Electric Vehicle Braking Control for Pitching Suppression
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Solution Overview
Problem
Conventional control systems for electric vehicles reduce the total braking force by decreasing the accelerator de-actuation regenerative braking force just before stopping, leading to a diminished deceleration feeling for the driver, which can cause discomfort.
Innovation Solution
A control apparatus that outputs instructions to generate a first regenerative braking force when the accelerator pedal is returned and a brake actuation braking force when the brake pedal is pressed, reducing the total braking force by a smaller second regenerative braking force when the vehicle speed is below a predetermined speed, thereby maintaining a consistent deceleration feeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the accelerator de-actuation regenerative braking force is reduced just before the vehicle is stopped, then pitching is suppressed, but the total braking force is reduced causing diminished deceleration feeling
Solution Approach 1:
The control apparatus changes the parameter of regenerative braking force from its normal value to a reduced value when specific conditions are met (vehicle speed below threshold and brake pedal pressed). This dynamic parameter adjustment suppresses pitching by reducing the regenerative braking force component while maintaining appropriate total braking force through coordinated control of friction braking.
Solution Approach 2:
The system dynamically adjusts the regenerative braking force based on real-time vehicle conditions (speed, brake pedal state). The control apparatus continuously monitors these parameters and modifies the braking force distribution between regenerative and friction braking systems to maintain stability while preserving deceleration feeling.
2Stability of the object's composition
If the regenerative braking force is reduced just before stopping, then vehicle pitching is suppressed, but the driver feels diminished deceleration causing discomfort
Solution Approach 1:
The control apparatus dynamically changes the regenerative braking force parameter based on vehicle speed and brake pedal state. By reducing regenerative braking force only under specific conditions (low speed with brake pressed), it suppresses pitching while maintaining natural deceleration feeling through coordinated friction braking control.
Solution Approach 2:
The system uses feedback from vehicle speed sensors and brake pedal position sensors to continuously monitor driving conditions. Based on this feedback, the control apparatus adjusts the regenerative braking force in real-time to achieve both pitching suppression and maintained deceleration feeling, creating a closed-loop control system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Prevents the driver from feeling diminished deceleration just before the vehicle stops by adjusting the regenerative and frictional braking forces, ensuring a consistent braking experience and improved controllability.
Implementation Method 1
a regenerative braking force generated when an accelerator pedal is returned after being pressed
Implementation Method 2
a frictional braking force generated when a brake pedal is pressed
Data Source
AI summary
An apparatus includes a control apparatus for an electric vehicle. The control apparatus outputs an instruction to reduce the first regenerative braking force according to the physical amount regarding the stroke of the brake pedal to the electric motor. The control apparatus also outputs an instruction to add a braking force corresponding to a third regenerative braking force, which is a regenerative braking force corresponding to an amount of the reduction in the first regenerative braking force, to the brake actuation braking force when the signal regarding the pressing of the brake pedal is input after the signal regarding the return of the pressed accelerator pedal is input.