Multi-Agent Path Planning via Boolean Satisfiability
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Solution Overview
Problem
Existing robotic navigation systems face challenges in efficiently planning and coordinating paths for multiple robotic devices in complex environments, particularly in large warehouses, due to limitations in kinematic and geometric representations, which restrict the movement of robotic devices with varying footprints and directions.
Innovation Solution
The system generates a roadmap graph by smoothing prototype graphs to account for vehicle kinematics, using Euler spirals for track transition curves, and discretizes the roadmap into a discrete planning graph with uniform edge costs, allowing for the representation of conflicts as Boolean equations solvable by SAT solvers, enabling efficient multi-agent path finding and coordination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a roadmap graph is generated by smoothing prototype graphs to account for vehicle kinematics, then the adaptability of robotic devices with varying footprints and directions is improved, but the device complexity increases due to the need for Euler spirals and track transition curves
Solution Approach 1:
The patent replaces complex kinematic and geometric reasoning with a discrete graph representation where edges encode feasible transitions. Instead of continuously representing vehicle kinematics with Euler spirals and track transition curves, the system discretizes the configuration space into nodes and edges, where each edge represents a valid motion primitive. This substitution of continuous mechanical models with discrete graph structures reduces computational complexity while preserving adaptability to different vehicle types.
Solution Approach 2:
The patent changes the representation parameters from continuous kinematic models to discrete graph states. Each node in the discrete graph represents a discretized pose (position and orientation), and edges represent valid transitions between poses. This parameter transformation allows the system to handle varying vehicle footprints and directions by simply updating the discrete transition rules rather than reconfiguring continuous kinematic models.
2Productivity
If the roadmap is discretized into a discrete planning graph with uniform edge costs, then the productivity of path planning is improved through efficient SAT solver execution, but the measurement precision of path costs deteriorates due to uniform cost assumptions
Solution Approach 1:
The patent segments the continuous configuration space into discrete nodes and edges, creating a graph structure that can be efficiently processed. Each edge represents a discretized motion primitive with an associated cost. This segmentation enables the use of SAT solvers and other discrete optimization algorithms that operate on finite state spaces, dramatically improving computational efficiency compared to continuous optimization methods.
Solution Approach 2:
The patent transforms the continuous cost function into discrete edge weights in the graph representation. While this discretization enables efficient computation using SAT solvers and discrete optimization techniques, it introduces quantization effects that reduce the precision of cost representation. The uniform edge cost assumption further simplifies computation but loses information about varying terrain, obstacles, and motion difficulties.
3Productivity
If multiple robotic devices are coordinated using Boolean equations and SAT solvers, then the productivity of multi-agent path finding is improved, but the device complexity increases due to the need for conflict representation and solving mechanisms
Solution Approach 1:
The patent creates a logical copy of the multi-agent pathfinding problem in the form of Boolean variables and constraints. Each possible state and transition for each agent is represented as a Boolean variable, and conflict avoidance requirements are encoded as Boolean constraints. This logical copying allows the use of highly optimized SAT solver algorithms to find conflict-free assignments, achieving efficient multi-agent coordination without implementing complex real-time communication and negotiation protocols between agents.
Data Source
AI summary
Systems and methods related to roadmaps for robotic devices are provided. A computing device can receive a roadmap representing a plurality of paths through an environment. The computing device can discretize the roadmap to obtain a discrete planning graph having a plurality of states corresponding to discretized segments of the plurality of paths of the roadmap such that states corresponding to adjacent discretized path segments are connected in the discrete planning graph. The computing device can determine a Boolean equation representing at least a portion of the discrete planning graph. The computing device can determine a sequence of states from the plurality of states of the discrete planning graph such that the determined sequence of states satisfies the Boolean equation. The computing device can provide a route through the environment for a robotic device based on the determined sequence of states.


