Brake-By-Wire Pedal Decoupling for Plausible Brake Request Validation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing brake-by-wire systems in vehicles lack sufficient redundancy and fail to prevent unintended brake actuation, especially in automated driving scenarios, due to hydraulic fallback mechanisms that can lead to immediate brake pressure buildup.
Innovation Solution
A redundant braking system with a hydraulically and mechanically decoupled brake pedal, utilizing multiple sensor arrangements to independently detect braking requests, validate and verify actuation signals, and implement braking maneuvers based on signal validity and plausibility, with a secondary system capable of independent operation in case of primary system failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydraulic fallback mechanism is used in brake-by-wire systems, then the system maintains mechanical coupling for safety, but unintended brake pedal actuation leads to immediate pressure buildup in wheel brakes
Solution Approach 1:
The braking system is divided into two independent hydraulic circuits: a primary braking system and a secondary braking system. The brake actuation unit is hydraulically decoupled from both systems, eliminating the unintended pressure buildup issue while maintaining safety through redundancy. Each sensor arrangement independently monitors one hydraulic circuit, allowing fault isolation and preventing harmful effects from propagating across the entire system.
Solution Approach 2:
Two independent sensor arrangements act as intermediaries between the brake actuation unit and the respective hydraulic braking systems. These sensors detect actuation information and enable the control unit to validate signals before implementing braking requests, preventing unintended actuation while maintaining reliable brake-by-wire operation.
2Reliability
If multiple sensor arrangements are used to detect braking requests, then system reliability and fault detection improve, but device complexity increases
Solution Approach 1:
The monitoring function is segmented across two independent sensor arrangements, each connected to a separate hydraulic braking system. This segmentation allows the system to detect faults in individual sensors or circuits without compromising overall functionality, improving reliability while keeping each sensor unit relatively simple.
Solution Approach 2:
The control unit performs multiple functions: it processes signals from both sensor arrangements, validates actuation information for plausibility, determines braking requests, and controls both primary and secondary braking systems. This multi-functionality consolidates complexity into a single control unit rather than requiring separate processing systems.
3Object-affected harmful factors
If the brake pedal is hydraulically decoupled from the braking system, then unintended brake actuation is prevented, but the system loses immediate hydraulic response capability
Solution Approach 1:
The direct mechanical-hydraulic coupling is replaced with an electronically controlled system. Sensor arrangements detect brake requests and transmit actuation information to the control unit, which then commands the primary or secondary braking systems to apply brakes. This substitution eliminates unintended pressure buildup while maintaining rapid response through electronic actuation.
Solution Approach 2:
The sensor arrangements continuously monitor the brake actuation unit and prepare actuation information for processing. The control unit validates signals and pre-configures the braking systems, ensuring that when a legitimate brake request occurs, the system can respond immediately without the delays associated with mechanical coupling.
Data Source
Figure 1
Figure 2a~2c
Figure 3
AI summary
The invention relates to a method for operating a braking system (100) of a vehicle, wherein the braking system (100) comprises a primary hydraulic braking system (102) and a brake actuation unit (114) hydraulically decoupled from the primary braking system (102). The brake actuation unit (114) has at least two sensor arrangements (126, 128) which are designed to detect, independently of one another, items of actuation information (200, 202) of the brake actuation unit (114) which describe a brake request. The method comprises: determining a first item of actuation information (200) using a first of the sensor arrangements (126); determining a second item of actuation information (202) using a second of the sensor arrangements (128); checking (204, 206) whether the determined items of actuation information (200, 202) are each valid; if the items of actuation information (200, 202) are valid, checking (212) whether the determined items of actuation information (200, 202) are plausible with respect to one another; and converting the brake request according to the items of actuation information (200, 202) and/or issuing a warning and/or performing a predefined braking manoeuvre using the braking system (100) depending on the validity and plausibility of the items of actuation information (200, 202). The invention also relates to a corresponding braking system (100).