The application of semi-automated gantry cranes in empty container depots

<p>Purpose – The storage and supply of empty containers is a bottleneck in the global supply chain. In the wake of increasing containerisation and globalisation, improving efficiencies of processing within empty container depots can realise efficiencies. The overall objective of this research project is to propose an efficient and effective solution for reducing waste in an empty container depot using a crane. The issue of applying gantry cranes to empty container depots will cover both an operational and a strategic evaluation of the following research questions: 1) What are the potential solutions for a specific yard based on lean thinking, and which solution should be used within the constraints and contexts of this yard? 2) Who are the key stakeholders, and what are their stakes while implementing the solution in the yard to reduce waste? Design/methodology/approach – A review of the literature around empty container depots revealed that while lean operations have been applied to manufacturing, warehousing, and ports, it has not yet been applied to empty container depots. Whereas warehouses primarily deal with stock-holding and ports deal with quayside operations, empty container depots act as a conduit between consignors and consignees. In the vein of American Pragmatism, Design Science Research, and Strategy-as-Practice, this thesis shows that in the context of empty container depots a gantry crane is an artefact that can create efficiencies, reduce costs, as well as explore further effects on the organisation and its wider geo-political habitus. Case Study – A New Zealand company that handles roughly half a million TEUs per annum cooperated with this study. The study was conducted by analysing data from four working depots (Auckland, Tauranga, Napier) selected to illustrate variations in container volumes, types of flows (imports, exports, seasonality), and depot layouts. The current operations of these depots were analysed using lean operations, value stream mapping, and operations interwork centre flow graphs. Of the four sites identified, one (the Auckland OCP site) was shown to achieve the greatest results from a gantry crane. The results of the analysis were then used to develop a potential solution in which waste was identified and eliminated, primarily around excess handling and land utilisation. Findings – A key finding was that efficiency gains differ from site to site based on their unique demands and overall layouts. Furthermore, changes towards the current yard using gantry cranes need to be implemented incrementally based on continuous improvement. This is due to practical constraints around operations, culture change, cashflow management, the acquisition of capital, and broader market/stakeholder influences. Originality/value – The practical applications of this research case are scalable on a vast level. The effects of this research are explored in how the introduction of an artefact affects the organisation, its vision of itself, its strategies, and the broader supply chain in which this organisation operates. The results are further re-contextualisted in order to offer a holistic view of an artefact in its situated environment.</p>

The application of semi-automated gantry cranes in empty container depots

<p>Purpose – The storage and supply of empty containers is a bottleneck in the global supply chain. In the wake of increasing containerisation and globalisation, improving efficiencies of processing within empty container depots can realise efficiencies. The overall objective of this research project is to propose an efficient and effective solution for reducing waste in an empty container depot using a crane. The issue of applying gantry cranes to empty container depots will cover both an operational and a strategic evaluation of the following research questions: 1) What are the potential solutions for a specific yard based on lean thinking, and which solution should be used within the constraints and contexts of this yard? 2) Who are the key stakeholders, and what are their stakes while implementing the solution in the yard to reduce waste? Design/methodology/approach – A review of the literature around empty container depots revealed that while lean operations have been applied to manufacturing, warehousing, and ports, it has not yet been applied to empty container depots. Whereas warehouses primarily deal with stock-holding and ports deal with quayside operations, empty container depots act as a conduit between consignors and consignees. In the vein of American Pragmatism, Design Science Research, and Strategy-as-Practice, this thesis shows that in the context of empty container depots a gantry crane is an artefact that can create efficiencies, reduce costs, as well as explore further effects on the organisation and its wider geo-political habitus. Case Study – A New Zealand company that handles roughly half a million TEUs per annum cooperated with this study. The study was conducted by analysing data from four working depots (Auckland, Tauranga, Napier) selected to illustrate variations in container volumes, types of flows (imports, exports, seasonality), and depot layouts. The current operations of these depots were analysed using lean operations, value stream mapping, and operations interwork centre flow graphs. Of the four sites identified, one (the Auckland OCP site) was shown to achieve the greatest results from a gantry crane. The results of the analysis were then used to develop a potential solution in which waste was identified and eliminated, primarily around excess handling and land utilisation. Findings – A key finding was that efficiency gains differ from site to site based on their unique demands and overall layouts. Furthermore, changes towards the current yard using gantry cranes need to be implemented incrementally based on continuous improvement. This is due to practical constraints around operations, culture change, cashflow management, the acquisition of capital, and broader market/stakeholder influences. Originality/value – The practical applications of this research case are scalable on a vast level. The effects of this research are explored in how the introduction of an artefact affects the organisation, its vision of itself, its strategies, and the broader supply chain in which this organisation operates. The results are further re-contextualisted in order to offer a holistic view of an artefact in its situated environment.</p>

Port Equipment Downtime Prediction and Lifetime Data Analysis: Evidence from a Case Study

Prediction of downtime and lifetime data for gantry cranes in a container terminal is a crucial concern for port terminals due to the requirement for maintenance planning and capital expenditure. Correct estimation of lifetime behavior for gantry cranes is complex since multiple cranes are involved, each with different costs, capacities; installation, and retirement dates. This paper develops statistically-oriented predictions for the lifetimes of container terminals company fleet of gantry cranes. Data records on downtime for cranes were collected and analyzed using Weibull, normal, and Rayleigh distributions regarding a port in southwestern Nigeria. The downtime, probability density function, cumulative density function, reliability, and hazard rate were analyzed for three shape functions of Weibull, β=0.5, 1, and 3. The same was analyzed for Rayleigh and normal distribution functions. The mean downtime was 30.58 hrs. The highest PDF, CDF, R(t) for all β =0.5, 1, and 3, were 0.26, 0.78, .030 and 13.13, respectively. However, the least values for these parameters are 0.01, 0.71, 0.25, and 0.04, respectively. These values are means for thirty data points and concern the Weibull distribution function. For the Rayleigh distribution, the mean PDF, CDF, R(t) and h(t) are 0.002, 0.042, 0.958 and 0.002 while they are 0.002, 0.456, 0.542 and 35.755 for the normal distribution. This article provides new insights into the lifetime analysis of gantry cranes in a container terminal.

Routing two stacking cranes with predetermined container sequences

The scheduling of gantry cranes with respect to mutual interference has received considerable attention in recent years. We consider a subproblem which arises when each crane has a sequence of tasks to be assigned. The problem is concerned with resolving the interference between two cranes by determining which crane avoids the other in order to let it complete its next task first. We provide a fairly general problem framework accounting for different crane systems and various side constraints. We assume a cost function for each task that determines the cost of completing the task at a specific point in time. We then distinguish between the objectives to minimize both the total cost and the maximum cost among tasks. A general dynamic programming framework is provided which allows us to solve all problem versions in pseudo-polynomial time. Furthermore, we show that while the general problem aiming for minimum total cost is binary NP-hard, the general problem aiming for minimum maximum cost can be solved in polynomial time. Finally, we address two important special cases of the former, and we show that they can be solved in polynomial time as well.

Selecting Suitable, Green Port Crane Equipment for International Commercial Ports

Responding to the increasing global need for environmental protection, a green port balances economic vibrancy with environmental protection. However, because exhaust emissions (e.g., CO2 or sulfide) are difficult to monitor around ports, data on such emissions are often incomplete, which hinders research on this topic. The present study aimed to fill this gap in this topic. To remedy this problem, this study formulated a new data envelopment analysis (DEA) method for collecting CO2 emissions data at their source. This method was applied to collect real-world operating data from a large container-handling company in Taiwan. Specifically, we provide a real example using a novel green energy index to account for undesirable outputs. Our main objective was to formulate two methods that combine: (1) data envelopment analysis based on a modified slack-based measure, and (2) a multi-choice goal programming approach. The contributions of this paper included the finding that rubber-tired gantry cranes are the greenest and should be used in ports. Finally, our findings aid port managers in selecting port equipment that provides the best balance between environmental protection and profitability.

Dynamic simulation of a high altitude gantry crane with cable hoisting. Part one. 2D model

Introduction. Simulation of the 2D dynamic motion of a high altitude wide span gantry crane with a rope hoisting mechanism is addressed. Such large gantry cranes with a height of more than 50 meters, have been unstudied very well so far. A small swing angle of the payload, it's fast hoisting, and the fast motion of the trolley are critical for these cranes and, hence, they need to be analyzed in detail. Materials and methods. The generalized formulation of the two-dimensional crane dynamics is efficiently performed and simulated in Mathcad. This is a single mass model that has a non-elastic cable. The formulation is derived using the Lagrange method, and differential equations are correctly solved using the Runge-Kutta method in Mathcad. In this model the crane is fixed, and all the subsystems are considered as rigid bodies without any deflection in terms of the trolley and the payload. Results. The results are verified using MSC ADAMS (Academic) that indicates satisfactory convergence. The considerable influence of the payload oscillation on the trolley motion is visible in both Mathcad and ADAMS models. The implemented Mathcad code can be useful for students and researchers. Conclusions. The maximum speed of the trolley is 1.716 m/s to prevent the payload swinging angle from exceeding 0.5 deg. The calculated velocity of the trolley is reasonable for such a large crane if limitations like wind effects and resonance are ignored.

Research on Nonlinear Coupled Tracking Controller for Double Pendulum Gantry Cranes With Load Hoisting/lowering

Gantry cranes, which have attracted extensive attention, are mostly simplified as nonlinear single pendulum systems without load hoisting/lowering. However, in fact, due to the existence of the hook, gantry cranes produce double pendulum swing. With an extra underactuated degree of freedom, the anti-swing control of the double pendulum gantry cranes becomes more difficult than that of single pendulum gantry cranes, especially when load hoisting/lowering is considered simultaneously. Moreover, large swings, which lead to problems such as inaccurate positioning and low transportation efficiency, may be caused by double pendulum gantry cranes with load hoisting/lowering. In this paper, a nonlinear coupled tracking anti-swing controller is proposed to solve these problems. In this controller, a smooth tracking trajectory is introduced to ensure the stable start and run of the trolley, and a coupled signal is constructed to eliminate the residual swing angles of gantry crane system. The system stability is analyzed by using Lyapunov method and Barbarat theorem. Theoretical derivation, simulation and experimental results show that the proposed controller has excellent control performance, specifically, not only does it ensure accurate positioning of the load, but also it suppresses and eliminates the hook/load swing angle effectively. The proposed controller can still achieve good control effects and has strong robustness under the condition of changing the load mass, trolley target displacement, system initial swing angles and adding external disturbance.