Hamad Karki

A review of robotics in onshore oil-gas industry

With shrinking resources and increasing demand for petroleum products, oil and gas industries are forced to rethink over their present pace for automatization of industry. New oil fields, mostly located in extreme conditions, are posing serious challenges to both human and environment in terms of safety. Tasks which are repeated, dirty, and dangerous and require high degree of accuracy are already automatized in manufacturing industry. This success has inspired oil and gas industry to lend some of its highly dangerous and repetitive tasks for automation. Most of the processes are remotely operated, and require highly skilled operator. Such processes benefits not only in terms of overall health and safety, by removing humans from hazardous environment, but also by reduction of number staff members required for continuous inspection and manipulation of plant facilities. Considering the sensitivity of inflammable products involved in this industry usage of completely autonomous robots is still a far fetch choice. Therefore, semi-autonomous robots are excellent choice for this industry at-least as near future solution. In oil and gas industry, robots are used both in upstream and downstream process such as pipe handling in drilling operations, pipe inspection, tank inspection, and remote controlled underwater vehicles (ROVs). This paper presents the state of art technology particularly related to application of robotic solutions to in-pipe inspection robots (IPIRs) and tank inspection robots (TIRs) at onshore oil and gas facilities.

Draft: Stick-Slip Motions of a Rotor-Stator System

In the current study, the authors examine the torsional vibrations of a rotor enclosed within a stator subjected to dry friction. Through the experiments, it is demonstrated that forward whirling of the rotor occurs while in contact with the stator, backward whirling occurs with contact, as well as impacting motions, which are characterized by nonsynchronous whirling with rotor-stator collisions. While undergoing these motions, the torsional oscillations are excited by stick-slip interactions. Experimental data are presented to show the presence of a stable torsional mode dominated motion while subjected to stick-slip forces during dry-friction whirling. In this motion state, the torsional oscillation response occurs at a combination of frequencies including drive and whirl frequencies. A finite dimensional model is constructed and simulations carried out by using this model are able to capture the system dynamics, including the torsional responses observed during dry-friction whirling. Numerical results obtained by using this model are consistent with experimental observations. The findings of this study are relevant to whirling motions experienced by rotating, long flexible structures, such as drill strings used in oil-well explorations.

WiFi based communication and localization of an autonomous mobile robot for refinery inspection

Oil and gas refineries can be a dangerous environment for numerous reasons, including heat, toxic gasses, and unexpected catastrophic failures. In order to augment how human operators interact with this environment, a mobile robotic platform is developed. This paper focuses on the use of WiFi for communicating with and localizing the robot. More specifically, algorithms are developed and tested to minimize the total number of WiFi access points (APs) and their locations in any given environment while taking into consideration the throughput requirements and the need to ensure every location in the region can reach at least k APs. When multiple WiFi APs are close together, there is a potential for interference. A graph-coloring heuristic is used to determine AP channel allocation. In addition, WiFi fingerprinting based localization is developed. All the algorithms implemented are tested in real world scenarios with the robot developed and results are promising.

Rotor Torsion Vibrations in the Presence of Continuous Stator Contact

The purpose of this study is to examine the torsion response of a rotor while in continuous contact with a stator for both forward synchronous whirling and backward dry-friction whirling. Experimentally obtained torsional strain data for both of these motions are presented, and the results indicate that the major contributions to the motions occur at the drive speed fd, twice the drive speed 2fd and the first torsional natural frequency ft for forward whirling. During backward whirling, the dominant response occurs at the drive speed fd and the sum of the whirl speed plus the drive speed at fw + fd. A distributed-parameter model in combination with a force-interaction model is used to capture the qualitative aspects of the system response. Simulations with this model reveal that the torsional vibrations are excited by stick-slip forces while undergoing backward whirling. Numerical and experimental results also show that motion at the first torsion natural frequency is the dominant component during forward whirling.Copyright

Autonomous tracking and navigation controller for an unmanned aerial vehicle based on visual data for inspection of oil and gas pipelines

This paper presents automated navigation control of an Unmanned Aerial Vehicle (UAV) based on visual data gathered by onboard camera. With depletion of easy resources and health, safety and environmental (HSE) challenges in exploiting newly found resources in hostile conditions are forcing oil and gas companies to look for robotic solutions for their problems. Pipelines carrying inflammable and toxic petroleum products are one of the most critical component of oil and gas industry. Being laid in extreme environmental conditions these critical assets require continuous inspection and maintenance. An UAV carrying non-contact sensors is proposed to use for external inspection of the visible pipeline sections. Till now UAVs are mostly used for general purpose visual surveillance while flying at very high altitude but in this novel work we propose accurate tracking and inspection while flying at very low altitude in close vicinity of the ground pipeline structure. Proposed automated inspection of the pipelines by the UAV has two stages firstly identification of the pipeline and secondly navigation control of the UAV for tracking of the pipeline structure. Both identification and tracking are based on visual data gathered by onboard cameras without any additional help of GPS information. This novel navigation control mechanism further has double layers of correction loops namely angular and lateral corrections. Navigation control uses heuristically tunes PID controllers and required geometrical parameters for angular and lateral corrections are extracted from visual data generated by onboard video camera.

Development of an Oil and Gas Refinery Inspection Robot

Oil and gas refineries present challenging environments in which to work and operate, especially in places like the Middle East where temperatures can reach 50 C and sand storms which can reduce visibility to a few meters. In addition, there can be gas or steam leaks which present health and safety hazards to the workers. At present, continuous operation of these plants requires that human workers venture out into these conditions in order to observe and report on the conditions within the plant. The goal of this work is to design, fabricate, assemble, and test an inspection robot in an effort to reduce the exposure and risks to human operators while increasing the flexibility and range of remote observations provided by a mobile robot. In this paper, we will report on the design approach taken, the subsystems identified and developed, the software environment chosen, and the application tasks envisioned. We will also report on the challenges of developing a robust localization algorithm for use in the challenging environment of a refinery as well as the needs for robust wireless communications in order to maintain command and control from the operators control room. An overview of the fivedegree-of-freedom arm designed and fabricated, and its realtime control will also be presented. Results from GPS navigation and localization experiments will be presented. While average errors during parked operations were often less than one meter for the WAAS enabled GPS system, locational errors during dynamic operations were often more than three meters. This is due to multi-path signals near building structures and piping infrastructure. Real-time arm control has been implemented using FPGAs and while tuning presented some challenge, the FPGA has provided smooth and repeatable operation. Sensors include gas detectors, acoustic sensors, thermal imaging, and video camera streaming. In addition, we will report on a multi-faceted approach to localization using three different sensor technologies and integrated using a Kalman filter. NOMENCLATURE DOF Degrees-of-Freedom GPS Global Positioning System FPGA Field Programmable Gate Array PWM Pulse Width Modulation

Identification of a Box-Jenkins model for rotary drilling laboratory prototype

Conventionally, analytical modelling is used to analyse the dynamics of complex non-linear processes. This paper presents identification of mathematical models by the black box modelling method for non-linear systems. The non-linear system concerned in this work is a laboratory prototype of a rotary drilling rig. The system concerned is distinguished for its additive non-linearity at the output end. The step by step analysis of the procedures and criteria used to select an accurate model for a non-linear process by the black box identification method is explained. The model identified in the paper is a Box-Jenkins model. The model selection procedure uses least squares method, pole zero plots and residual analysis. Accurate simulation results with less than 0.05% error are obtained. The identified Box-Jenkins model is validated by a twofold validation procedure.

Teleoperation by Using Nonisomorphic Mechanisms in the Master–Slave Configuration for Speed Control

This paper presents modeling, simulation, and control of a novel teleoperated mechanism, where two nonisomorphic manipulators are used in one integrated system, with the purpose of usage in oil and gas industry in the future. Overall integration of the teleoperated system has been done in the master–slave configuration, where a stuart-type 6-DOF parallel manipulator is used as a master robot and a 6-DOF serial manipulator is used as a slave robot. Since the parallel manipulator has a closed-loop structure and serial manipulator is an open-loop structure, their work spaces are of completely different nature in terms of overall shape and size. A novel task-space mapping mechanism has been proposed in this work to integrate these two completely nonidentical manipulators. Damped least-squares (DLS) method is used for overcoming the singularity of proposed task-space mapping matrix. This paper also presents detailed dynamic modeling of the parallel manipulator along with comprehensive analysis of proposed novel control technique. The biggest benefit of using proposed integration mechanism is the fullest access of the complete cartesian task spaces of both the master and slave manipulators. This paper also proposes usage of lag compensator for the improved tracking performance. Multilevel control architecture with local actuator-space and joint-space controllers, for the parallel and serial manipulators, respectively, has also been presented in this work.

Autonomous tracking of oil and gas pipelines by an unmanned aerial vehicle

This paper presents automated navigation control of an Unmanned Aerial Vehicle (UAV) for inspection of oil and gas pipelines. The pipelines carrying inflammable and toxic petroleum products require continuous inspection. An UAV equipped with non-contact sensors can be used for external inspection of the pipeline. Most of the UAVs used for surveillance purpose fly at very high altitude and same mechanism can not be used for low flying UAV while tracking ground structures such as pipelines. Current research work proposes novel two layers of autonomous navigation and tracking by UAV. First stage is identification of pipeline and second stage is tracking of it at low altitude. Identification and tracking of the pipelines as linear structure is based on image processing techniques without any assistance of GPS based localization. This autonomous navigation and tracking further has two layers of control loops, firstly angular correction and secondly lateral correction. Both the controllers are based on heuristically tuned simple PID controllers. Overall tracking has shown very good results in terms of stability and visibility of tracked structure from bottom camera of the UAV.

Stick-Slip and Whirl Motions of Drill Strings: Numerical and Experimental Studies

The dynamics of drill strings, which are long structures used in drilling operations, are explored numerically and experimentally within this article. A reduced-order distributed parameter model that allows for coupled bending and torsional motions is presented along with forces that take into account interactions between the drill string and the wellbore. Further, a scaled experimental apparatus is presented along with results. Both experimental results and model predictions show backward whirling. Stick-slip interactions are investigated numerically, and the simulation results are seen to be in good agreement with experimental observations. These results could prove useful when designing control schemes for mitigating undesirable torsional and bending motions.© 2011 ASME