Hydraulic Brake Force Compensation for Friction Coefficient Drift
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Solution Overview
Problem
The friction coefficient of vehicle brake friction materials varies with bushing degree and seasonal changes, leading to inconsistent brake force generation and potential safety hazards.
Innovation Solution
A method for brake force compensation using feedforward control based on hydraulic brake energy accumulation and seasonal adjustments, with correction gains determined by driving mileage and bushing degree, to proactively correct brake force deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If brake friction material is used without compensation for bushing degree and seasonal changes, then the brake system structure remains simple, but brake force consistency deteriorates due to friction coefficient variation
Solution Approach 1:
The system performs preliminary correction of the torque factor based on predicted bushing degree and seasonal conditions before brake application. The correction value is calculated in advance using the relationship between driving mileage/brake energy accumulation and friction coefficient changes, allowing the brake control to compensate for expected variations rather than reacting to them after they occur.
Solution Approach 2:
The system establishes a feedback mechanism where the torque factor is continuously corrected based on accumulated brake energy data and driving mileage. The correction value is fed back into the brake control system to adjust subsequent brake force applications, creating a closed-loop control that maintains brake force consistency despite friction material degradation and environmental changes.
2Reliability
If feedback-based brake force correction is used, then brake force deviation can be corrected, but response time is delayed compared to proactive compensation
Solution Approach 1:
The system calculates and applies correction values in advance based on driving mileage and accumulated brake energy, rather than waiting for brake force deviation to occur. This preliminary correction approach proactively compensates for friction coefficient changes before they affect brake performance, eliminating the time delay inherent in reactive feedback systems.
Solution Approach 2:
The system prepares correction values in advance to cushion against upcoming friction coefficient changes. By predicting bushing degree progression and seasonal effects based on historical brake energy accumulation, the system pre-adjusts the torque factor to prevent brake force deviation rather than correcting it after the fact.
3Reliability
If torque factor correction based on driving mileage and brake energy accumulation is implemented, then friction coefficient variation can be compensated, but calculation complexity increases
Solution Approach 1:
The system uses the vehicle's own operational data (driving mileage and accumulated brake energy) to automatically determine correction values without requiring external input or complex manual calibration. The brake control system self-adjusts the torque factor based on its own usage history, making the compensation process autonomous and reducing the need for external intervention or complex configuration.
Solution Approach 2:
The system changes the torque factor parameter based on measurable variables (driving mileage and brake energy accumulation) that directly correlate with friction coefficient changes. By establishing a relationship between these parameters and friction material degradation, the system can calculate correction values using straightforward mathematical relationships rather than complex multi-variable models.
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
Reduces brake force deviations by accurately compensating for friction coefficient changes due to bushing and seasonal variations, enhancing safety and consistency.
Implementation Method 1
Since a friction coefficient of a vehicle brake friction material is changed depending on a bushing degree thereof or a seasonal change
Data Source
AI summary
A method for controlling corrected target hydraulic brake force to be generated by estimating friction coefficient variation depending on a bushing degree of a brake friction material and a season change, may include: determining a hydraulic brake torque required for hydraulic braking according to a driver's request brake torque; converting the hydraulic brake torque into a brake hydraulic pressure by use of a torque factor which is a friction capability of a brake friction material in the hydraulic brake torque; and determining a correction amount of the torque factor according to a season and a bushing degree of the brake friction material, which influences a friction coefficient which is an element of the torque factor.