Continuous Caster Scheduling Using Search Trees for Slab Grouping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional caster scheduling systems fail to achieve an optimal solution for grouping slabs due to the inability to effectively handle slabs shared by different groups, leading to suboptimal daily schedules in steel processing.
Innovation Solution
A method and system that utilize a search tree with priority queues to find an optimal scheduling sequence by grouping compatible orders into scheduling units, where each node represents a scheduling unit formed from a priority queue, and each path through the tree represents a sequence of orders with an associated priority score, allowing for the identification of the highest-priority path as the optimal schedule.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional bottom-up scheduling systems are used to determine smaller scheduling units first, then the scheduling process is simplified, but the solution fails to reach optimal grouping of slabs in a charge when slabs may be shared by different groups
Solution Approach 1:
The patent inverts the conventional bottom-up scheduling approach by implementing a top-down method. Instead of first determining small scheduling units (charges) and then forming larger units (casts), the system first identifies optimal cast sequences and then determines the charges within each cast. This inversion allows slabs to be properly shared across different charge groups while maintaining scheduling simplicity, thereby resolving the contradiction between process simplicity and grouping optimality.
2Ease of operation
If fixed grouping of slabs in a charge is predetermined, then the scheduling process becomes more straightforward, but optimal solutions cannot be achieved for slabs that may be shared by different groups
Solution Approach 1:
The patent implements dynamic charge grouping within the top-down scheduling framework. Instead of fixing slab groupings in advance, the system dynamically determines which slabs belong to which charges based on the optimal cast sequence and real-time compatibility constraints. This dynamic approach maintains operational simplicity while achieving optimal productivity by allowing slabs to be flexibly assigned to different charge groups as needed.
3Use of energy by moving object
If weekly schedules are used for caster processing optimization, then computational resources are reduced, but monthly capacity plans cannot be effectively supported for order due dates
Solution Approach 1:
The patent segments the scheduling problem into hierarchical levels: monthly capacity planning, weekly optimization schedules, and daily charge sequences. The top-down approach generates an optimal monthly/weekly cast sequence that serves as a framework, then fills in detailed charge assignments. This segmentation allows the system to support long-term monthly plans with minimal computational resources while maintaining the ability to meet order due dates through the structured hierarchical decomposition.
Data Source
AI summary
Methods and systems for scheduling include implementing a schedule based on a path in a search tree having an optimal associated priority score. Each node in the search tree represents a scheduling unit formed from a priority queue that includes orders from multiple mutually compatible sets of orders. Each path through the search tree represents a sequence of orders and has an associated priority score.