Electric Brake Thrust Estimation Using Dual Rigidity Slopes
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Solution Overview
Problem
Existing brake control systems struggle to accurately estimate rigidity changes due to temperature, uneven wear, and disc inclination, leading to potential instability and reduced safety during braking, especially in high thrust regions, with increased memory load and approximation errors.
Innovation Solution
A brake control device and method that estimates rigidity changes by analyzing the relationship between piston position and thrust using first and second inclinations, along with position deviation, to improve accuracy and reduce memory load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If polynomial approximation of multiple measurement points is used for rigidity estimation, then estimation accuracy may be improved, but memory load increases
Solution Approach 1:
The patent extracts only the essential characteristics needed for rigidity estimation by using two specific inclination values (first inclination from initial contact to maximum thrust, second inclination from maximum thrust to thrust recovery) rather than processing all measurement points. This extraction approach maintains estimation accuracy while significantly reducing memory requirements compared to polynomial approximation of multiple points.
Solution Approach 2:
The braking process is segmented into distinct phases, each characterized by a specific inclination value. The first inclination characterizes the pressing phase (initial contact to maximum thrust), and the second inclination characterizes the recovery phase (maximum thrust to thrust recovery). This segmentation allows accurate rigidity estimation using minimal data points from each phase, avoiding the need to store and process multiple measurement points.
2Quantity of substance
If single inclination estimation is used, then memory load is reduced, but estimation accuracy deteriorates in high thrust regions
Solution Approach 1:
The patent adopts a dynamic estimation approach by using two different inclination values that capture the rigidity characteristics at different phases of the braking process. The first inclination reflects rigidity during the pressing phase, while the second inclination reflects rigidity during the recovery phase. This dynamic multi-inclination approach accurately captures rigidity changes in high thrust regions without increasing memory load, as only two key inclination values are stored.
3Speed
If frequent rigidity updates are performed during braking, then control responsiveness is improved, but vehicle stability deteriorates
Solution Approach 1:
The patent performs preliminary action by calculating both the first and second inclination values during the braking process itself, using the actual thrust measurement data collected during braking. These inclination values are then used to update the rigidity estimation. This approach enables responsive control updates without requiring separate stabilization phases, as the rigidity information is extracted directly from the braking data as it occurs.
Data Source
AI summary
There are provided a brake control device and a brake control method capable of estimating a rigidity change due to a temperature change, uneven wear of a brake pad, an inclination of a brake disc, or the like with a low memory load and with high accuracy up to a region with larger thrust than a measurement range. A brake control device controls a braking unit including a friction member pushed on a braking target member, a piston that abuts on the friction member and moves in a linear motion direction by rotation of an electric motor, and a thrust detection unit that detects thrust of the friction member to the braking target member. The brake control device estimates a relation between a piston position being rigidity of the braking unit, and the thrust, based on a first piston range that is a thrust change as a first inclination with respect to the piston position, and a second piston range that is a thrust change as a second inclination different from the first inclination, with respect to the piston position.