Operated Vehicle Research Articles

Image Based Visual Servoing for Floating Base Mobile Manipulator Systems with Prescribed Performance under Operational Constraints

This paper presents a novel Image-Based Visual Servoing (IBVS) control approach for Floating Base Mobile Manipulator Systems (FBMMSs) that imposes prescribed transient and steady-state response on the image feature coordinate errors while satisfying the visibility constraints that arise owing to the camera’s limited field of view. The proposed control strategy does not incorporate any knowledge on either the FBMMS dynamic model, the exogenous disturbances, or the inevitable camera calibration and depth measurement errors. More specifically, it guarantees: (i) predefined behavior in terms of overshoot, convergence rate, and maximum steady-state error value of the image features and system velocities tracking errors; (ii) satisfaction of camera field of view constraints; (iii) bounded closed-loop control signals, and (iv) reduced design and implementation complexity. Additionally, the performance of the developed scheme is solely determined by certain designer-specified performance functions/parameters, and it is fully decoupled by the control gains selection. The efficiency of the proposed scheme is demonstrated via a realistic simulation study, using an eye-in-hand Underwater Vehicle Manipulator System (UVMS) as a test-bed FBMMS platform.

Cooperative Control of Underwater Vehicle-Manipulator Systems Based on the SDC Method.

The paper considers the problem of cooperative control synthesis for a complex of underwater vehicle–manipulator systems (UVMS) to perform the work of moving a cargo along a given trajectory. Here, we used the approach based on the representation of nonlinear dynamics models in the form of state space with state-dependent coefficients (SDC-form). That allowed us to apply methods of suboptimal control with feedback based on the state-dependent differential Riccati equation (SDDRE) solution at a finite time interval, providing the change in control intensity with the transient effect of the system matrices in SDC form. The paper reveals two approaches to system implementation: a general controller for the whole system and a set of independent subcontrollers for UVMSs. The results of both approaches are similar; however, for the systems with a small number of manipulators, the common structure is recommended, and for the systems with a large number of manipulators, the approach with independent subcontrollers may be more acceptable. The proposed method of cooperative control was tested on the task of cooperative control for two UVMSs with six-link manipulators Orion 7R. The simulation results are presented in the article and show the effectiveness of the proposed method.

Self-Management of ROV Umbilical Using Sliding Buoys and Stop

The umbilical of Remote Operated Vehicle (ROV) has two main problems: it is subject to entanglement with obstacles or itself, and its shape is difficult to predict for the navigation. To address these issues, this article proposes a passive self-management of an ROV’s umbilical, suitable for underwater and seafloor exploration. By adding two buoys moving freely on the umbilical, the described method avoids self-entanglement of the cable by stretching it, and gives it a predictable shape. A fast time computational model of the cable is proposed to provide feedback to the operator. The buoys move on their own to keep the cable taut without a motorized system, making this method easy to adapt to existing ROVs with few constraints on their navigation. Simulations and experimentation in pool show the effectiveness of the method.

Hybrid Visual SLAM for Underwater Vehicle Manipulator Systems

This paper presents a novel visual feature based scene mapping method for underwater vehicle manipulator systems (UVMSs), with specific emphasis on robust mapping in natural seafloor environments. Our method uses GPU accelerated SIFT features in a graph optimization framework to build a feature map. The map scale is constrained by features from a vehicle mounted stereo camera, and we exploit the dynamic positioning capability of the manipulator system by fusing features from a wrist mounted fisheye camera into the map to extend it beyond the limited viewpoint of the vehicle mounted cameras. Our hybrid SLAM method is evaluated on challenging image sequences collected with a UVMS in natural deep seafloor environments of the Costa Rican continental shelf margin, and we also evaluate the stereo only mode on a shallow reef survey dataset. Results on these datasets demonstrate the high accuracy of our system and suitability for operating in diverse and natural seafloor environments. We also contribute these datasets for public use.

Laboratory Investigation on Detecting Bridge Scour Using the Indirect Measurement from a Passing Vehicle

For bridges with surface foundations, scour is one of the main reasons for bridge failures. In regard to structural health monitoring, vibration-based scour detection techniques have received increasing attention over the past two decades. Scour occurs below the water surface in rivers or sea, leading to difficulty in equipment installation and maintenance. Recently, the concept of “drive-by” SHM using the indirect measurement of passing vehicle responses has been developed rapidly due to its convenience and low cost. This paper proposes a method to detect scour using the vehicle responses under an operational vehicle speed. The wavelet transform was applied to vehicle accelerations to obtain the wavelet energy. It was found that the wavelet energy increases with the increase in the scour damage level. However, the wavelet energy may also be affected by the on-site operating environments, such as sensor noise and other variabilities, which interferes with the identification of scour in practice. Hence, in this work, a statistical-wavelet-based approach was presented to effectively detect the presence of scour and even its location. The feasibility of the proposed approach is verified in both numerical simulation and lab experiments. The results show that the proposed method has a good potential to detect scour using indirect measurements.

INOVASI PELAYANAN “SI JARAN IJO” (JEMPUT BOLA RENTAN ADMINDUK ISO JUJUK OMAH) DI DINAS KEPENDUDUKAN DAN PENCATATAN SIPIL KABUPATEN BLITAR

The service innovation of Si Jaran Ijo (Pick Ball Vulnerable Adminduk Iso Jujuk Omah) is an innovation created by the Department of Population and Civil Registration (Dispendukcapil) of Blitar Regency to provide convenience for population administration services (Adminduk) especially the recording of Electronic Identity Cards (e-KTP). for people who are included in the category of vulnerable populations, such as neglected, remote, people with mental disorders (ODGJ), people with disabilities, and elderly people. Si Jaran Ijo's innovation is carried out with a ball pick-up system where the Dispendukcapil will immediately deploy a Si Jaran Ijo team to visit the applicant's homes according to the application from the village and sub-district. Si Jaran Ijo's innovation arises because of problems that occur in the field, namely there are still many people in Blitar Regency who do not yet have an e-KTP, one of which is due to the limitations that the community has in accessing population administration services at the Dispendukcapil. The purpose of this study is to describe the service innovation of Si Jaran Ijo in the Dispendukcapil Blitar Regency. The type of research used is descriptive research with a qualitative approach. The focus of his research is using public service innovations according to Bloch (2010), including Product, Process, Organizational, Communication. Data collection techniques through interviews, observation, and also documentation. Data analysis techniques are data collection, data reduction, data presentation, and drawing conclusions. The results of the research on service innovations of Si Jaran Ijo (Pick Ball Vulnerable Adminduk Iso Jujuk Omah), namely: 1) Product, the Dispendukcapil Blitar Regency has produced a product in the form of an e-KTP through the innovation of Si Jaran Ijo. 2) The process, the innovation service of Si Jaran Ijo is carried out with a ball pick-up system, meaning that Si Jaran Ijo officers will visit the applicant's homes to record the e-KTP. 3) The organization, in carrying out Si Jaran Ijo's innovation, the Dispendukcapil of Blitar Regency formed a team of four people to provide services placed in each TLA (Adminduk Service Place) and collaborate with RT, RW and Village to help the success of innovation . 4) Communication, to introduce Si Jaran Ijo's service innovation to the community, the Blitar Regency Dispendukcapil party conducts socialization before the innovation is launched using mass media and also social media. The researcher's suggestions are to add Si Jaran Ijo's operational vehicle in the form of a car so that during the rainy season the implementation of Si Jaran Ijo's innovation can still run smoothly, add officers to the Si Jaran Ijo team so that applicants do not wait too long to get services, and increase socialization related to innovation. Si Jaran Ijo services, one of which can be done by installing a banner.

Coralligenous assemblages of continental shelf: Multiple spatial scale variability in the western Sardinia

Mediterranean mesophotic hard bottoms are mostly characterized by coralligenous banks. Although investigations on this habitat have increased in the last years, knowledge about its structure and spatial variability is still very limited as most studies are focused on the description of assemblages of peculiar and small locations such as biodiversity hotspots. This study aimed at i) describing coralligenous megafauna on the western Sardinian continental shelf between 80 and 120 m of depth, ii) assessing the distribution of the dominant taxa, and iii) estimating patterns of spatial variability at different scales. The coralligenous banks were studied along five sectors of the western Sardinian continental shelf by means of Remote Operated Vehicles (ROVs) and images were analyzed to identify the main taxa or morphological groups and their abundance. Results highlighted several common patterns among sectors, with assemblages dominated by the gorgonians Eunicella cavolini and Callogorgia verticillata. On the other hand, some taxa (e.g. Callogorgia verticillata, Paramuricea hirsuta, Antipathella subpinnata, Corallium rubrum Paramuricea clavata, Poecillastra compressa and Aplidium spp.) mainly contribute to segregate the coralligenous assemblages within the considered sectors of this study. A high small-scale variability was also observed. The presence of extensive and well diversified mesophotic animal forests stresses the importance to improve the conservation of the western Sardinian continental shelf.

A Quantitative Parametric Study on Output Time Delays for Autonomous Underwater Cleaning Operations

Offshore pipelines and structures require regular marine growth removal and inspection to ensure structural integrity. These operations are typically carried out by Remotely Operated Vehicles (ROVs) and demand reliable and accurate feedback signals for operating the ROVs efficiently under harsh offshore conditions. This study investigates and quantifies how sensor delays impact the expected control performance without the need for defining the control parameters. Input-output (IO) controllability analysis of the open-loop system is applied to find the lower bound of the H-infinity peaks of the unspecified optimal closed-loop systems. The performance analyses have shown that near-structure operations, such as pipeline inspection or cleaning, in which small error tolerances are required, have a small threshold for the time delays. The IO controllability analysis indicates that off-structure navigation allow substantial larger time delays. Especially heading is vulnerable to time delay; however, fast-responding sensors usually measure this motion. Lastly, a sensor comparison is presented where available sensors are evaluated for each ROV motion’s respective sensor-induced time delays. It is concluded that even though off-structure navigation have larger time delay tolerance the corresponding sensors also introduce substantially larger time delays.

ANALISIS TUGAS POLISI PAMONG PRAJA DALAM PENCEGAHAN DAN PENGENDALIAN COVID-19

Abstract Enforcement carried out by the Lampung Province civil service police enforcement officers in implementing the 2020 regional regulation Number 3 regarding the adaptation of new habits in preventing, controlling COVID-19, by coordinating with the Bandar Lampung City enforcement apparatus. From the observations made by the researchers, the task of the competent authorities in carrying out COVID-19 prevention measures in implementing the Governor's Regulation has not been maximized due to the lack of budget so that operational vehicles and equipment used are limited. Besides that, many people also ignore health protocols when they are outside. This study aims to determine the duties of the Lampung Provincial Civil Service Police and to find out the Prevention and Control of Covid 19 carried out by the Lampung Provincial Civil Service Police. The research method used is qualitative research methods, data collection techniques through observation, interviews, and documentation. The task of the Civil Service Police has not been maximized in enforcing the 'Lampung Provincial Regulation Number 3 of 2020 concerning the Adaptation of New Habits in the Prevention and Control of Covid-19'. Based on the results of the study, it is known that the cause has not been maximized due to the minimal budget so that operational vehicles and equipment used are limited and in the prevention and control of Covid-19 there are still many people who do not wear masks when outside. Keywords: Prevention, Control, Covid-19

The mineralization and early diagenesis of deep-sea coral Madrepora oculata

The skeletons of aragonitic corals carry essential information about oceanic environmental changes in the past. However, coral-based geochemical proxies are sensitive to vital effect and post-depositional diagenetic processes, which have not been well understood for deep-sea corals. In this study, we have investigated the mineralization and early diagenetic process of the dendroid stem of a dead deep-sea scleractinian coral sample (Madrepora oculata) collected by Remote Operated Vehicle (ROV) from a seamount in the Caroline Ridge, western Pacific. Despite being only ~270 years old, as dated by the U-series disequilibrium method, this sample already has extensive diagenesis including a visible chalky layer. The outermost chalky layer and the adjacent pristine skeleton of the sample were characterized by multiple mineralogical (SEM, XRD, EBSD, Raman Spectroscopy) and geochemical (ICP-OES, LA-ICP-MS, IR-MS, MC-ICP-MS) techniques. Skeletal stable C and O isotopes display strong linearity, with a trend pointing toward the theoretical isotopic composition of inorganically-precipitated aragonite from local seawater. This observation suggests that the epithecal mineralization of M. oculata is far from equilibrium with seawater and can be quantitatively explained by bio-mineralization models developed for solitary scleractinian corals. We further show that chalking of the outer layer, a common feature in sub-fossilized deep-sea corals, is caused by microbial-driven boring and μm-scale dissolution voids at an average rate of 3.5 μmol/cm2/y (scaled to the skeleton surface) without notable secondary infillings or mineralogical alternations. The higher average δ13C and δ18O of the chalky part than the pristine part might be due to the preferential dissolution of carbonate relatively depleted in 13C and 18O during alteration, and/or reduced isotope fractionation from seawater during coral mineralization of the outer layer. The chalky layer shows significantly higher Mn/Ca and Th/Ca ratios than the pristine part, characterized by Th/Mn ratios similar to that of the dissolved component of local seawater. Our study suggests that the incorporation of external Th into the coral skeleton is most likely associated with organic binding rather than detrital contamination, secondary carbonate mineral formation, adsorption onto surfaces of chalky aragonite or ferromanganese oxides, with important implications for coral U-series geochronology.

다물체동역학 기반의 수중트랙차량 디지털 트윈 모델링 연구

In the field of underwater robots, Remotely Operated Vehicle (ROV) operators are seriously affected by the possibility of remote control by dust generated during submarine work. Thus, research on Cyber-Physical Operation Systems (CPOSs) has been conducted to improve remote controllability. The CPOS consists of a real-time physical engine, real-time visualization with VR, and Human-in-the-loop simulation. The purpose of this paper is to study the digital twin modeling of a real-time physics engine for a CPOS. Accordingly, a thorough analysis of an ROV

Offshore wind farms contribute to epibenthic biodiversity in the North Sea

The North Sea was once abundantly covered with hard substrates such as oyster beds, coarse peat banks and glacial erratics, providing habitat to a rich community of marine species. Most of these habitats were destroyed by bottom-trawl fisheries over the past century, and today, the seabed hosts a relatively poor species community. Emerging offshore windfarms include the re-introduction of hard substrate by means of scour protection around the foundation of wind turbines. It is assumed that the new habitat will contribute to marine biodiversity, and this study aims to demonstrate that. Video data were collected using a Remotely Operated Vehicle in four wind farms in the southern North Sea. A quantitative assessment was made to determine the effect of scour protection on community structure. The assessment revealed distinct community clusters for geographic location and seabed type. Windfarms closely located to each other had a more similar epibenthic community compared to those further away. The epibenthic community at the rocky armour layer of the scour protection had a different species composition and a higher species abundance than the one at the sandy seabed surrounding it. Species diversity by means of richness, evenness and the Shannon diversity index was not consistently higher or lower for the communities at the different seabed types.This study shows that marine life inhabits scour protection in offshore wind farms and that it is different from the community living at the surrounding seabed. Knowing the potential epibenthic community structure at and around a scour protection supports the development of new wind farms that include components to enhance their ecological value. Herewith, our study contributes to efforts to restore biodiversity in the North Sea.

The Bike-courier as an Energy Efficiency Instrument at the University of Guadalajara (Pilot Study)

Introducción: The struggle and concern for climate change, the optimization of natural resources, the well-being of future generations, has permeated the public institutions of our country. In particular, the University of Guadalajara, a public body for higher education, has launched projects aimed at this direction. The year 2020 at the University of Guadalajara was declared as the "Year of the Energy Transition at the University of Guadalajara”. Likewise, the Program of Austerity, Rationality and Efficiency of Institutional Resources of the University of Guadalajara was launched, implemented and applicable to the entire University Network and of a mandatory nature, to rationalize institutional spending by establishing: A decrease in energy resources through rational, responsible and sustainable use, proposing "to reduce spending on fossil fuels and lubricants by 40%, optimizing its consumption" together with a gradual transition of the vehicle fleet, "The conversion of the vehicle fleet to the electric and hybrid type will be strengthened".
 Materials and Methods: Considering the above and associated with the opportunity to take as a pilot test the Transport Office of the Rectory General, it was established to replace by bike-courier the delivery of documents and light parcels in dependencies with distances less than 5 km of radius of the administrative building of the University of Guadalajara that is currently carried out using a car, seeking energy reduction, without losing efficiency in deliveries and contributing to meet the institutional goals of resource optimization and environmental contribution. The messaging and departure requests of the agency's operational vehicles were tracked during the year 2019.
 Results and Discussion: Accounting for the annual record, only the requested trips with distances less than 5 km are those considered to be made by bicycle because they are requests for delivery of documentation, being 40.88% of these those susceptible to be delivered by bicycle, representing 2,237.54 kilometers and 187.05 liters of fuel saved, contributing to the fulfillment of the institutional goal of reducing fossil fuels by 40%. It was also evidenced that the efficiency of the bike-courier, in most cases is higher than the automotive, under the criteria and variables analyzed, using the Data Enveloping Analysis (DEA).

Effects of transition turbulence modeling on the hydrodynamic performance prediction of a rim-driven thruster under different duct designs

The rim-driven thruster (RDT) is an innovative marine propulsion device. During the design process, scale models of RDTs are frequently used and also smaller sized units used in Underwater Remotely Operated Vehicles (ROVs) or Autonomous Underwater Vehicles (AUVs) are often likely to operate under conditions where the boundary layer on the surface of the propeller makes a transition from a laminar to a turbulent regime. Accurately resolving this transitional boundary layer can help improve the performance prediction of RDTs. Studies addressing this are scarce and hence the present work investigates the influence of transition turbulence modeling on the hydrodynamic performance prediction of an RDT with different duct configurations by means of computational fluid dynamics (CFD). The turbulence models employed in this study are the two-equation SST k−ω model and the four-equation γ−Reθ transition model. For this purpose, three duct designs are considered, notably two modified 19A and 37 ducts, and one symmetric duct design often seen in RDT designs. Numerical calculations are performed using ANSYS Fluent 19.1 whilst a verification and validation study is firstly carried out to ensure the accuracy of the numerical model. The results demonstrate that the γ−Reθ transition model can better capture the transitional flow on the blade’s surface, and substantial discrepancies are observed between both turbulence models with regard to the streamline patterns near the blades on the one hand and skin friction profiles on the other. The torque calculated using the transition model better fits the experimental data, suggesting that it is more suitable to estimate the RDT performance. Three RDT duct designs are simulated which enable different ways to guide the incoming flow and it is shown that they have an important influence on the propeller performance. The results of the open water performance of the three different duct profiles are presented and compared, along with detailed analyses of the flow fields.

Modular modeling and coordination control scheme for an underwater cooperative transportation performed by two I-AUVs

Intervention Autonomous Underwater Vehicles (I-AUVs), also known as Underwater Vehicle Manipulator Systems (UVMSs), are an alternative for reducing costs and increasing safety in underwater operations which require dexterous manipulation. Beyond the well-posed and currently studied manipulation scenarios, the cooperative underwater transportation is a promising and challenging task, still not extensively explored. This paper aims to contribute to this latter problem by addressing the modeling and control system design of a cooperative underwater transportation performed by two planar I-AUVs, each of them composed by an AUV linked to a 2-Degrees of Freedom (DoFs) serial manipulator. A hierarchical approach for deriving the equations of motion through the Modular Modeling Methodology (MMM) is presented. Also, a complete coordination scheme composed of the Inverse Kinematics (IK) and motion control modules is proposed. A new IK control is formulated on the jerk level with the Super-Twisting Algorithm (STA) to prevent numerical drift and uncertainties while considering secondary objectives. The low-level motion control is synthesized within a continuous Sliding Mode Control (SMC) algorithm to compensate for the modeling errors and external disturbances. The coordination scheme is verified through numerical simulation considering a scenario in which an object is transported by the two I-AUVs over a predefined path. The analysis is made more realistic by considering the thrusters and motors dynamics along with sensors measurements, sampling effects and an optimal state estimator. Modeling errors and external disturbances are also considered in the analysis. The results reveal the suitability of the proposed modeling and coordination approaches for numerical simulation and control of the I-AUVs during underwater transportation.

Research on Trajectory Tracking Control of Underwater Vehicle Manipulator System Based on Model-Free Adaptive Control Method

In order to improve the trajectory tracking accuracy of an Underwater Vehicle Manipulator System (UVMS) under uncertain disturbance conditions of ocean current, a Model-free Adaptive Control (MFAC) method was used. Combined with Radial Basis Function Neural Networks (RBFNN), the RBFNN-MFAC method is proposed to improve the performance of the controller. A hydrodynamic model of UVMS was defined in the commercial software, Fluent, to calculate hydrodynamics disturbance, and the mechanism of the dynamic model of UVMS was defined in the commercial software, Adams, to simulate the motion of UVMS. The trajectory tracking performance with various control schemes, including PID (Proportional Integral Derivative), MFAC and RBFNN-MFAC, were analyzed with the Adams and Simulink joint simulation model. The results show that the position tracking accuracy and the speed tracking accuracy with the MFAC control scheme were 68.1% and 81.0% better, respectively, than those with PID control scheme. The position tracking accuracy and the speed tracking accuracy with the RBFNN-MFAC control scheme were 66.3% and 43.1% better, respectively, than those with the MFAC control scheme. The MFAC control scheme and the RBFNN-MFAC control scheme proposed in this paper exhibit good trajectory tracking performance without the precise dynamic model of UVMS, which is of great importance to applications in engineering.

Technology Focus: Deepwater Fields (May 2022)

As several countries and major oil companies continue on a virtuous road toward net zero by exploiting other available energy resources, a fundamental question remains about the future of the oil and gas industry and its role in the energy market during the next decades. According to the International Energy Agency, the oil and gas industry accounts for approximately 45% of anthropogenic greenhouse-gas emissions across the world. Such a number is alarming to our industry, making it a target for many environmental groups who would like to see it phased out and eliminated. As this crisis continues to transform societies’ perceptions, the upcoming inevitable energy transition will map the future of energy companies in one way or another. Deepwater and ultradeepwater projects in the outer continental shelf are, by nature, the most complex in the industry’s landscape, susceptible to several serious challenges. Operators of these assets are under growing pressure to optimize their portfolios despite the enormous proved and probable hydrocarbon reserves in these assets and the anticipated upsurge in demand for energy exceeding the current annual increase of 1.5–2%, especially in countries not affiliated with the Organisation for Economic Co-Operation and Development. Technical advancements and innovative solutions have played a key role in the successful journey of sustainability of deepwater developments. These concepts will remain a catalyst for these assets for the next decades, provided the availability of appropriate resources and executive vision. With the current evolution in all technical aspects, continual efforts to improve operations and process safety are vitally needed. The deepwater segment cannot overcome another Macondo. To stay the course, thrive, and safeguard the interests of the stakeholders, it is crucial for deepwater operators to develop specific, measurable, attainable, relevant, and time-based (SMART); comprehensive; and collaborative strategic plans to - Improve seismic imaging - Focus on full-fledged green designs and operations - Develop integrated and hybrid energy solutions - Use the power of growing digital innovation - Optimize existing and future facilities - Improve operational efficiency and reduce risks - Minimize both capital and operational expenditures Selection of the appropriate initiatives and technologies under each of these objectives should be carried out through a meticulous technical rollout system with comprehensive assortment criteria considering the effects of geographic location, market demand, stakeholder sentiment, country commitment toward COP26 and the Paris Climate Agreement, environmental policies, economics of local development plans, local regulations and legislations, and the availability and reliability of sustainable resources. Vocational preparation of manpower is exceptionally important for the oil and gas industry to ensure the attainability of the concrete foundation needed for technical advancements. The oil industry is experiencing a decline in the number of young professionals joining it, and the consequences of the pandemic have worsened this trend. It is imperative to heed this issue and align personnel planning with upcoming demand. The future of deepwater projects is today, and the clock is ticking, urging a relentless return to deep water rather than relying on forecasting. This industry has experienced many failures in forecasting. Time is of the essence for industry leaders to pinpoint areas of vulnerability and identify a cloudless depiction of all components to step up to the challenge of inventiveness and ingenuity. Now is probably the groundbreaking stage for the majors to reinvent our industry and consider having an independent deepwater-governing autonomous ecosystem where only the foremost decisions come from the control center. Recommended additional reading at OnePetro: www.onepetro.org. SPE 201218 - Recent Technological Advances Provide Highly Efficient and Reduced-Risk Solutions for Conveying Wireline Formation Evaluation Toolstrings in Deepwater Operations by Stephen McCormick, Petromac, et al. OTC 30970 - Optimizing Deepwater Rig Operations With Advanced Remotely Operated Vehicle Technology by Bernard McCoy, TechnipFMC, et al. IPTC 21778 - Automation and Digitization Technologies Value Estimation Methodology—A Deepwater Well Construction Case by Jose Daniel Telles, Schlumberger, et al.

A Predictive Control Approach for Cooperative Transportation by Multiple Underwater Vehicle Manipulator Systems

This article addresses the problem of cooperative object transportation for multiple underwater vehicle manipulator systems (UVMSs) in a constrained workspace involving static obstacles. We propose a nonlinear model predictive control (NMPC) approach for a team of UVMSs in order to transport an object while avoiding significant constraints and limitations, such as kinematic and representation singularities, obstacles within the workspace, joint limits, and control input saturation. More precisely, by exploiting the coupled dynamics between the robots and the object and using certain load sharing coefficients, we design a predictive controller for each UVMS in order to cooperatively transport the object within the workspace’s feasible region. Moreover, the control scheme adopts load sharing among the UVMSs according to their specific payload capabilities. In addition, the feedback relies on each UVMS’s onboard measurements and no explicit data are exchanged online among the robots, thus reducing the required communication bandwidth. Finally, realistic simulation results conducted in the UwSim dynamic simulator running in robot operating system (ROS) environment as well as real-time experiments employing two small UVMSs and demonstrated the effectiveness of the proposed control strategy.

A Modular Open-Source Continuum Manipulator for Underwater Remotely Operated Vehicles

Abstract Continuum manipulators are a class of robots with many degrees-of-freedom, leading to highly flexible motion with inherent compliance. These attributes make them well suited for manipulation tasks and physical interaction with the environment. A high impact yet challenging field for exploring continuum robot designs is free-floating underwater manipulation with a remotely operated vehicle (ROV). In this article, we propose a modular, reconfigurable, cable-driven continuum arm for free-floating underwater manipulation and present a corresponding kinematics, control, and computation framework. The mechanical design consists of a continuum arm, an actuation unit, and a waterproof enclosure. The kinematics model is introduced as two mappings between three spaces: the joint space, the configuration space, and the task space. The differential kinematics for each mapping is also derived. An electronics system design is proposed for underwater applications, including the communication framework between the topside computer (above surface), on-board computer, and manipulator mechatronics. Experimental validation is presented to demonstrate the robot’s underwater functionality, test the limits of its articulation, and evaluate the arm’s stiffness. Future work includes field testing with an ROV platform and development of advanced controls and planning for manipulation tasks.

Total Design in the Design and Development Process of a Remotely Operated Vehicle (ROV) with Particular Consideration of Sensorization

This paper provides a methodological proposal for the design and development process of a remotely operated vehicle (ROV). The design core and product design specifications (PDS) of Pugh’s Total Design model are considered, with a focus on the early stages of the product design and development process. A modularization of the functional groups of an ROV is proposed, focusing attention on the sensor system. The main concepts regarding ROVs are presented, Pugh’s Total Design model is explained, justifying the application interest in technological projects, a methodological proposal adapted to ROV projects is provided, based on Pugh’s Total Design model, with special interest in the early stages of the new product development process (NPD), the suitability of applying our own model of industrial design engineering in an ROV system is analyzed, and the contribution of this study is evaluated, proposing future work and lines of research.