Development of Self-powered Distributed Sensors/Reporters for Integrated Offshore Asset and Local Environment Monitoring

The monitoring of floating and subsea offshore asset and their surrounding environment is essential to the oil exploration and production in the Gulf of Mexico. An ideal solution is to deploy distributed sensors/reporters that can sense local conditions and then report to the control center. A major challenge to this approach is the electrical power supply in the remote deep sea, especially the distributed power to individual sensors. This issue becomes more severe when there is a power outage due to manmade or natural emergency or disaster. The goal of this project is to design, manufacture and test the self-powered blinkers that are made of triboelectric generators and light-emitting diodes. These blinkers will emit flashing light without external power and allow them to be detected and tracked 24/7 in any environmental conditions. They function as a transponder of a plane or a ship, are the simplest forms of sensors/reporters. Since sufficient electricity can be stored or expanded through a network of triboelectric generators, important parameters such as temperature, pressure and salinity can be measured by integrated sensors, more sophisticated communication through light or sound can be added, thus an integrated monitoring and tracking of offshore asset can be realized in the future. Such technique of self-powered sensors/reporters will provide a reliable and long-term solution for safe operation of oil exploration and production in the Gulf of Mexico, as well as many other areas around the world.

Practical Implementation of Organic Electrochemical Transistors (OECTs) for Subsea Detection

The proposed sensors have much broader applications beyond leak detections and therefore will be of interest to companies in oil and gas, water and wastewater treatment, and biomedical industries. We actively seek out firms that have a potential need for chemical sensor systems for subsea applications.

Development of self-powered distributed sensors/reporters for integrated offshore assets and local environment monitoring.

SSI, looks to develop self-powered distributed sensors/reporters for integrated offshore assets and local environmental monitoring by:

1. Developing self-powered sustainable reporters/sensors that can be attached and deployed to assets of an offshore platform for integrated asset monitoring and management;
2. Designing self-powered blinkers that can emit flashing lights as a reporter. Using the triboelectric effect, these sensors, reporters will harvest energy from ocean waves or marine currents.

SSI, will research the practical implementation of OECT by:

1. Evaluating OECT sensor sensitivity and performance under realistic subsea conditions;
2. Improving the specificity and sensitivity of MIPs by implementing machine learning (ML) to optimize the chemistry of MIPs.

Task 1: Development of self-powered distributed sensors/reporters for integrated offshore asset and local environment monitoring

• Goal 1: Design of highly efficient buoyant triboelectric blinkers
• Goal 2: Fabrication and characterization of buoyant triboelectric blinkers
• Goal 3: Test of buoyant triboelectric blinkers in a tank and Galveston Bay
• Goal 4: Design subsea triboelectric blinkers and quantify the lifetime
• Goal 5: New Technology Qualification (NTQ) and third-party verification
• Goal 6: Design subsea triboelectric blinkers

Task 2: Practical Implementation of Organic Electrochemical Transistors (OECTs) for Subsea Detection

• Goal 7: Evaluate OECT sensor sensitivity and performance
• Goal 8: Improve the specificity and sensitivity of MIPs
• Goal 9: Test a multiplexed array of sensors
• Goal 10: Quantify the lifetime and stability of OECTs in subsea conditions

Multi-port Energy Router using Intelligent Transformers (MERIT): Energy Management and Supervisory Control

The investigators are actively working with the offshore industries in the area of power and energy systems to advance the research that can positively impact safe and reliable exploration and energy production, particularly in the Gulf of Mexico. The team recently started an industry consortium in the area of subsea power and energy systems to advance the subsea oil extraction that will lead to higher efficiency and lower emissions. The name of the consortium is “Power electronics - Energy storage - Microgrids and Subsea Electrical Consortium” (PEMSEC). The proposed research is one of the projects suggested by the existing consortium members as part of the future scope of PEMSEC. This project will advance the knowledge on advanced power conversion, energy management and control of offshore RESs with the MERIT system.

Optimal Sizing of Onsite Generation Resources for Self-Sustainable Offshore Loads

With various renewable generation and storage technologies being available, it becomes practically possible to replace traditional diesel/gas generators with a hybrid energy system supplying clean power. This project will design such a system and optimize the onsite energy resources considering cost and reliability. The proposed system will ensure continuous power supply to offshore platforms in an economic and reliable manner. The cost-benefit analysis will estimate the levelized cost of electricity; this information can be used to facilitate the decision-making for stake holders in the O&G industry. The success of this project will not only benefit the offshore loads in the Gulf of Mexico but also the offshore loads in other part of the world. In addition, this project is consistent with many initiatives on industry electrification and will lead to a substantial reduction of CO2 emissions and thus mitigate climate change.

Multi-port Energy Router using Intelligent Transformers (MERIT): Energy Management and Supervisory Control.

In phase II of the MERIT project, SSI proposes to develop energy management and supervisory control strategies for interfacing the primary renewable energy sources using the Multi-port Energy Routers with Intelligent Transformers. SSI will:

1. Develop a detailed energy management scheme and supervisory control architecture for the seamless transfer of energy between the renewable energy resources and the MERIT system, and to the loads, by analyzing the source side and load side characteristics.
2. Study the state-of-the-art and develop power conversion schemes, along with control methods, to interface the primary renewable energy resources with the MERIT with both MVDC and MVAC grid interconnection.
3. Assess the controllability and efficiency of the power converters, and employ advanced techniques (like machine learning), and also modeling of different system components for drive including transformer, sine filter, long transmission line, transformer, and the PM motor to improve the performance with the energy management and supervisory controllers. Validation of the developed model in Typhoon HIL/ MATLAB simulation.
4. Development of algorithms for automatic parameter estimation of the equivalent circuit model for the complete system from drive perspective in subsea applications, and design and development of efficient control strategies for subsea drive systems.
5. Evaluate the overall power conversion scheme, energy management and supervisory control architecture on how well they satisfy the requirements of IEEE-1547 standards in terms of voltage sag/swell, low voltage ride through (LVRT) and reactive power.
6. Implement the system in a real time emulator and verify the overall operation using a simulator unit, such as Typhoon Hardware-in-the-loop (HiL) system.

The proposed research aims to design offshore renewables-dominated energy systems for supplying continuous power to offshore loads in a self-sustainable manner with onsite resources. The proposed system consists of clean and renewable generation and energy storage resources. The resources’ sizes will be optimized to meet the offshore demand while considering economics and reliability. This project focuses on the system architecture design.

1. Establish the models and conduct parameterization for offshore renewable resources and energy storage resources;
2. Develop a long-term planning model for energy asset investment decision-making considering battery degradation; time-domain simulations will be conducted to evaluate the designed hybrid energy system.
3. Develop an open-source tool that implements the proposed research and makes it publicly available. This tool will be able to handle customized resource specifications and projected electrical loads at an offshore platform that will allow academia and industry to use it.

Task 1: Multi-port Energy Router using Intelligent Transformers (MERIT): Energy Management and Supervisory Control

• Goal 1: Energy management and supervisory control strategies
• Goal 2: Modeling power conversion and control methods
• Goal 3: Modeling of the system components
• Goal 4: Performance improvement of the power conversion/control stages
• Goal 5: Providing grid services and satisfying interconnection standard

Task 2: Optimal Sizing of Onsite Generation Resources for Self-Sustainable Offshore Loads

• Goal 6: Modeling and parameterization of renewable resources and energy storage
• Goal 7: Battery degradation modeling and quantification in an offshore environment
• Goal 8: Optimal system planning with renewable resources and energy storage
• Goal 9: Stability analysis of designed hybrid energy systems
• Goal 10: Open-source tool development for the proposed research

Robotic Fish Enabled Pipeline Inspection

The research will lead to time-efficient and cost-effective intelligent robotic systems for underwater pipeline inspection. Through this robotic system, pipeline anomalies due to seismic activity, offshore drilling, turbulence, and ship anchoring may be detected at early stages allowing operators to make informed decisions on maintenance and repairs of the pipeline. It is expected that this research will build stronger ties with many companies in offshore energy industry, and will lead to major industrial support. The results of this research will be valuable not only to international deep-water oil and gas markets, but also to subsea renewable energies and subsea mining.

Autonomous Underwater Vehicle Navigation through Steel Scaffolding

This proposal will break new ground in underwater sensing and in robotic navigation by using 3D magnetic sensors to navigate through an underwater environment. As part of the process, this proposal will test two types of terrestrial magnetic sensors for localizing, tracking, and sensing ferrous underwater objects: fluxgate magnetometers and arrays of Hall-effect probes paired with active inductors.

Innovative Research in Monitoring Subsea Connections Using Percussion and Machine Learning

Since flanges are commonly used in subsea oil and gas exploration and production facilities, the proposed research will contribute to the improved level of safe operations of such facilities by providing early warnings of malfunctional flanges. Additionally, with minimum efforts, the proposed research can be extended to other types of connections.

Robotic Fish Enabled Pipeline Inspection

The goal of this project is to develop transformative robotic pipeline inspection technology that will lead to a time efficient and cost-effective system for underwater pipeline inspection which can prevent thousands of oil leakage. Such robotic systems will consist of a swarm of bio-inspired autonomous underwater vehicles (BAUVs) equipped with video cameras and underwater communication device with machine learning based image processing and edge computing capabilities. The BAUVs will be able to autonomously swim along a subsea pipeline, detect the ruptures of pipeline, intelligently. Interpret results through unsupervised machine learning and edge computing, and communicate with a nearby station through an underwater communication device.

Autonomous Underwater Vehicle Navigation through Steel Scaffolding

In this project, we propose to explore the design and implementation of a system that uses magnetometers to sense and navigate around magnetic (e.g., metal) structures. Our goal is to produce theoretical and experimental insights towards the use of magnetic sensing and subsea navigation to aid with subsea docking, localization, and repair.

Innovative Research in Monitoring Subsea Connections Using Percussion and Machine Learning

The general goal of this SSI (Subsea Systems Institute) project is to conduct innovative research to improve the percussion method with machine learning for the purpose of monitoring subsea flanges. The specific goals of this project are:

1. Develop an innovative approach to monitoring subsea flanges so that the baseline data is no longer needed
2. Develop a new machine learning method to increase robustness of the percussion approach.
3. To investigate the effectiveness of the percussion approach in monitoring a pipeline with multiple flanges and to determine the least number of needed percussions.

Task 1: Robotic Fish Enabled Pipeline Inspection

• Goal 1: Robotic fish design and camera orientation control
• Goal 2: Underwater surveying and pipeline tracking
• Goal 3: Deep machine learning based on pipeline detection
• Goal 4: Mobile edge computing implemented on robotic fish & comprehensive testing

Task 2: Autonomous Underwater Vehicle Navigation through Steel Scaffolding

• Goal 5: Hall-effect array sensing
• Goal 6: Fluxgate magnetometer testing
• Goal 7: Potential field navigation with magnetic sensors
• Goal 8: High precision cable localization rig
• Goal 9: Material detection/classification

Task 3: Innovative Research in Monitoring Subsea Connections Using Percussion and Machine Learning

• Goal 10: Develop an innovative approach to monitoring subsea flanges
• Goal 11: Develop an integrated deep-learning and shallow-learning method
• Goal 12: Investigate the effectiveness of the percussion approach in monitoring

Characterization of deep-water Gulf of Mexico salt domes and proximal sediments for storage of hydrogen & sequestration of CO2

We are bringing together four strong geoscience and engineering groups at University of Houston (UH) plus substantial industry interaction which promise to bring transformational results to the offshore energy industry. The work will have major impact on the preparation and planning for future marine energy and effluent storage in the Gulf of Mexico in addition to extending offshore asset life, enhancing its integrity via monitoring, and assisting with the integration of renewable energies.

Developing Methods of Producing and Processing Marine Algae to Biocrude

The benefit of developing this process is multiprong which include: Using marine algae to sequester GHG could be used by different existing industries (petrochemical, natural gas/coal powerplant and others) located in the Gulf of Mexico coastal areas that release significant amount GHG in the atmosphere.

1. Sea water is widely available in coastal area and using them to produce marine algal biomass will be sustainable.
2. Developing the close loop integrated process will efficiently recycle the soluble waste stream rich in nutrients (nitrate, phosphate, minerals, hydrolyzed protein and carbohydrates) produced in FH process will help to efficiently managing the soluble liquid stream.
3. produce renewable biocrude using HTL process can be used in existing petroleum refinery infrastructure in Gulf of Mexico producing drop in biofuels benefit environment and reducing our dependence of fossil fuel.
4. Producing co-products such as biochar and HTL aqueous stream (rich in mineral and nutrients) could be used as soil amendments increasing soil organic carbon and plant growth promoting ingredients respectively benefiting agriculture

Extending the Life of Offshore Oil and Gas Infrastructure in the Gulf of Mexico for Profitable New uses in Power and Hydrogen Generation in Preparation for the Energy Transition

The results of this project have the potential to guide new investments in low carbon energy projects, resulting in multiple pathways of benefits for the US GOM region. Offshore operators and regulatory bodies will stand to benefit from continued revenue generation from installed infrastructure through low carbon energy projects. A significant portion of the decommissioning expenditure can be delayed by a decade or two. The skilled workforce in the oil and gas sector can be productively employed beyond the end of the oil and gas phase of this infrastructure. And most importantly, the offshore GOM infrastructure will play a critical role in supplying low carbon energy to the population centers along the Gulf Coast.

Characterization of deep-water Gulf of Mexico salt domes and proximal sediments for storage of hydrogen & sequestration of CO2

We will use our world-class laboratories and teams at UH to undertake core measurements, scaled salt body surveys (please see photographs below), algorithm development, and offshore field data analysis for substantial energy and environmental benefit.

Subsurface storage and sequestration begins with gas, fluid, and rock properties. Thus, we will conduct novel and difficult experiments on salt and salt-proximal sediments while saturating them with CO2, helium, and hydrogen to better understand their flow, elastic, and mechanical behavior (lab photos below).

 

Developing Methods of Producing and Processing Marine Algae to Biocrude

Marine microalgae sequester greenhouse gases such as CO2 and use them as carbon source to build their body mass comprising of carbohydrates, lipids, and proteins. Several cultivation methods have been developed to produce marine algal biomass using sea water and used as sustainable feed stock for producing biocrude. Here, we propose to develop a cost-effective method of producing marine microalgae Nannochloropsis gaditana contain (35-40% lipids) using sea water in a vertical tubular reactor system. The cultivated algal will be separated after flocculation by changing the pH and sedimentation. After de-watering, the algal slurry (10-15 wt %) will be pumped through a continuous flow-through hydrothermal Flash hydrolysis (FH) skid mount reactor. The FH processes results in breakdown algal cell wall producing hydrolyzed slurry comprising of soluble and insoluble streams. The insoluble algal stream is rich in lipid and soluble algal stream comprised of hydrolyzed peptides and carbohydrates. The insoluble stream will be subjected Hydrothermal Liquefaction (HTL) to produce biocrude and biochar. The soluble algal liquid stream will be used as growth media for cultivating N. gadiatana effectively managing the waste stream. Our preliminary studies have shown that the lipids content in the insoluble stream has been increased from 33.5% in N. gadiatana to 65.5 wt. % (dry weight) and the ash content has been reduced by 70%. Further, HTL processing insoluble algal stream produce 69% biocrude, 2% biochar and remaining 29% are converted to aqueous phase, gases, and losses.

There are four major objectives for the proposed project to achieve the project goal.

1. Evaluate the feasibility of growing N. gadiatana algal biomass using recycled FH nutrients, flocculate, and separation.
2. Perform FH hydrolysis of N. gadiatana algal biomass slurry (10-15 wt.%).
3. Process the insoluble algal solid stream generated in FT process to biocrude using HTL process and characterize their chemical properties.
4. Determine the mass and energy balance for the proposed integrated process using reported procedures.

Extending the Life of Offshore Oil and Gas Infrastructure in the Gulf of Mexico for Profitable New uses in Power and Hydrogen Generation in Preparation for the Energy Transition

1. Phase 1: High grading existing infrastructure locations in Texas GOM for potential life extension. Deliverables: LCOE and LCOH maps for the Texas Gulf of Mexico; Ranked list of existing infrastructure locations with a high potential of life extension.
2. Phase 2: Concept Optimization Studies for high graded locations. Deliverable: Integrated system model; optimized concept for each high graded location.

Task 1: Characterization of deep-water Gulf of Mexico salt domes and proximal sediments for storage of hydrogen & sequestration of CO2

• Goal 1: Rock physics measurements and analysis in the petroleum engineering lab
• Goal 2: Properties of sub-salt sand potential reservoirs
• Goal 3: Physical modeling
• Goal 4: Seismic simulation, processing, and interpretation
• Goal 5: Review of GOM salt distributions

Task 2: Developing Methods of Producing and Processing Marine Algae to Biocrude

• Goal 6: Evaluate the feasibility of growing N. gaditana algal biomass
• Goal 7: Perform FH hydrolysis of N. gaditana algal biomass slurry 10-15wt.%
• Goal 8: Process the insoluble algal solid stream generated in the FT process
• Goal 9: Determine the mass and energy balance

Task 3: Extending the Life of Offshore Oil and Gas Infrastructure in the Gulf of Mexico for Profitable New uses in Power and Hydrogen Generation in Preparation for the Energy Transition.

• Goal 10: High grading existing infrastructure locations in Texas GOM
• Goal 11: Conducting concept optimization studies

To design and develop a MERIT system for integrating renewable energy sources, energy storage and the Medium-Voltage Direct Current (MVDC) grid with the subsea loads. The project also explores the control strategy of the MERIT system to reduce the intermittency of the renewable energy sources, in order to ensure the safety and stability of the grid interconnection. Another goal is to assess the performance of Coupled Inductor Hybrid Circuit Breaker (CIHCB) Topology with integration of Resistive-Superconducting Fault Current Limiter (R-SFCL)

The estimated financial loss for incidents due to poor power quality in the O&G sector is $300,000-800,000 a day. To increase the energy efficiency and reduce the CO2 and NOx emissions, several solutions have been proposed in the literature. Among these solutions, the supply of electric power to the subsea loads from the shore as HVAC (50 Hz/60 Hz) or HVDC power transmission has been increasingly examined. In addition, other techniques such as low frequency AC transmission from the shore have also been considered. In order to supply reliable power to the subsea loads at high system efficiency and low emissions, there is a growing interest in employing offshore renewable resources close to the point of use. However, such a system has predominantly stayed in the conceptual stage so far. Hence, there is a compelling need to develop technical methodologies for interconnecting multiple megawatt-scale systems offshore.

The MERIT system incorporates features like instantaneous voltage compensation, power outage compensation, fault isolation, and bi-directional power flow capability. Widespread implementation of the developed synergies will improve the economics of both renewables and oil and gas projects and can lead to over 50% reduction in the emissions caused by the activities in oil and gas production.

The overarching aim of the proposed project is to explore and develop a system of Multi-port Energy Routers using Intelligent Transformers (MERIT) to interface renewable resources and subsea oil and gas (O&G) factories with the High Voltage DC, ‘HVDC’ (or Medium Voltage DC, ‘MVDC’) Grid. This research intends to advance the state-of-the-art power converter hardware and control technologies to enable seamless energy transfer between offshore renewable energy sources, subsea loads (such as in O&G factories) and the DC grid to improve the system efficiency, reliability and availability. The project will also evaluate the integration of fault current limiters including the possibility of adding resistive superconducting fault current limiter (R-SFCL) in series with hybrid DC circuit breakers (HCBs) to lower the high fault current to such a level where circuit breakers can operate safely.

1. Study the different types of loads in an offshore oil & gas (O&G) production system, focusing on the subsea factories and design the electrical architecture of an offshore wind energy farm to interface with the DC grid (Type of Tasks: software and real-time simulation)
2. Design a MERIT system to interconnect hybrid renewable energy sources (including wind and fuel cells) with subsea loads (Type of Tasks: software and real-time simulation)
3. Explore the integration of additional renewable energy sources – such as floating solar photovoltaic (PV) panels, battery energy storage (BES) and wave energy – with the MERIT system in order to supply 100 % of the demand of the subsea factory using renewable energy resources via HVDC or MVDC link (Type of Tasks: software and real-time simulation)
4. Design, build, control and evaluate a lab-scale three-terminal MERIT system using solid state transformer (SSTs) as a proof of concept (Type of Tasks: hardware experiments)
5. Investigate the fault limiting performance of a coupled-inductor based fast switching DCCBs (Type of Tasks: software simulations)
6. Evaluate fault interruption capability under various network conditions to obtain the optimum configuration with R-SFCL integrated in series with DCCB (Type of Tasks: software simulations)

• Completed study of electrical loads in offshore O&G production system
• Simulated system level architecture to interconnect offshore wind farm via DC collection grid
• Task I completed
• Discussion with industry partners on the voltage/power levels, made design updates
• Design and development of the proposed MERIT system to interconnect multiple renewable energy sources with subsea loads
• Simulation of fault interruption of CIHCB and the modular DCCB

1. Obtained the load profile of a typical subsea field. To supply the power to the subsea field, the required number of wind turbines and backup energy sources were determined
2. Developed electrical architecture of a subsea field with an energy router to interface wind power and backup energy sources
3. Multiport Energy Router (MER) was realized by using series-parallel combination of medium frequency based Triple Active Bridge Converters to achieve considerable reduction in footprint in the offshore platform
4. Developed energy management scheme for the MERIT system facilitates. The intermittency of the wind power can be mitigated
5. Optimized number of the wind turbine, solar panels, wave energy converter and battery storage capacity to operate the MERIT system autonomously. Cost of the generated renewable energy will be minimum due to the adopted optimization technique
6. Proposed a control scheme for the MER for controlling the power flow among the ports
7. Verified the performance of R-SFCL integrated coupled inductor hybrid circuit breaker (CIHCB) topology
8. Considering the fast response times and reduction in ratings of main breaker, integration of R-SFCL with proposed DC circuit breakers is an optimal solution for protection of subsea HVDC systems

A timely inspection of infrastructure, especially topside valves in platforms are thus the key to extend the lifetime of an offshore asset. Current inspection techniques often involve trained human operators and requires excessive amounts of time and money. With state-of-the-art robotic and inspection technologies, such limitations may be remediated and a much-needed extra layer of safety will be added. Robotic enabled valve maintenance not only reduces costs and increases accuracy, but also prevents workers from contacting the leaking valves. Robots do not experience fatigues or loose concentration and can work continuously, and in general robotic approaches are effective and less prone to error.

Combining this work with percussion holds much potential in monitoring the looseness of subsea bolted connection due to its simplicity and suitability with robotics integration.

The goal of this project is to develop transformative robotic valve inspection technology that will lead to a time efficient and cost-effective system for valve inspection and maintenance which can extend the life cycle of existing oil platforms. Through the proposed autonomous robotic system (i.e., autonomous ground service) equipped with valve operation and inspection tool, valve anomalies due to mechanical failures will be detected at early stages, which allows operators to make informed decisions on maintenance and repairs of abnormal valves.

This project will also develop robotics enabled percussion approach to subsea connection inspection. Since the Grayloc clamp connectors, with the advantages of compact design, are commonly used in oil and gas industry, in this research both flange type and Grayloc connections under the submerged condition will be experimentally studied. Via a remote operated vehicle (ROV) that is equipped with a hydrophone, a visual-servoing system, and a percussion component, we can detect bolt looseness in subsea flanges and Grayloc connections.

1. Develop a ground service robot that can climb stairs and track lanes in oil platforms
2. Develop a valve inspection tool that can detect stuck valves while operating them
3. Develop a vision-based lane tracking for the robot to track lanes in oil platforms
4. Develop a vision-based recognition algorithm to locate valves for inspection
5. Develop a machine-learning based underwater percussion method
6. Develop a tapping and listening device to enable percussion based bolted structure inspection
7. Conduct comprehensive testing after integration of key components

Ultimately, the project will push the boundaries of what can be accomplished by integrating robotics and structural health monitoring technologies.

• Set up testbed and designed new tool for valve operation and inspection
• Demonstrated the percussion method for monitoring flange looseness is effective for under water application
• Demonstrated stair climbing using mobile platform
• Fabricated and tested a new tool for valve operation and inspection
• Programmed a Husky unmanned ground vehicle
• Tested YOLO algorithm for valve detection
• Conducted more test of percussion based bolted structure inspection
• Fabricated a robotic tapping device
• Set up a (32' long x 16' wide x 4.3' deep) research tank for comprehensive testing

• Developed a mobile platform which can climb stairs
• Developed>Developed a valve operation and inspection tool
• Developed a visual serving control for the mobile platform to track the detected lane
• Developed a machine learning based valve detection algorithm
• Developed a machine learning approach to train in-air and in-water impact-induced sound signals
• Developed a deep learning approach to train in-air and in-water impact-induced sound signals
• Classified flange looseness status to five classes using the proposed approaches

Discussions with commercial advisors helped us outline some of the shortcomings of current EM based localization systems, including low range due to high attenuation and potential interference from metallic structures.

We have conducted preliminary studies on the use of triaxial magnetic induction (MI) coil antennas for localization at short distances between robots. At this range, MI antennas are affordable to produce and deploy (no moving parts), and have strong, high bandwidth signals that do not require line of sight. Their unique capabilities may be particularly suited for missions that require robots to dock with subsea structures.

1. Study short distance, high-accuracy MI-based localization
2. Research software and hardware approaches to attenuate EM interference caused by the ROV thrusters and electronics
3. Identify limitations of competing optical, acoustic, and RF localization technologies and compare these solutions with the proposed new method
4. Investigate MI detection/tracking of steel structures
5. Investigate the effect of updating the MI antenna design to be conformal to the frame of an AUV, with the goal of minimizing footprint of the antennas

• Conformal antennas have been constructed, waterproofed, and mounted on the remotely operated vehicle (ROV)
• Multi-feedback bandpass filters work well at specified frequencies for electromagnetic interference (EMI) filtering
• For MI-based Localization, the cable penetrator was fixed to the Doppler Velocity Logger (DVL) so it can be attached to the ROV’s electronics enclosure
• A circuit was designed to oversample a received MI signal. This circuit uses a logarithmic amplifier like our previous approach to deal with the extensive dynamic range
• We implemented Mᴀᴛʟᴀʙ functions that can compute the acoustic absorption coefficient as a function of the frequency and the acoustic path loss as a function of the transmission distance. These functions will be used to help select the most efficient transmission method (e.g. acoustic, MI, frequency range) depending on the distance and environment

• Derived methods to estimate relative position and orientation of two sensor systems using only unsigned amplitude measurements.
• Demonstrated that conformal electro-magnetic coils enable longer distance communication with a small impact on robot size and drag.
• Demonstrated image transmission between underwater magnetic induction antennas.

Constantly monitoring and repairing subsea infrastructures and equipment play important roles in extending the lifetime of those multi-million-dollar offshore assets. Decommissioning of offshore assets also call for underwater service robots to disassemble the subsea infrastructures and cleanup the sea floor environment.

Fine distributed buoyancy control, which is not feasible with current thruster/ballast mechanisms, will enable adaptive maneuvering and forceful interaction with the environment in confined spaces similar to how marine swimmers do. A combination of the traditional thruster/ballast mechanism for gross buoyancy and motion, and the proposed soft robotics mechanism (fuel cells/water electrolysers) for fine and distributed buoyancy will undoubtedly provide AUV's with unprecedented capabilities. The broader impact of this research includes the opportunities created in exploring and expanding solid state fuel cell/electrolyzing technology as a soft robotics mechanism to address immediate exploration and production challenges in the Gulf of Mexico. The results of this research will be valuable not only to international deepwater oil and gas markets, but also to subsea renewable energies and subsea mining.

1. Develop Buoyancy Control Device Enabled by Reversible Fuel Cells
   • Task 1.1: Design a self-enclosed buoyancy control device to house an IPMC electrolyzer, a micro fuel cell, and two gas chambers. Demonstrate an open-loop control test
   • Task 1.2: Develop a back-stepping nonlinear control with a nonlinear observer
   • Task 1.3: Demonstrate an close-loop control of the BCD which can oat and sink with a large depth change (more than 3 m)
2. Develop an Underwater Service Robot
   • Task 2.1: Develop two water-proof robotic grippers
   • Task 2.2: Integrate two BCDs and robotic grippers into the AUV
   • Task 2.3: Open-loop control test of underwater service robot
3. Modeling and Control
   • Task 3.1: Develop 3D nonlinear dynamic model of the service robot
   • Task 3.2: Develop depth control for the service robot
   • Task 3.3: Develop orientation control of the service robot
4. Comprehensive Test at NASA's Neutral Buoyancy Lab (NBL)
5. Senior Design Competition Between UH and Rice

• Developed a gas consumption rate control
• Fabricated a service robot integrating a blue ROV, four BCDs, and a robotic gripper
• Developed a nonlinear dynamic model of the service robot
• Developed depth and orientation control using both hard and soft actuators for the service robot
• Validated the control in simulation

• Developed a volume-to-electricity engine enabled by reversible fuel cell
• Developed buoyancy control device (BCD) using that engine
• Developed a service robot with BCDs and robotic gripper
• Developed a 6-DOF dynamic model for the service robot
• Developed a hybrid control of hard and soft actuators for both depth and orientation control.

The novelty of the work is in the development of a new, low-cost, wireless sensor for selective chemical detection in deep sea environments. Prior work has not explored the combination of organic electrochemical transistors (OECTs) or thin film transistors (TFTs) with molecularly imprinted polymers (MIPs) for selective chemical sensing or the development and testing of OECTs and TFTs in seawater. The results of this work will demonstrate a proof-of-principle of versatile, low-cost sensors that can aid in the early detection for leak and spillage detection.

Figure 1: Schematic for an organic electrochemical transistor with an MIP layer shown in purple, a proposed sensor array, and sensors in a distributed pipeline network, which can respond to leaks and spills in the vicinity of the sensor

Altogether, this work will demonstrate a novel platform for continuous, real-time monitoring of chemicals and contaminants underwater. This will enable more rapid detection of leaks and contaminants during deep sea operations. Furthermore, the sensors proposed are compact and easy to fabricate, resulting in low-cost devices that can be fabricated to scale and replaced when necessary.

To address the failure of CPM to identify leaks, we will develop a precise and sensitive amperometric sensor platform based on molecular-level recognition by molecularly imprinted polymers (MIPs) and electronic transduction through organic thin film transistors (TFTs) and organic electrochemical transistors (OECTs). We will build a sophisticated real-time sensor for chemical binding events that can be used to detect the presence of specific chemicals in the aqueous environment. In the proposed research, we plan to create and use a modified electrochemical sensor model to investigate the performance of sensors at low temperatures and subsea conditions.

1. Design and testing of MIP layers
2. Fabrication and testing of OECTs and TFTs
3. Integrate OECTs and TFTs with MIPs and analyze response to target chemicals
4. Test integrated sensors in the presence of interfering species
5. Develop a model for the response of OECTs and TFTs

Materials and devices used in oil and gas (O&G) production and exploration experience extreme environmental conditions. With the continuous upsurge in demand for autonomous devices, there has been an increased need for energy storage systems that is high-energy and high-power that can operate safely under the most aggressive conditions.

The overarching scope of the proposed project is to develop and fabricate high-energy and high-power quasi-solid lithium batteries that can operate under a wide range of temperatures and pressure. Further, we plan to explore the possibilities of such batteries for various conditions including thermal/pressure fluctuations, leakage currents, self-discharge etc. and thus these devices provide safe and reliable power supply for extended operation of offshore infrastructure and continuous uninterrupted production from Deepwater facilities. More specifically the scope includes:

• Optimization of quasi-solid lithium battery by balancing power and energy. Use of high energy density cathodes such as NCA and/or NMC against metallic lithium to build high energy/power lithium batteries
• Compatibility studies of electrodes/quasi-solid electrolytes and electrochemical testes to understand battery life, stability (self-discharge) at high temp./pressure

1. Combination of cathode and quasi-solid electrolyte systems
2. Electrode assembly and quasi-solid-state batteries fabrication
3. Electrochemical performance