AGW for efficient freight transport in container yard: models and costs

Abstract Different modes of transport are frequently used to transfer goods from origin to destination, especially on medium-long distances, in relation to the network supply, the available services, the costs. The transfer from one carrier to another, in an interchange node such as a port, a rail station, a logistics terminal, often implicates an increase of monetary and temporal costs, connected to material and immaterial operations. The principal aim is to minimize the overall cost of transport, but the freight interchange node can represent critical steps in logistics chain and for this reason much attention is now committed to actions to make efficient the functional organization of the terminal. In the last years an increasing interest is directed to the use of vehicles technologically advanced with automation of functions. The paper focuses on a particular technology, conceived recently, otherwise an intelligent rail wagon called AGW (Automated Guided Wagon) for handling of containers in a port. The use of intelligent system AGW as handling unit of containers in the yard, would allow the overcoming of diseconomies of scale and the reduction of the handling times and costs through a flexible management in relation to the characteristics of the transport supply and demand, the latter subject to a high variability. In the paper, after a brief description of the AGW technology and the advantages connected to the use of this handling system in a freight interchange node, the attention is focused on a comparative analysis between the handling system now operating in the container port (RTG, Straddle Carrier, AVG, etc.) and the system that involves the use of AGW. This analysis is made on the operational characteristics of the different handling systems, through the use of: functional schemes, with the aim to carry out evaluations related to the spatial, organizational and relational structure of container yard equipped with different handling unit; network models (graphical representation of links and paths; basic cost parameters) for the schematization and simulation of container handling in the yard; cost models for quantitative evaluation of monetary and temporal impacts, that derive from the use of different handling unit in the yard

Control of free-ranging automated guided vehicles in container terminals

Container terminal automation has come to the fore during the last 20 years to improve their efficiency. Whereas a high level of automation has already been achieved in vertical handling operations (stacking cranes), horizontal container transport still has disincentives to the adoption of automated guided vehicles (AGVs) due to a high degree of operational complexity of vehicles. This feature has led to the employment of simple AGV control techniques while hindering the vehicles to utilise their maximum operational capability. In AGV dispatching, vehicles cannot amend ongoing delivery assignments although they have yet to receive the corresponding containers. Therefore, better AGV allocation plans would be discarded that can only be achieved by task reassignment. Also, because of the adoption of predetermined guide paths, AGVs are forced to deploy a highly limited range of their movement abilities while increasing required travel distances for handling container delivery jobs. To handle the two main issues, an AGV dispatching model and a fleet trajectory planning algorithm are proposed. The dispatcher achieves job assignment flexibility by allowing AGVs towards to container origins to abandon their current duty and receive new tasks. The trajectory planner advances Dubins curves to suggest diverse optional paths per origin-destination pair. It also amends vehicular acceleration rates for resolving conflicts between AGVs. In both of the models, the framework of simulated annealing was applied to resolve inherent time complexity. To test and evaluate the sophisticated AGV control models for vehicle dispatching and fleet trajectory planning, a bespoke simulation model is also proposed. A series of simulation tests were performed based on a real container terminal with several performance indicators, and it is identified that the presented dispatcher outperforms conventional vehicle dispatching heuristics in AGV arrival delay time and setup travel time, and the fleet trajectory planner can suggest shorter paths than the corresponding Manhattan distances, especially with fewer AGVs.Open Acces

Sustainable supply chain management in the digitalisation era: The impact of Automated Guided Vehicles

Internationalization of markets and climate change introduce multifaceted challenges for modern supply chain (SC) management in the today's digitalisation era. On the other hand, Automated Guided Vehicle (AGV) systems have reached an age of maturity that allows for their utilization towards tackling dynamic market conditions and aligning SC management focus with sustainability considerations. However, extant research only myopically tackles the sustainability potential of AGVs, focusing more on addressing network optimization problems and less on developing integrated and systematic methodological approaches for promoting economic, environmental and social sustainability. To that end, the present study provides a critical taxonomy of key decisions for facilitating the adoption of AGV systems into SC design and planning, as these are mapped on the relevant strategic, tactical and operational levels of the natural hierarchy. We then propose the Sustainable Supply Chain Cube (S2C2), a conceptual tool that integrates sustainable SC management with the proposed hierarchical decision-making framework for AGVs. Market opportunities and the potential of integrating AGVs into a SC context with the use of the S2C2 tool are further discussed

An auction-based approach with closed-loop bid adjustment to dynamic task allocation in robot teams

Dynamic task allocation is among the most difficult issues in multi-robot coordination, although it is imperative for a multitude of applications. Auction-based approaches are popular methods that allocate tasks to robots by assembling team information at a single location to make practicable decisions. However, a main deficiency of auction-based methods is that robots generally do not have sufficient information to estimate reliable bids to perform tasks, particularly in dynamic environments. While some techniques have been developed to improve bidding, they are mostly open-looped without feed-back adjustments to tune the bid prices for subsequent tasks of the same type. Robots' bids, if not assessed and adjusted accordingly, may not be trustworthy and would indeed impede team performance. To address this issue, we propose a closed-loop bid adjustment mechanism for auction-based multi-robot task allocation, with an aim to evaluate and improve robots' bids, and hence enhance the overall team performance. Each robot in a team maintains and uses its own track record as closed-loop feedback information to adjust and improve its bid prices. After a robot has completed a task, it assesses and records its performance to reflect the discrepancy between the bid price and the actual cost of the task. Such performance records, with time-discounting factors, are taken into account to damp out fluctuations of bid prices. Adopting this adjustment mechanism, a task would be more likely allocated to a competent robot that submits a more accurate bid price, and hence improve the overall team performance. Simulation of task allocation of free-range automated guided vehicles serving at a container terminal is presented to demonstrate the effectiveness of the adjustment mechanism.postprintThe World Congress on Engineering (WCE 2011), London, U.K., 6-8 July 2011. In Proceedings of WCE, 2011, v. 2, p. 1061-106

Performance optimisation of mobile robots in dynamic environments

This paper presents a robotic simulation system, that combines task allocation and motion planning of multiple mobile robots, for performance optimisation in dynamic environments. While task allocation assigns jobs to robots, motion planning generates routes for robots to execute the assigned jobs. Task allocation and motion planning together play a pivotal role in optimisation of robot team performance. These two issues become more challenging when there are often operational uncertainties in dynamic environments. We address these issues by proposing an auction-based closed-loop module for task allocation and a bio-inspired intelligent module for motion planning to optimise robot team performance in dynamic environments. The task allocation module is characterised by a closed-loop bid adjustment mechanism to improve the bid accuracy even in light of stochastic disturbances. The motion planning module is bio-inspired intelligent in that it features detection of imminent neighbours and responsiveness of virtual force navigation in dynamic traffic conditions. Simulations show that the proposed system is a practical tool to optimise the operations by a team of robots in dynamic environments. © 2012 IEEE.published_or_final_versionThe IEEE International Conference on Virtual Environments Human-Computer Interfaces and Measurement Systems (VECIMS 2012), Tianjin, China, 2-4 July 2012. In Proceedings of IEEE VECIMS, 2012, p. 54-5

Smart ports: towards a high performance, increased productivity, and a better environment

Ports are currently competing fiercely for capital and global investments in order to improve revenues, mostly by improving performance and lowering labor costs. Smart ports are a fantastic approach to realize these elements since they integrate information and communication technologies within smart applications, ultimately contributing to port management improvement. This leads to greater performance and lower operational expenses. As a result, several ports in Europe, Asia, Australia, and North America have gone smart. However, there are a lot of critical factors to consider when automating port operations, such as greenhouse gas emissions, which have reached alarming proportions. The purpose of this study is to define the most essential tasks conducted by smart ports, such as the smart ship industry, smart gantry and quayside container cranes, transport automation, smart containers, and energy efficiency. Furthermore, it gives a model of the smart port concept and highlights the critical current technologies on which the ports are based. Each technology’s most significant contributions to its development are noted. This technology is compared to more traditional technologies. It is hoped that this effort would pique the curiosity of fresh researchers in this sector

A study of Intelligent Transport Systems (ITS) in Dublin Port in conjunction with the Intelligent Transport for Dynamic Environment (InTraDE) Project

In the last four decades the container as an essential part of a unit load-concept has achieved authentic importance in international sea freight transportation. With ever increasing containerization the number of port container terminals and competition among them has become quite remarkable. Port container operations are nowadays unthinkable without effective and efficient use of Intelligent Transport Systems (ITS) (Steenken & Stahlbock, 2004). The main problem in handling increasing levels of cargo is managing the internal traffic and optimizing space inside smaller and medium sized ports. A gap exists between automated cargo handling equipment that is suitable for use in the larger container terminals such as Rotterdam and its suitability in smaller terminals such as Dublin. A new generation of cargo handling technology has been designed in the form of an Intelligent Autonomous Vehicle (IAV). The IAV is a clean, safe, intelligent vehicle which will contribute to improving the traffic management and space optimization inside confined space by developing a clean, safe and intelligent transport system. This technology has been designed and developed as part of the ‘InTraDE’ (Intelligent Transport for Dynamic Environment) project to which the research has contributed. By using ITSs, logistics operations could be improved by enhancing the exchange of information and real-time status updates regarding different business operations in different modes of transportation (Schumacher et al., 2011). Maritime transport has recently gained increased attention, especially in connection to the building and further development of ITS (Pietrzykowski, 2010). This research looks at the main logistic processes and operations in port container terminals. It discusses the extent to which the terminal shipping operators in Dublin Port currently meet the demands of their customers and whether the introduction of ITS could enhance the efficiency and productivity of such services