Crosswalk Trajectory Planning With Relaxed Safety Constraints

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Solution Overview

Problem

Automated vehicles face safety challenges at crossing systems, such as crosswalks, due to unexpected pedestrian appearances or perception errors, leading to situations where a collision-free trajectory cannot be found, especially when sudden obstacles render rule-compliant stopping impossible.

Innovation Solution

A method that involves receiving environmental signals, specifying boundary conditions and instructions for a crossing system maneuver, and planning a target trajectory. If the original trajectory cannot be fulfilled, relaxed boundary conditions and instructions are used to ascertain a fallback target trajectory, incrementally softening requirements to minimize violations, allowing the vehicle to escape critical situations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the motor vehicle strictly adheres to rule-compliant stopping requirements at the crossing system, then safety compliance is improved, but the ability to respond to unexpected situations (such as sudden pedestrian appearances) deteriorates, making collision-free trajectory impossible when braking distance is insufficient

Engineering Contradiction:

Improvesafety complianceVSAvoidresponse to unexpected situations

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The planning system dynamically adjusts the specification between original and relaxed versions based on situational assessment. When unexpected situations are detected (e.g., sudden pedestrian appearance), the system transitions from strict rule-compliant planning to relaxed specification planning, enabling adaptive response while maintaining safety through controlled relaxation of boundary conditions

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes parameters of the specification by introducing relaxed versions with modified boundary conditions and instructions for action. This allows the planning system to adjust the strictness of requirements based on the situation, transforming the rigid original specification into a flexible relaxed specification that can accommodate unexpected events

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the motor vehicle maintains strict boundary conditions and instructions for action, then safety standards are met, but the ability to find a valid target trajectory in critical situations deteriorates

Engineering Contradiction:

Improvesafety standards complianceVSAvoidtrajectory planning feasibility

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The planning process is segmented into multiple levels: original specification planning and relaxed specification planning. This segmentation allows the system to attempt strict safety-compliant planning first, and only if that fails, transition to relaxed planning with modified boundary conditions, thereby maintaining safety standards while ensuring trajectory planning feasibility

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system prepares relaxed specifications in advance as fallback options. When critical situations arise, the pre-prepared relaxed specifications can be immediately activated, avoiding the need for complex real-time adjustments and ensuring smooth transition between planning modes

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If the motor vehicle uses relaxed boundary conditions and instructions for action to find fallback trajectories, then the ability to escape critical situations is improved, but the strictness of safety requirements deteriorates

Engineering Contradiction:

Improvecritical situation handlingVSAvoidsafety requirement strictness

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system implements feedback mechanisms to continuously assess whether relaxed specifications are being used and under what conditions. This feedback allows the system to learn from critical situations and adjust future relaxation decisions, ensuring that safety requirements are maintained as much as possible while handling critical situations effectively

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS20250022365A1Method for increasing safety at a crossing system

Publication Date: 2025.01.16 ROBERT BOSCH GMBH

AI summary

A method for increasing safety at a crossing system including crosswalk. The method includes: receiving environmental signals representing an environment, including a crossing system, of a motor vehicle approaching the crossing system and wanting to cross the crossing system; specifying a boundary condition and/or an instruction for action for a crossing system maneuver to be planned for the motor vehicle on the basis of the environmental signals; planning a crossing system maneuver for the motor vehicle based on the environmental signals including ascertaining a target trajectory, fulfilling the specification, for the motor vehicle based on the specification, wherein, if no target trajectory fulfilling the specification can be ascertained for the motor vehicle, the planning includes using a relaxed, at least one boundary condition and/or a relaxed, at least one instruction for action to ascertain a fallback target trajectory fulfilling the relaxed specification; outputting the correspondingly ascertained target trajectory.