Payload's sway angle measurement for container in the crane system based on remote sensing

The demand for a high quickly measuring angle in the port crane system should be considered when the container has been transferred from one place to another place. It is significant to build the feedback linking of payload's angle in the integrated crane system. The value of accurate measurement of the angle can be used to optimize the crane control system. In this context, the design and implementation of the experimental setup associated with emulated cranes will be carried out. Several solutions for remote angle measurement were considered one of the considered solutions being represented by millimeter microwave radar sensors. Special developments of algorithms to calculate the sway angle of payload or container were considered as so as the real-time processing using Arduino Uno computation platform. The following objectives were successfully reached. 1. Development of remote sensing system for payload's swing angle measurement considering radars such the sensing devices; 2. Development of a novel angle algorithm measurement and real-time processing of data; 3. Development of a prototype characterized by real-time processing and remote detection capabilities considering short-range and long-range measurements, such as lidar sensor or radar sensor.A demanda por um ângulo de medição rápido e alto no sistema de guindaste portuário deve ser considerada quando o contêiner for transferido de um local para outro. É significativo construir a ligação de feedback do ângulo da carga útil no sistema de guindaste integrado. O valor da medição precisa do ângulo pode ser usado para otimizar o sistema de controle do guindaste. Neste contexto, será realizada a concepção e implementação da configuração experimental associada a gruas emuladas. Diversas soluções para medição remota de ângulos foram consideradas uma das soluções consideradas sendo representadas por sensores de micro-ondas milimetrados. Desenvolvimentos especiais de algoritmos para calcular o ângulo de oscilação da carga útil ou contêiner foram considerados, assim como o processamento em tempo real usando a plataforma de computação Arduino Uno. Os seguintes objetivos foram alcançados com sucesso. 1. Desenvolvimento de sistema de sensoriamento remoto para medição do ângulo de oscilação da carga útil considerando radares como os dispositivos de detecção; 2. Desenvolvimento de um novo algoritmo de medição de ângulos e processamento de dados em tempo real; 3. Desenvolvimento de um protótipo caracterizado por processamento em tempo real e capacidade de detecção remota considerando medições de curto e longo alcance, como sensor LIDAR ou sensor de radar

Vision-based control of a knuckle boom crane with online cable length estimation

A vision-based controller for a knuckle boom crane is presented. The controller is used to control the motion of the crane tip and at the same time compensate for payload oscillations. The oscillations of the payload are measured with three cameras that are fixed to the crane king and are used to track two spherical markers fixed to the payload cable. Based on color and size information, each camera identifies the image points corresponding to the markers. The payload angles are then determined using linear triangulation of the image points. An extended Kalman filter is used for estimation of payload angles and angular velocity. The length of the payload cable is also estimated using a least squares technique with projection. The crane is controlled by a linear cascade controller where the inner control loop is designed to damp out the pendulum oscillation, and the crane tip is controlled by the outer loop. The control variable of the controller is the commanded crane tip acceleration, which is converted to a velocity command using a velocity loop. The performance of the control system is studied experimentally using a scaled laboratory version of a knuckle boom crane

Minimum Time Control of a Gantry Crane System with Rate Constraints

This paper focuses on the development of minimum time control profiles for point-to-point motion of a gantry crane system in the presence of uncertainties in modal parameters. Assuming that the velocity of the trolley of the crane can be commanded and is subject to limits, an optimal control problem is posed to determine the bang-off-bang control profile to transition the system from a point of rest to the terminal states with no residual vibrations. Both undamped and underdamped systems are considered and the variation of the structure of the optimal control profiles as a function of the final displacement is studied. As the magnitude of the rigid body displacement is increased, the collapse and birthing of switches in the optimal control profile are observed and explained. Robustness to uncertainties in modal parameters is accounted for by forcing the state sensitivities at the terminal time to zero. The observation that the time-optimal control profile merges with the robust time-optimal control is noted for specific terminal displacements and the migration of zeros of the time-delay filter parameterizing the optimal control profile are used to explain this counter intuitive result. A two degree of freedom gantry crane system is used to experimentally validate the observations of the numerical studies and the tradeoff of increase in maneuver time to the reduction of residual vibrations is experimentally illustrated

Improving Automated Operations of Heavy-Duty Manipulators with Modular Model-Based Control Design

The rapid development of robotization and automation in mobile working machines aims to increase productivity and safety in many industrial sectors. In heavy-duty applications, hydraulically actuated manipulators are the common solution due to their large power-to-weight ratio. As hydraulic systems can exhibit nonlinear dynamic behavior, automated operations with closed-loop control become challenging. In industrial applications, the dexterity of operations for manipulators is ensured by providing interfaces to equip product variants with different tool attachments. By considering these domain-specific tool attachments for heavy-duty hydraulic manipulators (HHMs), the autonomous robotic operating development for all product variants might be a time-consuming process. This thesis aims to develop a modular nonlinear model-based (NMB) control method for HHMs to enable systematic NMB model reuse and control system modularity across different HHM product variants with actuators and tool attachments. Equally importantly, the properties of NMB control are used to improve the high-performance control for multi degrees-of-freedom robotic HHMs, as rigorously stability-guaranteed control systems have been shown to provide superior performance. To achieve these objectives, four research problems (RPs) on HHM controls are addressed. The RPs are focused on damping control methods in underactuated tool attachments, compensating for static actuator nonlinearities, and, equally significantly, improving overall control performance. The fourth RP is introduced for hydraulic series elastic actuators (HSEAs) in HHM applications, which can be regarded as supplementing NMB control with the aim of improving force controllability. Six publications are presented to investigate the RPs in this thesis. The control development focus was on modular NMB control design for HHMs equipped with different actuators and tool attachments consisting of passive and actuated joints. The designed control methods were demonstrated on a full-size HHM and a novel HSEA concept in a heavy-duty experimental setup. The results verified that modular control design for HHM systems can be used to decrease the modifications required to use the manipulator with different tool attachments and floating-base environments

Simulation and Control of an Anti-Swing System for a Suspended Load attached to a moving Base Robot

Master's thesis Mechatronics MAS500 - University of Agder 2018Advanced motion compensation is an important eld of engineering in today's o shore industry. Performing advanced load handling operations at sea requires high attention to both safety and e ciency. In environments governed by wave motion and harsh weather conditions, these types of operations are complex tasks. Most of the load handling scenarios are performed by advanced o shore loader cranes, where many of these are equipped with the industry's state-of-the-art Active Heave Compensation. This technology is capable of compensating for the wave height disturbance, meaning that the load is kept at a constant height above the sea oor. A common problem arises when equipment or personnel have to be transported from a moving vessel to another vessel or o shore installation. In these scenarios compensation of the side-to-side motion is of equal importance as the relative height movement. This thesis proposes a method to reduce this side-ways motion. An anti-swing system has been developed for a simulation model of a suspended load attached to a moving base robot. The work focuses on deriving mathematical models of the related systems, where control systems are designed to the reduce the swing motion of the suspended load by actuation of the load handling robot. The developed system models are based on the available equipment of the Norwegian Motion-Laboratory. Results of the proposed system are obtained from the simulation of the motion system, which yields a system capable of tracking the robotic tool-point reference signal with acceptable accuracy and reducing the suspended load's swing-angles with satisfactory performance

Design of paired column semisubmersible hull

There is a constant effort to reconfigure column stabilized semisubmersible unit to meet the challenging demands associated with deep water exploration. Paired column semisubmersible platform is one of the recent column stabilized semisubmersible hull configured to allow top-deck well head compatibility for oil reserves in deep waters. Its unique ability to maintain reduced vertical motion in extreme weather conditions despite its hull size and payload create a high payload to motion ratio, as compare to conventional semisubmersible hulls. This unique feature makes it recommendable for other hull applications in ocean engineering. A study has been carried out to harness this high payload to motion ratio offered by this new hull concept in the development of drilling and production platforms in deep waters, support and foundation systems. Numerical models were developed to understand the semisubmersible hull (dynamics of the reduced vertical motion and its ability to withstand bending and twisting behaviour from extreme wave conditions). Prior to this, a preliminary CFD model was developed in to understand the vortex shedding effect on the arrayed columns. An experimental setup was also put together to understand this motion behaviour, alongside a detailed review of the first model. The motion response of a scaled hull model was studied in a wave tank with a Digital Image Correlation (DIC) system known as Imetrum. To further investigate its application for other ocean depths and support systems, series of hydrodynamic models were developed in ANSYS AQWA with weather conditions as recommended by API, DNV, and ABS. The AQWA model was validated with results recorded by Imetrum system from the wave tank experimental test. The wave forces and moments were studied for different draft sizes and ocean conditions, and their response where checked in ORCAFLEX. A finite element model was finally developed in APDL to understand the nature and effect of stresses from wave, current and wind loads, alongside topside integration. The results obtained from the FE model was use to postulate reinforcement during scantling, for different hull applications. The results for motion response showed favourable heeling moment for smaller draft sizes as recommended by regulatory bodies, but a reconfiguration for heave displacement might be required for smaller draft size. In such case, an increase in pontoon area or an additional heave plate attachment has been recommended. Furthermore, the effect of wavecurrent interactions was observed to create unique motion behaviour for all draft sizes at resonance frequency range. A fluid-structure interaction model of multi-phase flow will be required to understand this behaviour. The stress concentration on the columns generated from hydrodynamic loads was observed to be higher on the inner columns, relative to the outer ones

Motion Control of Hydraulic Winch Using Variable Displacement Motors

The paper II is excluded from the dissertation with respect to copyright.To compete in the open market of the offshore crane industry, it is imperative for the manufacturer to continuously improve crane operability. In this context, the crane operability is expressed by means of a so-called weather window. The weather window is computed from the crane characteristics in combination with that of the vessel and the payload to be handled. It returns a set of boundaries for when it is accepted to perform a planned lift, mainly in terms of current sea-state and wind. The most important crane operability characteristics that enter into the computation of the weather window are maximum wire velocity and load capacity. This thesis focuses on how to improve the operability of active heave compensated offshore cranes. Two ways of achieving that goal have been investigated, namely, an improved control strategy and the use of model-based lift planning. The system investigated is the hydraulic active/passive winch system used by National Oilwell Varco. A new control strategy for the system was developed, tested, and implemented. The new strategy utilizes that variable displacement of the hydraulic motors of the active system of the winch drive. The strategy, semi secondary control, gave significant benefits in terms of reduced peak-pressure, increased load capacity, increased wire-speed capacity, and smoother winch performance at low winch speed. The results were validated and verified through simulations and in-field measurements.publishedVersio