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Hierarchical Control of Equipment
in Automated Container Terminals
Jianbin Xin, Rudy R. Negenborn, and Gabriel Lodewijks
Delft University of Technology, Marine and Transport Technology
Transport Engineering and Logistics,
Delft, The Netherlands
{
j.xin,r.r.negenborn,g.lodewijks
}
@tudelft.nl
Abstract.
The performance of container terminals needs to be improved
to adapt the growth of handled containers and maintain port sustainabil-
ity. This paper provides a methodology to improve the throughput of the
container terminal in an energy-ecient way. The behaviors of equipment
are considered as consisting of a higher level and a lower level represent-
ing discrete-event dynamics and continuous-time dynamics, respectively.
These dynamics need to be controlled. For controlling the higher level dy-
namics, a minimal makespan problem is solved. For this, the minimal time
required for carrying out a task at the lower level is needed. The minimal
time for carrying out a task at the lower level is obtained by Pontryagin's
Minimum Principle. The actual operation time, allowed by the higher level
for completing a task by one piece of equipment at the lower level, is de-
termined by the scheduling algorithm at the higher level. The lower level
dynamics are controlled using optimal control to achieve the minimal en-
ergy consumption when the operation time allowed is given. A simulation
illustrates how energy-ecient management of equipment for the minimal
makespan could be obtained by the proposed methodology.
Keywords:
Optimal control, hierarchical control, container terminals,
energy consumption.
1 Introduction
Over the last decades, there has been a significant growth of global freight trans-
port due to the enormous commercial trade. Over 60% of worldwide deep-sea
cargo is transported by containers [12]. The management of freight transport
needs to accommodate this increasing demand of containers. Intermodal trans-
port [5] is hereby considered frequently since it provides flexibility and scalability
as different transport modalities can cover different areas with respect to trans-
port distance. As an intermodal transport hub, a container terminal represents
the interface among the modalities of vessel, barge, train and truck. Therefore,
container terminals play a crucial role in freight transport.
The increasing amount of containers that arrive and depart with container
ships provides much pressure for terminal operators. The throughput, i.e., the
