Hydraulic Brake Piston Displacement Sensing for Air Bubble Detection
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Solution Overview
Problem
Autonomous vehicles with hydraulic braking systems face safety issues due to air bubbles in brake fluid, which compromise braking capabilities, especially since they often lack a brake pedal for traditional testing methods.
Innovation Solution
A method and apparatus that use an actuator to apply a force to a piston in the hydraulic braking system, measuring piston displacement and fluid pressure to detect anomalies like air bubbles, and subsequently flush them to ensure safe operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional brake pedal testing methods are used, then braking system can be tested manually, but autonomous vehicles cannot be tested using these traditional methods due to lack of brake pedal
Solution Approach 1:
The patent introduces an actuator as an intermediary device to replace the brake pedal in autonomous vehicles. The actuator applies controlled forces to the piston, enabling automated testing of the braking system without requiring a brake pedal or manual intervention. This mediator bridges the gap between traditional manual testing methods and autonomous vehicle testing requirements.
Solution Approach 2:
The patent replaces the mechanical brake pedal system with an automated actuator system. The actuator uses controlled mechanical force application to simulate brake pedal operation, allowing automated testing of hydraulic braking systems in autonomous vehicles that lack traditional brake pedals.
2Reliability
If air bubbles are present in brake fluid, then braking capabilities are compromised, but detecting air bubbles requires complex measurement systems
Solution Approach 1:
The patent implements a feedback mechanism where the actuator applies a known force to the piston, and the system measures the resulting piston displacement. By comparing the expected displacement (based on applied force and fluid properties) with the actual displacement, the system detects anomalies such as air bubbles in the brake fluid. This feedback-based approach simplifies detection by using the existing actuator and displacement sensors rather than requiring complex dedicated detection equipment.
Solution Approach 2:
The braking system performs self-diagnosis by using its own actuator and displacement measurement capabilities to detect air bubbles. The system tests itself by applying controlled forces and monitoring piston response, eliminating the need for separate complex detection systems or manual inspection methods.
3Measurement precision
If force is applied to piston to detect anomalies, then air bubbles can be identified, but the system requires precise measurement of piston displacement
Solution Approach 1:
The patent makes the displacement indication arrangement serve multiple functions: it measures piston displacement during normal braking operation and simultaneously measures piston displacement during anomaly detection testing. This multi-functionality eliminates the need for separate measurement systems, reducing overall system complexity while maintaining the required measurement precision for detecting air bubbles and other anomalies.
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
Effectively identifies and removes air bubbles in the brake fluid, ensuring the safe operation of autonomous vehicles by utilizing an actuator to apply forces and measure displacements within the hydraulic braking system, even in vehicles without a brake pedal.
Implementation Method 1
determining when a pressure of the fluid reaches a target pressure
Data Source
AI summary
According to one aspect, a method includes applying a first force to a piston using an actuator that includes a displacement indication arrangement. The piston is part of a hydraulic braking system included in a vehicle. The hydraulic braking system includes fluid, wherein when the first force is applied to the piston, the piston moves. The method further includes determining when a pressure of the fluid reaches a target pressure, obtaining at least a first measurement of a displacement of the piston when the pressure of the fluid reaches the target pressure using the displacement indication arrangement, and determining when the at least first measurement of the displacement of the piston indicates an anomaly in the hydraulic braking system. When it is determined that the at least first measurement of the displacement of the piston indicates the anomaly, the anomaly in the hydraulic braking system is identified.