USE Network launch I UAV Works VALAQ l Cable harnesses l USVs insight l Xponential 2020 update l MARIN AUV l Suter Industries TOA 288 l Vitirover l AI systems l Vtrus ABI

67 MARIN modular AUV | Digest typical durations of our in-facility tests [around 2-4 hours between charging]. However, when we start going to sea trials, the need to improve the mAUV’s endurance will require some rethinking of the power system. “For example, we could increase the battery capacity, we could reselect or reconfigure the onboard electronics to make them more energy efficient, or we might provide underwater charging stations. A key requirement for subsea charging stations is that the UUV can be accurately manoeuvred to a docking and connecting position – something the mAUV is well-equipped for.” Digital twin In the course of developing the mAUV, the team made extensive use of MARIN’s pre-existing CFD simulation and calculation software tools. “These enable us to determine the hydrodynamic behaviour of any new hull form in the earliest stages of our vehicle design processes,” Ypma explains. “In addition, we can use the digital twin of the mAUV to develop our control algorithms and sensor fusion, and test the whole system using a hardware in-the-loop approach. And during the facility tests we collect measurement data that further validates and improves the digital twin.” The digital twin software models a vast number of different forces that act on (and are generated by) the mAUV during missions. These include the thrust and torque of the propellers, hydrostatic forces such as buoyancy, the effects of the ballast tanks and moving mass inside the UUV, wave forces against the hull, and of course key hydrodynamic forces such as drag and lift. As the basin experiments continue, the team will amass more measurements that will further improve the accuracy of these simulated forces. In particular, the thruster models, simulations of the mAUV’s manoeuvring, and calculations of wave forces are expected to more closely predict and capture real-life movements and behaviours over time. The future In addition to improving simulation data, and the planned experiments already mentioned, MARIN’s engineers anticipate a few more critical modifications and tests in the near future. For one, the team plans to integrate actuators for rudders in order to perform tests at higher speeds (at which tunnel thrusters might be relatively less effective for pitch and roll). Also, more sensors will be added to expand the mAUV’s range of data and functions, and enhance its autonomous capabilities; sidescan sonars, DVLs, or forward-scanning sonars for obstacle detection and avoidance are being considered here. Unmanned Systems Technology | June/July 2020 Dimensions: 3.1 x 0.35 m Weight: 235 kg Propulsion: battery-electric Hull: aluminium Operating speed: 4.5 kph Endurance: 8 hours stationary, 2-4 hours moving Ballast volume: 1400 cm 3 Some key suppliers Thrusters: Blue Robotics IMU: iXblue Attitude and heading reference system: Xsens Operating system: Windows Specifications Printed black-and-white ArUco markers around the hull are used for the optical navigation system to calculate the mAUV’s position and attitude