Autonomous Vehicle Parking Brake Control Unit Power Failure Response
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Solution Overview
Problem
Autonomous vehicles with fluid-operated brake systems face safety deficiencies during autonomous driving mode, as they lack a reliable braking mechanism in case of power failure or defects, leading to potential uncontrolled acceleration or lane departure.
Innovation Solution
A brake system with a parking brake device and control unit that uses a combination of pneumatic and hydraulic pressure, featuring electromagnetic valves to automatically engage the spring-loaded brake cylinder in case of power failure, ensuring braking even if the service brake fails, and can control all wheels and trailer brakes to maintain vehicle stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If an electrohydraulic service brake system is used in autonomous vehicles, then braking performance is improved, but safety deteriorates in case of power failure
Solution Approach 1:
The system performs preliminary action by automatically actuating the parking brake device when power failure is detected, before the vehicle can experience uncontrolled acceleration or rolling. The control unit monitors power supply status and preemptively engages the spring-loaded brake cylinder to secure the vehicle.
Solution Approach 2:
The system implements self-service by having the control unit automatically detect power failure conditions and activate the parking brake without human intervention. The electromagnetic valves and control circuitry autonomously manage the brake engagement, eliminating the need for driver action during critical failures.
2Reliability
If a driver monitors the journey in autonomous mode, then safety is improved, but the level of automation deteriorates
Solution Approach 1:
The system enables fully autonomous operation by implementing self-monitoring and self-correcting capabilities. The control unit continuously monitors power supply status and automatically activates safety brakes when failures occur, eliminating the need for driver monitoring while maintaining safety.
Solution Approach 2:
The system employs feedback mechanisms where the control unit monitors power supply conditions and automatically responds to failures by activating the parking brake. This closed-loop monitoring and response system maintains safety without requiring human intervention, preserving the autonomous driving level.
3Ease of operation
If the spring-loaded brake cylinder is kept pressurized during autonomous driving, then ease of operation is improved, but reliability deteriorates in case of power failure
Solution Approach 1:
The control unit performs preliminary action by detecting power failure conditions and automatically venting the spring-loaded brake cylinder before the vehicle can experience uncontrolled motion. This preemptive engagement of the parking brake ensures safety while maintaining ease of operation during normal conditions.
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
The solution provides a reliable braking effect in autonomous driving mode, preventing uncontrolled acceleration or rolling, and ensures the vehicle comes to a safe stop even in the event of power failure or other faults, enhancing safety without the need for a driver to intervene.
Implementation Method 1
a spring in the spring-loaded brake cylinder applies brake pads on the wheel and thus achieves a braking effect
Implementation Method 2
The valve unit includes, in particular, a plurality of suitably connected electromagnetic valves, which can be switched electrically by means of the control unit
Implementation Method 3
a pneumatic or hydraulic pressure in a spring-loaded part of the spring-loaded brake cylinder is reduced, so that a spring in the spring-loaded brake cylinder applies brake pads on the wheel
Data Source
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AI summary
The invention relates to a control unit (20) for a parking brake device (4, 4') of a vehicle (100) which can be operated in an autonomous driving mode. The invention further relates to the parking brake device (4, 4'), a braking system (2, 2') and a vehicle (100) having said system, and a corresponding method (74) for operating the vehicle (100). The control unit (20, 20') actuates a valve unit (28) of the parking brake device (4, 4') in order to block a first output (12) of the parking brake device (4, 4'), connected to a spring mechanism (10) of at least one spring mechanism brake cylinder (8) of the vehicle (100) in a pressure-transferring manner, against a pressure sink (32, 58) in regular driving operation of the vehicle (100). The control unit (20, 20') has a control circuit (26, 26') which actuates the valve unit (28, 28') such that, in response to a power failure on the parking brake device (4, 4') in regular driving operation, the first output (12) is connected in a pressure-transferring manner to the pressure sink (32, 58) by automatic changeover of a monostable shut-off valve (A) in autonomous driving mode, in order to actuate the spring mechanism brake cylinder (8) for braking the vehicle (100).