Electronic Parking Brake Feedback Control for Pad Swelling
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Solution Overview
Problem
Standard electronic parking brake (EPB) systems operate in an open loop, failing to account for real-time variations in brake pad thickness due to temperature changes and vehicle weight, leading to force loss and potential material damage, especially when parked on inclined surfaces.
Innovation Solution
A closed-loop control system utilizing sensors (accelerometer, inclinometer, normal and shear force sensors) to measure and compensate for brake pad swelling, temperature changes, and external loads, adjusting braking force in real-time to maintain vehicle stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If open loop control is used in standard EPB systems, then the system is simple to implement, but the braking force varies due to temperature changes and pad swelling
Solution Approach 1:
The patent implements a closed-loop control system that uses temperature sensors to monitor brake pad temperature and adjusts the braking force accordingly. The controller receives temperature feedback and modifies the actuator command to compensate for thermal expansion and contraction of the brake pad material, thereby maintaining consistent braking force throughout the cooling process.
Solution Approach 2:
The system dynamically changes the braking force parameter based on temperature measurements. As the brake pad cools and swells, the controller reduces the actuator force to compensate, and as temperature increases, it increases the force accordingly. This parameter adjustment ensures reliable braking force consistency despite thermal variations.
2Reliability
If periodical force re-application is used to compensate for force loss, then the vehicle remains stationary, but the repeated forces weaken and damage the brake pads
Solution Approach 1:
The system performs preliminary action by applying braking force in advance before the vehicle begins to move or roll. The controller monitors temperature and adjusts the braking force proactively to maintain vehicle stability, eliminating the need for repeated corrective force applications that would damage the brake pads over time.
Solution Approach 2:
The closed-loop feedback system continuously monitors temperature and vehicle status, adjusting the braking force in real-time to maintain stability. This prevents the need for periodic re-application of force, as the system proactively compensates for thermal effects, thereby extending brake pad lifespan while ensuring vehicle remains stationary.
3Reliability
If the EPB system is designed with overestimated forces and size, then the vehicle remains stable on inclines, but the system complexity and material usage increase
Solution Approach 1:
The patent implements dynamic adjustment of braking force based on real-time temperature measurements and vehicle status. Instead of using fixed overestimated forces, the system continuously adapts the braking force to match actual thermal conditions and vehicle load, maintaining reliability on inclines while optimizing the EPB system design to avoid excessive complexity and material usage.
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
Ensures consistent braking force application, preventing vehicle slip and minimizing brake pad wear by dynamically adjusting to thermal and load variations, thereby enhancing EPB performance and longevity.
Implementation Method 1
a temperature sensor integrated in the brake element for real-time detection of signals relating to temperatures of the brake element
Implementation Method 2
a normal force sensor integrated in the brake element for real-time detection of signals relating to normal forces applied to the brake element
Implementation Method 3
a shear force sensor integrated in the brake element for real-time detection of signals relating to shear forces applied to the brake element
Implementation Method 4
the change in the pad thickness due to the swelling of the materials (for example due to the temperature cooling down)
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A vehicle electronic system including a parking brake equipment, comprising a brake element (2) including either a brake pad or a brake shoe, said brake element (2) including an electrical circuit equipped with one or more sensors (3, 4, 5) for real-time detection of signals relating to temperatures and/or to normal forces and/or to shear forces and having electrical terminals arranged in a zone for collecting the signals from the brake element, said vehicle electronic parking brake system further comprising an actuator (8) of the brake element (2), a controller (7) delivering a braking force command to the actuator (8), and regulating means (9, 10) driving the controller (7), wherein the regulating means (9, 10) include a closed regulating loop of the braking force including a reference braking force generator (10), said closed regulating loop of the braking force being communicating with said sensors (3, 4, 5) to acquire at least one of temperatures and/or normal forces and/or shear forces measurements.