Braking Force Controller for Vehicle Deceleration Comfort
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Solution Overview
Problem
Existing vehicle braking systems fail to provide adequate ride comfort and operation feeling during the coasting state, as they often generate excessive negative jerk and negative acceleration due to gear shifting, which can deteriorate the deceleration feeling and overall vehicle experience.
Innovation Solution
A braking force controller with a first actuator unit and a second actuator unit, including a target jerk calculation unit, first and second estimation units, and a control unit, which calculates and adjusts the braking force to achieve a target jerk, reducing negative jerk and enhancing deceleration feeling by compensating for increased braking force caused by factors like gear shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If gear shifting increases braking force, then braking effectiveness is improved, but negative acceleration and negative jerk decrease beyond an adequate range, deteriorating operation feeling
Solution Approach 1:
The control unit predicts when gear shifting will occur and proactively adjusts the braking force of the second actuator unit before the transmission braking force increases. By applying preliminary anti-action to counteract the expected increase in braking force from gear shifting, the system maintains stable deceleration characteristics and prevents excessive negative jerk that would deteriorate operation feeling.
Solution Approach 2:
The system performs preliminary action by adjusting the brake actuator's braking force in advance when detecting conditions that will lead to excessive braking force from gear shifting. This preliminary adjustment prevents the occurrence of excessive negative jerk before it happens, maintaining adequate operation feeling while still providing necessary braking effectiveness.
Data Source
AI summary
A braking force controller includes: a target jerk calculation unit; a first estimation unit configured to estimate an increment of braking force when a prescribed factor that increases braking force to be generated by the first actuator unit currently occurs; a second estimation unit configured to estimate the increment of the braking force when the prescribed factor occurs within a prescribed period; and a control unit configured to determine a negative jerk generated when the second actuator unit generates the braking force such that a sum of the negative jerk and the jerk generated by the first actuator unit without the prescribed factor becomes the target jerk. When the increment of the braking force due to the prescribed factor is larger than a prescribed value, the control unit corrects the determined negative jerk such that an absolute value of the negative jerk becomes smaller.