Vehicle Braking Force Coordination for Small Pedal Deceleration
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Solution Overview
Problem
Existing vehicle braking systems face challenges in providing suitable braking force control when the operation amount of the accelerator pedal is small, leading to discomfort for users accustomed to driving vehicles with improved aerodynamic characteristics.
Innovation Solution
A braking force control device that includes a target acceleration calculation unit, a powertrain capability acquisition unit, and an instruction unit, which calculates and instructs the powertrain and brake controllers to generate braking forces based on the accelerator pedal operation, ensuring suitable braking force control by distributing the braking force between the powertrain and brake systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If aerodynamic characteristics are improved and friction is lowered, then fuel efficiency is improved, but vehicle deceleration becomes smaller leading to user discomfort
Solution Approach 1:
The patent combines the powertrain braking capability with the brake system to achieve the target deceleration. When the powertrain alone cannot provide sufficient braking force, the brake system supplements the braking force to reach the desired deceleration level, merging two different braking mechanisms into a coordinated system.
Solution Approach 2:
The patent changes the control parameters by calculating target acceleration based on accelerator pedal operation amount and using this to determine the required braking force. The system dynamically adjusts the braking force distribution between powertrain and brake based on real-time operational parameters to maintain familiar deceleration characteristics.
2Ease of operation
If braking force is supplemented when accelerator pedal operation is small, then user discomfort is reduced, but control complexity increases
Solution Approach 1:
The patent segments the braking control into distinct processes: acquiring accelerator pedal operation amount, calculating target acceleration, determining required braking force, checking powertrain capability, and distributing braking force between powertrain and brake. This segmentation makes the complex control logic more manageable and implementable.
Solution Approach 2:
The patent incorporates feedback by continuously monitoring the accelerator pedal operation amount and adjusting the braking force accordingly. The system uses the detected pedal position to calculate target acceleration and dynamically adjust the braking force distribution to maintain user comfort.
3Manufacturing precision
If braking force is distributed between powertrain and brake, then braking control precision is improved, but system complexity increases
Solution Approach 1:
The patent implements dynamic braking force distribution by continuously evaluating powertrain capability and adjusting the division of braking force between powertrain and brake. The system dynamically adapts the braking strategy based on real-time conditions, optimizing control precision while managing system complexity through adaptive rather than static control.
Data Source
AI summary
A braking force control device includes a target acceleration calculation unit that calculates a first target acceleration based on an acquired operation amount of an accelerator pedal, a powertrain capability acquisition unit that acquires a braking force that is generable by a powertrain, and an instruction unit that instructs generation of braking forces in the powertrain and a brake. The instruction unit is configured to, when a first braking force for achieving the first target acceleration is equal to or less than the braking force that is generable by the powertrain, instruct a controller of the powertrain to generate the first braking force, and when the first braking force is larger than the braking force that is generable by the powertrain, instruct the controller of the powertrain to generate the braking force that is generable by the powertrain.