Brake System Hydraulic Decoupling for Autonomous Driving Safety
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Solution Overview
Problem
In autonomous or partially autonomous driving modes, unwanted braking can occur due to accidental actuation of the brake pedal by a sleeping driver, compromising driving safety.
Innovation Solution
A method involving hydraulic decoupling of the brake pedal from the wheel brake using a valve arrangement, including shut-off valves and a fluid accumulator, to prevent unintended braking, while allowing for haptic feedback to awaken the driver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the brake pedal is directly coupled to the wheel brake, then the driver can easily control braking, but accidental actuation causes unwanted braking during autonomous driving
Solution Approach 1:
A hydraulic arrangement with controllable shut-off valves is introduced as an intermediary between the brake pedal and the wheel brake. This mediator allows the system to selectively disconnect the direct mechanical-hydraulic connection, preventing accidental braking while maintaining normal brake control functionality when needed.
Solution Approach 2:
The brake system transitions from a static direct coupling to a dynamic controllable connection. The shut-off valves can be actuated to change the hydraulic connection state between coupled and decoupled, allowing the system to adapt its behavior based on driving mode and detect actual driver intent.
2Reliability
If the brake pedal is decoupled from the wheel brake during autonomous driving, then accidental braking is prevented, but the driver loses haptic feedback and braking capability
Solution Approach 1:
The system dynamically adjusts the hydraulic connection based on operational context. During autonomous driving, the connection is decoupled for safety, but can be re-established when the driver needs to take control, allowing flexible transition between autonomous and manual operation modes.
Solution Approach 2:
The system monitors driver input signals and vehicle operating conditions to determine when to couple or decouple the brake pedal. This feedback mechanism ensures the brake system remains responsive to driver intent while preventing unwanted activation during autonomous operation.
3Reliability
If a hydraulic arrangement with shut-off valves is introduced, then accidental braking is prevented, but the device complexity increases
Solution Approach 1:
The hydraulic arrangement with shut-off valves serves multiple functions: it enables normal brake operation, prevents accidental braking during autonomous driving, and allows selective decoupling based on driving mode. This multi-functionality justifies the added complexity by consolidating several control requirements into a single integrated system.
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
Enhances safety by preventing accidental braking during autonomous driving and providing haptic feedback to alert a sleeping driver, ensuring safe operation of the vehicle.
Implementation Method 1
The brake system can have a hydraulic arrangement. The hydraulic arrangement can be or become effective between the brake cylinder and the at least one wheel brake. The brake cylinder can be designed to build up a hydraulic pressure at the at least one wheel brake, for example via the hydraulic arrangement.
Implementation Method 2
A method involving hydraulic decoupling of the brake pedal from the wheel brake using a valve arrangement, including shut-off valves and a fluid accumulator, to prevent unintended braking, while allowing for haptic feedback to awaken the driver.
Data Source
AI summary
A method for operating a brake system of a motor vehicle, wherein the brake system has a brake pedal, which can be actuated by a driver of the motor vehicle, a brake booster, which can be coupled or is coupled to the brake pedal, a brake cylinder, such as a brake master cylinder, which can be coupled or is coupled to the brake booster and can be supplied with hydraulic fluid, and a hydraulic arrangement, which acts between the brake cylinder and at least one wheel brake, wherein the method comprises at least the step of: decoupling the brake pedal from the at least one wheel brake by the hydraulic arrangement, and a computer program, control unit or system having a plurality of control units and brake system.