Waveguide Position Sensor Propagation Velocity Compensation
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Solution Overview
Problem
Conventional waveguide position sensors face inaccuracies due to temperature-dependent changes in propagation velocity, requiring additional circuitry and memory for compensation, and are affected by external factors like magnetic fields and manufacturing tolerances, leading to position measurement errors.
Innovation Solution
A position sensing system that includes a waveguide, a magnet, and a compensator to determine the position of the magnet relative to the waveguide by measuring both the reflected pulse and the end-of-line pulse, allowing for compensation of propagation velocity variations through controlled timing or independent position calculation, thereby reducing temperature and other factor-induced errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional temperature compensation using lookup tables is used, then temperature-dependent position measurement errors are reduced, but device complexity increases due to additional circuitry, memory, and processing requirements
Solution Approach 1:
The patent extracts the harmful temperature-dependent propagation velocity variations from the position measurement calculation by using a two-pulse method. The first pulse measures the actual propagation velocity, which is then used to compensate for temperature effects in the second pulse measurement, eliminating the need for complex lookup tables and additional compensation circuitry.
Solution Approach 2:
The system uses itself to compensate for temperature effects by measuring its own propagation velocity characteristics with the first pulse. This self-measured velocity information is then applied to correct the position measurement from the second pulse, eliminating the need for external temperature sensors, lookup tables, or complex processing capability.
2Device complexity
If propagation velocity variations due to temperature and other factors are not compensated, then device complexity remains low, but position measurement precision deteriorates
Solution Approach 1:
The patent employs periodic action by sending a sequence of pulses through the waveguide, where the first pulse serves as a velocity measurement pulse and the second pulse serves as the position measurement pulse. This periodic two-pulse sequence continuously compensates for propagation velocity variations without requiring complex continuous monitoring systems.
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 position measurement independent of temperature and other velocity-altering factors, eliminating the need for extensive additional circuitry and memory, and ensuring reliable operation across varying conditions.
Implementation Method 1
The waveguide 12, however, is often temperature dependent. More specifically, temperature may affect the permittivity, capacitance, permeability, and/or inductance of the waveguide 12. Accordingly, the velocity of waves transmitted through the waveguide 12 may change
Implementation Method 2
The magnet 14 creates an impedance discontinuity 11 in a region of the waveguide 12 proximate to the magnet 14. A reflection of the pulse 21 is reflected from the point of impedance discontinuity 11, resulting in reflected pulse 23.
Data Source
Figure 1A~1B
Figure 2~3
Figure 4~5
AI summary
A position sensing system including a waveguide, a magnet movable relative to the waveguide, and a compensator configured to compensate for a change in propagation velocity of the waveguide in determining a position of the magnet relative to the waveguide. The compensator coupled to the waveguide and configured to receive a pulse, an end of line pulse corresponding to the pulse transmitted through the waveguide, and a reflected pulse corresponding to a reflection of the pulse at a point in the waveguide. The compensator configured to determine the point based at least in part on the pulse, the end of line pulse, and/or the reflected pulse.