Event-triggered formation control of n-link networked stochastic robotic manipulators

This article proposes an event-triggered control framework to satisfy the tracking formation performance for a group of uncertain non-linear n-link robotic manipulators. The robotic manipulators are configured as a multi-agent system and they communicate over a directed graph (digraph). Furthermore, the non-linear robotic manipulator-multi-agent systems are subject to stochastic environmental loads. By introducing extra virtual controllers in the final step of the backstepping design, a total number of n event-triggering mechanisms are introduced independently for each link of all the robotic manipulator agents to update the control inputs in a fully distributed manner. More precisely, the actuator of each link of a particular agent is capable of being updated independent of other link actuator updates. A rigorous proof of the convergence of all the closed-loop signals in probability is then given and the Zeno phenomenon is excluded for the control event-triggered architectures. The simulation experiments finally quantify the effectiveness of proposed approach in terms of reducing the number of control updates and handling the stochastic environmental loads.

APPLICATION OF PHYSICAL INTERNET IN INTRALOGISTICS – A SIMULATION STUDY

One of the biggest challenges today is to make traditional systems more sustainable. Physical Internet (PI, π) based logistics systems provide one of the most defining solutions. In our opinion, it is worthwhile to deal with the intralogistics conversion of the Physical Internet because traditional systems can no longer operate with sufficient efficiency to meet growing customer expectations and demands. This research focuses on restructuring a factory from its traditional operating to a PI-based system using our previously defined intralogistics components. The article surveys the possibility of creating PI-hub and virtual PI-hub in a factory process. The warehouses were converted to PI-hubs, and virtual PI-hubs were placed near the two manufacturing to create a more flexible structure. We created a simulation study in AnyLogic where we examine the efficiency achievable by automated guided vehicles (AGVs) in a PI-based system. The results were compared based on the traditional and PI-based systems. Based on the simulation the inefficiency of the PI-based system is lower (by ~18%) at higher control event values. This allows achieving a more efficient, flexible, sustainable, and balanced operation.

How Industry Collaboration Can Manage an Effective Source Control Emergency Response

Responding to a Source Control event requires a significant amount of resources, both in terms of engineering complexity and skilled personnel. The pool of available hardware is ever increasing, not only in quantity but in operational complexity. Service providers store and maintain a range of equipment, including capping stacks, subsea dispersant application tooling, technology to allow landing of capping stacks in shallow water and flowback systems. To mount a response, it is highly likely that these assets would be mobilised from various global locations. It would also require the support from many organisations with expertise in various fields. Industry has invested significantly in workshops and exercises to test and continuously improve the service provisions in place. This paper aims to: Re-visit industry led source control exercises completed to date and identify the impact they have had on preparednessDiscuss key developments industry is taking to tackle complex planning activity, including regional expertise forumsWork through the core subjects that require industry collaboration to develop a successful Source Control Emergency Response Plan (SCERP - detailed below) Industry led exercises & workshops have identified several key items that require detailed analysis to develop a successful SCERP: Response Time Modelling – understanding and planning complex supply chain requirementsResource mapping – identifying global experts who can provide engineering, modelling and operational supportMutual aid – in the event of a mobilisation, how can industry work together to ensure the most experienced people can work collaborativelyEquipment fabrication – whilst there is a range of hardware available, certain scenarios will require the fabrication of specific equipment. How can this be managed and pre-planned?Exercising and testing – how can the above subjects be effectively tested, with industry maximising experience and ensuring continuous development of lessons learned This paper will explore the steps industry has taken to methodically work through these challenges to ensure that preparedness remains a high priority. The range of industry developed guidelines that have also been developed to act as a handrail for planning purposes will be discussed. Whilst planning and executing Source Control exercises can take a significant amount of time and investment, the lessons learned, and experience gained is invaluable not only directly to industry, but wider support organisations (i.e. logistics providers). It is paramount that these lessons are built on and the experience gained is maintained for the future.

Development of the Global Equipment Inventory and Network for Subsea Well Response

ABSTRACT 1141381 The Montara (2009) and Macondo (2010) incidents resulted in step change in safety for the oil & gas industry. Since then many improvements have been implemented to keep the highest standard of safety in drilling operations. Through industry collaboration subsea well response equipment not available at the time of these incidents is now globally accessible. Technology continues to be developed to provide comprehensive response capabilities. A recent area of focus for industry was how to cap an incident well in water depths less than 600 meters where vertical access may not be possible due to hydrocarbons at surface and a possible gas boil in the case of a gas well. An innovative concept was developed, manufactured and tested to deal with a loss of well control event in shallow water. The Offset Installation System (OIS) allows a capping stack to be deployed and installed on a blowing out well in shallow water, deployed and controlled by vessels offset from the incident well. In addition, the OIS can be used for debris clearance, removal of the lower marine riser package (LMRP), and deployment of other subsea response hardware. By virtue of their source control operational function capping stacks are relatively large and heavy pieces of hardware. Despite these physical characteristics, there is expectation by stakeholders and international regulators for capability to transport capping stack equipment across significant distances in an expeditious manner to respond to an incident. For remote areas of the globe, capping stacks air transported as a single unit could provide an effective solution. A key objective in responding to a subsea loss of well control event is the ability to effectively mobilise source control equipment and trained personnel to readily manage an emergency response scenario in a timely manner globally. A number of companies with a range of capabilities will be required to provide a comprehensive response. To further assist, initiatives focused on personnel resources have been developed including a global subsea response network, and continuing industry collaboration for mutual aid of personnel. This paper will provide information on the development of the global subsea response equipment inventory available to industry. Latest developments such as OIS and air freightable capping stacks for transportation to remote areas will be discussed in detail as well as the above-mentioned initiatives for personnel.

A Constellation of Satellites Hunting Methane Leaks Is Launching Soon

A blowout in Ohio in 2018 was the first ever where the emissions could be measured from space, though it was at best a rough estimate based on data gathered on the 13th day after the XTO Energy well control event began. A year later, a blowout of a Devon well near Victoria, Texas, was measured starting the day after it occurred, with data collected on 3 days over the next 2 weeks. Using the measurement of carbon dioxide, it was estimated that the flare was 87% effective in burning about 4,800 metric tons of the leaking methane gas. Emission estimates varied wildly, and both the Ohio (Pandey et al. 2019) and Texas (Cusworth, Duren, Thorpe et al. 2020) efforts to use satellites led to technical papers to consider how they addressed this challenge. For those with blowouts next year, chances are a lot better methane-emission data would be available because of the launch of a constellation of specialized methane-measurement satellites by the two groups that played a key role in the earlier tests. In presentations at CERAWeek by IHS Markit, GHGSat said it has two methane-detection satellites in orbit and plans the launch of eight more, and the Environmental Defense Fund (EDF) said it is moving forward with the launch of its first one next year. Both are aiming to cover the lion’s share of oil and gas operations and measure the flow rate of the gas rather than concentrations in the atmosphere. They said they can do that far more accurately than was possible with the general-purpose climate observation satellites by focusing their equipment on the wavelength of methane. GHGSat said its satellites, which are about the size of a microwave oven, can measure the potent greenhouse gas from an elevation of 500 km and up. They are placed in polar orbit, which allows them to cover the globe every 2 weeks as the Earth rotates. Launching more satellites will allow more frequent looks. There are differences in the GHGSat and EDF designs, reflecting their contrasting missions. The Canadian company GHGSat, whose satellite initiative was initially supported by Schlumberger and the Oil and Gas Climate Initiative, is building tiny satellites with extremely high resolution to serve clients in the oil and mining businesses. During the presentation, Stéphane Germain, chief executive officer of GHGSat, displayed an image and said its satellites can tell if the methane is “coming from a particular facility and even tell what part of the facility it is coming from.” The company also sells the services of similarly equipped planes that can create more-detailed images using similar equipment at elevations of 3000 m and higher. EDF raised $100 million from donors, including Elon Musk, and has hired Raytheon to build a satellite equipped with a detector from Ball Aerospace. It can survey an area that is 260 km wide. That is far wider than the GHGSat satellites, which have the advantage of being able to zero in on smaller details when looking for leaks. The environmental group points out its device is more sensitive to methane emissions, detecting levels down to two parts per billion.

Simple and Scalable Streaming: The GRETA Data Pipeline

The Gamma Ray Energy Tracking Array (GRETA) is a state of the art gamma-ray spectrometer being built at Lawrence Berkeley National Laboratory to be first sited at the Facility for Rare Isotope Beams (FRIB) at Michigan State University. A key design requirement for the spectrometer is to perform gamma-ray tracking in near real time. To meet this requirement we have used an inline, streaming approach to signal processing in the GRETA data acquisition system, using a GPU-equipped computing cluster. The data stream will reach 480 thousand events per second at an aggregate data rate of 4 gigabytes per second at full design capacity. We have been able to simplify the architecture of the streaming system greatly by interfacing the FPGA-based detector electronics with the computing cluster using standard network technology. A set of highperformance software components to implement queuing, flow control, event processing and event building have been developed, all in a streaming environment which matches detector performance. Prototypes of all high-performance components have been completed and meet design specifications.

A Path from Collective Threat to Eudaimonia: Mediating Role of Awe

How do people react to collective threats such as natural disasters or the COVID-19 pandemic? Magnificent catastrophic events might have an impact on emotions of not only those who experienced direct harm from it but also those who feel threat without actual harm. The current study demonstrated that such threat enhances self-transcendent values that further leads to general well-being, mediated by the emotion of awe. Two surveys were conducted immediately after a severe typhoon hit Japan (Study 1) and during the early phases of the COVID-19 spread in Japan (Study 2). Predisposition to feel negative awe predicted participants’ attention to both collective threat events, which led to an affirmation of self-transcendent values and general well-being. Furthermore, when participants were asked to recall a collective threat (vs. control event), they felt more awe which led to more engaged meaning making during the event, in turn predicting their affirmation of self-transcendent values.