency of the movable part in a direction along the second direction is maintained at a constant value,
• the angular velocity is configured to be detected on a basis of a signal from the fixed part detection electrode,
• the mass part includes
• a first mass part,
• a second mass part arrayed along the second direction, and
• a link spring coupling the first mass part with the second mass part and configured to displace the first mass part and the second mass part along the second direction,
• the movable part has, as the second resonance frequency, a detection resonance frequency in an in-phase mode, in which the first mass part and the second mass part vibrate in a same direction along the second direction, and a non-detection resonance frequency in a reverse phase mode, in which the first mass part and the second mass part vibrate in opposite directions along the second direction, and
• the spring constant of the detection spring is configured to be adjusted by controlling the detection spring adjustment part, such that, as the second resonance frequency, the detection resonance frequency or the non-detection resonance frequency is maintained at a constant value.