Ultrasonic Hitch Angle Estimation at High Trailer Articulation
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Solution Overview
Problem
Current systems for estimating Hitch Articulation Angle (HAA) during towing operations using Ultra-Sonic Sensors (USSs face challenges such as high signal interference and uncertain trailer shapes, limiting their effectiveness, especially at higher angles where accurate returns from both sensors are not available.
Innovation Solution
The implementation of a controller that receives ultrasonic sensor range measurements, determines curve characteristics through clustering analysis and curve-fitting functions, and applies these characteristics to estimate HAA values even when only one sensor is available, expanding the range of calculable angles and improving accuracy at higher hitch angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional geometric equations or kinematic models are used to calculate HAA, then the calculation is straightforward, but the method fails at high HAA angles where accurate USS returns from both sensors are not available
Solution Approach 1:
The system pre-determines USS curve characteristics (including curve-fitting functions, upward-bounding functions, and lower-bounding functions) during normal operating conditions when both sensors provide accurate returns. These pre-determined characteristics are stored and later applied to estimate HAA at high angles where traditional methods fail, allowing the system to prepare solutions in advance for extreme conditions.
Solution Approach 2:
The patent introduces USS curve characteristics as an intermediary element that bridges the gap between limited sensor data and HAA estimation. The curve characteristics (derived from clustering analysis and curve-fitting) act as a mediator that enables HAA calculation even when direct geometric methods cannot obtain accurate sensor returns from both ultrasonic sensors.
2Adaptability or versatility
If USSs are used to estimate HAA, then the system can operate in various towing conditions, but the system suffers from high signal interference and uncertain trailer shapes that limit effectiveness
Solution Approach 1:
The patent segments the USS measurement data into valid and invalid clusters using clustering analysis. By dividing the data space and identifying valid clusters, the system can filter out unreliable measurements caused by signal interference and uncertain trailer shapes, maintaining reliability while operating in diverse towing conditions.
Solution Approach 2:
The system uses feedback mechanisms by continuously monitoring USS range measurements and comparing them against pre-determined curve characteristics. When measurements fall within the bounds defined by the curve characteristics, the system accepts them; otherwise, it rejects or corrects them, providing continuous feedback to maintain reliable HAA estimation despite signal interference.
3Measurement precision
If the system requires accurate returns from both USSs to calculate HAA, then the calculation accuracy is maintained, but the system cannot operate at high HAA angles where only one sensor returns are available
Solution Approach 1:
The system pre-determines USS curve characteristics during normal operations when both sensors are functional. These pre-established characteristics enable the system to later operate with only one sensor return at high HAA angles, maintaining operational availability without sacrificing accuracy because the pre-determined curves provide the missing information.
Solution Approach 2:
The patent applies partial action by using only one USS return when necessary at high HAA angles, rather than requiring both sensors. The pre-determined curve characteristics compensate for the missing sensor data, allowing the system to operate with partial sensor input while maintaining acceptable HAA estimation 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
This solution enables accurate estimation of HAA values across a wider range of angles, including high HAA scenarios where traditional methods fail, enhancing vehicle and trailer motion control during towing operations.
Implementation Method 1
An Array of Ultra-Sonic Sensors (USSs) can be used for estimation of Hitch Articulation Angle (HAA) when towing trailers
Implementation Method 2
a USS range measurement for a specific USS provides a measurement of a distance between the specific USS and a face of the towed trailer
Data Source
AI summary
Systems, methods, and apparatus are provided in a vehicle having a Hitch Articulation Angle (HAA) calculation system for estimating an HAA between the vehicle and a towed trailer. The method includes: receiving a plurality of ultrasonic sensor (USS) range measurements for a first USS on the vehicle while the vehicle is towing the trailer in a forward direction; receiving a plurality of HAA values calculated using geometric equations or a kinematic model that correspond to the plurality of USS range measurements; receiving a USS range measurement for the first USS while the vehicle is operating in a reverse direction or experiencing a high HAA but not from a second USS; estimating an HAA value from the USS range measurement by applying the USS curve characteristics for the first USS; and providing the estimated HAA value to a vehicle motion control system for use in controlling vehicle and trailer motion.