Yaw Rate Sensor Antiparallel Drive Vibration Spurious Mode Suppression
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Solution Overview
Problem
Conventional yaw rate sensors suffer from spurious modes that result in false signals due to superimposed vibration modes, leading to unstable operation.
Innovation Solution
A yaw rate sensor design incorporating multiple Coriolis elements with an antiparallel collinear drive vibration, coupled detection elements, and a coupling device that shifts spurious modes to higher frequencies, utilizing a double rocker and coupling springs to separate use and spurious modes in the frequency range, thereby reducing excitation of spurious modes and enhancing stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional yaw rate sensors use multiple vibration modes including spurious modes, then the sensor can detect yaw rate, but spurious modes result in false signals and unstable operation
Solution Approach 1:
The patent applies mechanical vibration by exciting the Coriolis element at a specific drive frequency to generate controlled vibrational motion. The drive device vibrates the Coriolis element in the y-direction at frequency ωd, creating the necessary motion for yaw rate detection while avoiding excitation of spurious modes through careful frequency selection
Solution Approach 2:
The patent changes the frequency parameter by operating the sensor at a drive frequency that is deliberately different from the natural frequencies of spurious modes. This parameter change ensures that the drive frequency does not coincide with spurious mode frequencies, preventing their excitation and the resulting false signals
2Device complexity
If spurious modes are present in the frequency range, then the sensor structure is simple, but false signals occur due to mode superposition
Solution Approach 1:
The patent uses mechanical vibration to distinguish between useful and spurious modes by exciting the Coriolis element at a specific drive frequency. The evaluation device then detects vibrations at this known frequency, filtering out spurious modes that occur at different frequencies and thus maintaining measurement precision without increasing structural complexity
3Use of energy by moving object
If the drive frequency coincides with spurious mode frequencies, then energy transfer is efficient, but spurious modes are excited causing false signals
Solution Approach 1:
The patent changes the drive frequency parameter to a value that avoids coincidence with spurious mode frequencies. The evaluation device is configured to detect vibrations at this specific drive frequency, ensuring that energy is efficiently transferred to the useful detection mode while spurious modes remain unexcited due to frequency mismatch
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
The design effectively suppresses spurious modes, resulting in a more stable operation by increasing the frequency separation between use and spurious modes, leading to accurate yaw rate detection with reduced false signals.
Implementation Method 1
the drive device is connected to the multiple Coriolis elements in such a way that the Coriolis elements undergo a vibration in the opposite direction
Implementation Method 2
When the body having the yaw rate sensor mounted thereon undergoes a rotary motion about a rotational axis which is not parallel to the vibration direction of the vibrating masses, and at the same time the two vibrating masses are excited to undergo their antiparallel vibrating motions, Coriolis forces act on the two vibrating masses. As a result of the Coriolis forces, the two vibrating masses are each deflected perpendicularly to their vibration direction
Implementation Method 3
The two vibrating masses are deflected in opposite directions due to the antiparallelism of the vibrating motions of the two vibrating masses. Such an opposed vibration direction may also be referred to as an antiparallel detection vibration. This antiparallel detection vibration may capacitively detected and converted into a yaw rate with the aid of an evaluation electronics system
Data Source
AI summary
A yaw rate sensor is described which includes a drive device, at least one Coriolis element, and a detection device having at least two detection elements which are coupled to one another with the aid of a coupling device, the drive device being connected to the Coriolis element for driving a vibration of the Coriolis element, and an additional coupling device which is connected to the detection device and to the Coriolis element for coupling a deflection in the plane of vibration of the Coriolis element to the detection device in a direction orthogonal to the vibration.