Parking Brake Pre-Positioning for Autonomous Brake Failover
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Solution Overview
Problem
Autonomous or semi-autonomous vehicles face safety risks due to failures in the service brake system, leading to potential collisions, as the parking brake does not effectively take over braking functions in such scenarios.
Innovation Solution
The parking brake is brought into a predetermined operating state that allows it to partially or fully take over the braking function in case of service brake system malfunctions, ensuring continued safe operation by providing a controlled braking effect, which is dynamically adjusted based on vehicle state and component availability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the service brake system is used for autonomous braking functions, then the braking performance and response time are sufficient, but the system reliability decreases when brake failures occur
Solution Approach 1:
The parking brake is pre-positioned and pre-configured as a backup braking system before any failure occurs. The control unit continuously monitors service brake status and has the parking brake ready to activate immediately upon detecting a service brake failure, ensuring no gap in braking capability
Solution Approach 2:
The system implements a redundant braking mechanism where the parking brake serves as a protective backup against service brake failures. This cushioning approach ensures that even if the primary service brake fails, the vehicle retains braking capability through the parking brake, preventing catastrophic failures during autonomous operation
2Reliability
If the parking brake is fully activated as a backup, then the safety is improved, but the vehicle mobility and normal operation are compromised
Solution Approach 1:
The parking brake activation is dynamically controlled based on real-time service brake status. When service brake failure is detected, the parking brake transitions from a static backup to an active braking system. The control unit continuously adjusts the parking brake application based on ongoing monitoring, allowing the system to switch between normal and backup modes seamlessly
Solution Approach 2:
The parking brake is designed to serve dual functions: its traditional parking/holding function and its role as an emergency backup braking system for autonomous operation. The control unit intelligently determines when to activate the parking brake for emergency braking versus when to keep it disengaged for normal vehicle operation, maximizing the utility of this single component
3Speed
If the parking brake is positioned closer to the braking surface, then the response time is reduced, but the braking force becomes too strong for controlled autonomous operation
Solution Approach 1:
The control unit dynamically adjusts the parking brake actuation parameters including force magnitude and application timing based on the detected operating conditions. When service brake failure occurs, the control unit modulates the parking brake force to provide appropriate deceleration levels rather than full parking brake engagement, enabling controlled autonomous braking operation
Solution Approach 2:
The system applies partial braking force through the parking brake rather than full activation. The control unit calculates the required braking force based on the autonomous braking demand and applies only that necessary portion through the parking brake, avoiding excessive braking force while still providing sufficient deceleration for safe autonomous operation
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
This solution enhances the safety and availability of autonomous driving functions by enabling the parking brake to effectively intervene in case of service brake failures, maintaining vehicle control and preventing collisions.
Implementation Method 1
the parking brake is brought from a rest state into a predetermined operating state, wherein the predetermined operating state of the parking brake is determined in such a way that the parking brake produces no braking effect or a braking effect which is significantly lower than when fully activated
Data Source
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AI summary
The method according to the invention for operating a motor vehicle, in which at least one autonomous or partially autonomous motor vehicle operating mode can be activated and the motor vehicle has a service brake and a parking brake, is characterised in that in response to a detected operative condition of the motor vehicle the parking brake is shifted from an inoperative condition to a predefined operative condition, the predefined operative condition of the parking brake being determined by the fact that the parking brake produces no braking effect or a markedly lesser braking effect in comparison with the fully activated condition.