Shipboard Cranes Research Articles

Advanced Control for Shipboard Cranes with Asymmetric Output Constraints

Considering the anti-swing control and output constraint problems of shipboard cranes, a nonlinear anti-swing controller based on asymmetric barrier Lyapunov functions (BLFs) is designed. First, model transformation mitigates the explicit effects of ship roll on the desired position and payload fluctuations. Then, a newly constructed BLF is introduced into the energy-based Lyapunov candidate function to generate nonlinear displacement and angle constraint terms to control the rope length and boom luffing angle. Among these, constraints with positive bounds are effectively handled by the proposed BLF. For the swing constraints of the unactuated payload, a carefully designed relevant constraint term is embedded in the controller by constructing an auxiliary signal, and strict theoretical analysis is provided by using a reductio ad absurdum argument. Additionally, the auxiliary signal effectively couples the boom and payload motions, thereby improving swing suppression performance. Finally, the asymptotic stability is proven using LaSalle’s invariance principle. The simulation comparison results indicate that the proposed method exhibits satisfactory performance in swing suppression control and output constraints. In all simulation cases, the payload swing angle complies with the 3° constraint and converges to the desired range within 6 s. This study provides an effective solution to the control challenges of shipboard crane systems operating in confined spaces, offering significant practical value and applicability.

Shipboard crane digital twin: An empirical study on R/V Gunnerus

The maritime industry is constantly facing new challenges and technological advancements, making the adaptation of innovative solutions like digital twins a bridge enhancing safety and efficiency between theoretical models and real-world maritime applications. Digital twin simulators for complex dynamic operation systems such as shipboard cranes, allow the operators to practice demanding operations in a risk-free immersive environment with various scenarios. This paper presents the process of developing a digital twin-based simulation tool designed for shipboard crane operations. It is based on co-simulation using the Functional Mock-up Interface (FMI) standard. This allows for the integration of the operation scenarios with different physical domain models, including such as the ship, environmental forces, hydraulic power systems, and controllers. In addition, the digital twin has opened up new opportunities for the optimization of maritime systems. It can be used to identify the optimal operating conditions, predict potential risks, and provide onboard support to the operator. A demo crane digital twin is implemented for the Palfinger crane on the Gunnerus research vessel with system validation via a series of marine operations being real-time monitored by the Remote Control Center (RCC).

The examination of operator performance when controlling a shipboard crane anti-sway control system within a virtual-reality simulator

The examination of operator performance when controlling a shipboard crane anti-sway control system within a virtual-reality simulator

On the Stability of a 3DOF Vibrating System Close to Resonances

Abstract Purpose In the current work, the motion of a three degrees-of-freedom (DOF) dynamical system as a vibrating model is examined. The proposed system is of high importance in vibration engineering applications, such as the analysis of the control of flexible arm robotics, flexible arm vibrational motion as a dynamic system, pump compressors, transportation devices, rotor dynamics, shipboard cranes, and human or walking analysis robotics. Methods Lagrange's equations (LE) are used to derive the equations of motion of the controlling system. The analytic solutions (AS) are obtained utilizing the multiple-scales method (MSM) up to the third order. Results The framework for removing secular terms provides the requirements for the solvability of this problem. Various resonance scenarios are categorized and the modulation equations (ME) are constructed. To graphically demonstrate the beneficial impacts of the distinct parameters of the problem, the time histories (TH) of the approximate solutions as well as the resonance curves (RC) are depicted. The Runge-Kutta algorithm (RKA) is employed to obtain the numerical solutions (NS) of the regulating system. Conclusion A comparison of the AS and NS reveals the accuracy of the perturbation approach. The stability/instability zones are studied using Routh-Hurwitz criteria (RHC), and then they are examined using a steady-state situation. Basically, the used perturbation method is considered a traditional method that is applied to solve a new dynamical system. Then, the achieved results are considered new because they weren’t obtained previously, which indicates the novelty of this work.

A gap analysis for automated cargo handling operations with geared vessels frequenting small sized ports

With the Yara Birkeland, the world’s first autonomous cargo ship developed for commercial use, nearing regular unmanned operation, it is crucial to assess the availability and readiness of unmanned cargo handling solutions. While there are already fully automated container terminals at large international ports, the purpose of this study is to consider solutions to support autonomous ships for small sized ports with little infrastructure, typical of coastal harbors in Norway. The analysis centers on geared cargo vessels that can navigate such ports with minimal or no crew onboard, and the primary method used involved workshops and interviews with personnel from relevant industries. An important finding is the lack of skilled crane operators that are willing to follow the ship. The study concludes that it is important to address the following 3 key technological gaps: (1) the autonomous connection and release of break-bulk, (2) automatic securing and lashing of onboard cargo, and (3) shipboard cranes that can operate without an onsite crane operator.

Lyapunov-Based Model Predictive Control for Shipboard Boom Cranes Under Input Saturation

A Lyapunov-based model predictive control (MPC) scheme is firstly developed for shipboard boom cranes with ship rolling, while considering optimization and input saturation. By integrating the ship rolling into original state variables, the shipboard boom crane model is transformed to facilitate the successive controller design. A Lyapunov-based MPC framework is then constructed for the new dynamical model, while respecting actuator capability. To ensure the recursive feasibility and stability of the established framework, a contractive constraint with a bounded energy-based controller is further introduced, for which the bounds are intrinsical with the utilization of the arctan function. Stability analysis for the bounded controller is also discussed based on Lyapunov theory and LaSalle&#x2019;s invariance principle. Compared with the bounded controller, optimization is taken into account by the Lyapunov-based MPC. Suboptimal solutions are also accepted to ease the computational burden. Moreover, the conservation existing in the bounded controller can be entirely circumvented by the Lyapunov-based MPC, so the capacity of actuators can be fully exploited while obeying the input saturation. Finally, numerical simulations are elaborately devised and implemented to show the effectiveness of the bounded controller and superiority of the Lyapunov-based MPC controller. <i>Note to Practitioners</i>&#x2014;Shipboard crane is an important industrial equipment in ocean transportation and offshore engineering. Cranes are installed on ship deck, so the movements of ship, such as rolling, and pitching, may introduce difficulties, inefficiency, and unsafety to the manual operation. The conditions mentioned above motivate the study of automation control for shipboard cranes. A Lyapunov-based model predictive control (MPC) framework is constructed in this paper. Based on this framework, the payload can be conveyed to the desired location accurately and eliminate the swing quickly. Simultaneously, optimization is considered, thus, better control performance can be achieved by consuming less energy. Moreover, the physical limits of the actuators can be satisfied all the time. The present research only considers 3 degrees of freedom (DOF) shipboard boom cranes, for which the slew movement of boom and payload tangential swing are not involved. In the future research, the 5-DOF shipboard boom cranes will be studied to promote the application of the method proposed in this paper.

Nonlinear Model Predictive Control of Shipboard Boom Cranes Based on Moving Horizon State Estimation

As important equipment in offshore engineering and freight transportation, shipboard cranes, working in non-inertial coordination systems, are complicated nonlinear systems with strong couplings and typical underactuation. To tackle the challenges in the controller design for shipboard boom cranes, which is a representative type of shipboard cranes, a comprehensive framework embedding moving horizon estimation (MHE) in model predictive control (MPC) is constructed in this paper while considering disturbances and noise. By utilizing MHE, velocity information can be estimated with high precision even though this is influenced by disturbances and measurement noises. This expected superiority can greatly ease the difficulties in directly measuring all states of shipboard boom cranes. Then, the estimated information can be passed to MPC to derive the optimal control law by solving a constrained optimal problem. During this process, the physical limits of shipboard boom cranes are fully considered. Therefore, the practicability of the proposed framework is highly suitable for the actual requirements of shipboard boom cranes. Finally, the framework is verified by designing three typical scenarios with different disturbances and/or noises. Comparisons with other control approaches are also performed to demonstrate the effectiveness.

Self-tuning anti-sway control for shipboard cranes providing combined world and deck-frame compensation

Self-tuning anti-sway control for shipboard cranes providing combined world and deck-frame compensation

Dynamic Modeling and Analysis of the Telescopic Sleeve Antiswing Device for Shipboard Cranes

In order to explore the dynamic characteristics of the telescopic sleeve antiswing device for shipboard cranes under coupling excitation, a three-dimensional dynamic model of the ship crane telescopic sleeve antiswing device is established in this study, and the accuracy of the model is verified through experiments. By dynamic analysis, the influence of sleeve extension and contraction, damper parameters, and ship excitation on the payload swing is found; meanwhile, the influence of payload swing on ship stability is discovered. At the same time, the simulation results show that the three-dimensional dynamic model can accurately simulate the swing reduction characteristics of the antiswing device. The in-plane and out-plane angles of the swing are reduced by 70% and 90%. The research results have great significance to further explore the antiswing mechanism and structural design of the mechanical antiswing device.

Dynamic modeling and self-tuning anti-sway control of a seven degree of freedom shipboard knuckle boom crane

Dynamic modeling and self-tuning anti-sway control of a seven degree of freedom shipboard knuckle boom crane

A generalized approach to anti-sway control for shipboard cranes

A generalized approach to anti-sway control for shipboard cranes

Review of antiswing control of shipboard cranes

Shipboard cranes are extensively utilized in numerous fields such as cargo transferring and offshore engineering. The control of shipboard cranes, especially the antiswing control of payloads, has attracted much research attention due to their typical underactuation characteristics and complicated dynamics. Through comparisons of the traditional land-fixed cranes, a brief review on modeling and dynamics analysis is presented to illustrate the tremendous challenges and difficulties in controller design for shipboard cranes. A comprehensive review and brief analysis of shipboard crane control strategies are further presented. Some future research directions are also put forward for reference. It is expected that the paper will be useful for improving existing control schemes and generating novel control approaches for shipboard crane systems.

Nonlinear Stable Transportation Control for Double-Pendulum Shipboard Cranes With Ship-Motion-Induced Disturbances

From the practical perspective, with large-scale cargoes or nonnegligible hook masses, the centers of gravity of cargoes and hooks do not coincide with each other, and shipboard cranes usually exhibit complex double-pendulum effects during ship-to-ship or ship-to-harbor transportation, which dramatically increase the complexity of dynamic characteristics and make the control issue very challenging. At present, there is no reported work on control of double-pendulum shipboard cranes yet. To tackle such problems, this paper obtains the dynamic model of double-pendulum shipboard cranes and then provides an effective nonlinear antiswing feedback controller to achieve stable cargo transportation. Specifically, new state variable signals are generated by combining the original state variables with the ship motion (induced by sea wave perturbations). Based on this, by adding some elaborately designed nonlinear terms, an antiswing feedback controller is proposed, which can achieve stable transportation with suppressed swing, and the closed-loop asymptotic stability is proven without any linearizations or approximations to the original complex nonlinear dynamics, with rigorous theoretical analysis. As far as we know, the paper provides the first solution for both controller design and stability analysis of double-pendulum shipboard cranes. Also, several groups of hardware experiments are implemented on a self-built hardware experiment platform, which verify the effectiveness of the proposed method.

Integrated Planetary Gearboxes for Hoisting Winches in Shipboard Cranes

Описаны конструкции редукторов, выполненных по дифференциально-замкнутой схеме для грузовых лебедок судовых кранов. Каждый из редукторов является отдельной сборочной единицей и встраивается во внутреннюю полость барабана. Разработка вариантов опирается на режимы нагрузки, а также комплекс исследований несущей способности зубчатых передач, опор сателлитов и закономерностей распределения нагрузки между элементами планетарной передачи. В основе разработанных редукторов лежит планетарная передача типа А. Выбор таких передач во многом обусловлен необходимостью обеспечения массо-габаритных показателей и реализацией кинематических особенностей привода. В статье обосновано применение передач типа А. Передаточное отношение в некоторых вариантах разработанных конструкций реализуется путем комбинирования типов передач, а именно одним рядом цилиндрической передачи и несколькими рядами планетарных передач. В одном из случаев, когда быстроходная ступень выполнена цилиндрической, привод осуществляется от двух гидромоторов, а в другом - от восьми. Особенностью второго варианта является необходимость размещения восьми гидромоторов по окружности относительно центральной оси редуктора с обеспечением требуемого диаметрального габарита и, что самое важное, необходимых прочностных характеристик зубчатых передач. Частота вращения вала гидромотора для этого редуктора составляет порядка 10000 об/мин. Разработаны варианты, в которых предусмотрено уменьшение габаритного размера редуктора в осевом направлении. Принято решение отказаться от применения по классической схеме сферических роликовых двухрядных самоустанавливающихся подшипников в опорах сателлитов. Радиальную нагрузку от троса барабана воспринимает подшипник, установленный на водило тихоходной ступени редуктора. Полученные результаты полностью отвечают требованиям технического задания.

Landing sling use increases data accuracy and sampling opportunities for large marine fishes captured during fishery-independent longline surveys

Landing sling use increases data accuracy and sampling opportunities for large marine fishes captured during fishery-independent longline surveys

Feedforward Control Law For A Shipboard Crane With Maryland Rigging System

A state-space model of the Maryland Rigging shipboard crane is derived from Newton's law under the assumptions of boom stiffness, fully controllable boom motion, no cable elasticity, no damping, and full control authority for changing the length of the rope. A chaotic rolling moment, with a dominant frequency of the same order as the resonance frequency of the shipboard crane, is applied to the ship as an external disturbance. The effect of this disturbance is studied. Since designing a controller by means of analytical methods for this system is too complex, we use a novel approach to this problem that focuses on the equilibrium point. By deriving the equations for calculating the position of the equilibrium point of the load in space, we change the problem to minimizing the change in the position of this point. A feedforward type controller is then designed as to keep the load closest to the “equilibrium point” for the actual roll angle. The controller seeks to suppress the load sway caused by the ship's rolling motion by changing the luffing angle while the friction in the pulley is assumed to be negligible. Changing the luffing angle seems to be the most effective control action in shipboard cranes. The feedforward gain is then optimized by numerical methods. The simulation results for this controller show a huge decrease in the sway magnitude as compared to the cases with no control. The roll angle, luffing angle of the boom, and the length of the rope are changed individually and then the related optimum feedforward gains are numerically obtained. Using these data, the mapping of the optimum gain based on these variables is derived. Scheduling the gain based on this mapping greatly improves the performance of the feedforward controller. This procedure can be repeated for similar applications.