Brake Device Reaction Force Control for Driver Fatigue Reduction
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Solution Overview
Problem
Conventional brake-by-wire systems face issues with driver fatigue and controllability due to unpredictable changes in brake pedal reaction force during vehicle deceleration, which can lead to increased braking distance and compromised operability.
Innovation Solution
A brake device with a reaction force generator and a reaction force changing mechanism that allows for adjustable reaction force characteristics based on driver preference, independent of mechanical connection to the hydraulic pressure generator, using a housing, brake pedal, sensor, and electric motor to modify the pedaling force characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional brake-by-wire system is used without mechanical connection between brake pedal and hydraulic pressure generator, then braking control precision can be improved, but driver fatigue increases due to unpredictable reaction force changes
Solution Approach 1:
The patent introduces a reaction force generator as an intermediary component between the brake pedal and the hydraulic pressure generator. This mediator provides predictable reaction force characteristics to the driver while the electronic control unit independently controls the hydraulic pressure, thus resolving the contradiction between improved braking control precision and reduced driver fatigue.
Solution Approach 2:
The patent changes the parameter of reaction force characteristics by introducing an adjustable reaction force generator. The reaction force magnitude can be modified through adjustment mechanisms, allowing the system to maintain predictable tactile feedback for the driver while achieving precise electronic control of braking force, thereby reducing driver fatigue without compromising control precision.
2Device complexity
If reaction force magnitude is fixed in brake-by-wire system, then device complexity is reduced, but adaptability to different driver preferences deteriorates
Solution Approach 1:
The patent applies dynamics by making the reaction force magnitude adjustable rather than fixed. The reaction force generator incorporates adjustment mechanisms that allow the magnitude to be changed according to different driver preferences, transforming a static system into a dynamic one that can adapt to varying operational conditions and user requirements.
Solution Approach 2:
The patent achieves universality by designing a reaction force generator that can serve multiple functions: providing baseline reaction force, allowing adjustment for different driver preferences, and maintaining predictable characteristics. This multi-functional component addresses diverse driver needs without requiring multiple separate systems, thus balancing adaptability with controlled complexity.
3Productivity
If reaction force changes during vehicle deceleration, then braking force control is improved, but operability deteriorates due to unpredictable pedal feedback
Solution Approach 1:
The patent segments the braking system into two independent parts: the reaction force generation system that provides predictable tactile feedback to the driver, and the hydraulic pressure control system that achieves efficient braking force control. This segmentation allows each subsystem to optimize its function without compromising the other, maintaining operability while improving braking efficiency.
Solution Approach 2:
The reaction force generator acts as an intermediary that decouples the tactile feedback function from the force control function. It provides stable, predictable reaction force to the driver independent of the hydraulic pressure changes, thereby maintaining pedal operability while enabling efficient braking force control through electronic actuation.
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 solution reduces driver fatigue and improves controllability by allowing customizable reaction force settings, enhancing the precision of vehicle braking control according to individual driver preferences.
Implementation Method 1
The reaction force generator has one end connected to the brake pedal and the other end connected to the housing so as to generate a reaction force against a depression force applied to the brake pedal by a driver
Implementation Method 2
The reaction force generator includes an electric motor and an elastic member connected to each other, the elastic member generating an elastic force
Data Source
AI summary
A brake device for a brake-by-wire system includes a brake pedal, a sensor, a reaction force generator, and a reaction force changing mechanism. The brake pedal is rotatably mounted on a housing and not mechanically connected to a hydraulic pressure generator. The sensor outputs a signal corresponding to a stroke amount of the brake pedal to an electronic control unit. The reaction force generator has one end connected to the brake pedal and the other end connected to the housing so as to generate a reaction force against a depression force applied to the brake pedal by a driver. The reaction force changing mechanism generates a reaction force against a depression force applied to the brake pedal by the driver, and is able to change a magnitude of the reaction force in advance according to the driver.