Autonomous Crosswalk Cost Planning for Pedestrian-Aware Trajectories
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Solution Overview
Problem
Autonomous vehicles face safety concerns when navigating crosswalks, particularly those without traffic control devices, as relying solely on traffic signals may lead to unsafe situations due to pedestrians crossing unexpectedly.
Innovation Solution
A vehicle computing system determines costs associated with crosswalks using a tree search algorithm, considering factors like vehicle velocity, distance to crosswalk boundaries, object proximity, and object characteristics to plan safe trajectories, incorporating sensor data and prediction components to adjust vehicle actions such as slowing down or stopping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle relies solely on traffic control devices (traffic lights, stop signs) to plan trajectories across crosswalks, then the planning system is simple to implement, but safety is compromised when pedestrians cross unexpectedly at uncontrolled or unprotected crosswalks
Solution Approach 1:
The planning system performs preliminary evaluation of crosswalk costs before the vehicle reaches them. The system proactively identifies crosswalks ahead of time, calculates associated costs based on protection status and object proximity, and incorporates these costs into trajectory planning in advance, rather than reacting only to traffic control devices when encountered
Solution Approach 2:
The patent introduces a cost function as an intermediary mechanism that mediates between the simple traffic control device detection and the complex safety requirements. This cost function quantifies the safety risk of each crosswalk based on multiple factors (protection status, object proximity, object characteristics) and integrates this information into the trajectory optimization process without requiring complex real-time decision-making at the crosswalk
2Reliability
If the vehicle slows down or stops frequently to check for pedestrians at every crosswalk, then safety is improved, but navigation efficiency and productivity decrease
Solution Approach 1:
The system dynamically changes the parameter of vehicle velocity based on the calculated crosswalk cost. Instead of applying a fixed speed reduction at all crosswalks, the planning system adjusts velocity profiles continuously based on the cost associated with each crosswalk, allowing the vehicle to maintain higher speeds when costs are low and reduce speed only when necessary
Solution Approach 2:
The system applies partial action by selectively slowing down or stopping only at crosswalks where the cost indicates potential pedestrian presence or risk. For unprotected crosswalks with no nearby objects or low cost values, the vehicle may proceed without full stopping, applying the minimal necessary action to maintain safety while preserving navigation efficiency
Data Source
AI summary
Techniques and methods for crosswalk handling for vehicles. The vehicle may identify a crosswalk and an object associated with the crosswalk in the environment. The vehicle may determine a heatmap based on sensor data and map data. The vehicle may determine a factor associated with the crosswalk relative to one or more of the vehicle and/or object based on the heatmap associated with the crosswalk. The vehicle may determine a cost associated with the crosswalk based on the factor. The vehicle may determine a trajectory for the vehicle to operate in the environment based on the cost associated with the crosswalk and follow the trajectory to travel in the environment.