Vehicle Control Device Correcting Wheel Speed for Turning Drivability
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Solution Overview
Problem
Conventional vehicle control systems prematurely reduce or stop driving torque or braking torque when a vehicle is turning, leading to a risk of loss of drivability due to early determination of wheel slip states.
Innovation Solution
A vehicle control apparatus that corrects wheel speed based on vehicle specifications, including steering angle and yaw rate, to ensure accurate slip state control and prevent premature intervention, thereby maintaining drivability during turns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If correction is made only to the target slip ratio and estimated vehicle body speed, then the slip state detection becomes more responsive, but control intervention occurs too early during turns causing loss of drivability
Solution Approach 1:
The patent changes the parameter being monitored from raw wheel speed to corrected wheel speed that compensates for turning effects. By introducing a correction value based on steering angle and yaw rate, the system adjusts the speed parameter to reflect actual slip conditions rather than geometric effects of turning, thereby delaying premature control intervention while maintaining accurate slip detection.
Solution Approach 2:
The patent introduces an intermediary correction value that mediates between the detected wheel speed and the control decision. This correction value, calculated from steering angle and yaw rate, acts as a mediator to compensate for the turning effect before the slip state is evaluated, preventing false early detection of slip during turns while maintaining responsiveness to actual slip conditions.
2Device complexity
If wheel speed is not corrected for turning effects, then the system remains simple, but the outer wheel speed during turns causes error in vehicle body speed estimation
Solution Approach 1:
The patent modifies the speed parameter by introducing a correction term that accounts for turning effects. The corrected wheel speed is calculated as the detected wheel speed plus a correction value derived from steering angle and yaw rate. This parameter transformation enables accurate vehicle body speed estimation during turns without requiring complex multi-sensor fusion systems.
Solution Approach 2:
The patent applies preliminary correction to the wheel speed data before it is used for vehicle body speed estimation and slip state determination. By pre-compensating for the turning effect using readily available steering angle and yaw rate information, the system eliminates estimation errors before they affect control decisions, avoiding the need for complex post-processing corrections.
Data Source
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AI summary
The present invention provides a vehicle control apparatus capable of ensuring drivability when a vehicle is turning. The vehicle control apparatus calculates a vehicle body speed based on a wheel speed of each of wheels, and controls a slip state of each of the wheels according to states of a corrected wheel speed, which is acquired by correcting the wheel speed based on vehicle specifications indicating a position of each of the wheels, and based on the vehicle body speed. Alternatively, the vehicle control apparatus calculates a corrected wheel speed, which is acquired by removing a wheel speed change component generated along with a turn from a wheel speed of each of a plurality of wheels, and controls a slip state of the wheels according to states of the control wheel speed and the vehicle body speed.