Hybrid Encoder System for Curvilinear Position Monitoring
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Solution Overview
Problem
Magnetic encoder systems in industrial control systems require calibration and are sensitive to temperature variations, making them unreliable for precise position monitoring of carts on tracks with varying geometries.
Innovation Solution
A linear and curvilinear encoder system using an encoder mover and stator with excitation and pick-up coils to generate and sense magnetic fields, eliminating the need for calibration and temperature compensation, allowing for precise position monitoring on tracks with linear and curvilinear sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic sensors are used to determine cart position, then position detection capability is provided, but the system requires calibration and is sensitive to temperature variations
Solution Approach 1:
The patent replaces magnetic sensor-based position detection with a transformer-based electrical system. The encoder scale with conductive traces and excitation/pickup coils creates an electrical field interaction system that is inherently more stable to temperature variations than magnetic sensors, eliminating the need for calibration while maintaining high measurement precision.
Solution Approach 2:
The patent changes the physical principle from magnetic field interaction to electrical field interaction through transformer coupling. This parameter change in the detection mechanism fundamentally improves temperature stability since electrical impedance changes with temperature are more predictable and can be compensated compared to magnetic sensor sensitivity variations.
2Measurement precision
If magnetic encoder scales with arrays of magnetic sensors are used, then absolute position determination is achieved, but hardware complexity and system cost increase
Solution Approach 1:
The patent uses a simplified encoder scale with conductive traces that copies the essential function of complex magnetic encoder scales. The trace patterns on the scale create electrical field distributions that provide the same position encoding information without requiring arrays of magnetic sensors, thereby reducing hardware complexity while maintaining absolute position determination capability.
3Adaptability or versatility
If tracks with varying geometries including curvilinear sections are used, then system versatility is improved, but position monitoring accuracy deteriorates
Solution Approach 1:
The patent employs a flexible encoder scale that can be conformally mounted on tracks with varying geometries including curvilinear sections. The scale flexes with the track shape while maintaining the integrity of the conductive trace patterns, allowing the system to adapt to different track configurations without losing position monitoring accuracy.
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 temperature-stable position monitoring of carts on tracks with varying geometries, reducing hardware requirements and system costs while maintaining high resolution and absolute mechanical position detection.
Implementation Method 1
The one or more excitation signals can be applied to the one or more excitation coils on the mover or the stator to generate one or more magnetic fields
Implementation Method 2
the one or more pick up signals can be received by one or more pick up coils on the mover or the stator for sensing changes in the magnetic fields produced by motion of the mover on the track
Data Source
AI summary
A linear and curvilinear encoder is provided in which absolute mechanical position and high resolution position determination can be obtained using a cart having a mover with “hybrid” teeth, configured in a curvilinear profile or shape, moving along a curvilinear track with a stator having teeth. The absolute mechanical position and high resolution position determination can be detected on the track by applying an excitation signal to a coil surrounding particular teeth of the stator to produce an electromagnetic (EM) field which can be influenced by the profile or shape of the teeth of the mover. A resulting pick-up signal can then be detected in a pick-up coil surrounding particular teeth of the stator with different harmonics in the pick-up signal corresponding to harmonics of the profile or shape of the teeth.