Autonomous Vehicle Safety Stoppage Device

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Solution Overview

Problem

Autonomous road vehicles face challenges in safely bringing themselves to a halt in case of severe system faults, where control systems are unable to maintain safe autonomous driving, necessitating a solution to handle such situations effectively.

Innovation Solution

A safety stoppage device with a primary and redundant brake and steering system, where each unit monitors for faults and executes pre-stored control profiles or trajectories independently of the autonomous drive-control unit, ensuring safe braking and steering even if primary systems fail, with redundant systems overriding primary ones in case of faults and continuous calculation and storage of control profiles and trajectories for robust operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If redundant brake and steering systems are implemented with independent fault monitoring and pre-stored control profiles, then safety and reliability are improved, but device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control system is segmented into functionally independent primary and redundant brake-control units, each with separate fault monitoring and pre-stored control profiles. This segmentation allows the redundant system to operate independently if the primary system fails, improving reliability while managing complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Control profiles for safe stoppage are pre-calculated and stored in both primary and redundant brake-control units before faults occur. This preliminary action ensures that when a fault is detected, the system can immediately execute pre-planned safe stoppage maneuvers without requiring complex real-time calculations, thus improving safety response time

Inventive Principle:
Principle #10Preliminary action

2Loss of time

If the primary brake-control unit executes pre-stored longitudinal control profiles independently upon fault detection, then response time is reduced, but control precision may be compromised

Engineering Contradiction:
Improveresponse timeVSAvoidcontrol precision
Core Design Contradiction:
Loss of timeVSManufacturing precision

Solution Approach 1:

Longitudinal control profiles for safe stoppage are pre-calculated and stored in the primary brake-control unit with high precision before any fault occurs. These profiles contain optimized braking trajectories that balance stopping distance, comfort, and safety. When a fault is detected, the pre-stored profile is executed immediately, achieving both fast response time and maintained control precision

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The pre-stored longitudinal control profiles are copied to both the primary and redundant brake-control units, ensuring that identical high-precision control data is available in both systems. This copying mechanism ensures that the redundant system can execute the same precision control if needed

Inventive Principle:
Principle #26Copying

Data Source

PatentEP3363698B1Safety stoppage device and autonomous road vehicle equipped therewith
Publication Date: 2021.05.26 VOLVO CAR CORP
  • EP3363698B1 patent drawingFigure 1
  • EP3363698B1 patent drawingFigure 2
  • EP3363698B1 patent drawingFigure 3a~3c

AI summary

A safety stoppage device (1) for an autonomous road vehicle (2) having control networks (11) and sensors (12), and an autonomous drive-control unit (13) for processing sensor- and communication-signals and providing control signals for lateral and longitudinal control. A primary brake-control unit (4) is arranged to monitor the longitudinal control signals for faults and upon determination of a such fault arranged to execute a longitudinal control profile, stored independent from the autonomous drive-control unit (13), to perform braking to a stop. A primary steering-control unit (8) is arranged to monitor the lateral control signals for faults and upon determination of a such fault arranged to control a primary steering actuator (9) to follow a lateral control trajectory, stored independent from the autonomous drive-control unit (13), and, if not already triggered, simultaneously trigger the primary brake-control unit (4) to execute the stored longitudinal control profile to control wheel brakes (6) to perform braking to a stop during execution of the lateral control trajectory.