Automation

Automation Design
June/07 Cargo Systems 47 www.cargosystems.net

Project Executive Group

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IT IS HARD to imagine the automotive or food industries without automation, or what the cost of a simple
glass would be if it had to be hand-blown. In manufacturing industries, automation guarantees quality,
productivity, repetitiveness, and control over operations. However, automation is received with reluctance
and doubt in the container industry. Container handling has a lot of similarities with manufacturing.
Repetition and simplicity of tasks within well-defined physical boundaries seem to be appropriate for
automation. Working at a port – with its three shifts, noisy conditions, industrial and polluted areas – is
not the typical boy’s dream. Still, unions fight to the last men to secure their position. Automation in container
terminals has not really taken off. With ECT in the Netherlands (1993), and more recently CTA in Germany
(2002), the breed of fully automated terminals is a rare species. However, things are changing: automation
is being taken more seriously. In many of the terminal design projects, automated handling system
components are considered. Most well-informed terminal operators know that automation will bring
substantial cost savings, and will lead to a predictable and controllable operation.

Is it possible to define the best handling system concept for a medium-sized to large terminal? Is this
possible in a business environment that demands high productivity – berth productivity on mainline
vessels above 150-200 gross moves per hour, and crane productivities of 35 gross moves and beyond – and
suffers from high labour cost, and high societal demands for environmental friendliness, efficient land
utilisation, safety and security? Are these factors key for considering automation? Yes and no. Yes, in the
sense that automation will be easier to sell to risk-averse decision makers when these factors apply, but no
in the sense that there are many other reasons for automation. Otherwise, the hi-tech factories of Philips and
Nokia in China would not exist. Automation offers more, so which handling system concepts are eligible for
implementation in medium to large sized terminals?

It is a good habit to look to the past when designing the future. So what can be learned from the two fully
automated terminals at ECT and CTA? The two terminals are highly successful, proven by their customers.
Both terminals are profitable and are operating at capacity – up to 95% stack density. Their productivity may
not be state-of-the-art, but their cost-efficiency is exemplary, especially when considering their environment.
ECT is operating three terminals on one peninsula with a total of 38 quay cranes, more than 130 automated
stacking cranes (ASCs), and a fleet of 260 automated guided vehicles (AGVs). The annual volume is around
3.5m containers, and the performance is typical for the Hamburg-Le Havre range, where only Antwerp
excels. CTA is smaller, but still a decent size terminal, with 14 quay cranes – 12 of which are semi-
automated double trolley cranes – with 52 ASCs, and around 70 AGVs. As with ECT’s Delta terminals, CTA
operates at capacity, which equals around 1.4m containers. A special feature of CTA is the ASC design,
which consists of two RMGs of different sizes that are able to pass each other. While ECT relies on a single
RMG per stack module, CTA has redundancy built in. What could improve in the design with hindsight?
ECT, now at capacity, could use a second ASC since the With several years worth of data on automated
terminal performance, Yvo Saanen and Joan Rijsenbrij assess the best handling systems available
Which system fits your hub? CTA includes 12 semi-automated double trolley quay cranes ECT includes 130
automated stacking cranes and 260 automated guided vehicles CS June07 p47-51 29/5/07 16:25 Page 47
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utomation Design 48 Cargo Systems June/07 www.cargosystems.net
stacks were heightened (the original design was based on one-over-one high only, and they are now at one-
over-four high), thus allowing for simultaneous waterside and landside operations. Also the AGVs are the
older (slower) types. Finally, the operation between the quay crane legs (in gauge) makes the AGV cycle
longer than at CTA, where hand off takes place in the crane’s backreach. At CTA, the amount of equipment
for high peak operations may be considered too low to achieve high productivity (40+). Since the land is
fully occupied, additional ASCs are not an option. Today’s design on new automated terminals embroiders
on a theme. Systems with separated waterside and landside operations are being looked at, with the storage
area in the middle, operated by ASC perpendicular to the wharf (see Figure 1). So can a definition be made
of the best handling system concept for a medium-sized to large terminal?

The best way to do this is to compare a number of handling systems on their merits, and draw conclusions
form those. However, for specific cases, the best option may be different due to local circumstances,
economic reasons, or just as a result of belief or disbelief in a particular concept. The method of assessment
is based on comparing the different available systems on their productivity-cost ratio under similar
circumstances. Put simply: which system offers the best balance between the operational cost and
performance, while still meeting today’s minimum performance demands, in terms of storage capacity and
handling capacity. In order to answer this question, a definition needs to be made of the circumstances under
which the comparison will take place, as well as the minimum demands.

The first criterion is that the terminal is medium to large – with an end capacity of 2m teu upwards. As a
state-of-the-art terminal, it will be equipped with 10 quay cranes only, which should be capable of running at
least 4,000 hours per year. Berth productivity demands should be a minimum of 200 moves per hour – with
five or six cranes – in order to sustain the coming 10-20 years. This translates back to minimum gross crane
productivities of 35 moves per hour. By gross, this includes all delays between the start and end of the
operation. Adding up all productive crane hours, this easily exceeds 2m teu, assuming a teu factor of 1.6.
The berth length equals 1km, and the available space for stacking equals 1km x 500m (50ha) – a nice and
rectangular terminal, typical for a reclaimed area. Another important factor for terminal design is the
transhipment rate, which is tricky because it may be difficult to predict. In order to find the most robust
systems, it is necessary to analyse the handling systems under different transhipment ratios, The
transhipment ratio determines to a large degree the peak handling demands at waterside and landside –
respectively the demand from vessel and gate/rail traffic. In this particular case, gate traffic is only
accounted for. Based on typical conditions, it is necessary to define the following relation between the
transhipment ratio and the peaks at the landside. The methodology consists of two main tools: dynamic
simulation to analyse the productivity under realistic operational conditions; as well as cost analysis,
translating productivity and working hours into operational costs and investments. The simulation is compiled
of two parts: the yard handling systems are compared by analysing a single stack module under maximum
workload (always a job available); the transport systems are compared under typical peak conditions in
a terminal.

Figure 1: Snapshot from the layout from quay wall until first container; this area has
been kept the same for all systems

Figure 2: Relationship between transhipment ratio and peak demand at the landside in total for a terminal
with a waterside volume
of 2m teu. The load per stacking module then depends on the number of modules.

Landside moves at maximum volume (per hour)
0 10 20 30 40 50 60 70 80 90 100
Transhipment percentage
Landside container moves in peak conditions bx/h)
600
500
400
300
200
100
0
Volume: 2m teu
Peak factor: 1.15
Teu factor: 1.6
19% of weekly volume on peak day
10% of daily volume in peak hour

Both simulations will be conducted under varying transhipment ratios – varying balances between waterside
and landside demand. The final step of the comparison is the cost analysis, which consists only of the
discriminating factors, all other things being equal. The cost analysis also has two parts: first, the investment
side, then the operational cost side. Both should be assessed in conjunction, although the risk averse among
us, focus on the first and the pay back or NPV method only. The life span of a terminal is at least 20 years,
so the operational costs have more weight than the short-term oriented NPV. Both have been applied to get
the complete picture.
T
he operational cost consists of running costs (energy and maintenance), capital costs and depreciation.
Labour costs mainly differentiate the automated transportation systems and the manned ones. The
considered alternatives:stacking systems Three contenders have been identified, all of which are
ASCs, and all of which will shortly be deployed or have already been deployed in real operations.

The three options are: the twin-ASC (scheduled for Rotterdam’s forthcoming Euromax terminal, and the first
four units are now operating at Antwerp Gateway); the crossover twin-ASC (now operating at Hamburg’s
CTA); and the crossover tri-ASC (being installed now at Hamburg’s CTB). The single-ASC, (operating
at ECT) has not been included since it is important to have redundancy in the system.

It is assumed that all small cranes can potentially run at the same speeds, acceleration and deceleration (for
gantry, trolley, and hoist), although individual suppliers may claim differently, or choose differently. The large
cranes are slower because of their dimensions. All concepts span 10 containers wide, five high and 40teu
long, giving a stacking capacity of 2,000teu per block. The width of the twin-ASC is 35 metres and the cross-
over ASCs are 42.5 metres wide (the additional space being necessary for the cross-over functionality).
The interchange zones are similar in terms of design, all equipped with an interchange for AGVs at the
waterside (five lanes), and for road trucks/terminal trucks at the landside (five lanes). The considered
alternatives:

transportation systems

Although the market for automated transportation equipment is still small – in comparison with the market for
manned equipment – there are various systems on the market. Not all are proven yet – a major
requirement from many operators – but they are available for a conceptual battle on similar terms.
The following options are available:
The good old AGV (Gottwald), currently running in Rotterdam and Hamburg. The diesel-electric version has
been used.
The automated shuttle/straddle carrier (Kalmar) currently running in Brisbane.
The cassette AGV (TTS, diesel-hydraulic), not yet operational, but several trials in ports have been
conducted. This AGV carries cassettes around, and is able to drop and pick-up cassettes by itself.
The lift AGV (Gottwald, also diesel-electric), based on the existing AGV but with the possibility to pick-up and
drop a container by itself at the interchange of the ASC. This concept allows mixing with existing fleets of
AGVs, as the machines are almost identical, apart from a lifting platform on top of the AGV.
The manual shuttle carrier (Kalmar, Noell); a one-over-one straddle carrier, which will soon be running in
several places (Antwerp, Norfolk), and currently in operation in Southampton.
The tractor-trailer has been left out, although feasible, since it has quite similar characteristics to an AGV –
coupled interchange at ASC and quay crane.

The five alternatives have been compared under similar operational conditions: an operation with 10 quay
cranes (single trolley, single hoist) and 25 stacking modules, equipped with twin-ASCs. Each handling
system has been tuned to utilise its capabilities to the full extent – decoupling and usage of the buffers at the
stacking crane, efficient placing of empty cassettes, efficient job dispatching of transportation vehicles and
stacking cranes.

The cassette AGV and the lift AGV do not decouple at the quay crane. Although being an opportunity, there
was a greater need for empty cassette transportation, only decreasing performance when decoupling
at the quay crane. The lift AGV requires platforms where the containers can be placed, and these would have
to move with the quay crane, which was considered too complex in practice. Of course, all systems
apart from the traditional AGV decouple at the ASC transfer point.

Comparison of ASC systems

In order to determine the maximum capability of a single stack module, a model was created in which there
is a continuous demand from the waterside (on average 50% loading, 50% discharge), generated by two
quay cranes. The waterside transportation is executed by means of AGVs. As the number is sufficient, there
is no waiting time of the ASC for horizontal transportation. The landside demand is varied, to represent the
different types of cargo flows, from true transhipment – for which this terminal layout is certainly not meant,
a parallel layout would be more appropriate – to 100% import/export. In all scenarios the landside ASCs are
allowed to support the waterside ASCs.

In the cross-over scenarios, the large ASC can actually access the interchange zone, in the twin
configuration, the landside ASC can only pre-position the export containers closer to the waterside. Of
course, the busier the landside ASCs get (with an Main properties of the stacking cranes
Twin ASC Cross twin ASC Cross tri ASC
Both Large Small Large Small
Gantry speed 4 m/s 3 m/s 4 m/s 3 m/s 4 m/s
Gantry acc/dec 0.35m/s2 0.35m/s2 0.35m/s2 0.35m/s2 0.35m/s2
Hoist speed 36-72m/min 36-72m/min 36-72m/min 36-72m/min 36-72m/min
Hoist acc/dec 0.35m/s2 0.35m/s2 0.35m/s2 0.35m/s2 0.35m/s2
Maximum height 17.8 metres 21.7 metres 17.8 metres 21.7 metres 17.8 metres
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Automation Design
50 Cargo Systems June/07 www.cargosystems.net
increase of landside demand),
the lesser the ASCs can support
the waterside.
In the configuration with
three ASCs, the small landside
ASC only does landside moves
(shuffles and productive moves),
and the large ASC can support
both waterside and landside.
The job assignment is a
critical component in order to
make each of these three
configurations productive.
It considers empty travelling
(which should be avoided), job
urgency (sequence), and tries to
use idle time for pre-productive
moves.
Another important control
component is the conflict
avoidance and the passing
algorithm for the cross-over
ASCs. When to pass and when
to wait is a delicate issue. For
more information regarding
the actual decision-making,
refer to Saanen and Valkengoed
(2006).
What it does boil down to is
shown in Figure 3, where the
productivity of each
configuration is shown
dependent on the landside
demand. In addition, shuffle
moves and pre-position moves
have been executed, but they
are not shown in the graph.
What can be concluded from
Figure 3?
First, that per stack module
the tri RMG is the most
productive in all cases.
However, the contribution
of the third crane is at best two
productive moves per hour
compared with the twin RMG.
The twin cross-over RMG
outperforms the twin RMG by a
maximum of 1.2 moves per hour
(in case of 100% transhipment).
In the range of 55-70%
transhipment they are almost
equal, and below 50%
transhipment the twin RMG
delivers higher productivity per
stack module. Were the
performance of the twin RMG
corrected for the lesser width
(15%), the twin RMG would be
the best performing one. This
would be important in case the
width of the terminal is a
limiting factor.
When translating these
figures into performance under
peak conditions in a terminal,
these values cannot be used,
because the utilisation per stack
module varies in time, and
therefore the performance under
maximum workload is typically
much higher than under entire
terminal conditions – and here
most static calculations fail.
In Figure 4 the main result of
the comparison of
transportation systems can be
seen: the quay crane
productivity depending on the
number of vehicles deployed.
In all cases, there was global
pooling of vehicles, allowing
empty travel to be minimised.
This is obvious for the
automated equipment types, less
obvious for the manned
Figure 3: Comparison of productivity of a single stack module in combination with AGVs under maximum
load waterside, and a
varying load landside. There is always an AGV available. The results are almost similar for the combination
with shuttle carriers.
Figure 4: Net QC productivity for each transportation system, depending on the number of vehicles
Number of container moves landside
Productive moves per hour all cranes
Transhipment ratio
RMG: Productive moves all cranes
100% 85% 70% 55% 40% 25% 10%
40
35
30
25
20
0 3 6 9 12 15 18
Twin
Dual (Large LS+WS)
Tri (Large LS+WS)
QC productivity – vehicle comparison
[10 QCs@45 ccph, 25 Twin RMG modules, 350 landside bx/h]
Productivity (bx/hr)
Total number of vehicles available
15 20 25 30 35 40 45 50 55 60 65 70 75
50
45
40
35
30
25
20
15
10
5
0
AGV
ShC
AGV–Lift
ALV
C-AGV
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Automation Design
June/07 Cargo Systems 51 www.cargosystems.net
machines.
The maximum achievable
productivity is approximately 45
container moves per hour,
starting with an average cycle
time of the quay cranes of 80
seconds, and 85 seconds when
operating in backreach (only in
case of the manned shuttle
carriers).
What can be concluded from
Figure 4?
First of all, that all systems
can deliver a similar productivity
by deploying sufficient vehicles,
and in case of adequate control
software. So the perception that
automated systems cannot
deliver the same productivity as
manually driven machines, is
not true – it requires more
vehicles though.
The second conclusion is
that the effect of decoupling is
considerable: when just
comparing the traditional AGV
with the lift-AGV, a
performance increase of up to
30% can be observed, or a
reduction of vehicles (at
comparative performance) of up
to 50% (at 40 boxes per hour).
The cassette AGV also
shows an improvement
compared with the AGV, but
less so, as a result of the empty
cassette moves (the average
driving distance per container is
almost 40% higher).
Also the process at the quay
crane takes quite long due to the
necessity to lower the cassette
onto the ground to avoid impact
loads on the vehicle.
Another study showed that
in case of more transfer points at
the quay crane (four instead of
the two used in this study) the
latter effect could be minimised.
However, more than two
transfer points are not feasible in
case of larger crane clusters, as
used in this study (up to seven
cranes in one cluster). The only
systems with three transfer
points per quay crane are the
shuttle carriers, manned and
automated.
Finally: what is needed to
achieve 40 boxes per hour? In
this particular terminal setting,
27 manned shuttle carriers
(pooled), 30 automated shuttle
carriers, 33 lift AGVs, 50
cassette AGVs and 65 AGVs.
The cost analysis departs from
a few assumptions:
The labour cost per
operating man-hour are
assumed to be t40 and the cost
of fuel t0.80 per litre. The
prices of the vehicles (including
platforms for the lift-AGVs and
cassettes for the cassette-AGVs)
are:
AGV: t380,000
Lift-AGV: t500,000
Cassette-AGV: t565,000
Automated shuttle carrier:
t960,000
Manned shuttle carrier:
t480,000
The fuel consumption for
the various vehicles (which
determine to a large extent the
operating cost per hour) is also
a result from the simulation,
based on the engine
characteristics.
Also considered are the
additional investments in
software required for the
automated systems (up to t2.3m
additionally). Capex and Opex
are shown in Figure 5.
What can be concluded?
First of all, all automated
systems are obviously less
expensive than the manned
alternative, even considering the
higher capital expenses.
This means that the
additional investment for an
automated system (ranging
from t7m for the lift-AGV to
t19m for the automated shuttle
carrier) will be earned back in
two (lift-AGV) to five years
(automated shuttle carrier).
Secondly, the least
interesting automated system,
despite its capability to fully
decouple is the automated
shuttle carrier, mainly due to its
high price, and relatively high
maintenance costs.
There is still a lot of ground
to cover for fully automated
terminals. However, with the
lessons learned from past
implementations (lack of
decoupling, little software
robustness, equipment
specifications), the case for
automated terminals is strong.
Economically, there is no
question that full automation
pays off in a short period of time.
Performance-wise, automated
systems require more equipment,
but they can achieve similar
performance levels as manned
equipment. Prerequisite is
intelligent, flexible and robust
software, which has to be proved
in practice yet.
Finally, what about the social
impact of automation? Yes, in
direct labour, jobs will be lost, or
more moves per labour hour will
be moved. On the other hand, it
requires more intelligence in the
construction and maintenance of
equipment and software, also
creating more interesting jobs.
Furthermore, can the
automotive industry be thought
of without automation? So, in
order to stay competitive,
automation in yard handling and
horizontal transportation needs
to be considered, and balanced
against other interests.
Dr Yvo Saanen is MD of
consultancy firm TBA, and Joan
Rijsenbrij is professor in large scale
transportation systems in the
faculty of mechanical, maritime
and materials engineering at the
Delft University of Technology
Figure 5: CAPEX to purchase the transportation equipment to support 10 quay cranes at a peak berth
productivity of 400 boxes per
hour. Yearly OPEX of operating this fleet of equipment, including labour cost, running costs, maintenance and
capital costs at an
interest rate of 7%.
Shuttle carrier
Yearly Expense (m t)
Investment (m t)
Automated shuttle
carrier
Lift AGV Cassette AGV AGV (diesel electric)
Handling system
20
15
10
5
0
Yearly expense
t15m
t9.2m
t6.6m
t30m
t39m
t9.5m
t8.2m
t35m
t42m
t23m
Investment
200
150
100
50
0
Comparison of yearly expenses/investment quay transport
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