Vehicle Brake Air Gap Determination via Actuation Stroke Derivative
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Solution Overview
Problem
Current methods for determining the clearance of vehicle brakes are not sufficiently precise and robust, particularly due to fluctuations in brake rigidity and response pressure, which can lead to increased maintenance costs and reduced brake performance over time.
Innovation Solution
A method that records the actuation stroke measurement signal during a braking process, forms a time derivative using a suitable algorithm to determine the point in time of maximum actuation speed, and calculates the clearance based on this, allowing for precise monitoring and adjustment without requiring precise assumptions about brake rigidity and response pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods for determining brake clearance are used, then the system can operate with simple measurement, but the measurement precision is insufficient due to fluctuations in brake rigidity and response pressure
Solution Approach 1:
The patent applies dynamics by determining the time derivative of the actuation stroke signal and identifying the maximum point dynamically during the braking process. This transforms the static measurement approach into a dynamic one that adapts to changing brake conditions, allowing accurate clearance determination despite fluctuations in brake rigidity and response pressure. The method evaluates the rate of change of the actuation stroke to identify the precise moment of brake pad contact, making the measurement robust against disturbance variables.
2Measurement precision
If the clearance determination requires precise assumptions about brake rigidity and response pressure, then measurement accuracy might improve, but the device complexity and measurement reliability worsen due to uncertain physical parameters
Solution Approach 1:
The patent extracts the essential measurement information by taking the time derivative of the actuation stroke signal and identifying only the maximum point. This extraction method removes the need for complex assumptions about brake rigidity and response pressure, isolating the critical clearance information from unnecessary system parameters. By focusing only on the maximum point of the derivative signal, the system achieves accurate clearance determination without requiring detailed knowledge of the brake system's physical characteristics.
3Reliability
If traditional sensor devices only record actuation stroke position, then the system remains simple, but the ability to determine clearance robustly deteriorates due to influence of disturbance variables
Solution Approach 1:
The patent applies preliminary action by recording the actuation stroke signal continuously during the braking process and preparing the time derivative calculation in advance. The system evaluates the derivative and identifies the maximum point before the braking process completes, allowing for robust clearance determination without delaying the measurement. This preliminary evaluation ensures that the clearance value is determined accurately and promptly, maintaining high productivity while achieving reliable results.
Data Source
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AI summary
The invention relates to a method for determining an air gap of a vehicle brake, in particular for a motor vehicle, wherein the vehicle brake comprises an application device, a wear adjustment device (10), a sensor apparatus (15) for detecting an actuation stroke of the application device, and a vehicle control system (21). The method comprises the following steps: (S1) receiving a measurement signal of the actuation stroke, which measurement signal is provided by the sensor apparatus (15), within a previously specifiable time window during a braking process and storing the measurement signal as data pairs of actuation stroke and time during a braking process; (S2) calculating a time derivative of the measurement signal in the time window by means of a suitable algorithm in order to determine a point in time at a maximum; and (S3) determining the air gap on the basis of the point in time thus determined and forwarding the value of the air gap thus determined to the vehicle control system. A vehicle brake is equipped with a device for determining an air gap for performing the method.