Vehicle Braking Control Device Rear Wheel Torque Segmentation
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Solution Overview
Problem
Existing vehicle braking control systems face challenges in balancing directional stability and deceleration performance, particularly during turning and on split friction surfaces, as they often prioritize one over the other.
Innovation Solution
A vehicle braking control device that includes an actuator for adjusting each wheel's braking torque, wheel speed sensors, a yaw rate sensor, and a controller to independently manage rear wheel braking based on wheel speed, yaw rate, and steering angle, using a deflection index to balance braking torque and maintain stability and deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If select low method is used for rear wheel braking pressure control, then directional stability is ensured during turning and split road braking, but deceleration performance deteriorates
Solution Approach 1:
The patent divides the rear wheel braking control into two independent control channels - one for the inside rear wheel and one for the outside rear wheel. The inside rear wheel braking pressure is controlled based on anti-skid requirements, while the outside rear wheel braking pressure is independently adjusted based on vehicle stability requirements. This segmentation allows simultaneous optimization of both deceleration (through inside wheel control) and directional stability (through outside wheel control), resolving the contradiction between the select low method's stability benefit and deceleration performance.
2Speed
If independent rear wheel braking control is implemented, then deceleration performance is improved, but vehicle stability may deteriorate during turning
Solution Approach 1:
The patent applies different control strategies to different rear wheels based on their local conditions. The inside rear wheel (on the turning inside) is controlled for anti-skid to maximize deceleration, while the outside rear wheel (on the turning outside) is controlled to maintain directional stability by preventing excessive braking that would cause vehicle instability. This local quality approach allows each wheel to be optimized for its specific functional requirement, resolving the contradiction between overall deceleration performance and directional stability.
Data Source
AI summary
In a braking control device, a controller is configured to determine an inside and an outside of a turn by using the yaw rate, to calculate a deflection index based on a standard turning amount corresponding to a steering angle and an actual turning amount corresponding to a yaw rate, to reduce the braking torque of the rear wheel on the outside of the vehicle turn based on the deflection index when an excessive deceleration slip of the rear wheel on the inside of the vehicle turn is inhibited during an execution of anti-skid control.