Gyroscope Self-Test via Coriolis Rotation
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Solution Overview
Problem
Conventional gyroscope self-test methods require costly testing platforms and extensive time, and existing self-test methods either cannot test both drive and sense systems simultaneously or compromise stability due to compliant frame structures, making them susceptible to external disturbances.
Innovation Solution
A gyroscope design where the proof mass vibrates at a drive frequency and is rotated around an input axis using an actuator with a signal frequency substantially twice the drive frequency, allowing simultaneous testing of both systems and enhancing stability through stiffer actuation structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional self-test methods vibrate the proof mass along the sense axis to test sense system functionality, then sense system can be tested, but drive system functionality cannot be tested simultaneously requiring extra time and effort
Solution Approach 1:
The patent combines the testing of both drive and sense systems into a single self-test operation by applying a rotation input to the proof mass that simultaneously activates both systems. The rotation is applied about an axis perpendicular to both the drive and sense axes, causing the proof mass to experience both drive motion and sense response concurrently, thus eliminating the need for separate testing procedures.
Solution Approach 2:
The self-test mechanism is designed to serve multiple functions simultaneously: it tests both the drive system and sense system functionality in one operation. The actuator that applies rotation serves dual purposes by both driving the proof mass and enabling sense system verification through the resulting Coriolis force, making the test mechanism universal rather than specialized for a single function.
2Ease of operation
If compliant frame structures are used to allow large angle rotation for self-test, then self-test can be performed, but the sensor becomes susceptible to unwanted external effects like package stresses and vibrations
Solution Approach 1:
The patent changes the operational parameters of the self-test by applying rotation at a frequency substantially twice the drive frequency rather than using low frequency rotation. This frequency parameter change allows the use of stiffer frame structures while still achieving effective self-test, because the higher frequency excitation produces sufficient Coriolis force signals for detection without requiring large amplitude motions that would demand compliant structures.
Solution Approach 2:
The patent employs dynamic actuation by applying rotation at twice the drive frequency, which creates a time-varying Coriolis force that can be detected through synchronous detection techniques. This dynamic approach allows the frame to be stiffer while still achieving the necessary test sensitivity, as the high-frequency modulation enables signal extraction even with smaller motion amplitudes.
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 method enables efficient full functionality testing of gyroscopes while maintaining stability against external disturbances, allowing for simultaneous testing of drive and sense systems and improved resistance to mechanical shocks and vibrations.
Implementation Method 1
an actuator operable to rotate the proof mass around an input axis to generate a Coriolis force on the proof mass
Data Source
AI summary
A self-test method by rotating the proof mass at a high frequency enables testing the functionality of both the drive and sense systems at the same time. In this method, the proof mass is rotated at a drive frequency. An input force which is substantially two times the drive frequency is applied to the actuation structures to rotate the proof mass of the gyroscope around the sensitive axis orthogonal to the drive axis. An output response of the gyroscope at the drive frequency is detected by a circuitry and a self-test response is obtained.