Safe-Point Routing Pattern for Deadlock-Free Carrier Transport
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Solution Overview
Problem
Existing laboratory sample distribution systems face challenges with deadlock problems and suboptimal performance, particularly due to carriers blocking each other on the transport plane.
Innovation Solution
The method involves defining a global pattern of safe points on the transport plane, independent of module boundaries, and calculating partial routes for carriers such that they can only stop at safe points and have a free path to the next safe point, preventing deadlocks and enhancing system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If carriers are allowed to move freely on the transport plane without restricted stopping positions, then the flexibility and speed of carrier movement is improved, but deadlock problems occur where carriers block each other
Solution Approach 1:
The transport plane is segmented into discrete logical positions forming a grid, with specific positions designated as safe points where carriers can stop. This segmentation restricts carrier stopping to predefined locations, preventing deadlocks while maintaining movement flexibility.
Solution Approach 2:
Safe points act as intermediary positions between carriers' movement paths. By requiring carriers to stop only at these designated safe points, the system mediates carrier interactions to prevent blocking scenarios while maintaining efficient transport flow.
2Reliability
If a global pattern of safe points is defined independently of module boundaries, then deadlock prevention is improved, but the complexity of route calculation increases
Solution Approach 1:
The global safe point pattern serves multiple functions: it prevents deadlocks across the entire transport plane, works independently of module boundaries to provide universal applicability, and simplifies route calculation by providing consistent stopping positions throughout the system.
Solution Approach 2:
The safe point pattern merges the deadlock prevention function with the route calculation system. By integrating safe points into the global routing logic, the system achieves reliable deadlock prevention without adding separate complex control mechanisms.
3Reliability
If carriers must stop only at safe points with guaranteed free paths, then system reliability and deadlock prevention are improved, but the flexibility in route selection is reduced
Solution Approach 1:
Safe points are predetermined and pre-configured on the transport plane before carrier movement begins. The routing system pre-calculates paths between safe points, ensuring that carriers always have access to reliable stopping positions while maintaining route flexibility through multiple possible safe point combinations.
Data Source
AI summary
A method of operating a distribution system having carriers that carry objects and a transport plane supporting the carriers. A grid of logical positions is defined on the transport plane and a drive system moves the carriers between the logical positions. A router calculates routes for the carriers and applies a global pattern of safe points on the transport plane. Safe points are logical positions selected based on a range of motion for a carrier occupying the logical position, such that on the safe points a carrier can be placed and then moved away. The global pattern is applied onto the transport plane independently of module boundaries. Partial routes for the carriers are calculated so that an end position of each partial route is either a safe point or has a free path to a safe point to be reachable in the next partial route using the router.