Vehicle Braking Force Control for Regenerative Plateau Compensation
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Solution Overview
Problem
The existing vehicle braking method experiences a delay in increasing hydraulic pressure braking force when regeneration braking force hits its ceiling, leading to a decrease in vehicle deceleration and a different feeling for the operator, as the hydraulic pressure braking force is increased after the regeneration braking force has peaked.
Innovation Solution
The method adjusts the braking force by increasing the regeneration braking force and limiting its increase ratio before it reaches the maximum, while simultaneously increasing the hydraulic pressure braking force to compensate for the deficiency at the regeneration braking force ceiling, ensuring a smoother and more consistent vehicle deceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the hydraulic pressure braking force is increased after the regeneration braking force hits its ceiling, then the required braking force can be achieved, but the vehicle deceleration is delayed and the operator feels a different braking sensation
Solution Approach 1:
The control device predicts when the regeneration braking force will hit its ceiling and starts increasing the hydraulic pressure braking force before that moment occurs. This preliminary action ensures continuous vehicle deceleration without the time lag that would occur if hydraulic pressure were only increased after regeneration braking reached its maximum.
2Use of energy by moving object
If the regeneration braking force is increased to meet the required braking force, then energy recovery is maximized, but the hydraulic pressure braking force must be increased later causing a delay in vehicle deceleration
Solution Approach 1:
The control device calculates the predicted regeneration braking force ceiling timing and begins increasing hydraulic pressure braking force in advance. This allows the system to maintain maximum energy recovery through regeneration braking while avoiding any delay in vehicle deceleration by preparing the hydraulic pressure increase beforehand.
Data Source
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AI summary
Provided is a vehicle braking device that is capable of suppressing the uncomfortable sensation felt by a driver when a regenerative braking force plateaus. This vehicle braking device has a hydraulic braking force generation unit (2) for generating a hydraulic braking force, a regenerative braking force generation unit (3) for generating a regenerative braking force on the wheels, a braking operation amount detection means (72) for detecting an operation amount of a braking operation member (10), and a required braking force calculation means for calculating a required braking force on the basis of the operation amount of the braking operation member (10). The vehicle braking device controls the hydraulic braking force generation unit (2) and the regenerative braking force generation unit (3) so as to apply the required braking force to the wheels. The vehicle braking device has a braking force adjustment control means for executing braking force adjustment control for limiting the rate at which the regenerative braking force is increased and increasing the hydraulic braking force before the current regenerative braking force reaches a maximum regenerative braking force, that is, the maximum braking force that can be generated by the regenerative braking force generation unit (3).