Multi-Robot Path Planning Using Swept Regions and Force Vectors

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Solution Overview

Problem

Existing robotic systems face challenges in efficiently planning paths that avoid obstacles and collisions, especially in high-traffic environments where multiple robots interact, as current methods often require complex and computationally intensive calculations to account for the future movements of all robots.

Innovation Solution

The implementation of an elastic path planning technique that uses force vectors to shape candidate paths, taking into account the swept regions of multiple robots, allowing the system to aggregate and adjust paths based on traffic levels, thereby avoiding high-traffic areas and optimizing routes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the system uses traditional path planning methods to account for future movements of all robots, then collision avoidance is improved, but computational complexity and processing time increase significantly

Engineering Contradiction:
Improvecollision avoidanceVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system segments the path planning problem by dividing the environment into discrete grid cells and representing robot paths as sequences of grid positions. This segmentation transforms the continuous path planning problem into a discrete optimization problem, reducing computational complexity while maintaining collision avoidance capabilities through the A* algorithm and time-parameterized path representations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary action by pre-calculating swept volumes for each robot based on their planned trajectories before final path optimization. These pre-computed swept volumes represent the spatial-temporal occupancy of each robot and are used as constraints in the optimization process, eliminating the need for real-time collision checking during path planning and significantly reducing computational burden.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If the system plans paths for multiple robots considering all future movements, then path safety is improved, but planning time increases

Engineering Contradiction:
Improvepath safetyVSAvoidplanning time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system applies dynamics by using time-parameterized path representations where each robot's path is defined as a sequence of positions at different time steps. This dynamic formulation allows the optimization algorithm to directly account for temporal aspects of robot movements, enabling collision-free path planning for multiple robots while reducing planning time through efficient gradient-based optimization methods that leverage the time-structured representation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system substitutes mechanical/computational collision checking with a mathematical optimization framework that directly minimizes collision risk. By formulating path planning as an optimization problem with collision constraints based on swept volumes, the system replaces iterative collision detection and resolution mechanisms with a unified optimization approach that simultaneously determines collision-free paths for all robots, significantly reducing planning time.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If the system uses elastic path planning with force vectors to avoid obstacles, then path optimization is improved, but computational requirements increase

Engineering Contradiction:
Improvepath optimizationVSAvoidcomputational requirements
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system changes parameters by transforming the path representation into a time-parameterized form and using gradient-based optimization to adjust path parameters. Instead of using complex force vector fields that require evaluating forces at numerous points, the system optimizes a compact set of path parameters (waypoint positions and timing) directly, achieving path optimization while reducing computational requirements through efficient gradient calculations and constrained optimization algorithms.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11833694B2Robot motion planning
Publication Date: 2023.12.05 INTRINSIC INNOVATION LLC
  • US11833694B2 patent drawing
  • US11833694B2 patent drawing
  • US11833694B2 patent drawing

AI summary

Methods, systems, and apparatus, including computer programs encoded on computer storage media, for planning a path of motion for a robot. In some implementations, a candidate path of movement is determined for each of multiple robots. A swept region, for each of the multiple robots, is determined that the robot would traverse through along its candidate path. At least some of the swept regions for the multiple robots is aggregated to determine amounts of overlap among the swept regions at different locations. Force vectors directed outward from the swept regions are assigned, wherein the force vectors have different magnitudes assigned according to the respective amounts of overlap of the swept regions at the different locations. A path for a particular robot to travel is determined based on the swept regions and the assigned magnitudes of the forces.