Autonomous Vehicle Yaw Control With Adaptive Reference Distance
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Solution Overview
Problem
Existing autonomous vehicle control methods fail to adequately address passenger comfort issues due to oscillations and instability in trajectory tracking, particularly at high speeds or during system faults, without compromising safety.
Innovation Solution
A control method that selects an ideal point on the reference trajectory to minimize yaw error by determining a reference distance based on vehicle speed and external constraints, using a control function to adjust steering for smooth trajectory adherence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed reference distance is used for trajectory control, then the control implementation is simple, but the vehicle exhibits oscillations and instability particularly at high speeds
Solution Approach 1:
The patent applies dynamics by making the reference distance variable rather than fixed. The reference distance is dynamically adjusted based on vehicle speed and lateral error, allowing the control system to adapt to different operating conditions. This resolves the contradiction by enabling stable trajectory tracking at high speeds while maintaining reasonable control complexity through a systematic adjustment approach.
Solution Approach 2:
The patent changes the parameter of reference distance from a constant value to a variable parameter that depends on vehicle speed and lateral error. This parameter change allows the control system to optimize performance across different speed ranges and error conditions, eliminating oscillations and instability while keeping the control law relatively simple.
2Stability of the object's composition
If the reference distance is dynamically adjusted based on speed and error, then trajectory stability improves, but control system complexity increases
Solution Approach 1:
The patent uses parameter changes by defining the reference distance as a function of vehicle speed and lateral error. This approach achieves improved trajectory stability through a relatively simple mathematical relationship, avoiding the need for complex control algorithms while still adapting to varying operating conditions.
Solution Approach 2:
The patent implements feedback by using lateral error information to adjust the reference distance. The control system continuously monitors the lateral deviation and modifies the reference distance accordingly, creating a closed-loop system that improves stability without requiring overly complex control architecture.
3Stability of the object's composition
If a longer reference distance is used, then trajectory tracking smoothness improves, but the response time to correct lateral deviations increases
Solution Approach 1:
The patent applies dynamics by making the reference distance adaptive rather than fixed. By adjusting the reference distance based on lateral error magnitude, the system achieves smooth trajectory tracking when errors are small while maintaining faster response capability when errors are large, thus resolving the trade-off between smoothness and response time.
Solution Approach 2:
The patent changes the reference distance parameter dynamically based on operating conditions. When lateral error is large, a shorter reference distance provides faster response; when lateral error is small, a longer reference distance provides smoother tracking. This parameter adaptation resolves the contradiction between smoothness and response time.
Data Source
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AI summary
The invention relates to a control method for controlling the movement of an autonomous motor vehicle (10) along a reference path (T). The control method comprises a step (E5) of determining a desired yaw speed (Wdes) as a function of a reference distance (L), and a step (E6) of determining a yaw error. The reference distance (L) is selected in such a way that the yaw error is less than or equal to a predetermined yaw error threshold (S1).