Abstract: Certain embodiments of the present application relate to a method for releasing a parcel from an unmanned aerial vehicle (UAV). The parcel is engaged with a hook attached to a line suspended from the UAV. The method includes lowering the hook such that the parcel is at least partially supported by a target surface, thereby performing an attempt to release the parcel from the hook, performing at least one iteration of an iterative procedure. The iterative procedure includes raising the hook, and determining whether the line remains loaded. The iterative procedure further includes lowering the hook an additional time in response to a determination that the line remains loaded, thereby performing an additional attempt to release the parcel from the hook. The iterative procedure further includes performing an additional iteration of the iterative procedure in response to the number of attempts failing to satisfy a threshold number of attempts.

Abstract: Certain embodiments of the present application relate to a method for releasing a parcel from an unmanned aerial vehicle (UAV). The parcel is engaged with a hook attached to a line suspended from the UAV. The method includes lowering the hook such that the parcel is at least partially supported by a target surface, thereby performing an attempt to release the parcel from the hook, performing at least one iteration of an iterative procedure. The iterative procedure includes raising the hook, and determining whether the line remains loaded. The iterative procedure further includes lowering the hook an additional time in response to a determination that the line remains loaded, thereby performing an additional attempt to release the parcel from the hook. The iterative procedure further includes performing an additional iteration of the iterative procedure in response to the number of attempts failing to satisfy a threshold number of attempts.

Abstract: Certain embodiments of the present application relate to an unmanned aerial vehicle including a control system, at least one rotor operable to generate lift under control of the control system, a spool mounted for rotation in a winding direction and an unwinding direction opposite the winding direction, a motor operable to rotate the spool in at least the winding direction under control of the control system, and a brake mechanism including a brake actuator operable to transition the brake mechanism between a locked state and an unlocked state under control of the control system. The brake mechanism in the locked state prevents rotation of the spool in at least the unwinding direction. The brake mechanism in the unlocked state does not prevent rotation of the spool in the unwinding direction.

Abstract: Certain embodiments of the present application relate to an unmanned aerial vehicle, comprising a chassis, a control system mounted to the chassis, at least one rotor operable to generate lift under control of the control system, a spool having a wound portion of a line wound thereon, the line including a free portion, an attachment device secured to the free portion of the line and configured to facilitate attachment of a parcel to the line, a motor operable to rotate the spool under control of the control system such that the control system is operable to raise the attachment device to a raised position and lower the attachment device from the raised position, and a spring positioned between the chassis and the attachment device such that the spring is engaged between the chassis and the attachment device when the attachment device is in the raised position.