Brake Control Device Pitch Angle Reduction
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Solution Overview
Problem
A large change rate of the pitch angle during vehicle braking can cause discomfort for occupants due to significant changes in the vehicle's nose dive and nose lift angles when braking forces are applied and released.
Innovation Solution
A brake control device that adjusts the braking force distribution ratio between the front and rear wheels by preferentially reducing the rear wheel braking force over the front wheel braking force during deceleration, ensuring a smaller braking force distribution ratio than the reference ratio, thereby minimizing the pitch angle change rate when braking is released.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the braking force is reduced uniformly between front and rear wheels, then the braking control is simple, but the pitch angle change rate becomes large causing occupant discomfort
Solution Approach 1:
The patent applies different braking force reduction strategies to different parts of the braking system (front vs. rear wheels). During deceleration, when the requested braking force decreases, the control unit preferentially reduces the rear wheel braking force while maintaining front wheel braking force, creating an asymmetric braking force distribution that counteracts the natural pitch angle change and reduces occupant discomfort.
2Object-affected harmful factors
If the rear wheel braking force is preferentially reduced, then the pitch angle change rate is minimized, but the braking force distribution becomes asymmetric
Solution Approach 1:
The patent dynamically adjusts the braking force distribution ratio between front and rear wheels based on the vehicle's deceleration state. When the requested braking force is decreasing during deceleration, the system transitions from a reference braking force distribution ratio to a modified ratio that preferentially reduces rear wheel braking force, thereby dynamically optimizing the pitch angle change rate while maintaining overall braking effectiveness.
3Object-affected harmful factors
If the braking force distribution ratio is changed during deceleration, then the pitch angle change is controlled, but the control logic becomes more complex
Solution Approach 1:
The control unit is pre-programmed with the logic to detect when the requested braking force is decreasing during deceleration and automatically apply the modified braking force distribution ratio. This preliminary programming allows the complex control logic to be embedded in the control unit's software, eliminating the need for complex mechanical adjustment mechanisms while achieving precise control over pitch angle change.
Data Source
AI summary
A brake control device includes: a decrease determination unit that determines whether a requested braking force for a vehicle is decreasing; and a brake control unit which, on the condition that the decrease determination unit determines that the requested braking force is decreasing during deceleration of the vehicle, executes ratio change decrease control of reducing the braking force of the vehicle according to the decrease of the requested braking force, while making a braking force distribution ratio smaller than a reference braking force distribution ratio. The reference braking force distribution ratio is the braking force distribution ratio at a time point when the requested braking force starts to decrease.