Automatic Parking Brake Recalibration Triggering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing recalibration methods for automatic parking brakes fail to reliably detect a load-free release state, leading to unnecessary recalibration processes due to the use of a fixed threshold value that does not account for varying operating conditions, resulting in incorrect interpretations of motor current profiles.
Innovation Solution
A method that calculates the expected motor current at a predetermined time based on the current operating conditions of the parking brake system, using an exponential function to approximate the current profile, thereby determining a situation-dependent triggering condition for recalibration, ensuring accurate detection of a load-free release state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed threshold value is used to detect load-free release state, then the detection method is simple, but the detection accuracy deteriorates due to varying operating conditions
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a static fixed threshold value to a dynamic threshold that adapts to varying operating conditions. The threshold is calculated based on motor parameters (resistance, constants, mass inertia) and operating conditions (temperature, voltage) that change during vehicle operation. This allows the detection system to maintain accuracy across different scenarios while preserving the simplicity of the overall method.
Solution Approach 2:
The patent implements parameter changes by modifying the threshold value based on changing operating parameters such as temperature, voltage, and motor characteristics. Instead of using a constant threshold, the system calculates a situation-dependent threshold that reflects the actual operating state, thereby maintaining detection accuracy under varying conditions without complicating the detection approach.
2Reliability
If the threshold value is raised to account for switch-on current surge, then false detection of load-free release is reduced, but unnecessary recalibration processes are triggered
Solution Approach 1:
The patent resolves this contradiction by dynamically adjusting the threshold parameter based on operating conditions rather than using a uniformly high threshold. The threshold is calculated considering motor resistance, voltage, temperature, and time constants, allowing it to adapt to the actual operating state. This prevents both false negatives (missing load-free release) and false positives (unnecessary recalibration) by matching the threshold to the specific situation.
Solution Approach 2:
The system uses feedback from motor parameters and operating conditions to continuously adjust the threshold value. By monitoring temperature, voltage, and motor characteristics, the system calculates an appropriate threshold that reflects the current state, thereby avoiding unnecessary recalibration while maintaining reliable detection of load-free release conditions.
3Measurement precision
If a situation-dependent threshold is calculated, then the detection accuracy improves, but the device complexity increases
Solution Approach 1:
The patent applies the self-service principle by having the control unit automatically calculate and adjust the threshold value based on readily available motor parameters and operating conditions. The system uses its own existing data (motor resistance, constants, mass inertia, temperature, voltage) to generate the situation-dependent threshold without requiring external intervention or complex additional hardware, thereby improving accuracy while limiting complexity increase.
Solution Approach 2:
The control unit performs multiple functions: it monitors motor operation, detects load-free release state, calculates situation-dependent threshold, and triggers recalibration when needed. By making the control unit universal and multi-functional, the patent avoids adding separate dedicated hardware for threshold calculation, thereby improving detection accuracy while minimizing the increase in overall device complexity.
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
This approach eliminates unnecessary recalibration processes by accurately determining the load-free release state, making the recalibration process more reliable and independent of voltage fluctuations and temperature variations.
Implementation Method 1
a brake motor (2) for generating an electromechanical braking force
Implementation Method 2
an exponential function to approximate the current profile
Data Source
AI summary
A method for determining a triggering condition for recalibration in an automatic parking brake includes determining a motor current which is expected at a predetermined time during a release process of the automatic parking brake. The method includes identifying motor current for a brake motor in the automatic parking brake that generates an electromechanical braking force during operation and releases the electromechanical braking force during the release process.