Multi-Robot Trajectory Planning Using Sweeping Space Obstacles
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Solution Overview
Problem
Existing robot trajectory generation methods face challenges in preventing overlap between the passing regions of multiple robot arms, especially when operation speeds or timing control shifts in a real environment, leading to potential interference and requiring significant calculation resources.
Innovation Solution
A method that generates operation instruction lists with trajectory definition data for starting and ending points, determines a trajectory generation order, and registers sweeping spaces as obstacles to avoid overlaps, allowing robot arms to operate without relying on precise timing or speed control, thereby reducing overlap risks and enabling high-speed trajectory generation even with low-speed control devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If path generation algorithms (RRT, PRM) are used to automatically generate trajectories, then the burden of teaching operation is reduced and paths can be recalculated quickly, but the calculation resources required increase significantly
Solution Approach 1:
The patent segments the trajectory generation process into two distinct phases: an offline planning phase that computes complete interference-free paths using algorithms like RRT or PRM, and an online execution phase that simply follows the pre-computed trajectories. This segmentation allows complex calculations to be performed when computational resources are abundant (offline), while runtime execution requires minimal calculation resources.
Solution Approach 2:
The patent performs preliminary trajectory planning and interference checking before actual robot operation begins. By pre-calculating complete trajectories that guarantee no interference between multiple robots, the system eliminates the need for complex real-time collision detection and adjustment during execution, thereby reducing online calculation resource requirements.
2Reliability
If priority order and occupied region calculation methods are used to avoid interference, then robot operations can be coordinated, but the system complexity and calculation load increase
Solution Approach 1:
The patent calculates complete trajectories for all robots in advance, determining their full paths through the working space before execution. This preliminary planning ensures that interference-free operation is guaranteed without requiring complex real-time coordination, priority arbitration, or dynamic occupied region tracking during operation.
Solution Approach 2:
The patent extracts the complex interference avoidance calculations from the real-time control loop and places them in the offline planning phase. By separating path planning from execution, the system removes the burden of complex interference checking from the runtime control system, simplifying the real-time control architecture.
3Reliability
If synchronized control with timing adjustment is used to prevent overlap, then interference can be avoided, but the system requires precise timing control and becomes more complex
Solution Approach 1:
The patent determines the complete trajectories of all robots in advance, including their temporal evolution, before execution begins. By pre-planning the timing and sequence of operations for multiple robots, the system guarantees interference-free operation without requiring complex synchronized control mechanisms or real-time timing adjustments during execution.
Solution Approach 2:
Instead of controlling robot speeds and timings during execution to avoid interference, the patent inverts the approach by pre-calculating complete trajectories that inherently avoid interference. The control system then simply follows these pre-determined paths without needing complex timing synchronization or speed adjustment mechanisms.
Data Source
AI summary
An operation instruction list including starting points and ending points of trajectories of a plurality of robot arms is generated (a trajectory definition data generation process). Order of generation of trajectories is determined in accordance with the operation instruction list (a generation order determination process). A trajectory of a specific robot arm included in the operation instruction list is generated in accordance with a starting point and an ending point such that the trajectory avoids obstacle spaces registered in the obstacle memory when trajectories of other robot arms are generated (a trajectory generation process). A sweeping space in which a structure of the arm sweeps when the robot arm is operated along the generated trajectory is added to the obstacle memory as an obstacle space to be avoided by the other robot arm (an obstacle registration process).