Parking Brake Actuator Control for Clamping Force Transition Detection
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Solution Overview
Problem
Existing parking brake control methods struggle to adjust clamping force effectively in various operating situations, particularly at lower currents, leading to inaccuracies and malfunctions, and fail to provide a sensitive and rapid build-up of clamping force as required by different driving conditions.
Innovation Solution
A method that modifies the control procedure of the parking brake actuator by detecting a transition from a phase without clamping force build-up to one with build-up, using parameters like current strength to identify a continuous increase in clamping force, allowing for early and robust detection of the transition and adjusting the speed and interruption of the application process to avoid unnecessary braking force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the clamping force is built up rapidly using the parking brake actuator, then the productivity of the braking process is improved, but the measurement precision of the clamping force detection deteriorates due to higher error components at lower currents
Solution Approach 1:
The braking process is divided into two distinct phases: a first phase where the parking brake actuator is operated to overcome free travel and air gap without building up significant clamping force, and a second phase where the clamping force is built up. This segmentation allows the system to separate the detection-critical phase (second phase) from the setup phase (first phase), enabling accurate detection during the force build-up while maintaining overall process efficiency.
Solution Approach 2:
The control procedure performs preliminary actions in the first phase by operating the parking brake actuator to overcome free travel and air gap before the actual clamping force build-up begins. This preliminary action prepares the system for accurate detection in the second phase by ensuring that the measurement starts only after the mechanical clearance has been eliminated, when the current signal is most reliable.
2Measurement precision
If the control procedure is made sensitive to detect early transition to clamping force build-up, then the measurement precision is improved, but the device complexity increases due to additional detection and control mechanisms
Solution Approach 1:
The control procedure continuously monitors the current strength of the parking brake actuator and uses this feedback to detect the transition from the first phase to the second phase. When the current strength exceeds a predetermined threshold for a defined period, the system automatically switches control modes, enabling sensitive detection without additional hardware complexity.
Solution Approach 2:
The system detects the transition between phases by monitoring changes in the current strength parameter of the parking brake actuator. The control unit evaluates whether the current strength has exceeded a predetermined threshold for a defined period, using parameter changes to trigger phase transitions without requiring complex detection mechanisms.
3Productivity
If the parking brake application process is performed quickly, then the productivity is improved, but the reliability deteriorates due to potential malfunctions at higher currents and inability to detect lower currents accurately
Solution Approach 1:
The control procedure dynamically adapts its behavior based on the detected phase. In the first phase, the system operates the actuator to overcome mechanical clearance. In the second phase, it switches to a control mode suitable for accurate clamping force build-up and detection. This dynamic adaptation ensures reliable operation across different operating conditions while maintaining overall process efficiency.
Solution Approach 2:
The system performs preliminary operations in the first phase to overcome free travel and air gap, preparing the mechanical system for reliable force application. By completing these preliminary actions before the second phase begins, the system ensures that the main braking function operates under optimal conditions, improving reliability without sacrificing overall productivity.
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
Enables precise and sensitive control of the parking brake, allowing for a robust and timely detection of the transition to the clamping force build-up phase, reducing errors and ensuring the parking brake can be adjusted to meet the requirements of specific operating situations, such as during vehicle testing or in adverse weather conditions.
Implementation Method 1
an electromechanical braking device having an electric brake motor
Data Source
AI summary
A method of applying an automated parking brake of a motor vehicle includes at least two phases. In a first preceding phase, no clamping force is produced by the parking brake. In a second following phase, a clamping force is produced by the parking brake via a controllable parking brake actuator configured to produce the clamping force. The method further includes detecting a transition from the first phase to the second phase based on a temporal progression of a specific parameter of a control of the parking brake actuator. A control unit is configured to perform according to the method, and a parking brake is configured to perform according to the method.