Journal of Robotics, Networking and Artificial Life, Vol. 4, No. 4 (March 2018) 334-337___________________________________________________________________________________________________________Development of Auto-Stacking Warehouse Truck
Kuo-Hsien Hsia, Ming-Guang Wu, Jun-Nong Lin, Hong-Jie Zhong, and Zh-Yao Zhuang

Department of Electrical Engineering, Far-East University, Taiwan
Tainan, 74448, Taiwan (R.O.C.)
E-mail: khhsia@mail.feu.edu.tw
www.feu.edu.tw

Abstract
Warehouse automation is a very important issue for the promotion of traditional industries. For the production oflarger and stackable products, it is usually necessary to operate a fork-lifter for the stacking and storage of the products
by a skilled person. The general autonomous warehouse-truck does not have the ability of stacking objects. In thispaper, we develop a prototype of auto-stacking warehouse-truck that can work without direct operation by a skill
person. With command made by an RFID card, the stacker truck can take the packaged product to the warehouse on
the prior-planned route and store it in a stacking way in the designated storage area, or deliver the product to theshipping area or into the container from the storage area. It can significantly reduce the manpower requirements ofthe skilled-person of forklift technician and improve the safety of the warehousing area.
Keywords: Warehouse automation, Stacking truck, Autonomous warehouse truck, RFID.

able to evolve to unmanned factories, it is usually stillnecessary to manually drive a forklift truck from factory
to warehouse or from warehouse to delivery, to inboundand outbound delivery of the warehouse, etc. to carry out
stacking and picking operations. To drive a stacker
requires professional training. In Taiwan, a technician
license (Technician for fork lift operation) with theMinistry of Labor is required to qualify for driving astacker. In addition, where people work, they must also
cooperate with lighting, air circulation, and various
conditions of work safety. Therefore, if it is not necessary
to work with manpower, then the cost of lighting and air
conditioning can be saved and the space can be used more
effectively. Hence many researchers have invested instorage automation research. Many logistics providers
also include warehouse automation as one of the mostimportant work items available today.
Giordano et. al considered a matrix-based discrete event
control approach for a warehouse [1]. Xie et al use RFID
(radio frequency identifier) and wireless sensor network

1. Introduction
The industrial automation has been developed for morethan 60 years. It includes manufacturing automation,
warehouse automation, and logistics automation. No
matter in which one of these automations, robots always
play an extremely important and crucial role in theindustrial automation. For the manufacturing industry,
object movement is always inevitable in the process ofpurchasing of raw materials or components, loading ofmaterials, assembling the parts, and packing or shipping
the finished products. A conveyor belt is usually used fordelivering the components, semi-finished products andfinished products in the production line. However, after
the product is completed and packaged, it is necessary to
use manpower to move the packaged products to thewarehouse and stack them to a designated storage
location.
Although the automation of manufacturing processes andthe automation of manufacturing industries have been

Copyright © 2018, the Authors. Published by Atlantis Press.
This is an open access article under the CC BY-NC license (http://creativecommons.org/licenses/by-nc/4.0/).
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Journal of Robotics, Networking and Artificial Life, Vol. 4, No. 4 (March 2018) 334-337___________________________________________________________________________________________________________in managing a warehouse [2]. In [3], Adinandra et al said
that autonomous mobile robots (AMR) have emerged asa means of transportation system in warehouses. Wang et
al proposed a positioning system composed of an RFID
reader equipped with forklift and terrestrial channels
embedded RFID tags to improve warehouse management
efficiency [4]. Amazon makes extensive use of robots for
product collation and warehouse management and had
45,000 robots across 20 fulfillment centers in the early2017 [5].
In this paper, we will develop a small warehouse truck
with the function of auto-stacking. Here “auto-stacking”
means the goods can be stored in stack manner with
detection of numbers of stacked goods and it will alarm
when the storage area is full.

ProductionLinePacking
Area

Warehouse
Area

Shipping
AreaFig. 1. Flow of goods with RFID tag.

2. System Architecture
In the case of a typical factory, when the goods aremanufactured by the production line and packaged, they
are usually manually moved to a van and then stacked bya technician of fork-lifter to the warehouse area. When
there is a shipping requirement, they will be transported
in the same way from the warehouse area to the shipping
area for packing or into the container. Different products
will be placed in different warehouses or different
counter. We assume that on the product or its package,there is an RFID (radio frequency identifier) tag foridentification. In addition, our scenario assumes that thewarehouse is an unmanned environment and all orders
are made in the shipping area or packing area. Because
an unmanned storage environment does not need any
lighting for vision and air-conditioning, it is energysaving. It also can reduce the possibility of potential
danger of injury caused by the devices movement orimproper operation since no person is required to work in
it. The flow of the goods with RFID tag is shown in
Figure 1.
Thus the warehouse truck with the auto-stacking ability
should be composed of three parts: the driver part todriving the motors of the truck and the mechanism of thefork-lift device, the control part to command the truck thedestination and route, and the sensor part including RFID
reader for commanding, sensors for obstacle avoidance
and tracking the route, and sensors for the fork of thetruck. The system architecture of the auto-stacking
warehouse truck is shown in Figure 2.

Fig. 2. System architecture of the auto-stacking warehousetruck.

3. Simulation
The scenery of our simulation includes a shipping area
(also the packing area) and two warehouse area. The
warehouse truck will be commanded to take the goods
from factory packing area to the correct location of thewarehouse and to leave the goods in the correct storage
counter or to take the correct good from the storage
counter of the warehouse to the shipping area. The goods
can be stacked in the designated warehouse. For
simplicity, the warehouse truck moves under the guide ofa marked curve on the floor. To distinguish different
warehouse, we marked a colored tag on the track. The
whole simulation scenery is shown in Figure 3.
Our experimental truck is based on aluminum extruded
material as a skeleton. A microchip 16-Bits MCU is usedas the kernel and an Arduino chip is supplemented tocontrol the truck. An infrared trace sensor is used todetect the route planned in advance, so that the truck canfollow the route. A color sensor is used to read different
storage areas. Truck moving and the fork moving up anddown is driven by a 12VDC deceleration motor. The fork335

Journal of Robotics, Networking and Artificial Life, Vol. 4, No. 4 (March 2018) 334-337___________________________________________________________________________________________________________stretching is to driven by a 5VDC stepper motor. Figure
4 shows our experimental auto-stacking warehouse truck.
The truck is initially in the packing area. We use an RFID
card to command the truck to pick up the goods and takeit to the designated storage counter. The goods will be
stored in a stacked manner.
There are two function buttons and an emergency stop
switch on the truck, with the green button for picking
goods up from the warehouse area to the shipping area,
and the yellow one for delivery goods to the warehousearea for stack. The different warehouses are distinguishedby two RFID cards. There is a stacking limitation in eachwarehouse area. The truck can move under the commandof pushed button and the read RFID message. Once thedestination warehouse is full of goods and a goods isplanned to be stacked into, the warning light will bebright. The alert can be released by changing thecommand mode. In our simulation, the goods can besmoothly transported from the packing area to the storage
area for stacking, or picked up from the storage area andtransported to the shipping area. Figure 5 shows thescenario that a goods is in transportation to the warehousearea A.
4.

Fig. 3. Simulation Scenery.

Discussion and Conclusion

In this paper, we have made a brief discussion of theadvantages of an unmanned warehouse. In order toimprove the space efficiency of the limited storage area,stacked storage of goods is a good idea. In order to realize
such a warehouse concept, we designed a simulated
warehouse truck with function of auto-stacking. It canmove on the specified route and store the goods in astacked way to the designated area. When the stack area
is full, it can alert the operator to change his instructions.
This idea can be realized in a real warehouse area withcubic packed goods such as televisions, refrigerators, or
air conditioners.

Fig. 4. Our experimental auto-stacking warehouse truck.

References
Fig. 5. A snap of the warehouse truck working.
1. V. Giordano, J.B. Zhang, D. Naso and F. Lewis, Integratedsupervisory and operational control of a warehouse with amatrix-based approach, IEEE Trans. Automation Sci. andEngr. 5(1) (2008) 53 – 70
2. Z. Xie, W. He, L. Lv and J. He, The implement ofwarehouse management system based on RFID andwireless sensor network, IET Int’l Conf. on WirelessSensor Network 2010 (2010) 98-103.
3. S. Adinandra, J. Caarls, D. Kostić, J. Verriet and H.
Nijmeijer, Flexible transportation in warehouses, in:Automation in Warehouse Development (Springer,London, 2012).

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Journal of Robotics, Networking and Artificial Life, Vol. 4, No. 4 (March 2018) 334-337___________________________________________________________________________________________________________

4. H. Wang, T. Cheng, and Z.A. Wu, Research on positioning
algorithm of forklift-mounted RFID reader, Sensors &Transducers 174(7) (2014)164.
5. S. Shead, Amazon now has 45,000 robots in its
warehouses, Business Insider, UK, Jan. 2017. Available at:
http://uk.businessinsider.com/amazons-robot-army-hasgrown-by-50-2017-1

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