Steering Angle Correction for Early Understeer and Oversteer Control
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Solution Overview
Problem
Existing vehicle control systems fail to detect and stabilize unstable driving states such as understeering and oversteering early enough, leading to potential accidents and increased risk due to late interventions by conventional stability control systems.
Innovation Solution
A vehicle control method that includes early detection of unstable driving states through setpoint trajectory analysis, defining steering angle corrections, and implementing steering-angle limitations or countersteering angles to stabilize the vehicle, combined with individual wheel deceleration to manage yaw moments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the position controller increases the steering angle to compensate for lateral deviation, then the vehicle attempts to return to the setpoint trajectory, but the vehicle stability deteriorates under adverse road conditions
Solution Approach 1:
The control system applies preliminary anti-action by detecting unstable driving states early (before they develop into full instability) and applying counteracting steering corrections. The system monitors trajectory deviation and vehicle response, and when instability is detected, it applies a steering correction opposite to the direction that would worsen the instability, thereby preventing the deterioration of vehicle stability while still addressing the trajectory deviation.
Solution Approach 2:
The system implements feedback by continuously monitoring the vehicle's actual response to steering inputs and comparing it with the expected response based on the setpoint trajectory. When the feedback indicates that the vehicle is not responding as expected (signaling unstable driving state), the system adjusts the steering angle correction accordingly, reducing or reversing the correction to maintain stability while still working toward trajectory compliance.
2Device complexity
If conventional stability control systems intervene only at large instabilities, then system complexity remains low, but the response time is delayed and accident risk increases
Solution Approach 1:
The system applies preliminary action by implementing early detection of unstable driving states through continuous monitoring of trajectory deviation and vehicle response characteristics. Instead of waiting for large instabilities to trigger stability control, the system detects potential instability early and takes preventive action, significantly reducing the response time while maintaining relatively simple system architecture by building upon existing stability control frameworks.
3Measurement precision
If further steering is applied to compensate trajectory deviation in unstable conditions, then the vehicle attempts to follow the setpoint trajectory, but the stability worsens
Solution Approach 1:
The system applies dynamics by making the steering correction adaptive rather than fixed. The steering correction is dynamically adjusted based on the detected unstable driving state, the type of instability (understeer or oversteer), and the vehicle's current response. The control system continuously modifies the steering angle correction to balance trajectory following accuracy with stability maintenance, applying different corrections for different instability conditions.
Solution Approach 2:
The system implements parameter changes by modifying the steering angle correction parameter based on the detected instability. When unstable driving state is detected, the system changes the steering correction from the original trajectory-compensating value to a corrected value that accounts for the instability type and severity, thereby preventing further stability deterioration while still working toward trajectory compliance.
Data Source
AI summary
A vehicle control method includes early detection of an unstable driving state of a vehicle at least using an actual variable and a setpoint trajectory; wherein it is ascertained during early detection whether the unstable driving state is understeering of the vehicle or oversteering of the vehicle; and in response to the early detection: definition of a steering angle correction for a setpoint steering angle, wherein the steering angle correction includes a steering-angle limitation of an actual steering angle that can be provided if the unstable driving state is understeering of the vehicle, and wherein the steering angle correction includes a countersteering angle directed counter to the setpoint steering angle if the unstable driving state of the vehicle is oversteering; and steering of the vehicle using the steering angle correction. A vehicle control system, a vehicle and a computer program product are configured to perform the method.