Vehicle Braking Force Control Reducing Pitch Fluctuation
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Solution Overview
Problem
Existing vehicle braking systems experience uncomfortable pitch attitude fluctuations when a driver overrides automatic braking control, leading to increased and decreased braking forces, which can cause discomfort for occupants.
Innovation Solution
A braking force control apparatus that adjusts the front/rear wheel distribution ratio of braking forces, using a control unit to calculate and apply target braking forces at different ratios to minimize pitch moment and reduce pitch attitude variations during override braking operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the braking force control mode is switched from automatic braking control to driver-based braking control, then the driver's braking intention is satisfied, but the pitch attitude of the vehicle body fluctuates causing occupant discomfort
Solution Approach 1:
The patent applies dynamics by making the front/rear wheel distribution ratio variable rather than constant. The control unit dynamically adjusts the distribution ratio based on the current braking mode (automatic braking control or driver-based braking control) to optimize pitch moment characteristics. This dynamic adjustment allows the system to adapt to different operating conditions and minimize pitch attitude fluctuations during mode transitions.
Solution Approach 2:
The patent changes the parameter of front/rear wheel distribution ratio to resolve the contradiction. By modifying this distribution parameter according to the braking mode, the system achieves both satisfaction of driver's braking intention and reduction of pitch attitude fluctuations. The control unit calculates appropriate distribution ratios that minimize pitch moment while maintaining effective braking.
2Device complexity
If a constant front/rear wheel distribution ratio is used in braking force control, then the control system is simple, but the pitch attitude fluctuation during mode switching cannot be reduced
Solution Approach 1:
The system transitions from a static constant distribution ratio to a dynamic variable distribution ratio that adapts to different braking modes. The control unit automatically adjusts the front/rear distribution based on whether automatic braking control or driver-based braking control is active, achieving pitch moment optimization without requiring complex manual intervention.
Solution Approach 2:
The control unit autonomously determines the appropriate front/rear wheel distribution ratio based on the current braking mode without requiring external input. The system self-adjusts the distribution parameter to minimize pitch attitude fluctuations, making the complexity management automatic rather than manual.
Data Source
AI summary
First target braking forces for front and rear wheels are calculated by distributing a target braking force of automatic braking to the front and rear wheels at a first front/rear wheel distribution ratio when braking operation is started by a driver during execution of the automatic braking control, second target braking forces for the front and rear wheels are calculated by distributing the braking force requested by the driver to the front and rear wheels at a second front/rear wheel distribution ratio preset to be different from the first front/rear wheel distribution ratio such that a pitch moment applied to a vehicle body due to braking forces of the front and rear wheels becomes zero, and braking forces of the front and rear wheels are controlled so as to be sums of the first and second target braking forces of the front and rear wheels, respectively.