Ultrasonic Position Sensor With Integrated Sound-Speed Measurement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing ultrasonic position sensors for fluid control systems face challenges due to varying sound speeds in fluids caused by temperature and fuel type changes, leading to increased complexity, size, cost, and weight, and requiring additional sensors to determine sound speed.
Innovation Solution
A position sensor system that uses acoustic transmitters and receivers to emit and detect acoustic waveforms across an acoustic interface within a fluid effector, determining position and speed without needing to know the sound speed in the medium, using ratiometric calculations based on time and phase differences of waveforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing time of flight ultrasonic position sensors are used, then position detection is achieved, but additional sensors are required to determine sound speed, increasing complexity, size, cost, and weight
Solution Approach 1:
The patent combines the sound speed determination function with the position detection function into a single integrated system. The same ultrasonic transducers used for position measurement are also used to measure the time of flight of ultrasonic signals, allowing sound speed to be calculated from the relationship between distance and time without requiring separate sound speed sensors.
Solution Approach 2:
The ultrasonic transducers serve multiple functions: they act as both position sensors and sound speed measurement devices. By measuring the time of flight of ultrasonic signals between transducers and knowing the fixed distance between them, the system simultaneously determines both sound speed and position information, eliminating the need for dedicated sound speed sensing hardware.
2Measurement precision
If LVDTs are used for position tracking, then position measurement is achieved, but actuator sizing is driven by LVDT installation requirements, increasing size
Solution Approach 1:
The patent replaces the mechanical LVDT system with an ultrasonic acoustic field-based measurement system. Instead of using a mechanical transformer that requires physical installation through the piston rod, the system uses ultrasonic transducers that emit and receive acoustic signals through the fluid medium, eliminating the mechanical coupling requirements and reducing actuator size.
Solution Approach 2:
The patent extracts the position measurement function from the mechanical actuator structure by using ultrasonic signals that propagate through the fluid. This allows position detection without requiring physical installation components like piston rod penetrations, thereby reducing the overall actuator volume and simplifying the mechanical design.
3Reliability
If additional sensors are added to determine sound speed, then sound speed measurement is achieved, but weight increases
Solution Approach 1:
The patent merges the sound speed measurement capability into the existing position detection system by utilizing the same ultrasonic transducers and signal processing hardware. The sound speed is derived from the time of flight measurements already being taken for position detection, eliminating the need for separate sound speed sensing components and their associated weight.
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 efficient, economical, and space-saving position sensing with improved accuracy and reduced mechanical and electronic complexity compared to LVDTs and existing ultrasonic sensors, without requiring knowledge of sound speed in the medium.
Implementation Method 1
emit a first emitted acoustic waveform in a first direction toward the first face, and emit a second emitted acoustic waveform in a second direction opposite the first direction toward the second face
Implementation Method 2
measure the amount of time until reflected echoes of the pings return. The amount of time between the transmission and return of the pings is generally dependent upon the distance between the transceiver and the object being measured
Implementation Method 3
The speed of sound of a medium can be sensed, but the inclusion of these additional sensors adds to the complexity, size, cost, and weight of such systems
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The subject matter of this specification can be embodied in, among other things, a position sensor system that includes a fluid effector that includes a housing having an inner surface defining a cavity, and a moveable body having a first face and a second face opposite the first face and configured to contact the inner surface and subdivide the cavity to define a first chamber and a second chamber, an acoustic transmitter system configured to emit a first emitted waveform toward the first face, and emit a second emitted waveform toward the second face, and an acoustic receiver system configured to detect a first reflected waveform based on a first reflection of the first emitted waveform based on the moveable body, and detect a second reflected waveform based on a second reflection of the second emitted waveform based on the moveable body.