Abstract: An example system includes a ground station, an aerial vehicle, a tether, a probe, and a control system. The tether includes a core having a strength member as well as an electrical conductor that is wound around the core. The probe is attached to the strength member so that the probe is able to measure an electrical property of at least a portion of the strength member. The control system is configured to measure the electrical property along the strength member at a predetermined measurement rate and also determine that the electrical property is outside a predetermined range. Based on the electrical property, damage to the tether core can be assessed.

Abstract: Offshore airborne wind turbine systems with an aerial vehicle connected to an undersea anchor via a tether are disclosed. A floating landing platform may be coupled to the tether and be dragged along the surface of the water along with the tether. The landing platform may be designed such that the tether can freely pass through the platform, allowing the aerial vehicle to ascend, descend, move laterally, and in crosswind flight, without creating a significant tension load on landing platform. The landing platform may also include a tether drive mechanism that can actively move the tether through the platform, thus changing the platform's location along the length of the tether.

Abstract: An Airborne Wind Turbine (“AWT”) may be used to facilitate conversion of kinetic energy to electrical energy. An AWT may include an aerial vehicle that flies in a path to convert kinetic wind energy to electrical energy. The aerial vehicle may be tethered to a ground station with a tether that terminates at a tether termination mount. In one aspect, the tether has a core and at least one electrical conductor. The tether core may be terminated at a first location in a tether termination mount along an axis of the termination mount, and the at least one electrical conductor may be terminated at a second location in the tether termination mount along the same axis that the core is terminated. This termination configuration may focus tensile stress on the tether to the tether core, and minimize such stress on the at least one electrical conductor during aerial vehicle flight.

Abstract: Systems and methods for operating aerial vehicles in water-based locations. The systems and methods include a plurality of landing stations. Each landing station of the plurality of landing stations is coupled to at least one of: another landing station or an underwater mooring point. The systems and methods also include an aerial vehicle coupled to a tether mooring point by a tether. The aerial vehicle is configured to land on at least one landing station of the plurality of landing stations.

Abstract: Airborne wind turbine systems with multiple aerial vehicles connected via multiple tethers to a single ground station are disclosed. A node is coupled to the tethers. The node includes a drive system. At a proximate end of the node, each of the tethers is adjacent to neighboring tethers. And at a distal end of the node, each of the tethers is separated from the neighboring tethers. The airborne wind turbine system includes a control system configured to operate the drive system to translate the node along the tethers.

Abstract: System and methods for controlling the oscillation of floating ground stations in aerial wind turbine systems are disclosed. Thrusters on the ground station or on one or more aerial vehicles associated with the ground station apply a compensatory force to the oscillating ground station to reduce and/or substantially eliminate wave-induced oscillations. Submerged thrusters may also rotate the ground station to a preferred alignment direction with the waves. Additionally, control systems use environmental and/or positional sensor data to develop a predictive force profile that maps desired compensatory force magnitude versus time. The control systems use that predictive force profile to direct the thrusters to apply a varying compensatory force over time.

Abstract: The present disclosure relates to an aerial vehicle with a horizontal tailplane disposed along a bottom edge of a vertical tailfin. Namely, the aerial vehicle includes an empennage attached to the fuselage via a tail boom and a tail coupling. The empennage includes a vertical tailfin that extends below the tail coupling. The empennage also includes a tube arranged along a leading edge of the vertical tailfin and below the tail coupling of the aerial vehicle. The empennage additionally includes one or more rotating actuators and a horizontal tailplane. The horizontal tailplane is coupled to the tail via the tube and includes a continuous leading edge and a cutout. The one or more rotating actuators are configured rotate the horizontal tailplane about an axis of the tube. At least a portion of the vertical tailfin is configured to pass through the cutout.

Abstract: Disclosed herein are systems and methods related to electric power transfer between an aerial vehicle of an airborne wind turbine and a power grid. An example power conversion system may include power converters, a DC bus connecting the power converters to the aerial vehicle, and an AC bus connecting the power converters to the power grid. The power converters may be configured to provide AC/DC power conversion between the aerial vehicle and the power grid. The power conversion system may also include switches operable to either (i) electrically connect a respective power converter to the DC bus or electrically isolate the respective power converter from the DC bus. The power conversion system may also include one or more power supplies that can be connected to the DC bus to provide backup power in the event a power converter or the power grid malfunctions.

Abstract: Methods and systems described herein relate to power generation control for an aerial vehicle. An example method may involve determining an asynchronous flight pattern for two or more aerial vehicles, where the asynchronous flight pattern includes a respective flight path for each of the two or more aerial vehicles; and operating each of the aerial vehicles in a crosswind flight substantially along its respective flight path, where each aerial vehicle generates electrical power over time in a periodic profile, and where the power profile of each aerial vehicle is out of phase with respect to the power profile generated by each of the other aerial vehicles.

Abstract: Faired tethers with internal support structures providing support to strength cores, and systems therewith, are described. The faired tethers include one or more electrical conductors and one or more rigid supports that inhibit movement of a strength core within a faired tether.

Abstract: Offshore airborne wind turbine systems with an aerial vehicle connected via a tether to an adjustably buoyant body. The tether may be coupled to an underwater mooring through which it may move, or it may be coupled to a floating platform through which it may move. The buoyancy of the buoyant body may be adjusted to change the tension in the tether or for other purposes.

Abstract: The present disclosure relates to systems and methods for rotating a floating platform. An example method includes determining a desired position of a floating platform in a yaw axis. The floating platform is fixed by an anchor leg to an underwater attachment point. The method includes receiving, from a position sensor, information indicative of an actual position of the floating platform in the yaw axis. The method also includes rotating the floating platform in a desired direction about the yaw axis based on the desired position and the actual position. Optionally, the floating platform may include a yaw member and an environmental sensor. In such scenarios, the method may include receiving information about a prevailing wind direction or water current direction. The method may include causing the actuator to adjust the yaw member based on at least one of: the prevailing wind condition or the prevailing water current direction.

Abstract: Tensile cables with transmission cables arranged in undulating paths are described. The tensile cables include deformable supports that define the undulating paths and deform in response to a tension force exerted on opposing ends of the transmission cables.

Abstract: A tether guide operable through a wide range of tether/fleeting angles while causing minimal wear and having a reduced size compared to a levelwind wheel. The tether guide may include a series of rollers approximating the curved shape and radius of levelwind wheel. The tether guide may include downward facing guide wings matched to a curved roller profile, but flaring out to capture and guide tether into rollers. Sensors may be included on the tether guide to provide information about tether location, including whether the tether is engaged in the tether guide.

Abstract: A power cable and method of forming the cable that includes a first conductor guide that includes (i) a first distal receiving hole and (ii) a first axial receiving hole on a longitudinal axis of the power cable. The power cable also includes a second conductor guide that includes (i) a second distal receiving hole and (ii) a second axial receiving hole on the longitudinal axis. The power cable also includes a flexible drive shaft that is disposed in the first axial receiving hole and the second axial receiving hole and a conductor that twists around the longitudinal axis. The conductor is disposed in the first distal receiving hole and the second distal receiving hole.

Abstract: A system for carrying a tether guide, including a counter-balanced support system with two pivot points, where a first pivot allows the tether guide to travel up and down and the second pivot allows the tether guide to match the tether angle. Both pivots may be passive pivots. A shuttle that carries the tether guide may be electronically cammed to follow variable pitch helical grooves of a winch drum as the tether guide traverses across the drum length.

Abstract: Systems, methods, and apparatuses for increasing the mechanical energy of an aerial vehicle as part of an Airborne Wind Turbine are disclosed. The aerial vehicle is coupled to a distal portion of a tether and a ground station is coupled to a proximal portion of the tether. A mass possessing a gravitational potential energy is also coupled to the proximal portion of the tether. A connector is configured to releasably hold the mass at an elevation. Release of the mass transfers energy to the aerial vehicle by increasing tension in the tether.