Absolute Position Detection Using 2D Optical Sensor Array
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Solution Overview
Problem
Traditional optical scales for determining absolute position along an axis of motion are prone to errors and loss of position data, especially when power is lost or objects are repositioned, leading to inaccurate measurements.
Innovation Solution
A measurement system using a scalar element with coded regions and a two-dimensional optical sensor array to capture images, allowing for the determination of absolute position without relying on index lines, enabling accurate and error-free positioning even when power is lost or objects are repositioned.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional optical scale with index marks is used to measure relative position, then the measurement system is simple and cost-effective, but the position data is lost when power is lost or objects are repositioned, leading to measurement errors
Solution Approach 1:
The patent transitions from one-dimensional index marks to two-dimensional coded regions containing encoded position information. The scalar element includes coded regions with multiple bits of position data arranged in a two-dimensional pattern that can be captured by a 2D sensor array, enabling absolute position determination without relying on continuous counting from a home position.
Solution Approach 2:
The patent encodes position information by creating optical copies of binary data in the coded regions. The 2D sensor array captures optical images of these coded regions, which contain encoded representations of absolute position values. This allows the system to read position data directly from the optical pattern without mechanical counting, eliminating data loss issues.
2Measurement precision
If index counting is used to determine position along an axis, then the measurement method is straightforward, but errors accumulate over time and the system requires a home location reference
Solution Approach 1:
The patent pre-encodes absolute position information into the coded regions of the scalar element before measurement begins. Each coded region contains encoded data representing a specific absolute position value, so the system does not need to count from a home position or recover from power loss. The position information is prepared in advance and readily available for immediate reading.
Solution Approach 2:
The patent replaces the mechanical counting method with an optical reading system. Instead of mechanically counting index marks from a home position, the 2D sensor array optically captures and decodes position information from coded regions. This substitution eliminates mechanical errors, accumulation issues, and the need for physical home position references.
3Ease of operation
If a traditional optical scale is used, then the system can measure relative motion, but it cannot determine absolute position without returning to a home location
Solution Approach 1:
The patent uses two-dimensional coded regions containing encoded absolute position data, allowing the system to determine position directly without continuous operation requirements. The coded regions encode sufficient information to establish absolute position immediately upon reading, eliminating the need for continuous index counting from a home position.
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 system provides accurate and reliable absolute position measurements by using coded regions and a two-dimensional optical sensor array, ensuring precise positioning and real-time feedback, reducing errors and the need for a home location.
Implementation Method 1
a two-dimensional optical sensor array configured to capture an image of a portion of the scalar element
Data Source
AI summary
A system for determining the absolute position of a first object with respect to a second object includes a scalar element attached to the first object and a measuring device attached to the second object. The scalar element comprises a series of coded regions. The coded region represents a number designating a position along an axis of the scalar element. The measuring device includes a two-dimensional optical sensor array configured to capture an image of a portion of the scalar element. The system also includes a processor configured to receive the image and determine an absolute position of the first object with respect to the second object based on at least one coded region of the series of coded regions.