Vehicle Lateral Position Control for Smooth Autonomy Handover
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Solution Overview
Problem
Autonomous vehicles experience excessive lateral acceleration during the transition from manual to autonomous control, particularly when sensor calibration is off or driving on inclined or curved lanes, leading to passenger discomfort and potential destabilization.
Innovation Solution
A method for regulating the lateral position of a vehicle on a traffic lane that includes calculating a reference state vector and an observed state vector, with an initialization step that sets the steering angle setpoint equal to the measured value at activation, using a regulation vector dependent on vehicle speed to minimize steering wheel turning angle and smooth transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If the regulation method is activated during driving to switch from manual to autonomous trajectory control, then the vehicle can autonomously follow a reference trajectory, but excessive lateral accelerations are generated causing passenger anxiety and potential vehicle destabilization
Solution Approach 1:
The patent applies preliminary action by calculating and applying a compensation value before the actual lane centering control begins. The compensation value is calculated based on the current steering angle and stored as an offset to be applied during the transition, preventing sudden steering movements that would cause excessive lateral acceleration.
Solution Approach 2:
The patent changes the parameter of steering angle by introducing a compensation value that adjusts the setpoint steering angle. This parameter modification ensures that the transition from manual to autonomous control does not result in abrupt steering angle changes, thereby reducing lateral acceleration while maintaining the ability to achieve lane centering.
2Measurement precision
If sensor calibration offset is present in the steering angle sensor, then the measured steering angle differs from the actual value, but this causes particularly high lateral accelerations during transition to autonomous control
Solution Approach 1:
The patent uses feedback by continuously monitoring the actual steering angle and comparing it with the setpoint steering angle that includes the compensation value. This feedback mechanism allows the system to adapt to sensor calibration offsets by adjusting the compensation value based on the difference between expected and actual steering behavior, thereby preventing excessive lateral acceleration even when sensor measurements are inaccurate.
3Adaptability or versatility
If the vehicle is moving on a sloping or cambered traffic lane at the time of transition, then the lane geometry changes, but this causes particularly high lateral accelerations during the transition to autonomous control
Solution Approach 1:
The patent applies preliminary action by calculating the compensation value based on the current steering angle before the transition to autonomous control begins. This pre-calculated compensation accounts for the vehicle's position on sloping or cambered lanes, allowing the system to smoothly adapt to lane geometry changes without generating excessive lateral acceleration during the transition phase.
Data Source
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AI summary
A method for regulating the lateral position of a vehicle (1) on a traffic lane (10) comprising: - a step (E21) of computing a reference state vector (Xref) of the vehicle; - a step (E22) of computing an observed state vector (Xobs) of the vehicle; - a step (E23) of computing a setpoint of a steering angle (δc) of steering wheels (2f) of the vehicle as a function of the difference (Xerr) between the reference state vector (Xref) and the observed state vector (Xobs); - an initialisation step (E1) executed when the regulation method is activated, the initialisation step comprising a sub-step (E11) of computing a component (X07) of an initial observed state vector (X0) so that the steering angle (δc) setpoint of the steering wheels is equal to a measured steering angle (δm) value of the steering wheels.