Rate-of-Turn Sensor Start-Up Frequency Sweep
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Solution Overview
Problem
Micromechanical rate-of-turn sensors often fail to oscillate at their main driving frequency due to spurious resonances, especially when using square-wave drive signals, leading to unreliable functionality and potential damage from high amplification.
Innovation Solution
The method involves gradually increasing the stimulation frequency from below the main driving frequency to above it, monitoring deflection or speed to determine the main frequency, and then locking into it, while regulating amplitude to prevent spurious resonances, and restarting the process if the sensor deviates from the main frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a square-wave drive signal is used to stimulate the mechanical oscillator, then the drive signal is easy to generate, but spurious resonances are stimulated and the oscillator may lock into unwanted frequencies
Solution Approach 1:
The patent applies preliminary action by performing a start-up sequence before normal operation begins. During start-up, the stimulation frequency is swept through a range and the oscillator is monitored to identify and lock onto the correct main driving frequency before spurious resonances can become stable. This preliminary frequency acquisition ensures reliable operation from the outset.
Solution Approach 2:
The patent uses feedback by continuously monitoring the oscillator's response during the start-up sequence and using this information to adjust the drive signal frequency. The system detects when the oscillator has locked onto the correct frequency and uses this feedback to confirm proper operation, preventing spurious resonances from taking hold.
2Measurement precision
If the comparator amplification is increased to detect small signals, then small input signals can be detected, but very weak spurious resonances are stimulated to become unwanted stable oscillations
Solution Approach 1:
The patent applies preliminary action by establishing the correct oscillation frequency and amplitude conditions before normal operation begins. During the start-up sequence, the system proactively sets up the proper operating state, preventing spurious resonances from being stimulated in the first place rather than reacting to them after they occur.
Solution Approach 2:
The patent applies preliminary anti-action by taking counter-measures before spurious resonances can become problematic. The start-up sequence includes frequency sweeping and monitoring that prevents the conditions necessary for spurious resonance stimulation, effectively countering the harmful effect before it can manifest.
3Reliability
If the oscillation amplitude is allowed to increase to ensure sufficient signal strength, then the oscillator can operate reliably, but the oscillator element may be damaged
Solution Approach 1:
The patent uses feedback by monitoring the oscillator's response during start-up and using this information to regulate the drive signal amplitude. The system adjusts the amplitude dynamically based on the actual oscillation strength, ensuring sufficient signal for reliable operation while preventing excessive amplitude that could damage the oscillator element.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the drive signal amplitude during the start-up sequence based on the oscillator's actual response. The system modifies the amplitude parameter in real-time to achieve the optimal balance between sufficient signal strength and preventing damage, rather than using a fixed amplitude setting.
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 ensures the rate-of-turn sensor reliably oscillates at its main driving frequency, preventing spurious resonances and maintaining secure operation even with external disturbances, and allows for automatic restarts if the sensor is affected by electrical or mechanical issues.
Implementation Method 1
They use the Coriolis effect to measure, e.g., the rate-of-turn around the vertical axis or longitudinal axis of the motor vehicle
Implementation Method 2
The mechanical oscillators can be stimulated to perform a periodic oscillating motion using driving forces that change periodically with time and are applied electrostatically
Implementation Method 3
The instantaneous deflection or the instantaneous speed of the oscillator element is measured using capacitive sensors located on the oscillator element
Data Source
AI summary
For operational control of a start-up of a rate-of-turn sensor including at least one oscillator element that is excitable to perform a mechanical oscillating motion, a signal proportional to the instantaneous speed or deflection of the oscillator element is amplified and used as the operating signal to operate the oscillator element, during the start-up process for the rate-of-turn sensor, the amplitude of the operating signal is set to a constant specifiable value, the stimulation frequency of the operating signal is increased essentially continuously from a starting value below the main driving frequency of the oscillating motion to a final value above the main driving frequency and below a spurious driving frequency while, simultaneously, the deflection and/or the speed of the oscillator element are monitored in order to determine the main driving frequency of the oscillating motion, once the final value is reached and the main driving frequency is determined, the stimulation frequency of the operating signal is set to the main driving frequency, and the operational regulation of the amplitude and the stimulation frequency of the operating signal are released.