Electropneumatic Brake Circuit Redundancy for Autonomous Steering
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Solution Overview
Problem
Current electric braking and steering systems in vehicles lack sufficient fail safety and redundancy, especially in autonomous driving scenarios, where faults in electronic controllers or energy supplies can lead to loss of steering and braking control, compromising safety and compatibility with series production due to high costs and complexity.
Innovation Solution
An electropneumatic service brake device with an electronic brake control system that generates pneumatic brake pressures independently of driver input, using dual energy supply circuits and sensors to ensure continuous operation of steering and braking functions even in fault conditions, allowing for automated control without driver intervention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant electronic system components and energy supply are implemented to improve fail safety, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The system is divided into two independent brake circuits (first and second brake circuits) with separate electronic control devices and energy supply circuits. This segmentation allows one circuit to fail while the other continues to operate, providing redundancy without requiring a completely duplicated system.
Solution Approach 2:
The second brake circuit is designed to serve dual purposes: it functions as a normal braking circuit during operation and as a steering substitute circuit when the first brake circuit fails. This multi-functionality provides redundancy without requiring dedicated separate systems for each function.
2Reliability
If completely redundant electronic system components are implemented to improve fail safety, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The second brake circuit and its associated electronic control device are designed to perform multiple functions: normal braking operation and steering substitution. This eliminates the need for completely separate redundant systems, reducing component costs while maintaining fail safety.
Solution Approach 2:
The electronic control device dynamically changes its operating parameters and control strategies based on the operational state of the brake circuits. When the first circuit fails, the control device switches to alternative control algorithms that utilize the second circuit for both braking and steering functions, maintaining performance without requiring additional hardware.
3Extent of automation
If steering and braking functions are completely automated for autonomous driving, then extent of automation is improved, but reliability decreases due to potential faults in electronic controllers
Solution Approach 1:
The system incorporates a backup brake circuit and alternative control strategies that are prepared in advance to take over in case of electronic controller faults. This prior cushioning ensures that automated control can continue even when electronic systems fail, maintaining reliability during autonomous operation.
Solution Approach 2:
The second brake circuit acts as an intermediary backup system that can mediate between the failure of electronic controllers and the need for continued automated steering and braking control. When primary electronic control fails, the second circuit provides an alternative pathway for maintaining automated vehicle control.
4Reliability
If selective braking of individual wheels is used to maintain steerability after steering component failure, then reliability is improved, but device complexity increases
Solution Approach 1:
The second brake circuit is designed to universally handle both braking and steering substitution functions. By using the existing brake infrastructure for dual purposes, the system maintains steerability after steering component failure without requiring complex additional steering mechanisms or control systems.
Solution Approach 2:
The system replaces the mechanical steering function with a braking-based steering substitution mechanism. By selectively applying brake force to individual wheels through the second brake circuit, the system generates yaw moments that substitute for failed mechanical steering, maintaining vehicle steerability through a different physical principle.
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 fail safety by enabling continuous steering and braking control in autonomous driving scenarios, reducing costs and complexity, and ensuring maximum braking power through redundant systems, while allowing driver override when necessary.
Implementation Method 1
The solenoid valve device (52) has an output connection (50) which is connected to the first control chamber (22)
Data Source
AI summary
A braking system and a method of operating such a braking system are provided for a vehicle having at least partly electric braking, a steering device containing an electric or electromechanical steering device, an electronic steering controller and an electric steering adjuster and containing a service brake device. The system includes an electropneumatic service brake device containing an electropneumatic service brake valve device, an electronic brake controller, electropneumatic modulators, pneumatic wheel brake actuators, a service brake actuating element, and at least one electric channel (130) with at least one electric brake value transmitter which senses activation of the service brake actuating element. The at least one electric brake value transmitter produces actuation signals which are relayed to the electronic brake controller. The electronic brake controller causes a first actuation force to be applied to at least one control piston of the service brake valve device to control at least one double seat valve of the service brake valve device to generate pneumatic braking pressures or brake control pressures for the pneumatic wheel brake actuators. The electronic controls are further configured to generate a second actuation force on the at least one control piston when a brake request independent of the driver's request exists, independent of a driver brake request. The electropneumatic service brake device is supplied with energy independently from energy supplied to the electropneumatic service brake valve device and the electric or electromechanical steering device.