Motion Encoder Using Digital Pattern Matching for Multi-Axis Measurement
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Solution Overview
Problem
Existing motion encoders are limited by their ability to measure movement in only one direction, require precise scales for accuracy, and are susceptible to misalignment and environmental contaminants, which affects their reliability and accuracy.
Innovation Solution
A motion encoder that measures movement by tracking pattern features between images, allowing for multi-axis measurement with a single sensor, is tolerant to misalignment and contaminants, and does not rely on precise scales, using template matching techniques and a motion model to quantify movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a precise scale is used to ensure measurement accuracy, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent replaces the precise physical scale with a digital copy of scale information stored in memory. The processing unit retrieves scale data from memory and applies it to image coordinates through coordinate transformation, eliminating the need for a complex physical scale while maintaining measurement accuracy.
Solution Approach 2:
The patent substitutes the mechanical/optical scale system with a computational system. Instead of relying on a physical scale that requires precise manufacturing, the system uses digital image processing and coordinate transformation algorithms to achieve accurate measurements.
2Device complexity
If a single optical sensor is used to reduce device complexity, then the ability to measure multi-axis movement is limited, but device complexity is reduced
Solution Approach 1:
The patent enables a single optical sensor to perform multiple measurement functions by capturing images that contain information about movements along multiple axes. Through coordinate transformation and image processing, the sensor system can determine positional changes in three-dimensional space, making one sensor universal for measuring movements along x, y, and z axes.
Solution Approach 2:
The patent transitions from one-dimensional linear measurement to three-dimensional spatial measurement by capturing two-dimensional images and applying coordinate transformations. This allows the system to extract multi-axis movement information from a single sensor's image data.
3Measurement precision
If a scale is used for measurement, then measurement capability is provided, but the system becomes susceptible to misalignment and environmental contaminants
Solution Approach 1:
The patent replaces the physical scale with a digital representation stored in memory. This digital copy is not affected by misalignment or environmental contaminants, allowing the system to maintain measurement capability while improving reliability and tolerance to adverse conditions.
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 solution enables more accurate and reliable multi-axis movement measurement with improved tolerance to environmental factors and reduced cross-talk, allowing for simpler and cost-effective design.
Implementation Method 1
The processing unit is configured to determine how image features corresponding to the pattern features transform between the received images by determining displacement of the image features between the received images
Data Source
AI summary
A motion encoder comprising a joint, the joint comprising a first part (304); and a second part (302) movably mounted with respect to the first part (304) to change the joint between a first joint condition and a second joint condition; a first image capture device (ICD) (310) comprising an array of light sensing elements arranged to generate images; a processing unit; and a pattern surface (312), the pattern surface (312) defining or being arranged to define a pattern (314) which moves relative to the first ICD (310) between a first pattern position and a second pattern position as the joint changes between the first joint condition and a second joint condition, the pattern (314) comprising pattern features, wherein the first ICD (310) has a field of view encompassing the first pattern position and the second pattern position such that the pattern features are visible to the first ICD (310) in both the first pattern position and the second pattern position; and the processing unit is communicatively coupled to the first ICD (310) to receive the images from the first ICD (310), the processing unit being configured to determine how image features corresponding to the pattern features transform between the received images to quantify the position and/or movement of the first part (304) relative to the first ICD (310).