Rescheduling Unit for Automated Rail-Mounted Gantry Cranes
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Solution Overview
Problem
Existing container terminal systems with non-passing automated rail-mounted gantry cranes face inefficiencies in throughput due to interference and workload imbalances, requiring substantial changes to address these issues.
Innovation Solution
A rescheduling unit is introduced to split work orders into new ones with intermediate positions, optimizing crane trajectories and workload distribution between cranes, allowing for dynamic rescheduling during execution without altering the existing terminal system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If non-passing automated rail-mounted gantry cranes operate on the same rail, then space utilization is improved, but interference between cranes increases and throughput decreases
Solution Approach 1:
The patent segments the continuous rail into discrete zones or positions that cranes can occupy. By dividing the operational space into manageable segments, the system can allocate specific zones to individual cranes, reducing interference while maintaining high space utilization. This segmentation allows for structured coordination and reduces random conflicts between cranes operating on the same rail.
Solution Approach 2:
The patent implements dynamic work order adjustment and crane assignment based on real-time system state. Rather than static allocation, the system continuously adapts crane positions, speeds, and task assignments to optimize throughput. This dynamic approach allows cranes to coordinate their movements and operations in real-time, minimizing interference while maintaining high productivity.
2Device complexity
If work orders are executed using first-come-first-served strategy, then system simplicity is maintained, but waiting times increase and workload imbalance occurs
Solution Approach 1:
The patent performs preliminary analysis and optimization of work orders before execution. The system pre-processes incoming work orders, predicts potential conflicts, and adjusts assignments in advance. This preliminary action allows the system to avoid waiting times and workload imbalances proactively, rather than reacting to problems as they occur during execution.
Solution Approach 2:
The patent implements feedback mechanisms where crane status, position, and workload information are continuously monitored and fed back to the control system. This feedback enables dynamic adjustment of work order assignments to balance workload and reduce waiting times while maintaining relatively simple system architecture through automated decision-making.
3Productivity
If crane trajectories are optimized to reduce interference, then throughput increases, but system complexity increases
Solution Approach 1:
The patent segments the rail into discrete positions and assigns cranes to specific segments, simplifying trajectory optimization. By working with discrete segments rather than continuous positions, the system reduces computational complexity while still achieving effective interference reduction and maintaining high throughput.
Solution Approach 2:
The patent optimizes trajectory parameters such as crane speed, position, and timing to reduce interference. By adjusting these parameters within a structured framework rather than redesigning the entire control system, the patent achieves throughput improvement with minimal increase in system complexity.
Data Source
AI summary
A system and a method for controlling at least two automated non-passing rail mounted gantry cranes (3a, 3b, 3c) are described. The system comprises for each of the cranes a crane control unit (2a, 2b, 2c) for ensuring execution of at least one work order (10a, 10b, 10c) received by the respective crane from an external scheduling system (9). In order to improve the crane efficiency, the system further comprises a rescheduling unit which performs a rescheduling of the at least one work order based on an expected trajectory along the rail (4a, 4b) determined for each work order. The rescheduling is achieved by splitting at least one of the work orders into at least two new work orders and by re-sequencing and reallocating the resulting work orders so as to reduce the number or duration of situations, where the expected trajectory of one crane blocks the expected trajectory of another crane and/or to reduce a workload imbalance between the cranes. The rescheduling unit operates in parallel with the crane control units (2a, 2b, 2c), i.e. during execution of the original work orders, and dynamically updates these original work orders.