Trailer Length Estimation Using Wheel Steer and Hitch Angle Ratios
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Solution Overview
Problem
Reversing a vehicle while towing a trailer is challenging due to the need for opposite steering inputs and amplified steering errors, and existing trailer backup assist systems are complex and costly, assuming a zero curvature path and requiring complex human-machine interfaces and multiple sensors for path determination and jackknife condition management.
Innovation Solution
A device and method for estimating trailer length using a processor with wheel steer angle and hitch angle sensors, determining a ratio between the two angles, and generating a running average to calculate the trailer length, which simplifies the trailer backup assist system by decoupling steering inputs and reducing the complexity of path determination and jackknife condition management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a trailer backup assist system assumes a zero curvature path and uses complex path determination methods, then the system can manage jackknife conditions, but the device complexity and cost increase significantly
Solution Approach 1:
The patent extracts the trailer length estimation function from the complex path determination system by using a dedicated ratio-based calculation method that independently estimates trailer length from wheel steer angle and hitch angle sensors, removing the need for complex camera-based path planning and multiple sensors while maintaining jackknife condition management capability
Solution Approach 2:
The system uses the vehicle's existing steering inputs and hitch angle measurements to self-determine trailer length through ratio calculations, eliminating the need for external path determination systems, cameras, or complex human-machine interface inputs, allowing the system to manage itself with minimal additional components
2Measurement precision
If multiple sensors and complex human-machine interfaces are used for path determination, then path accuracy improves, but the ease of operation deteriorates
Solution Approach 1:
The system automatically determines trailer length using existing sensor data (wheel steer angle and hitch angle) without requiring user input for path specification, obstacle detection, or goal setting, making the system easy to operate while maintaining accurate trailer length estimation through the ratio-based calculation method
Solution Approach 2:
The patent removes the complex human-machine interface requirements for path determination by extracting the essential function (trailer length estimation) and achieving it through simple ratio calculations from existing sensors, eliminating the need for cameras, path planners, and complex user interactions
3Measurement precision
If complex camera systems and inertial navigation are used for path following, then path following accuracy improves, but the device complexity and cost increase
Solution Approach 1:
The patent extracts the trailer length estimation function from complex camera and inertial navigation systems by using a simplified ratio-based calculation method that relies only on wheel steer angle and hitch angle sensors, achieving sufficient accuracy for backup assist without the high cost and complexity of vision-based or navigation-based systems
Solution Approach 2:
The system replaces complex optical (camera) and inertial navigation systems with a mechanical/mathematical ratio-based calculation approach that uses existing angular measurements to estimate trailer length, reducing device complexity while maintaining functional accuracy for trailer backup assist operations
Data Source
AI summary
A vehicle system for estimating a trailer length is disclosed and includes a first sensor for measuring a wheel steer angle and a second sensor for measuring a hitch angle. A processor is in communication with the at least one sensor and is operable to determine a ratio between the wheel steer angle and the hitch angle, generate a running average of the ratio, and calculate the trailer length based on an average ratio between the wheel steer angle and the hitch angle.