Autonomous Vehicle Trajectory Hierarchy for Safety Stop Release

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Solution Overview

Problem

Autonomous vehicles face challenges in safely transitioning back to nominal operating mode after encountering faults, such as sensor failures, due to the risk of unsafe trajectory selection by AI systems, necessitating a robust mechanism for validating and prioritizing trajectories to ensure collision avoidance and passenger safety.

Innovation Solution

The implementation of a trajectory manager process (TMP) that evaluates trajectories based on punctuality, consistency, feasibility, and collision checking criteria, prioritizing safety by selecting valid and collision-free paths and employing a hierarchy of trajectories, including emergency stops, to ensure the vehicle's safe operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If the AI system selects trajectories autonomously, then the responsiveness and automation of the vehicle are improved, but the reliability and safety may deteriorate due to potential unsafe trajectory selections

Engineering Contradiction:
Improveautonomous trajectory selectionVSAvoidsafety of trajectory selection
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The patent introduces a trajectory manager process as an intermediary between the AI system and the vehicle control systems. This intermediary validates AI-generated trajectories against safety criteria (collision detection, feasibility constraints, consistency checks) before execution, and can override unsafe selections. It also manages a hierarchy of backup trajectories (contingent, stored, transformed) that activate when AI trajectories fail validation, thus maintaining automation while ensuring reliability through layered validation and fallback mechanisms.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the system implements comprehensive trajectory validation and hierarchy management, then the safety and reliability are improved, but the device complexity increases

Engineering Contradiction:
Improvesafety of vehicle operationVSAvoidtrajectory management system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The trajectory management system is segmented into distinct functional modules: AI trajectory generation, validation subsystem (checking punctuality, consistency, feasibility), collision detection, hierarchy management (contingent, stored, transformed trajectories), and override mechanisms. This modular segmentation allows comprehensive safety validation while organizing complexity into manageable, independent components that can be developed and tested separately.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary validation of AI-generated trajectories before they are executed, checking multiple safety criteria in advance. It also pre-generates and stores contingent and stored trajectories as backup options, and pre-establishes transformation rules for modifying trajectories. These preliminary actions ensure safety is verified before critical decisions are made, reducing the complexity of real-time emergency responses.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the vehicle requires manual release signals after safety stops, then the reliability is improved by preventing premature resumption, but the productivity and response time decrease

Engineering Contradiction:
Improveprevention of premature mode switchingVSAvoidtime to resume nominal operation
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system implements feedback mechanisms where the trajectory manager continuously monitors system state and provides status information to remote operators. When a safety stop is triggered, the system waits for explicit release signals from remote operators based on feedback about the current situation. This feedback loop ensures that resumption decisions are informed by real-time system state assessment, preventing premature mode switching while allowing efficient recovery when conditions permit.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4003801B1System and method for effecting a safety stop release in an autonomous vehicle
Publication Date: 2024.12.11 ZOOX INC
  • EP4003801B1 patent drawingFigure 1
  • EP4003801B1 patent drawingFigure 2
  • EP4003801B1 patent drawingFigure 3

AI summary

A method and apparatus for selecting among a plurality of trajectories comprises receiving at least a first and second trajectory, each having an associated level in a trajectory hierarchy, determining whether the first trajectory is viable, determining a present level limit for trajectory selection, and if the first trajectory is viable and its level does not exceed the present level limit, executing the first trajectory. If the first trajectory is not viable or the associated level of the first trajectory exceeds the present level limit, the second trajectory is executed if it is viable and its associated level does not exceed the present level limit. A state variable is set such that when a trajectory lower in a trajectory hierarchy is executed, a trajectory selector waits for a message from a monitor or an operator before returning to the use of higher level trajectories.