Regenerative Braking Control for Electric Vehicle Following
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Solution Overview
Problem
Electric vehicles using a single operation member for acceleration and deceleration face challenges in smooth speed control during low-speed following maneuvers, leading to excessive braking and degraded drivability.
Innovation Solution
A braking control apparatus that utilizes an accelerator pedal to control regenerative braking, incorporating a controller and recognizer to adjust power regeneration based on the operation amount and inter-vehicle distance, implementing braking suppression control to prevent excessive braking force and enhance smooth speed control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking is performed when the accelerator pedal is released, then power regeneration efficiency is improved, but excessive braking force occurs during low-speed following maneuvers degrading drivability
Solution Approach 1:
The patent applies dynamics by making the regenerative braking control adaptive and variable based on real-time driving conditions. The controller dynamically adjusts the regenerative braking torque according to the detected driving state (acceleration, coasting, deceleration) and inter-vehicle distance, transitioning between different control modes to optimize both energy recovery and drivability across varying operating conditions.
Solution Approach 2:
The patent changes the parameter of regenerative braking torque based on inter-vehicle distance. When the distance exceeds a threshold, full power regeneration is enabled; when the distance falls below the threshold during coasting or deceleration, the regenerative braking torque is reduced or suppressed. This parameter adjustment resolves the contradiction by enabling high energy recovery when safe and reducing braking force when approaching another vehicle.
2Ease of operation
If braking suppression control is implemented to improve smooth speed control, then drivability is improved, but power regeneration efficiency decreases
Solution Approach 1:
The patent segments the driving state into distinct modes (acceleration, coasting, deceleration) and applies different regenerative braking control strategies to each segment. During coasting and deceleration phases, the system further segments control based on inter-vehicle distance thresholds, enabling full power regeneration when distance is sufficient and suppressing braking when distance is short, thus balancing smooth control and energy recovery.
Solution Approach 2:
The patent implements feedback by continuously monitoring the inter-vehicle distance and using this information to adjust regenerative braking torque. The recognizer detects the preceding vehicle and measures distance, feeding this information back to the controller which then modulates the regenerative braking force accordingly, creating a closed-loop system that balances drivability and energy recovery.
3Ease of operation
If one-pedal control is used to enable single operation member for acceleration and deceleration, then ease of operation is improved, but braking control precision deteriorates during low-speed following
Solution Approach 1:
The patent introduces an intermediary control system that mediates between the driver's accelerator pedal input and the actual braking force applied. The controller acts as an intermediary, interpreting the accelerator pedal position and inter-vehicle distance to determine appropriate regenerative braking torque, thereby refining the crude single-pedal input into precise braking control adapted to real-time conditions.
Solution Approach 2:
The patent replaces traditional mechanical braking control with electronic control of regenerative braking through the rotary electric machine. Instead of relying solely on mechanical brake systems activated by a separate brake pedal, the system uses electronic control of the motor generator to provide controlled regenerative braking, enabling more precise and adaptive deceleration control while maintaining one-pedal operation.
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
The apparatus facilitates smooth vehicle speed control by reducing regenerative braking power when approaching a preceding vehicle, preventing excessive braking and improving drivability during low-speed following, while ensuring safety by preventing rear-end collisions.
Implementation Method 1
control an amount of power regenerated by a rotary electric machine driven by wheels
Data Source
AI summary
A braking control apparatus to be installed an electric vehicle includes an acceleration and deceleration operation member, a controller, and a recognizer. The acceleration and deceleration operation member receives an acceleration request in accordance with an operation amount in a first direction from a neutral position, and receive a deceleration request in accordance with an operation amount in a second direction from the neutral position. The controller controls an amount of power regenerated by a rotary electric machine driven by wheels in accordance with the operation amount in the second direction. The recognizer recognizes a preceding vehicle traveling ahead of the electric vehicle. Upon detection of the preceding vehicle at a relative distance from the electric vehicle that is equal to or less than a threshold, the controller performs braking suppression control to decrease the amount of power regenerated in accordance with the operation amount in the second direction.