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IKTPLUSS-IKT og digital innovasjon

Autonomous Robots for Ocean Sustainability

Alternative title: Autonome roboter for bærekraftig hav

Awarded: NOK 16.2 mill.

Sustainable exploration and utilization of the oceans require underwater robotics: The oceans play a key role in addressing the global challenges of global warming, increasing population and the corresponding need for energy, food, and minerals. To sustainably harvest the marine resources while protecting biodiversity, there is an urgent demand for efficient, versatile and autonomous underwater robots. Existing marine robotics technology only provides limited access to the oceans: Today, subsea operations are performed using remotely operated vehicles (ROVs) and autonomous underwater vehicles (AUVs), and we generally have to choose between a robot that can interact with the environment (work class ROV), that is capable of long-range operations (survey AUVs), or that can gain access to narrow spaces (observation ROVs). Articulated intervention-AUVs (AIAUVs) are novel bioinspired marine robots with a snake-like, articulated body. These robots possess advantageous hydrodynamic properties at the same time as they can hover and perform light intervention tasks. Moreover, their slender and flexible bodies provide excellent access to narrow spaces. We consider the AIAUV concept to be the best foundation for the development of a truly autonomous and versatile underwater robot that can perform both observation and intervention operations in the same mission, e.g., mapping the seabed and collecting sediments, inspecting and repairing the net of an aquaculture fish cage, or detecting and gathering plastic and other debris polluting the oceans. Moreover, articulated robots possess advantages for visual and flow-based situational awareness (understanding the surrounding environment). The AROS project will develop methods to achieve higher levels of autonomy and endurance to fully realize the potential of AIAUVs for obtaining persistent presence in the oceans for ocean exploration and sustainability. Underwater visual perception requires the ability to deal with bad and rapidly varying illumination and with reduced visibility due to water turbidity. The verification of such algorithms is crucial for safe and efficient underwater exploration and intervention operations. Ground truth data play an important role in evaluating vision algorithms. However, obtaining ground truth from real underwater environments is in general extremely hard, if possible, at all. In a synthetic underwater 3D environment, however, (nearly) all parameters are known and controllable, and ground truth data can be accurate in terms of geometry. In AROS we present an underwater environment - VAROS, our approach to generating highly realistic underwater video and auxiliary sensor data with precise ground truth, built around the Blender modeling, and rendering environment. VAROS allows for physically realistic motion of the simulated underwater (UW) vehicle including moving illumination. Pose sequences are created by first defining waypoints for the simulated underwater vehicle which are expanded into a smooth vehicle course sampled at IMU data rate (200 Hz). This expansion uses a vehicle dynamics model and a discrete-time controller algorithm that simulates the sequential following of the waypoints. The scenes are rendered using the raytracing method, which generates realistic images, integrating direct light, and indirect volumetric scattering. The VAROS dataset version 1 provides images, inertial measurement unit (IMU) and depth gauge data, as well as ground truth poses, depth images and surface normal images. Power delivery remains a challenge for AUVs. Battery constraints limit their operational time, while tethers would limit their operational area and autonomy. Improving the energy efficiency of these systems will be a significant step forward in our attempts to design efficient AUVs. We want to pursue the idea of achieving energy autonomy by utilizing the energy in waves, currents and other hydrodynamic effects such as wakes behind bluff bodies. To this end, we have developed a controller that allows the AIAUV to hold a desired position with an undulatory motion, downstream from a bluff body. As a first step to achieving this, we have developed a controller that stabilizes the position of an AIAUV moving in the plane with an undulatory motion when moving against a time-varying current. Existing methods for stability analysis did not suffice for the analysis of the resulting closed-loop feedback control system. We, therefore, developed new Lyapunov theory for uniform practical asymptotic stability (UPAS) and utilized this to solve the problem of position control of a planar AIAUV. Moreover, we have developed control algorithms that enable the robot to autonomously find the optimal position that maximizes the energy harvested, and to stabilize this position.

The AROS researchers have previously developed the bioinspired marine robot AIAUV (Articulated Intervention-AUV) by combining the slender, multi-articulated body of snakes with propulsion provided by thrusters. This new marine robot is already well on its way towards disrupting subsea operations in the oil and gas industry. However, higher levels of autonomy and endurance are needed to fully realize the potential of AIAUVs for providing greener, safer and more cost-efficient operations and obtaining persistent presence in the oceans for ocean exploration and sustainability. AROS will close this knowledge gap. Specifically, we will combine the disciplines of engineering cybernetics, computer science and hydrodynamics, to achieve significant advances in the current state of the art of marine robotics and autonomy, with the goal of realizing true autonomy in underwater sensing, situational awareness, and motion planning, and to achieve unprecedented energy autonomy. The methods for underwater situational awareness will enable the AIAUV to understand, interpret and predict its surroundings. The energy efficient motion planning and the energy harvesting methods will enable extreme endurance and enlarge the areas covered beyond the capabilities of current marine robots. The project will educate five PhD candidates and more than 10 MSc students through six work packages addressing: WP1: Egomotion estimation and situational awareness for AIAUVs WP2: Next-best-view and 3D reconstruction for AIAUVs WP3: Flow sensing: Bio-inspired solutions for AIAUVs WP4: Motion planning: Redundancy resolution methods for AIAUVs WP5: Energy harvesting by AIAUVs. WP6: Simulation studies and experiments The results will be published in peer-reviewed papers at major international conferences and in top-ranked international journals.

Publications from Cristin

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IKTPLUSS-IKT og digital innovasjon