Ultrasonic Sensor Segmentation for Actuator Position Measurement
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Solution Overview
Problem
Ultrasonic position sensors face signal interference issues when measuring distances close to the end of travel position, particularly when the distance becomes less than a minimum threshold, leading to inaccurate position feedback in systems like aircraft actuators.
Innovation Solution
Implementing a system that switches to measuring distance from a secondary surface spaced beyond the minimum interference distance, allowing for accurate position feedback by ignoring unstable signals and calibrating the sensor using both surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ultrasonic waves are used to measure position at very close distances, then measurement precision is improved, but signal interference occurs between outgoing and reflected signals
Solution Approach 1:
The target surface is segmented into multiple surfaces at different distances from the sensor. The primary surface is positioned within the minimum distance range where high precision measurement is needed, while secondary surfaces are positioned beyond the minimum distance to provide alternative measurement points that avoid signal interference.
Solution Approach 2:
The system changes the measurement parameter by switching between different target surfaces based on distance conditions. When the primary surface approaches within the minimum distance threshold, the system switches to measuring the secondary surface, thereby changing which physical target is being measured to avoid interference.
2Measurement precision
If the sensor measures distance to the primary surface at end of travel position, then position feedback accuracy is improved, but the distance becomes less than minimum distance causing interference
Solution Approach 1:
The system performs preliminary switching action before the primary surface enters the problematic minimum distance range. By detecting when the primary surface is approaching the minimum distance threshold, the system proactively switches to the secondary surface measurement, preventing interference before it occurs.
Solution Approach 2:
The secondary surface acts as an intermediary measurement target. When the primary surface is too close for accurate measurement, the secondary surface provides an intermediate solution by being positioned at a safe distance while still representing the same actuator position through known geometric relationships.
3Object-affected harmful factors
If a secondary surface is introduced for measurement, then signal interference is avoided, but device complexity increases
Solution Approach 1:
The same ultrasonic sensor performs multiple functions by measuring different surfaces. The sensor is universally capable of measuring both the primary surface (for normal operation) and the secondary surface (for end-of-travel positioning), eliminating the need for separate sensors or measurement systems.
Solution Approach 2:
The measurement function for both primary and secondary surfaces is merged into a single sensor system. The control system combines the measurement capabilities and switches between surfaces based on position conditions, reducing overall system complexity compared to using separate measurement 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
Enables precise position measurement and calibration within the minimum distance range, preventing signal interference and ensuring accurate operation of actuators even at close proximity to the end of travel position.
Implementation Method 1
the sensor generally works by sending an outgoing signal which reflects off of a target surface and back to the sensor. The time of this travel is monitored to provide the position feedback.
Implementation Method 2
The minimum distance varies by the frequency of the signal and the speed of sound in the medium through which the signal is traveling.
Implementation Method 3
When the distance becomes less than a minimum distance, the outgoing signal can interfere with the incoming reflected signal.
Data Source
Figure 1A~1B
Figure 2
AI summary
A system (20) has an actuator (24) with a first surface (30) and a second surface (32), the first surface (30) being offset a step dimension from the second surface (32). A sensor (28) is configured to measure a distance between the sensor (28) and both the first surface (30) and the second surface (32) via a signal received by the sensor (28) after having reflected off the first surface (30) or the second surface (32). The step dimension is greater than a minimum dimension, which is defined in view of a medium through which the actuator (24) moves and a frequency of the signal.