Micromachined Gyroscope Three-Axis Detection
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Solution Overview
Problem
Micromachined disc-type gyroscopes have a low mass utilization rate and limited sensitivity, and can only detect rotations within the production plane, failing to simultaneously detect the third axis out of the plane.
Innovation Solution
A micromachined gyroscope design featuring a base with fan-shaped vibration structures, a comb-shaped driving structure, and sensing elements that detect Coriolis force-induced deviations, allowing for three-axis detection by vibrating in the x-y plane and outside it, with elastic members minimizing coupling and quadrature errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a disc-type gyroscope uses a traditional vibration structure, then the structure is simple, but the mass utilization rate is low and sensitivity is limited
Solution Approach 1:
The gyroscope structure is segmented into multiple fan-shaped vibration structures (first, second, third, and fourth vibration structures) arranged around a central anchor point. Each vibration structure is independently suspended by elastic members, allowing individual optimization of mass distribution and vibration characteristics while maintaining overall structural simplicity for manufacturing
Solution Approach 2:
The invention transitions from planar in-plane vibration detection to three-dimensional detection by enabling out-of-plane vibration modes. The vibration structures can vibrate both within the x-y plane and outside it, adding a vertical dimension to the detection capability. This dimensional expansion allows simultaneous detection of rotations about multiple axes (x, y, and z axes) without complicating the basic fan-shaped structure
2Device complexity
If a disc-type gyroscope detects only in-plane rotation, then the structure remains simple, but it cannot detect the third axis rotation out of the plane
Solution Approach 1:
The fan-shaped vibration structures serve multiple functions: they can vibrate in-phase for x-axis detection, out-of-phase for y-axis detection, and exhibit out-of-plane motion for z-axis detection. This multi-functionality is achieved within a single unified structure rather than requiring separate sensing elements for each axis, thereby enhancing versatility without proportionally increasing device complexity
Solution Approach 2:
The gyroscope utilizes dynamic vibration modes that can be selectively excited and detected. The vibration structures are designed to support multiple vibration modes including in-plane and out-of-plane motions. By dynamically switching between different vibration modes and detection modes, the system achieves three-axis detection capability while maintaining a relatively simple static structure
3Ease of manufacture
If elastic members have uniform properties, then manufacturing is easier, but coupling errors and quadrature errors increase
Solution Approach 1:
The elastic members are designed with differentiated local properties: the first elastic member has its smallest elastic coefficient in the radial direction, while the second elastic member has its smallest elastic modulus along the ring direction. This localized optimization of elastic properties compensates for structural asymmetries and minimizes coupling between different vibration modes, thereby reducing quadrature errors and improving measurement precision without requiring complex non-uniform manufacturing
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 enhances mass utilization and sensitivity, enabling simultaneous detection of all three axes and reducing interference and errors, thereby improving the gyroscope's performance and accuracy.
Implementation Method 1
a sensing element for detecting the deviation of the vibration structure caused by Coriolis force
Implementation Method 2
a first elastic member for connecting the anchor point and the vibration structure, and a second elastic member for connecting two adjacent vibration structures; the first elastic member has a smallest elastic coefficient in a radial direction
Implementation Method 3
the second elastic member has a smallest elastic modulus along the ring direction
Implementation Method 4
an in-surface transducer for coupling a mechanical field and an electric field in a plane where the vibration structure is located
Implementation Method 5
an energy conversion form of the in-surface transducer includes one or more combinations of capacitance, inductance, pyroelectric, and piezoelectric
Implementation Method 6
an out-surface transducer for coupling the mechanical field and the electric field outside the plane where the vibration structure is located
Implementation Method 7
an energy conversion form of the out-surface transducer includes one or more combinations of capacitance, inductance, pyroelectric, and piezoelectric
Data Source
AI summary
The present invention provides a micromachined gyroscope, including: a base; an anchor point fixed to the base; a number of vibration structures; and a drive structure used for driving the vibration structure to vibrate in a x-y plane along a ring direction. The drive structure includes at least four groups arranged at intervals along the ring direction and symmetrical about an x axis and a y axis. The micromachined gyroscope works in two vibration modes interchanging with each other, including a driving mode status working in a first mode status and a testing mode status working in a second mode status. By virtue of the configuration described in the invention, the micromachined gyroscope can realize three-axis detection at the same time, and greatly improves the quality utilization rate of the vibration structure.