Ultrasonic Sensor Threshold Compensation Using a Ground Wave Model
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Solution Overview
Problem
Conventional ultrasonic sensors in vehicles require excessive memory and computational resources for vehicle height compensation, leading to increased costs and reduced detection accuracy due to stepwise threshold adjustments without considering continuous height changes.
Innovation Solution
A system that adjusts ultrasonic sensor threshold values based on a ground wave model, using a vehicle height detection unit, ground wave modeling unit, and threshold value correction unit to calculate and apply optimal threshold values in real-time, reducing memory requirements and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If threshold values are corrected using experimental values for each vehicle height step, then detection accuracy is improved, but memory storage space and system cost increase six-fold
Solution Approach 1:
The patent extracts only the essential parameters needed for threshold correction (ground waveform start delay time and ground wave magnitude) from the complete experimental threshold value sets. By storing only these key parameters instead of full threshold value tables for each height step, the memory requirement is dramatically reduced while maintaining detection accuracy.
Solution Approach 2:
The patent changes the approach from storing complete threshold value profiles to storing fundamental physical parameters (delay time and magnitude). This parameter transformation allows the system to reconstruct appropriate thresholds dynamically based on vehicle height, reducing storage from 384 bytes to just 2 bytes while preserving measurement precision.
2Measurement precision
If threshold values are updated using LIN communication at 19,200 bits/sec, then compensation is applied, but detection timing is delayed by 160 ms
Solution Approach 1:
The ultrasonic sensor performs self-correction using the stored ground wave model parameters. Instead of requiring external controller intervention to update thresholds, the sensor autonomously adjusts its threshold values based on vehicle height and the pre-stored delay time and magnitude parameters, eliminating communication delays.
Solution Approach 2:
The ground wave model parameters (delay time and magnitude) are pre-calculated and stored during system initialization or manufacturing. This preliminary preparation allows the sensor to perform immediate threshold correction without real-time communication overhead, reducing detection timing delay while maintaining compensation accuracy.
3Device complexity
If height compensation is performed in discrete steps rather than continuously, then implementation complexity is reduced, but detection distance is shortened due to suboptimal threshold values
Solution Approach 1:
The patent implements continuous height compensation by using the vehicle height sensor output to dynamically calculate the ground waveform start delay time and ground wave magnitude in real-time. This dynamic approach allows the threshold to be continuously optimized for any vehicle height, maximizing detection distance while maintaining manageable implementation complexity through mathematical modeling.
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 enhances detection distance and accuracy by applying optimal threshold values continuously with reduced memory usage, minimizing computational overhead and system costs.
Implementation Method 1
typical automotive ultrasonic sensors use a threshold value curve to distinguish a ground-reflected wave from an obstacle
Implementation Method 2
a transmitter unit configured to transmit ultrasonic waves, a receiver unit configured to receive the ultrasonic waves reflected from an obstacle or ground
Implementation Method 3
a vehicle height detection unit configured to detect a vehicle height
Implementation Method 4
modeling a change in ground wave according to a change in vehicle height, estimating the start time of the ground wave and the magnitude of the ground wave with time
Data Source
AI summary
Provided is a system for adjusting an ultrasonic sensor threshold value according to a vehicle height on the basis of a ground wave model. The system includes a vehicle height detection unit configured to detect a vehicle height, a ground wave modeling unit configured to model a ground wave model by matching a ground waveform start delay time and a threshold value for each vehicle height detected by the vehicle height detection unit and provide the modeled ground wave model, and an ultrasonic sensor configured to store the ground wave model and a ground waveform reference threshold value measured at a lowest vehicle height of a vehicle and compensate a lowest vehicle height threshold value according to the current vehicle height using a ground waveform start delay time calculated according to the detected vehicle height.