C HAPTER 13
7. New Technologies used in Warehouses
The increasing importance of logistics and the strategic value of the warehousing in logistics encourage companies to seek improvements in warehousing activities. In addition, volatile conditions in warehousing make it difficult to perform the warehousing operations with the desired performance criteria. These changing conditions include (Frazelle 2002;
Renko and Ficko 2010).
The increase of the amount and variety of the products in warehouses, The increase of value-added activities in warehouses,
Shorter life cycles of products and fast delivery times, The high volume of product returns,
Expansion of international orders due to globalisation,
The increasing need to complete all warehousing activities in less time and with less error due to the high business competition.
As a result of all these requirements, it has become mandatory to utilise the latest technologies in the warehouses to reduce the costs, optimise operations and improve the quality of services. The main technologies used in the warehouse and the references are summarized in Table 2.
Table 2: Literature papers for warehouse technologies.
The technology References
Warehouse Management System
(WMS) Wang et al. 2010; Atieh et al. 2016; Ten Hompel and Schmidt 2007; Burke and Ewing Jr.
2014; A et al. 2012
Radio Frequency RFID Wang et al. 2010; Chen et al. 2013; Zhou et al. 2017 AS/RS systems De Koster et al. 2008; Lerher et al. 2010; Gagliardi et al. 2012
Internet of Things (IoT) Fleisch 2010; Gilchrist 2016; Lee et al. 2017; Witkowski 2017; Macaulay et al. 2015 Robotics Burke and Ewing Jr. 2014; Niku 2001; Bonkenburg 2016
Automated Guided Vehicles (AGVs) Schwab 2017; Schulze and Zhao 2007; Schulze and Wullner 2006
Drones Schwab 2017; Kückelhaus and Niezgoda 2014
7.1 Warehouse Management Systems
Warehouse Management System (WMS) is a software that performs the management of warehousing and its operations.
It guides planning, optimising, and controlling of the daily warehouse operations starting from receiving the products to shipment. Addition to the efficient use of storage areas, another purpose of WMS is to make the most efficient use of other resources such as warehouse elements, handheld terminals and transport vehicles and operators. The benefits of having an effective WMS can be listed as;
• Increasing the efficiency
• Monitoring the inventory and whole operations in real time
• Speeding up the process of order preparing and shipment
• Better management for the use of resources
• Increasing the accuracy of satisfying customers’ orders
• Maintaining the integration between the units
• Reducing the operational costs
• Enabling to easily report and online management as paperless
• Keeping record of all activities, help to monitor the performance of the warehouse
The WMS can be integrated with the connected devices and sensors which help increase the responsiveness and flexibility of the system. The automated WMS emerges as another benefit of this integration. Some human errors that may occur due to manual handling can be minimised by the automated WMS (Atieh et al. 2016). In an automated WMS, the transportation devices can communicate the WMS regarding their locations and expected arrival times to another position, to which the WMS in turn, can determine appropriate slot and route for the device and optimise the system in real-time (Barreto et al. 2017). Simultaneously, an RFID system can inform the WMS about the status of products shipped, in transit, on process and request a transportation device to move the goods. WMS can assign the most appropriate transport device to the job and optimise the routing.
Effective management and optimisation of the processes in a warehouse require to have a WMS. A company should be careful when choosing a WMS and determine the system based on the needs and the characteristic of the warehouse.
192 Logistics 4.0: Digital Transformation of Supply Chain Management
7.2 RFID Technologies
Radio frequency identification (RFID) is a technology for recognizing tags attached to the objects individually and automatically via radio waves. The two components of RFID are tag and reader. The best feature of RFID technology is that it does not need to read on the line of sight unlike the barcoding systems, which needs to scan the tag to read.
RFID tags can be of three different types such as passive, semi-passive and active tags. Passive tags, the cheapest and the simplest ones, do not have their own energy power and their energy needs are supplied by the reader. Semi-passive tags, on the other hand, have a small battery and do not need to get power from reader. These are more reliable and can respond quickly to the customer as they have a wide range of readability. Active tags have their own power supplies which allow them for running their circuits and generating a response signal. Although their performance is higher compared with other types of tags, they also have higher costs.
The implementation of RFID technology into warehouses and distribution centres bring about several benefits to the system. RFID technology improves the accuracy of inventory and order picking since it enables managers to monitor the products in real-time. Increasing the accuracy of the system will result in reducing errors which allows for keeping up with the customer expectations. As a result of being processes easier and faster, the labour costs will be reduced. As an another benefit, RFID tags are more durable, resulting in less errors such as falling off or damaged tags which are common for barcodes labels.
Despite all the benefits, there are some critical points to be considered for the implementation of RFID. The cost of having an RFID system can be very higher compared to the other barcoding systems. Thus, there should be a trade-off between the benefits and the costs as all the equipment and facilities have to be upgraded in compliance with RFID in order to obtain the desired benefit. Also, RFID systems can keep a very large dataset which requires to be managed and this is a challenging issue.
7.3 AS/RS Systems
An Automated Storage and Retrieval System (AS/RS) is a part of an automated warehouse technologies which is capable of processing the storing and picking of the products activities in an automated way. In spite of its applicability to a wide range of warehouses, the implementation of an AS/RS system in a high-altitude storage areas where shelves reach up to 40 meters is more essential.
Main component of an AS/RS system comprises of a crane or storage/retrieval machine, storage racks, input and output locations, and picking positions. The racks are the stationary places positioned on both sides of an aisle and the goods are stored within these racks. A crane or a storage/retrieval machine,which is capable of moving in the both horizontal and vertical directions, operates in the aisle to put the items into the shelves and retrieve them. The goods are taken from input location by the crane to store in the racks or the retrieved goods from the shelves are dropped to the output location. The input/output location is placed at the end of the aisle. The goods are picked up from the retrieval boxes from the shelves and placed in the picking zone. An example of an AS/RS system is presented in Figure 4.
The integration of an AS/RS system with a warehouse has several potential benefits that are listed below.
Capacity usage; AS/RS systems can utilize the space in warehouses and the automated system can reach to the places where manual access cannot be done to greater extent. It can also operate in a narrow aisles on which forklifts cannot work.
Reduction on labour cost; one time establishment of an AS/RS system can significantly reduce the labour cost since a single AS/RS can perform all order picking activities.
Increase in the accuracy of order picking and storage; in any case, there is an error factor for human who might retrieve wrong products or put in the wrong places. This causes inefficiencies of the functions of warehouse and these can be minimized by an AS/RS system.
Safety; occupational accidents caused by instant distraction, stress, hunger or other emotional reasons of the people using forklifts or other heavy machinery might result in a great tragedy. Replacing human factor with an automated system might reduce these unpredictable incidents.
As an example of the benefits of AS/RS, there could be a saving on aisles space up to 50%, reducing the waste space in a warehouse up to 85% and improving the accuracy of material handling up to 99.99% (Lerher et al. 2010; De Koster et al. 2008).
In addition to all the benefits of AS/RS systems, there exist some issues that should not be ignored. The cost of having an AS/RS system including initial setup cost and maintenance cost can be more expensive than traditional system in the