Parking Brake Clamping Force Adjustment via Hydraulic Path Comparison
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Solution Overview
Problem
Existing electromechanical parking brake systems face challenges in accurately setting the clamping force due to uncertainties in hydraulic pressure, leading to potential overestimation of the clamping force and reduced actuation of the electric actuator, resulting in an incorrectly set clamping force level.
Innovation Solution
A method that compares the pressure reference path with the actuator path, derived from motor state variables, to determine the plausibility of hydraulic pressure, allowing for compensatory adjustments to ensure accurate setting of the total clamping force by either relying solely on the electromechanical device or incorporating the hydraulic component, depending on the match between these paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If hydraulic pressure is used to support the clamping force, then the total clamping force can be increased, but the accuracy of clamping force setting deteriorates due to uncertainty in hydraulic pressure measurement
Solution Approach 1:
The system uses feedback by comparing the pressure reference path (expected hydraulic pressure behavior) with the actual actuator path (actual electric actuator movement). When the comparison shows significant deviation, the system assumes the pressure measurement is not trustworthy and adjusts the clamping force setting accordingly, either by relying more on the electromechanical component or by correcting the pressure-based calculation.
Solution Approach 2:
The system dynamically adjusts the clamping force setting based on real-time comparison between pressure reference path and actuator path. The control strategy changes adaptively: when paths match well, hydraulic support is utilized; when paths diverge, the system switches to or increases electromechanical actuation to ensure accurate clamping force delivery.
2Use of energy by moving object
If the electric actuator is reduced in actuation due to overestimation of clamping force, then energy consumption is reduced, but the clamping force setting accuracy deteriorates
Solution Approach 1:
The system continuously monitors the relationship between pressure reference path and actuator path to provide feedback on the reliability of pressure-based clamping force estimation. This feedback enables the system to optimize energy consumption by reducing electric actuator actuation when hydraulic pressure data is reliable, while maintaining accuracy by increasing actuator involvement when pressure data becomes unreliable.
Solution Approach 2:
The system changes the control parameters dynamically by adjusting the reliance on hydraulic pressure support versus electromechanical actuation. When the comparison between pressure reference path and actuator path indicates high reliability, the system increases hydraulic support (reducing energy use). When reliability decreases, the system shifts to greater electromechanical actuation to maintain precision.
3Productivity
If hydraulic pressure measurement is trusted without verification, then the electromechanical actuator can be actuated less, but the reliability of clamping force setting deteriorates
Solution Approach 1:
The system performs preliminary verification by comparing the pressure reference path with the actuator path before fully trusting the hydraulic pressure measurement. This preliminary check allows the system to quickly assess whether the pressure measurement is reliable, enabling fast decision-making about whether to use hydraulic support or rely on electromechanical actuation.
Solution Approach 2:
The comparison mechanism provides continuous feedback on the consistency between expected pressure behavior and actual actuator behavior. This feedback loop ensures that the system only trusts hydraulic pressure measurements when they are verified to be plausible, maintaining reliability while enabling rapid brake actuation when conditions are favorable.
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 method ensures accurate and reliable setting of the clamping force by accounting for hydraulic pressure influence, preventing overestimation and ensuring the parking brake assumes the correct effective clamping force, thereby optimizing the electromechanical braking device's operation.
Implementation Method 1
an electric actuator for generating a clamping force for fixing the vehicle at a standstill. The electric actuator is preferably an electric brake motor, the rotational movement of which is converted into an axial actuating movement of a brake piston
Implementation Method 2
A hydraulic brake device is used to support the clamping force, the hydraulic pressure of which is applied to the brake piston in a supporting manner
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a method for adjusting the clamping force applied by a parking brake, said force being produced by an electromechanical braking device and according to requirements, in addition to a hydraulic braking device. Said hydraulic pressure is determined and a pressure reference path is associated with the pressure and is compared to an actuator path.