Angular Velocity Sensor Unit Dual-Axis Failure Detection
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Solution Overview
Problem
Conventional angular velocity sensors can only perform failure judgments for one sensor, specifically the one measuring yaw axis angular velocity, while failing to do so for the sensor measuring roll axis angular velocity.
Innovation Solution
The angular velocity sensor unit includes two sensors with oscillators arranged such that their shaft portions are not parallel to the XY-plane, allowing failure judgment by comparing detection values of one sensor with the other's pseudo-calculated angular velocity and actual detection values, enabling failure detection for both sensors without increasing the number of parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two angular velocity sensors are arranged with shaft portions parallel to the XY-plane for measuring yaw and roll axis angular velocities, then the measurement function is achieved, but failure judgment can only be made for one sensor
Solution Approach 1:
The patent makes the second angular velocity sensor (measuring roll axis) serve dual functions: it measures roll axis angular velocity as its primary function, and simultaneously measures Z-axis angular velocity as a secondary function to enable failure judgment. This is achieved by arranging the shaft portion at a specific angle (not parallel to XY-plane) so that the sensor responds to both roll axis rotation and Z-axis rotation, allowing one sensor to provide data for judging failures of both sensors
Solution Approach 2:
The patent introduces a pseudo-calculated angular velocity as an intermediary reference value. This pseudo-angular velocity is calculated from other vehicle motion parameters and serves as a mediator to enable failure judgment of the first sensor, while the actual angular velocity measurements serve as mediators to enable failure judgment of the second sensor through comparison
2Ease of manufacture
If conventional sensor arrangement is used with shaft portions parallel to XY-plane, then manufacturing and installation is simplified, but failure judgment for both sensors cannot be achieved
Solution Approach 1:
The patent changes the orientation parameter of the second sensor's shaft portion from being parallel to the XY-plane to being at a specific angle relative to it. This parameter change enables the sensor to detect Z-axis angular velocity in addition to roll axis angular velocity, providing the necessary data for failure judgment without significantly complicating the installation process
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration allows for the detection of angular velocity about the Z-axis by both sensors, enabling failure judgment for both sensors, thereby improving posture control systems by ensuring reliable operation of both yaw and roll axis sensors.
Implementation Method 1
causes, for example, a tuning fork shaped oscillator to oscillate, in order to electrically detect a strain of the oscillator resulting from a generated Coriolis force
Data Source
AI summary
An angular velocity sensor unit judging whether there is a failure in both of two angular velocity sensors. The angular velocity sensor unit includes a first angular velocity sensor (12) and a second angular velocity sensor (13), each including an oscillator having a shaft portion and an oscillatory portion. Each of the angular velocity sensors (12, 13) is arranged such that its shaft portion is not in parallel with an XY-plane defined by an X-axis and a Y-axis of three orthogonal axes. The failure of the second angular velocity sensor is judged based on whether or not a detection value of an angular velocity about a Z-axis lies outside a tolerance range of a detection value of the angular velocity about the Z-axis by the other angular velocity sensor, and the failure of the first angular velocity sensor is judged by comparison with a pseudo-calculated angular velocity.