Vehicle Brake System Phase-Lag Control for Pedal Feel
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle brake systems fail to provide drivers with a realistic feeling of effective braking during the initial stages of braking, leading to a need for improved brake feeling and control.
Innovation Solution
A vehicle brake system incorporating a stroke detector, a motor actuator-based brake fluid pressure generator, and a controller that utilizes phase-lag processing on required-deceleration maps to enhance braking force feedback, ensuring a secure and immediate braking effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If phase-lag processing is applied to the second required-deceleration to increase braking force after brake pedal depression, then brake feeling and secureness are improved, but response delay occurs in sudden braking situations
Solution Approach 1:
The patent segments the required-deceleration calculation into two distinct maps: a first map that provides immediate response for sudden braking, and a second map that applies phase-lag processing to enhance brake feeling. This segmentation allows the system to selectively apply phase-lag processing only to the second map's output, resolving the contradiction between improved brake feeling and maintained response speed.
Solution Approach 2:
The patent dynamically adjusts the braking control strategy by combining outputs from two different maps. The first map provides immediate response without phase-lag, while the second map applies phase-lag processing to create a gradual increase in braking force. This dynamic combination allows the system to adapt between immediate response and enhanced brake feeling based on the braking situation.
2Ease of operation
If the second required-deceleration is increased with phase-lag processing to provide secure brake feeling, then braking force increases gradually, but the lag time may cause discomfort at low vehicle speeds
Solution Approach 1:
The patent dynamically adjusts the lag time parameter based on vehicle speed conditions. At low vehicle speeds, the system shortens the lag time to prevent driver discomfort, while at higher speeds, it maintains a longer lag time to provide secure brake feeling. This dynamic adjustment makes the brake control system adaptable to different driving conditions.
Solution Approach 2:
The patent changes the lag time parameter according to vehicle speed. By adjusting this critical parameter dynamically, the system maintains optimal brake feeling across different speed ranges, preventing discomfort at low speeds while preserving secure braking sensation at higher speeds.
Data Source
AI summary
A vehicle brake system for giving an excellent brake feeling to a driver includes: a stroke detector configured to detect a stroke of a brake pedal; a brake fluid pressure generator including a motor actuator and configured to generate a brake fluid pressure by operation of the motor actuator, and a controller configured to control the operation of the motor actuator on the basis of a detected value by the stroke detector. The controller has a base required-deceleration map for obtaining a base required-deceleration associated with a detected value by the stroke detector; a responsive-feeling required-deceleration map for obtaining a responsive-feeling required-deceleration associated with the detected value by the stroke detector; and a phase-lag processor applying phase-lag processing on the responsive-feeling required-deceleration, and control the operation of the motor actuator on the basis of the required-deceleration and the responsive-feeling required-deceleration applied with the phase-lag processing.