Autonomous Vehicle Steering Correction for Zero Point Shift
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Solution Overview
Problem
Existing methods for determining the target steering angle in driver assistance systems fail to account for dynamic changes in vehicle conditions, leading to transverse position errors and inaccurate steering control over the vehicle's lifetime.
Innovation Solution
A method that adjusts the target steering angle using a correction constant, calculated by combining a steering angle factor with zero point shift data, to compensate for steering angle offsets, ensuring accurate guidance by considering vehicle-specific parameters and excluding dynamic influences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed steering angle factor is established once using Ackermann's formula, then the initial steering accuracy is adequate, but the steering accuracy deteriorates over time due to vehicle condition changes
Solution Approach 1:
The patent transforms the static, fixed steering angle factor into a dynamic correction constant that is continuously adapted based on actual vehicle behavior. The correction constant is updated over time by comparing target trajectories with actual vehicle positions, allowing the system to compensate for changing vehicle conditions such as tire wear, road conditions, and steering system friction.
Solution Approach 2:
The patent implements a feedback mechanism where the actual vehicle position and trajectory are continuously monitored and compared with the target trajectory. The deviation information is used to adjust the correction constant, creating a closed-loop control system that maintains steering accuracy despite vehicle condition changes.
2Measurement precision
If the steering angle factor is adjusted frequently to compensate for vehicle changes, then the steering accuracy is maintained, but the system complexity increases
Solution Approach 1:
The patent performs preliminary determination of the correction constant during a calibration phase before normal operation. The correction constant is established based on initial vehicle characteristics and then refined over time through gradual adaptation, avoiding the need for complex real-time calculations during active steering control.
Solution Approach 2:
The patent changes the parameter representation from a complex multi-factor model to a single correction constant that encapsulates all vehicle-specific deviations. This simplification maintains accuracy while reducing computational complexity and system complexity.
3Measurement precision
If the target steering angle is continuously adjusted based on zero point shift, then the transverse position error is reduced, but the response time increases due to adaptation requirements
Solution Approach 1:
The patent applies partial adjustment by updating the correction constant only when necessary, based on threshold comparisons of trajectory deviations. Rather than continuously adjusting the steering angle, the system makes discrete corrections only when deviations exceed acceptable limits, reducing adaptation time while maintaining accuracy.
Data Source
AI summary
A method for partially or fully autonomously guiding a motor vehicle includes setting a target steering angle for guiding along a target trajectory. It is checked whether a zero point shift exists between a current position of the motor vehicle with respect to the target trajectory. The set target steering angle is adjusted on the basis of a correction constant in the event that a determined zero point shift exceeds a predefined threshold.