Comparison of Lift Path Planning Algorithms for Mobile Crane Operations in Heavy Industrial Projects

Heavy industrial projects, especially oil refineries, are constructed by modules prefabricated in factories, transported to sites and installed by mobile cranes. Due to a large number of lifts on the congested and dynamic site layouts in heavy industrial projects, the lift path planning has been attention for not only safe and efficient mobile crane operation but also better project productivity and safety. Although the path planning algorithms have been introduced over the years, they have not been used actively in practice since the comparison of these algorithms has not been examined yet based on the realistic mobility of mobile cranes and real site environment. Therefore, this thesis compares the path planning algorithms including A* search, rapidly exploring random tree (RRT), genetic algorithms (GA) and 3D visualization-based mathematical algorithm (3DVMA) under the same site environment in order to find a competent method using measurement metrics considering collision-free and optimal lift paths with the lower crane operation cost and less computation time. The proposed comparison is implemented in a case study that includes a series of modules lifted by a mobile crane on various site conditions. This comparison shows the advantages and disadvantages of each algorithm for the crane path planning in heavy industrial projects and suggests the direction of further research in this field

Integrated Method of Analysis and Visualization Based on HLA and Its Application to Collaborative Simulation in Shipbuilding

학위논문 (석사)-- 서울대학교 대학원 : 조선해양공학과, 2016. 2. 노명일.During ship construction and offshore installation, more than two cranes are required in many cases. Even using one crane, some signalmen also need to assist the crane operator. And it is noticeable that the probability of accidents is considerably high due to operators collaboration. In order to prevent potential risks and ensure safety of operation process, simulation technology is widely applied. In this study, collaborative simulation is developed which allows several workers to conduct the same operation simultaneously in visual environment and then investigate potential safety risks. The current study can be summarized into four parts. Firstly, in order to describe the crane and block as real as possible, and make it as working in the actual operation site, VR (virtual reality) technology that could improve the sense of reality and immersion is studied. Secondly, because the cranes and block in virtual environment should move like a real movement, research on physics analysis technology based on multibody system dynamic has been done. Thirdly, to control the cranes in the simulation, workers who operate the crane need a controller. Therefore, a scenario generator is developed which can convert the signals from the controllers to the input datum for VR and analysis. Finally, in order to effectively integrate the VR technology, multibody dynamic system technology and controller as well as consider of interoperability and reuse, this study proposes an integrated simulation interface based on the High Level Architecture. This study utilizes developed collaborative simulation, which can be applied in simulating block turn-over (rotating 90 or 180 degrees) operation and topside module installation. Each simulation allows four operators to operate under the same virtual environment simultaneously and during this process, some danger may occur due to operators mistakes. This study makes contributions in simulating potential outcomes caused by operators operations, and collecting detailed data for further investigation. This study can be applied in ensuring safety in complicated scenarios, training operators and many other aspects.1. Introduction 1 1.1. Background of this study 1 1.2. Four technologies for collaborative simulation 4 1.3. Related works 6 1.3.1. Summary of the realted works and this study 11 1.4. Overview of this study 12 2. Analysis based on multibody system dynamic 14 2.1. Introduction to multibody system 14 2.2. Configuration for the implementation of physics-based analysis program 16 2.2.1. Multibody system dynamics kernel 17 2.2.2. Force calculation kernel 17 2.2.3. Numerical analysis kernel 18 2.2.4. Hybrid DEVS/DTSS kernel 19 2.2.5. Scenario management kernel 19 2.2.6. Collision detection kernel 20 2.3. Procedure for solving equations of motion in physics-based analysis program 21 2.4. Modeling method in physics-based analysis program 22 3. Visualization for virtual reality 24 3.1. Introduction to virtual reality 24 3.2. Modeling method of virtual reality 26 4. Controller for interactive user input 27 4.1. Hardware parameters 27 4.1.1. Joystick 27 4.1.2. Head mounted display 28 4.2. Controller for scenario generation 29 5. Integrated simulation interface based on high level architecture 31 5.1. Necessity of HLA 31 5.2. Technical overview of HLA 34 5.2.1. Interoperability and reuse 34 5.2.2. Important concepts of HLA 35 5.2.3. HLA components 35 5.2.4. Management areas of RTI 37 5.3. Runtime infrastructure (RTI) 40 5.3.1. Process for selecting RTI 40 5.3.2. RACoN 40 5.3.3. Simulation Generator (SimGe) 40 5.3.4. Portico 41 5.4. Case study: chat federate application 43 5.4.1. Object model 44 5.4.2. The class structure 46 5.4.3. Implementation 47 5.4.4. Portico RTI initialization data 48 5.5. Framework of collaborative simulation 49 5.6. Integrated method of analysis, VR and controller 51 5.6.1. FOM design for block lifting example 51 5.6.2. Adapter design for block lifting example 52 5.6.3. Data transform procedure by using integrated simulation interface 53 6. Application examples of collaborative simulation in shipbuilding and offshore installation 54 6.1. Application to Block turn-over operation 56 6.1.1. Introduction to block turn-over operation 56 6.1.2. Collaborative simulation for block turn-over operation 58 6.1.3. Simulation components for block turn-over operation 59 6.1.4. Modeling result for analysis 60 6.1.5. Modeling result for VR 61 6.1.6. Inputs and outputs of simulation components 63 6.1.7. Data transform procedure by using integrated simulation interface 64 6.1.8. Prototype simulator based on the integrated simulation interface 69 6.1.9. Collaborative simulation results of the prototype simulator 70 6.1.10. Discussion on collaborative simulation results (wire tension) 74 6.2. Application to Topside module installation 77 6.2.1. Introduction to topside module installation 77 6.2.2. Collaborative simulation for block turn-over operation 79 6.2.3. Simulation components for block turn-over operation 81 6.2.4. Modeling result for analysis 82 6.2.5. Modeling result for VR 83 6.2.6. Inputs and outputs of simulation components 85 6.2.7. Data transform procedure by using integrated simulation interface 86 6.2.8. Collaborative simulation results of the prototype simulator 91 6.2.9. Discussion on collaborative simulation results (wire tension) 94 7. Conclusions 97 References 99 APPENDICES 101 A. Implemented services of RACoN 102 B. Prerequisites for RACoN 109 C. Portico environment configuration 110 초록 111Maste

An efficient adaptive fuzzy hierarchical sliding mode control strategy for 6 degrees of freedom overhead crane

The paper proposes a new approach to efficiently control a three-dimensional overhead crane with 6 degrees of freedom (DoF). Most of the works proposing a control law for a gantry crane assume that it has five output variables, including three positions of the trolley, bridge, and pulley and two swing angles of the hoisting cable. In fact, the elasticity of the hoisting cable, which causes oscillation in the cable direction, is not fully incorporated into the model yet. Therefore, our work considers that six under-actuated outputs exist in a crane system. To design an efficient controller for the 6 DoF crane, it first employs the hierarchical sliding mode control approach, which not only guarantees stability but also minimizes the sway and oscillation of the overhead crane when it transports a payload to a desired location. Moreover, the unknown and uncertain parameters of the system caused by its actuator nonlinearity and external disturbances are adaptively estimated and inferred by utilizing the fuzzy inference rule mechanism, which results in efficient operations of the crane in real time. More importantly, stabilization of the crane controlled by the proposed algorithm is theoretically proved by the use of the Lyapunov function. The proposed control approach was implemented in a synthetic environment for the extensive evaluation, where the obtained results demonstrate its effectiveness. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Wind-Wise Automated Decision Support Tool for Tower Crane type selection and location

Extreme wind speeds pose a serious threat to tower crane stability. Out-of-service wind loads trigger moments that may lead to overturning of a tower crane. Even if the tower crane is anchored to the ground, its structural integrity can be compromised by strong winds since the pressure exerted by the latter can lead to excessive deflections of the mast (which may be a main cause for collapse of the entire structure). Paradoxically, although strong winds have been linked to some catastrophic failures of tower cranes, their effect is often overlooked from a construction management perspective when the models for these cranes are selected during construction planning. Moreover, tower crane location and resources supply locations selection both significantly influence the tower crane model designation and subsequently the overall productivity of the project. This paper proposes a methodology which is consisting of (i) twofold mathematical distance-based-optimization technique encompassing the crane capacity (represented as the lifted moments) and hook operation time to analyze the tower crane site layout combinatorial optimization (determining the optimal crane and the corresponding material supply locations) therefore, facilitating selecting the tower crane model through the lifting critical radius. This optimization gives practitioners the option to explore the effect of different sets of constraints on productivity and overall lifting moments. In this respect, the planning team can choose to favor faster crane operations (i.e., a tighter schedule of crane operations), or they may opt to minimize the lifting-moment, choosing a more conservative crane capacity model to mitigate total cost (ii) a static wind analysis to investigate the efficiency of the tower crane model selected to withstand extreme wind speeds against overturning (through grounding bearing pressures reactions) and mast excessive deformation (compared to allowable deflection constraints). The proposed methodology is applied on a large-scale construction site with 514 crane and material supply location and the selected tower crane model resistance against maximum potential wind speed is examined and ballast base dimensions are determined. Additionally, a case study from the existing literature is investigated as a small-scale construction site and more improved site layout optimization is generated. Finally, a well-known-real-world crane accident is analyzed to validate the performance of the proposed wind static analysis method

Port safety, including, storage and the disposal of dangerous goods in Namibian ports

This paper; Port safety including handling, storage and disposal of dangerous goods, aims to enhance port safety and consequently efficiency and production in the ports of Namibia. It attempts to achieve this through the establishment of a soundly based safety policy common to all of the Namibian ports. The paper discusses the safety of employees; personnel protective equipment; safety conduct by the individual employees; legal obligations; plant and equipment; cargo handling gear and the disposal of dangerous cargo and the role of various national and international organizations in achieving port safety. It discusses the influences on safety and port development, especially with the increasing quantities of dangerous goods being handled in port today how accidents occur in the port due to various causes and all the preventive measures that may be taken to avert accidents. This paper recommends to make independent Namibia less dependent on Wai vis Bay (which still is under the control of S.A.) Luderitz Bay can be developed into a port for handling most of Namibia’s import and export requirements as it is a large natural habour with adequate space. The paper concludes, will ensure port efficiency and subsequent economic advantages for the Namibian nation

Federal Register

Daily publication of the U.S. Office of the Federal Register contains rules and regulations, proposed legislation and rule changes, and other notices, including "Presidential proclamations and Executive Orders, Federal agency documents having general applicability and legal effect, documents required to be published by act of Congress, and other Federal agency documents of public interest" (p. ii). Table of Contents starts on page iii

Fifteen-foot diameter modular space station Kennedy Space Center launch site support definition (space station program Phase B extension definition)

This document defines the facilities, equipment, and operational plans required to support the MSS Program at KSC. Included is an analysis of KSC operations, a definition of flow plans, facility utilization and modifications, test plans and concepts, activation, and tradeoff studies. Existing GSE and facilities that have a potential utilization are identified, and new items are defined where possible. The study concludes that the existing facilities are suitable for use in the space station program without major modification from the Saturn-Apollo configuration

Improving crane safety by agent-based dynamic motion planning using UWB real-time location system

The safe operation of cranes requires not only the experience of the operator, but also sufficient and appropriate support in real time. Due to the dynamic nature of construction sites, unexpected changes in the site layout may create new obstacles for the crane that can result in collisions and accidents. Limited research has been done on efficient re-planning for cranes with near real-time environment updating while considering communications between construction crews. To improve the safety of mobile crane operations and to provide more awareness on site, the present research proposes a near real-time monitoring and motion planning approach to improve crane safety on construction sites using an ultra wideband (UWB) real-time location system (RTLS) technology. In addition, an agent system framework is proposed to guide crane operators for safe crane operations by enhancing environment awareness and by providing intelligent re-planning. Location data are collected from tags attached to cranes and are processed by the agent system to identify the poses of dynamic objects, which is used to generate a new motion plan to guide the crane movement and thus to avoid potential collision. A motion planning algorithm, RRT-Con-Con-Mod, is proposed to efficiently generate safe and smooth paths for crane motions, mainly for the boom movement, while taking into account the engineering constraints and the path quality. A dynamic motion planning algorithm, DRRT-Con-Con-Mod, is proposed to ensure safety during the execution phase by quickly re-planning and avoiding collisions. In addition, an anytime algorithm is proposed to search for better solutions during a given time period by improving the path smoothness and by reducing the path execution time. The proposed algorithms are compared with other motion planning and re-planning algorithms. The results show that the proposed algorithms can quickly find a safe and smooth motion plan. Several tests of a UWB system have been applied in the laboratory and in indoor and outdoor environments to investigate the requirements of applying UWB on construction sites, that is, requirements including accuracy, visibility, scalability, and real-time. To satisfy these requirements, the configuration of the UWB system has been analyzed in detail to decide the sensors’ and tags’ locations and numbers based on heuristic rules. These tests show a good potential for using UWB tracking technology in construction sites by processing and organizing location data into useful information for near real-time environment updating. Furthermore, the framework of an agent system is proposed to integrate the proposed methodologies of motion planning and near real-time tracking. Different agents are created to represent the equipment, to coordinate tasks, and to update the site information. The functions of these agents include exchanging information, deciding priorities, etc. The current research will benefit the construction industry by providing more awareness of dynamic construction site conditions, a safer and more efficient work site, and more reliable decision support based on good communications

BUILDOUT AND UPGRADE OF CENTRAL EMERGENCY GENERATOR SYSTEM, GENERATOR 3 AND 4 ELECTRICAL INSTALLATION

SECTION 01000—SUMMARY OF WORK PART 1—GENERAL 1.1 SUMMARY The work to be performed under this project consists of providing the labor, equipment, and materials to perform "Buildout and Upgrade of Central Emergency Generator System, Generator 3 and 4 Electrical Installation" for the National Aeronautics and Space Administration at the Dryden Flight Research Center (NASA/DFRC), Edwards, California 93523. All modifications to existing substations and electrical distribution systems are the responsibility of the contractor. It is the contractor’s responsibility to supply a complete and functionally operational system. The work shall be performed in accordance with these specifications and the related drawings. The work of this project is defined by the plans and specifications contained and referenced herein. This work specifically includes but is not limited to the following: Scope of Work - Installation 1. Install all electrical wiring and controls for new generators 3 and 4 to match existing electrical installation for generators 1 and 2 and in accordance with drawings. Contractor shall provide as-built details for electrical installation. 2. Install battery charger systems for new generators 3 and 4 to match existing battery charging equipment and installation for generators 1 and 2. This may require exchange of some battery charger parts already on-hand. Supply power to new battery chargers from panel and breakers as shown on drawings. Utilize existing conduits already routed to generators 3 and 4 to field route the new wiring in the most reasonable way possible. 3. Install electrical wiring for fuel/lube systems for new generators 3 and 4 to match existing installation for generators 1 and 2. Supply power to lube oil heaters and fuel system (day tanks) from panel and breakers as shown on drawings. Utilize existing conduits already routed to generators 3 and 4 to field route the new wiring in the most reasonable way possible. Add any conduits necessary to complete wiring to fuel systems. 4. Install power to new dampers/louvers from panel and breakers as shown on drawings. Wiring shall be similar to installation to existing dampers/louvers. Utilize existing conduits already routed to louver areas to field route the new wiring in the most reasonable way possible. Add any conduits necessary to complete wiring to new dampers/louvers. 5. Install power to jacket water heaters for new generators 3 and 4 from panel and breakers as shown on drawings. Utilize existing conduits already routed to generators 3 and 4 to field route the new wiring in the most reasonable way possible. 6. Install new neutral grounding resistor and associated parts and wiring for new generators 3 and 4 to match existing installation for generators 1 and 2. Grounding resistors will be Government Furnished Equipment (GFE). 7. Install two new switchgear sections, one for generator #3 and one for generator #4, to match existing generator #1 cubicle design and installation and in accordance with drawings and existing parts lists. This switchgear will be provided as GFE. 8. Ground all new switchgear, generators 3 and 4, and any other new equipment to match existing grounding connections for generators 1 and 2, switchgear and other equipment. See drawings for additional details. Grounding grid is already existing. Ensure that all grounding meets National Electrical Code requirements. 9. Cummins DMC control for the generator and switchgear syst