Tree Search Scheduling Method for Manufacturing Operations
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Solution Overview
Problem
Current scheduling systems for manufacturers, such as those for semiconductors and electronics, are either too expensive or fail to provide accurate scheduling in a reasonable time, especially as the scale of operations increases.
Innovation Solution
A tree search-based scheduling method that uses multiple dispatching rules simultaneously, allowing for customizable scheduling by selecting rules from a library based on specific goals, such as minimum total completion time, and performs scheduling level by level to reduce erroneous scheduling and meet user needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If exact method (branch and bound) is used to obtain the best scheduling solution, then scheduling quality is improved, but processing time increases extremely long
Solution Approach 1:
The patent segments the scheduling problem into multiple levels of decision-making. The tree search algorithm divides the search space into hierarchical levels where each level represents a stage in the scheduling process, allowing the system to explore solutions systematically without examining every possible combination, thus reducing processing time while maintaining solution quality.
Solution Approach 2:
The patent changes the search parameters by implementing a tree search structure with configurable depth limits and pruning criteria. By adjusting search depth, node expansion rules, and cutting conditions, the system can balance between solution optimality and processing time based on specific scheduling requirements.
2Productivity
If dispatching rule (G&T algorithm) is used to complete schedule in short time, then processing time is reduced, but scheduling quality becomes unsatisfactory
Solution Approach 1:
The patent performs preliminary actions by pre-calculating and storing scheduling rules and parameters in a rule library before the actual scheduling execution. During scheduling, the system retrieves and applies pre-prepared rules rather than computing everything from scratch, which speeds up processing while maintaining solution quality through systematic rule application.
Solution Approach 2:
The patent introduces an intermediary tree search structure that mediates between the dispatching rules and the final schedule. The tree search acts as an intermediary mechanism that systematically evaluates and selects among multiple dispatching rules, combining their advantages while mitigating individual weaknesses to achieve both speed and quality.
3Manufacturing precision
If metaheuristic search method (genetic algorithm) is used for smaller scale problems, then scheduling quality is improved, but processing time increases significantly as scale increases
Solution Approach 1:
The patent implements a dynamic search strategy where the tree search parameters (depth, node expansion rate, pruning thresholds) are adjusted dynamically based on the problem scale and complexity. For larger scale problems, the system automatically adjusts parameters to reduce search intensity, maintaining acceptable solution quality while adapting processing time to the problem size.
Solution Approach 2:
The patent applies partial search action by implementing cutting conditions that limit the search to the most promising portions of the solution space. Rather than exhaustively searching all possibilities, the system performs partial searches focused on high-probability regions, achieving satisfactory solutions without the exponential time cost of complete search.
4Measurement precision
If multiple dispatching rules are used simultaneously, then scheduling accuracy is improved, but system complexity increases
Solution Approach 1:
The patent merges multiple dispatching rules into a unified tree search framework. Instead of running separate algorithms for each rule, the system combines them within a single hierarchical search structure that systematically evaluates and integrates the strengths of multiple rules, improving accuracy while managing complexity through unified control.
Solution Approach 2:
The patent creates a universal tree search platform that can accommodate multiple dispatching rules and scheduling objectives. The same core algorithm structure handles different rules by adjusting parameters and search strategies, providing multi-functionality without requiring separate complex systems for each rule type.
Data Source
AI summary
A tree search-based scheduling method and an electronic apparatus are provided. In the method, multiple order lists are received and a schedule is initialized, wherein each order list includes multiple production operations. In each order list, a first production operation which has not been joined into the schedule yet is selected, such that multiple prior operations are selected. An execution priority of the prior operations is calculated according to multiple dispatching rules, and multiple candidate operations are selected from the prior operations according to the execution priority. Afterwards, the candidate operations are listed as a next operation of the schedule respectively, and a scheduling simulation is performed according to the dispatching rules to obtain multiple scheduling indicators of the candidate operations. Scheduling is performed according to the scheduling indicators.