Yaw Rate Overshoot Control Through Selective Differential Limiting
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Solution Overview
Problem
Existing vehicle control systems experience reduced stability in yaw behavior due to excessive overshoot of the actual yaw rate during vehicle turning, which compromises the responsiveness of the vehicle's steering response.
Innovation Solution
A vehicle control device that includes processors to derive a target yaw rate and actual yaw rate deviation, preventing differential limiting when the deviation is not indicative of overshoot and causing differential limiting when overshoot occurs, using actuators to control transfer clutches in the differential limiting devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If differential limiting is continuously applied to suppress yaw rate deviation, then yaw behavior stability is improved, but steering responsiveness is degraded
Solution Approach 1:
The differential limiting force is dynamically adjusted based on the steering angle and yaw rate deviation. The control system continuously monitors these parameters and modulates the differential limiting force accordingly, applying stronger limiting when deviation is large and reducing or eliminating limiting when deviation is small or during initial steering phases, thereby resolving the contradiction between stability and responsiveness
Solution Approach 2:
The system changes the differential limiting force parameter based on operating conditions. By calculating the required differential limiting force as a function of steering angle and yaw rate deviation, the system adapts the limiting force parameter in real-time to achieve both responsive steering initiation and stable yaw behavior during sustained turning
2Stability of the object's composition
If differential limiting force is increased to reduce yaw rate overshoot, then yaw behavior stability is improved, but steering response speed is reduced
Solution Approach 1:
The control system applies differential limiting force in advance during the initial steering phase when the steering angle exceeds the threshold, before significant yaw rate overshoot can occur. This preliminary application of limiting force prevents overshoot development while maintaining quick steering response, as the limiting is applied proactively rather than reactively after overshoot begins
Solution Approach 2:
The differential limiting force is applied periodically or intermittently based on the oscillation of yaw rate deviation. When deviation exceeds thresholds, limiting force is applied; when deviation returns to acceptable ranges, limiting is reduced or removed. This periodic modulation allows the system to suppress overshoot while permitting rapid response during appropriate phases of steering motion
Data Source
AI summary
A vehicle control device for a vehicle includes: one or more processors; and one or more memories coupled to the one or more processors. The one or more processors are configured to execute a process including: deriving a target yaw rate based on a steering angle obtained by a steering angle sensor of the vehicle; deriving a deviation of an actual yaw rate, obtained by a yaw rate sensor of the vehicle, relative to the target yaw rate; when the deviation is not a value representing overshoot where the actual yaw rate is substantially higher than the target yaw rate, preventing execution of differential limiting by a differential limiting device of the vehicle; and when the deviation is a value representing the overshoot, causing execution of differential limiting by the differential limiting device.