Coordinated Braking Force Control for Electric Vehicles
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Solution Overview
Problem
Conventional braking force control systems in vehicles, such as fuel cell and electric automobiles, inadequately coordinate braking force control between the accelerator pedal and brake pedal, leading to suboptimal controllability during deceleration and regenerative braking.
Innovation Solution
A vehicle-mounted braking force control system that includes calculators for determining required friction and regenerative braking forces based on pedal positions, allowing for coordinated control of hydraulic and regenerative braking forces, with a regenerative total braking force calculation/execution portion and a friction total braking force calculation/execution portion to manage these forces effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If regenerative braking control is performed based only on accelerator pedal position without coordinating with brake pedal position, then regenerative power generation is simplified, but braking force controllability deteriorates
Solution Approach 1:
The patent merges the control logic for accelerator pedal and brake pedal into a unified braking force control system. The regenerative braking force calculation/execution portion integrates both accelerator pedal position (for regenerative power generation) and brake pedal position (for braking force request), coordinating their interactions to achieve smooth and controllable braking force distribution between regenerative and friction brakes.
2Ease of operation
If braking force control coordinates both accelerator and brake pedal positions, then braking force controllability is improved, but control system complexity increases
Solution Approach 1:
The patent segments the braking force control into distinct functional portions: a regenerative braking force calculation/execution portion that handles regenerative braking based on accelerator pedal position, and a friction braking force calculation/execution portion that handles friction braking based on brake pedal position. This segmentation allows coordinated control of both pedals while maintaining clear functional boundaries, managing system complexity through modular architecture.
3Reliability
If friction brake is used to supplement regenerative braking without coordination, then braking force is sufficient, but energy efficiency deteriorates
Solution Approach 1:
The patent implements feedback mechanisms where the regenerative braking force calculation/execution portion continuously monitors accelerator pedal position and adjusts regenerative braking force accordingly. The friction braking force calculation/execution portion monitors brake pedal position and supplements regenerative braking only when necessary, creating a coordinated feedback loop that maximizes energy recovery while ensuring sufficient braking force.
Solution Approach 2:
The patent dynamically changes the parameter of braking force distribution between regenerative and friction brakes based on pedal positions. When accelerator pedal is released (braking requested), regenerative braking is prioritized. When brake pedal is pressed (stronger braking requested), friction braking is added or increased. This parameter adjustment optimizes energy efficiency by maximizing regenerative braking while maintaining braking sufficiency.
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
This system enables excellent controllability by coordinating the acceleration and brake pedals, allowing for priority control between regenerative and friction braking, enhancing the overall braking performance.
Implementation Method 1
the travel motor is operated as a generator when the vehicle is decelerated or travels down a slope to generate power and perform regenerative braking
Implementation Method 2
a friction brake which brakes the wheel
Data Source
AI summary
A braking force (BF) control system includes: a first required BF calculator that calculates, based on a position of the brake pedal, a first required friction BF allocated to the friction brake and a first required regenerative BF allocated to regenerative control of the drive motor; a second required BF calculator that calculates, based on a position of the acceleration pedal, a second required friction BF allocated to the friction brake and a second required regenerative BF allocated to the regenerative control; a regenerative total BF calculation/execution portion that calculates a regenerative total BF based on the first and second required regenerative BFs and performs the regenerative control based on the regenerative total BF; and a friction total BF calculation/execution portion that calculates a friction total BF based on the first and second required friction BFs and controls the friction brake based on the friction total BF.