Adaptive Steering Control for Trailer Path Accuracy
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Solution Overview
Problem
Backing up a vehicle with a trailer is challenging due to the need for counter-steering and stabilization to prevent jack-knifing, and small steering errors amplify, causing the trailer to deviate from the desired path, which existing trailer backup assist systems do not effectively address.
Innovation Solution
A trailer backup assist system that uses a controller to output a steering signal based on kinematic parameters, adjusts the control parameter to maintain the trailer on a commanded backing path by determining the error between measured and predicted behaviors, and compensates for inaccuracies in hitch angle measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If trailer backup assist systems use standard steering control without error compensation, then the system structure remains simple, but the trailer cannot maintain accurate path following due to parameter estimation errors
Solution Approach 1:
The system implements feedback by continuously monitoring the actual trailer behavior (hitch angle, position) and comparing it with the predicted behavior based on the vehicle-trailer model. The error between measured and predicted values is fed back to the controller, which then adjusts the control parameter (commanded curvature) to compensate for parameter estimation errors, enabling accurate path following despite uncertainties in trailer dimensions or hitch position
Solution Approach 2:
The system dynamically adjusts the control parameter (commanded curvature of the backing path) based on the detected error between actual and predicted trailer behavior. By scaling the commanded curvature according to the error magnitude, the system adapts to parameter estimation inaccuracies without requiring complex recalibration or additional sensors
2Measurement precision
If the system scales the commanded curvature to compensate for errors, then path following accuracy improves, but the control algorithm complexity increases
Solution Approach 1:
The system scales the commanded curvature parameter based on the error between measured and predicted hitch angle behavior. This parameter adjustment compensates for inaccuracies in hitch angle measurements or model predictions, improving the overall precision of trailer position control while maintaining a relatively simple control algorithm structure
3Ease of operation
If the system uses user-input or estimated kinematic parameters, then the system ease of operation improves, but the reliability of path following deteriorates due to parameter inaccuracies
Solution Approach 1:
The system performs self-correction by using the error between actual and predicted trailer behavior to automatically adjust the commanded curvature. This self-service mechanism compensates for inaccurate user-input or estimated kinematic parameters without requiring manual recalibration or complex setup procedures, thereby maintaining both ease of operation and path following reliability
Solution Approach 2:
The feedback loop continuously monitors the discrepancy between predicted and actual trailer behavior caused by parameter inaccuracies and adjusts the control output accordingly. This feedback mechanism ensures reliable path following even when kinematic parameters are only estimated or user-provided, without compromising system simplicity
Data Source
AI summary
A system for assisting in reversing of a vehicle-trailer combination includes a vehicle steering system and a controller. The controller outputs a steering signal based on a control parameter to the steering system to maintain the trailer along a commanded backing path, determines an error between a measured behavior of a characteristic of the vehicle-trailer combination and a predicted behavior of the characteristic, and adjusts the control parameter based on the error.