Ray-Casting Grid Map Updates for Real-Time Movable Platform Routing

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Solution Overview

Problem

Current systems for movable platforms, such as UAVs, face inefficiencies in processing sensor data for real-time route planning and obstacle avoidance, as they often require processing the entire grid map at once, which can be time-consuming and resource-intensive.

Innovation Solution

The system divides the grid map into subsets of grid cells, allowing only the relevant cells to be updated and processed in real-time, using ray-casting status to determine cell values and optimize route planning, enabling efficient and accurate navigation while reducing computational load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the entire grid map is processed at once for route planning, then comprehensive route planning is achieved, but processing time and computational resources increase significantly

Engineering Contradiction:
Improveroute planning accuracyVSAvoidprocessing time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The grid map is divided into multiple subsets of grid cells, allowing the system to process only relevant portions of the map at any given time. This segmentation enables parallel processing and reduces the computational burden on single processing units, thereby decreasing overall processing time while maintaining comprehensive route planning capability through coordinated processing of all subsets.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system processes a subset of grid cells that are most relevant to the current platform position and mission objectives, rather than uniformly processing the entire map. This partial action approach focuses computational resources on critical areas, reducing unnecessary processing overhead while ensuring that essential route planning information is captured and updated.

Inventive Principle:
Principle #16Partial or excessive action

2Measurement precision

If the entire grid map is updated continuously, then real-time accuracy is maintained, but computational load and energy consumption increase

Engineering Contradiction:
Improvegrid map accuracyVSAvoidcomputational energy
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The grid map is segmented into multiple subsets that can be updated independently and asynchronously. This allows the system to update only those subsets that have changed or are relevant to current operations, rather than continuously refreshing the entire map. Independent subset updates reduce computational energy consumption while maintaining overall map accuracy through selective refreshment.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of continuous updating of the entire grid map, the system implements periodic updates for different subsets at different frequencies based on their relevance and change rates. Critical subsets near the platform position are updated more frequently, while less critical areas are updated less frequently, optimizing the balance between real-time accuracy and energy consumption.

Inventive Principle:
Principle #19Periodic action

3Loss of information

If ray-casting is performed on all grid cells, then complete environmental coverage is achieved, but processing complexity increases

Engineering Contradiction:
Improveenvironmental coverageVSAvoidprocessing complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

Ray-casting operations are distributed across multiple grid cell subsets rather than being performed uniformly on the entire map. Each processing unit handles ray-casting for its assigned subset, reducing the complexity of individual processing tasks. The segmentation allows for parallel execution of ray-casting operations, maintaining complete environmental coverage through coordinated results from all subsets.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system applies different ray-casting strategies to different grid cell subsets based on local requirements. Areas with higher uncertainty or greater importance receive more intensive ray-casting analysis, while already-well-explored areas receive less intensive processing. This local quality approach optimizes processing complexity by concentrating computational effort where it is most needed.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3631595B1Method and system for operating a movable platform using ray-casting mapping
Publication Date: 2021.08.18 SZ DJI TECH CO LTD
  • EP3631595B1 patent drawingFigure 1
  • EP3631595B1 patent drawingFigure 2A
  • EP3631595B1 patent drawingFigure 2B

AI summary

Systems and methods are used to plan a route for a movable platform. Sensor data representing location information of one or more objects adjacent the movable platform is obtained at a first time point. A new grid map of the first time point is generated by updating an existing grid map at a second time point prior to the first time point based on the sensor data at the first time point. Each grid map includes a plurality of grid cells each having a value representing a clearance status of ray casting through the grid cell at a corresponding time point. The route for the movable platform is updated based on the respective values of the plurality of grid cells of the new grid map.