Rotation Rate Sensor Spring Node Attachment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing rotation rate sensors suffer from cross feed of drive motion into detection motion due to non-ideal processing of spring elements, leading to significant quadrature signals that require costly suppression measures.
Innovation Solution
The detection springs are connected to force transmission elements at vibrational nodes, suppressing deformation and cross feed, allowing for an almost force-free and torque-free suspension of the seismic mass, thereby minimizing quadrature signals without the need for compensation structures or costly signal conditioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If spring elements are used to suspend Coriolis elements and drive means, then the sensor structure is mechanically stable and manufacturable, but production tolerances cause non-ideal processing leading to cross feed of drive motion into detection motion and significant quadrature signals
Solution Approach 1:
The patent introduces an intermediary mechanism (the specific spring element configuration with defined attachment points and geometric constraints) that mediates between the drive motion and detection motion. This intermediary structure is designed to decouple the drive and detection paths, preventing the cross feed caused by manufacturing tolerances from propagating to the detection system.
Solution Approach 2:
The patent changes key parameters of the spring element system, including the stiffness characteristics, attachment point locations, and geometric configuration. By optimizing these parameters, the system achieves insensitivity to manufacturing tolerances while maintaining mechanical stability and ease of manufacture.
2Power
If spring elements are stressed to produce drive motion, then the Coriolis elements are excited to vibrations, but the spring elements deflect orthogonally to the drive direction causing cross feed into detection motion
Solution Approach 1:
The patent employs asymmetric design in the spring element configuration and attachment geometry. The spring elements are positioned and oriented asymmetrically with respect to the drive axis, creating a mechanical arrangement where orthogonal deflections do not couple into the detection direction. This asymmetric geometry inherently suppresses the generation of quadrature signals during drive motion.
3Measurement precision
If costly compensation structures or signal conditioning are used to suppress quadrature signals, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent converts the potentially harmful effect of spring element deflection under manufacturing tolerances into a beneficial feature. By designing the spring system with specific geometric constraints and attachment points, the natural deflection behavior under stress is redirected away from the detection axis, transforming what would be a source of error into a mechanically robust design that inherently rejects quadrature signals.
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 approach effectively reduces quadrature signals, enabling precise detection of rotation rates with minimal inherent quadrature motion, thus eliminating the need for costly signal processing and compensation structures.
Implementation Method 1
the seismic mass is excited to the drive vibration about the drive axis by the drive unit
Implementation Method 2
a standing wave is produced in the force transmission elements
Implementation Method 3
a detection vibration of the seismic mass about a detection axis being caused by Coriolis forces
Data Source
AI summary
A rotation rate sensor having a substrate including a main extension plane, force transmission elements that are movably fastened on the substrate using detection springs and a seismic mass are provided, the seismic mass being suspended over the force transmission elements, movably relative to the substrate, in such a way that the seismic mass is able to be excited, using a drive unit, to a drive vibration about a drive axis that is parallel to the main extension plane, and in response to the presence of a rotation rate that extends in parallel to the main extension plane and perpendicular to the drive axis, the seismic mass is excitable, as a result of Coriolis forces, to a detection vibration about a detection axis that is perpendicular to the main extension plane, the detection springs being connected to the force transmission elements in the region of the vibrational nodes.