Design and Implementation of a Horizontal Transportation Simulation Model
Porras, Tomi (2021)
Porras, Tomi
2021
Automaatiotekniikan DI-ohjelma - Master's Programme in Automation Engineering
Tekniikan ja luonnontieteiden tiedekunta - Faculty of Engineering and Natural Sciences
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Hyväksymispäivämäärä
2021-05-18
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tuni-202104263566
https://urn.fi/URN:NBN:fi:tuni-202104263566
Tiivistelmä
The large volume of container traffic handled by the world’s container terminals requires more and more efficient operation. In this thesis, a simulation model for horizontal transportation (HT) is designed and implemented with MATLAB Simulink. HT operation covers the container handling between terminal quayside, terminal yard, and landside. In this thesis, HT is performed by straddle carriers (SCs), which can pick, ground and stack containers without other cranes. The model produces data regarding per crane productivity in the yard, as well as path-planning information.
The implemented simulation model is composed of the kinematic model of a SC controlled by a horizontal transportation manager (HTM). The modelled SCs can move realistically along the terminal yard and perform the necessary HT operation. The implemented HTM creates a lane system that connects distinct terminal yard areas together, and assigns picking and grounding jobs for the operational SCs. The HTM also handles the path-planning operation with a graph-based path-planning algorithm, to optimize the HT operation.
The kinematics of the SCs are implemented as a discrete time model and the HTM as an event-driven control logic. The model is designed and implemented according to extensive requirement analysis and is verified by the same requirements. The model’s realism is validated by simulating a SC in operation and comparing the results to values found in literature. The validation and verification prove that the implemented model can represent HT operation realistically enough. According to simulations the average per crane productivity was approximately 24 moves per hour. When the terminal yard was populated with more operational SCs, the per crane productivity started to diminish and collisions caused by other SCs increased. The implemented model lacked a complete collision avoidance system, and as such the complete effect on productivity caused by increasing number of operational vehicles could not be recorded.
Along with the limitations provided by the lack of collision avoidance, the implemented model also suffers from less-than-optimal job sequencing algorithm. The decrease in productivity caused by increasing number of SCs can be largely attributed to the unevenly distributed jobs among the operating fleet. For the model to be used for extensive HT productivity analysis, the job sequencing algorithm should be changed to a more sophisticated to manage the fleet more optimally. For realistic simulation, the collision avoidance system is required for the implemented model to produce results comparable to real-life systems.
The implemented simulation model is composed of the kinematic model of a SC controlled by a horizontal transportation manager (HTM). The modelled SCs can move realistically along the terminal yard and perform the necessary HT operation. The implemented HTM creates a lane system that connects distinct terminal yard areas together, and assigns picking and grounding jobs for the operational SCs. The HTM also handles the path-planning operation with a graph-based path-planning algorithm, to optimize the HT operation.
The kinematics of the SCs are implemented as a discrete time model and the HTM as an event-driven control logic. The model is designed and implemented according to extensive requirement analysis and is verified by the same requirements. The model’s realism is validated by simulating a SC in operation and comparing the results to values found in literature. The validation and verification prove that the implemented model can represent HT operation realistically enough. According to simulations the average per crane productivity was approximately 24 moves per hour. When the terminal yard was populated with more operational SCs, the per crane productivity started to diminish and collisions caused by other SCs increased. The implemented model lacked a complete collision avoidance system, and as such the complete effect on productivity caused by increasing number of operational vehicles could not be recorded.
Along with the limitations provided by the lack of collision avoidance, the implemented model also suffers from less-than-optimal job sequencing algorithm. The decrease in productivity caused by increasing number of SCs can be largely attributed to the unevenly distributed jobs among the operating fleet. For the model to be used for extensive HT productivity analysis, the job sequencing algorithm should be changed to a more sophisticated to manage the fleet more optimally. For realistic simulation, the collision avoidance system is required for the implemented model to produce results comparable to real-life systems.