Vehicle Trajectory Control via Wheel Braking and Steering Torque Compensation
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Solution Overview
Problem
Existing methods for controlling a motor vehicle's trajectory without steering control, such as those using ESP systems, face challenges in accurately accounting for steering torques and geometry changes, leading to slow dynamic corrections and potential accidents due to unforeseen vehicle reactions.
Innovation Solution
A method that applies maximum braking to a front wheel and records the steering assistance's response to maintain steering alignment, periodically testing to update control values and account for the vehicle's actual geometry, ensuring precise trajectory control and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If braking is applied to control vehicle trajectory without steering control, then trajectory control is achieved, but steering torques cause unexpected vehicle reactions and slow dynamic corrections
Solution Approach 1:
The system performs preliminary characterization of steering torques by applying test brake pressures and measuring resulting steering wheel rotations. This advance knowledge is stored and used during actual trajectory control to predict and compensate for steering torque effects, eliminating the need for slow reactive corrections.
Solution Approach 2:
The system implements feedback by continuously monitoring steering wheel rotation during braking operations and comparing it against pre-characterized torque values. This feedback enables real-time compensation for steering torque effects, maintaining fast and accurate trajectory control without unexpected vehicle reactions.
2Measurement precision
If steering geometry changes are not accounted for, then control calculations become inaccurate, but periodically testing and updating control values adds time and complexity
Solution Approach 1:
The system performs self-characterization by automatically applying test brake pressures, measuring steering wheel rotations, and updating control parameters without external intervention. This self-service approach maintains high measurement precision while minimizing the complexity burden on users.
Solution Approach 2:
The system implements periodic re-characterization at defined intervals or when specific conditions are met, balancing the need for accurate control calculations with operational efficiency. This periodic action ensures control precision is maintained without requiring continuous complex testing procedures.
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 method allows for quick and precise control of vehicle trajectory by accounting for steering torques and geometry changes, enhancing safety and responsiveness by directly establishing optimal braking pressures based on real-time vehicle conditions.
Implementation Method 1
acts automatically on certain wheel brakes to generate a yaw moment
Implementation Method 2
controls the steering assistance to deliver a reverse torque opposing this deflection
Data Source
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AI summary
A method for testing a trajectory control function of a motor vehicle in the absence of steering control of that vehicle, using a driving assistance system performing trajectory control from an individual action on the wheel brakes, the steering of the vehicle having an assistance that can control this steering, this method being notable in that during the movement of the vehicle it applies braking to a front wheel (40, 42), and depending on its effect on the steering, it controls the steering assistance to deliver an inverse torque opposing this steering in order to maintain the steering in the state, and it records values of this assistance control depending on the braking applied.