Hierarchical Map Path Planning for Mobile Robots
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Solution Overview
Problem
Conventional mobile robots face inefficiencies in path planning due to the use of high-resolution grid maps, which require large memory and computation resources, making real-time path planning difficult, and coarse maps may not allow precise movement through narrow areas due to large cell sizes.
Innovation Solution
A method that generates a coarse map with larger cells for initial path planning and updates it using a fine map with smaller sub-cells around obstacles to enable precise navigation through narrow passages, reducing computational demands and improving movement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a fine map with small cells (1-2 cm) is used for path planning, then the robot can clean every nook and corner effectively, but large amounts of memory capacity and computations are required, making real-time path planning impossible in embedded systems
Solution Approach 1:
The patent divides the map into two levels: a coarse map with large cells for overall path planning and a fine map with small cells for detailed navigation in specific areas. This segmentation allows the system to use computational resources efficiently by applying high-resolution processing only where necessary rather than across the entire environment.
Solution Approach 2:
The patent applies different map resolutions to different spatial locations based on their importance. Areas requiring precise navigation (nooks and corners) use fine map cells, while open areas use coarse map cells. This local differentiation optimizes both computational efficiency and cleaning effectiveness.
2Productivity
If a coarse map with large cells (20-25 cm) is used for path planning, then real-time map preparation becomes possible with reduced computational resources, but the robot cannot move through narrow areas effectively due to the large cell size
Solution Approach 1:
The patent segments the navigation system into two hierarchical layers: coarse map processing for rapid overall path determination and fine map processing for precise local navigation. This allows real-time performance for general path planning while maintaining the capability for precise movement when needed.
Solution Approach 2:
The patent performs preliminary path planning using the coarse map to identify general routes and destinations. This preliminary action allows the system to prepare basic navigation paths in real-time, then refine specific segments using fine map data only when approaching areas requiring precise movement through narrow passages.
3Adaptability or versatility
If a grid map is generated from sensor data for the whole area, then the robot can build a complete environmental map, but the map has great uncertainty and error that affects navigation accuracy
Solution Approach 1:
The patent segments the environmental map into coarse and fine representations. The coarse map provides a robust, low-resolution overview that is less susceptible to sensor errors, while the fine map provides high-resolution data for critical areas. This segmentation reduces the impact of uncertainty in any single map representation.
Solution Approach 2:
The patent changes the resolution parameter of the map based on spatial location and navigation requirements. By dynamically adjusting the level of detail in different regions, the system maintains adaptability for complete environmental mapping while improving accuracy in areas where precise navigation is critical.
Data Source
AI summary
A method, medium, and apparatus for performing path planning of a mobile robot is provided. The apparatus for performing path planning of a mobile robot includes a coarse map generation unit to generate a coarse map composed of a plurality of cells; a fine map generation unit to generate a fine map composed of a plurality of sub-cells into which at least one of the plurality of cells is divided, and a path generation unit to control the fine map generation unit to generate the fine map with respect to a specified position in the coarse map generated through the coarse map generation unit. The method of performing path planning of a mobile robot includes generating a coarse map composed of a plurality of cells, generating a fine map composed of a plurality of sub-cells into which at least one of the plurality of cells, which neighbors the cell where an obstacle exists, is divided, generating a moving path whereby the mobile robot can pass a narrow passage by using the fine map, and updating the coarse map by reflecting the moving path.