Spring-Mass Encoder for Latency-Free Angular Velocity Detection
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Solution Overview
Problem
Existing shaft position and rotational speed measurement systems require precise angle marks on encoder disks, leading to imprecision in rotational speed determination if marks are not accurately made.
Innovation Solution
A measuring system based on the spring-mass principle, utilizing a magnetic field sensor array with a mass element and spring element attached to a rotatable encoder, where centrifugal force moves the mass element radially, allowing for instantaneous angular velocity detection without latency, using a magnetic field sensor array that does not co-rotate with the shaft.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If angle marks are made very precisely on the encoder disk, then measurement precision is improved, but manufacturing precision requirements increase and device complexity increases
Solution Approach 1:
The patent replaces the conventional optical/magnetic pickup system that scans stationary angle marks with a spring-mass system where the mass element physically moves radially in response to centrifugal force during rotation. This mechanical displacement directly modulates the magnetic field sensed by stationary sensors, substituting mechanical motion for optical/magnetic field scanning and eliminating the need for precisely manufactured angle marks.
Solution Approach 2:
The patent changes the measurement parameter from scanning fixed angle marks to detecting radial displacement of a mass element. The mass element's position, governed by the balance between centrifugal force (proportional to rotational speed squared) and spring force, provides a continuous analog signal that directly represents rotational speed, transforming the measurement approach from discrete mark detection to continuous physical parameter detection.
2Measurement precision
If angle marks are made very precisely on the encoder disk, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces the conventional optical/magnetic pickup system that scans stationary angle marks with a spring-mass system where the mass element physically moves radially in response to centrifugal force during rotation. This mechanical displacement directly modulates the magnetic field sensed by stationary sensors, substituting mechanical motion for optical/magnetic field scanning and eliminating the need for precisely manufactured angle marks.
Solution Approach 2:
The patent extracts the measurement function from the encoder disk itself (the angle marks) and places it in the spring-mass system. The mass element's radial position, determined by rotational speed, becomes the measurement reference instead of fixed marks on the disk. This separation allows the encoder disk to be simple while the measurement function resides in the dynamically responsive mass-spring-sensor system.
3Speed
If conventional pickup systems are used to scan angle marks, then rotational speed can be determined, but measurement latency occurs and instantaneous angular velocity detection is not achieved
Solution Approach 1:
The patent replaces the conventional optical/magnetic pickup system that scans stationary angle marks with a spring-mass system where the mass element physically moves radially in response to centrifugal force during rotation. This mechanical displacement directly modulates the magnetic field sensed by stationary sensors, substituting mechanical motion for optical/magnetic field scanning and eliminating the need for precisely manufactured angle marks.
Solution Approach 2:
The patent achieves continuous measurement by having the mass element continuously respond to centrifugal force throughout the rotation cycle. Unlike discrete mark scanning that occurs at specific angular positions, the spring-mass system provides continuous analog modulation of the magnetic field as the mass element's radial position continuously varies with rotational speed, enabling instantaneous velocity detection without latency.
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
Enables precise detection of instantaneous angular velocity and rotation angle without latency, improving measurement accuracy and eliminating the need for precise angle marks on the encoder disk.
Implementation Method 1
The magnetic field sensor array is arranged toward the encoder to measure a change, caused by the movement of the mass element, in the magnetic field vector
Implementation Method 2
the mass element can be moved by the centrifugal force and the centrifugal force works against the spring force of the spring element
Implementation Method 3
the mass element can be moved by the centrifugal force and the centrifugal force works against the spring force of the spring element
Data Source
AI summary
A measuring system is provided that includes a magnetic field sensor array, an evaluation circuit for evaluating measurement signals of the magnetic field sensor array, and a rotatable encoder that has a mass element to change a magnetic field vector in the magnetic field sensor array. The encoder has a spring element in which the mass element is attached to the spring element. The encoder has a linear guide, and the mass element is guided in a radial direction in the linear guide such that during a rotation of the encoder the mass element can be moved by centrifugal force and the centrifugal force works against the spring force of the spring element. The magnetic field sensor array is arranged toward the encoder to measure a change, caused by the movement of the mass element, in the magnetic field vector.