Vehicle Lateral Guidance Control Under Saturation Limits
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Solution Overview
Problem
Existing methods for controlling vehicle lateral guidance during autonomous driving, such as back-calculation anti-windup, are limited to simple PID controllers and require experimental parameter tuning, failing to effectively compensate for saturation in cascaded controllers and vehicle trajectory kinematics.
Innovation Solution
A method that converts the difference between limited and unlimited vehicle dynamics parameters into residual curvature and yaw rate using a vehicle dynamics model, which is then converted into lateral and heading angle deviations, allowing compensation for saturation effects independently of controller structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If back-calculation anti-windup method is used to compensate for saturation, then controller overload is reduced, but the method is only applicable to simple PID controllers and requires experimental parameter tuning
Solution Approach 1:
The patent applies a saturation compensation method that works universally across different controller types (PID, state-based, model-based controllers) by using a model-based approach that calculates the difference between limited and unlimited manipulated variables. This universal method eliminates the need for controller-specific implementations while maintaining effectiveness in preventing integrator windup across various control architectures.
Solution Approach 2:
The patent replaces the experimental parameter tuning approach with a model-based calculation method. Instead of relying on empirical time constants determined through experimentation, the system uses a mathematical model to directly calculate the saturation compensation amount based on the difference between limited and unlimited manipulated variables, eliminating the need for iterative parameter adjustment.
2Reliability
If back-calculation anti-windup method is used, then saturation effects are compensated, but time-consuming experimental tuning is required and results are often insufficient
Solution Approach 1:
The patent implements preliminary action by pre-establishing a mathematical model that directly calculates saturation compensation without requiring experimental tuning. The model computes the difference between limited and unlimited manipulated variables and applies compensation in real-time, eliminating the need for time-consuming experimental parameter determination while ensuring adequate compensation effectiveness.
3Reliability
If limitation of vehicle dynamic parameters is applied for safety and comfort, then regulatory requirements are met, but integrating components become overloaded
Solution Approach 1:
The patent applies feedback by continuously monitoring the difference between limited and unlimited manipulated variables and using this information to adjust the control output. The system calculates the saturation compensation amount based on the actual limitation applied and feeds this back to prevent integrator windup, maintaining safety and comfort requirements while preventing controller overload through real-time adaptive compensation.
Data Source
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AI summary
The invention relates to a method for controlling a vehicle, comprising a driver assistance system by means of which at least partially autonomous driving functions are carried out, wherein a control loop (1) is provided for controlling the driving functions of the vehicle, which control loop receives as a target variable information (Δysoll, Δθsoll) that at least one controller is provided, which controller limits at least one driving dynamics variable by means of a limiter (6), that the change in the driving dynamics variable (δRest) produced on account of the limiting is converted into a curvature and/or yaw rate residual variable (κFzg,Rest) of the vehicle by means of a vehicle driving dynamics model (4), that the curvature and/or yaw rate residual variable (κFzg,Rest) of the vehicle is converted into a lateral and/or course angle deviation (ΔyRest, ΔθRest) produced due to limiting by means of a kinematic model (5) of the vehicle and that a measured lateral and/or course angle deviation (Δy, Δθ) of the vehicle is modified based on the lateral and/or course angle deviation (Δysoll, Δθsoll) produced due to limiting, as a result of which a modified lateral and/or course angle deviation (Δy', Δθ') is formed, and wherein a control error (ΔyErr, ΔθErr) is calculated based on the target variable (Δysoll, Δθsoll) and based on the modified lateral and/or course angle deviation (Δy', Δθ').