Systems and methods for controlling a fixed-wing aircraft during flight are disclosed. The aircraft comprises first and second flight control surfaces of different types. The method comprises determining that a pilot command of the first flight control surface will excite a structural flexible mode of the aircraft and then executing the pilot command of the first flight control surface in conjunction with a command of the second flight control surface to mitigate the effect of the excitation of the structural flexible mode of the aircraft.

Embodiments described herein provide active dampening of flexible modes of a UAV during flight operations. During operation of a UAV having a flexible airframe, the thrust and/or torque of the motor(s) coupled to propellers can induce flexing in the airframe that reduces the flight performance of the UAV. Measurements of a linear acceleration and/or an angular rate at a location proximate to the motor are performed, and flexible modes in the airframe of the UAV are identified based on the measurements. An operation of the motor(s) is modified based on the measurements to dampen the flexible mode.

Embodiments described herein provide active dampening of flexible modes of a UAV during flight operations. During operation of a UAV having a flexible airframe, the thrust and/or torque of the motor(s) coupled to propellers can induce flexing in the airframe that reduces the flight performance of the UAV. Measurements of a linear acceleration and/or an angular rate at a location proximate to the motor are performed, and flexible modes in the airframe of the UAV are identified based on the measurements. An operation of the motor(s) is modified based on the measurements to dampen the flexible mode.

The present disclosure provides methods and system for controlling the operation of a fly-by-wire aircraft. One or more yaw commands are received from an operator control, and one or more actual induced rolls rates are determined based on the yaw commands. A yaw signal and a roll-countering command are sent to flight control components of the aircraft, the yaw signal to cause a yaw motion in the aircraft, and the roll-countering command to counter the actual induced rolls. A standardized roll rate command is determined based on the yaw command, and the standardized roll rate command is sent to the flight control components to cause a roll motion in the aircraft.

Systems and methods for operating control surfaces of an aircraft. The method involves receiving, by an aircraft control system from one or more sensors, deflection information related to a shape and motion of an aircraft, and decomposing, by the aircraft control system, the deflection information into a detected modal state including a first known mode having a first mode strength. The method may further involve determining, by the aircraft control system, a first modal compensation based on the first mode strength, and identifying, by the aircraft control system, a desired control corresponding to a second known mode. The method may yet further involve determining a first control response for a control surface having a first modal weight and a second modal weight, based on the first modal compensation and the first modal weight, and determining a second control response for the control surface based on the desired control and the second modal weight. The method may still further involve generating a control command for the control surface based on the first control response and the second control response.

Systems and methods for controlling a coaxial rotary-wing aircraft including a co-axial main rotor assembly and a pusher-propeller. One system includes an electronic controller configured to receive a reference velocity of the aircraft and receive a reference flight path angle of the aircraft. The electronic controller is also configured to simultaneously control the co-axial main rotor assembly and the pusher-propeller based on the reference velocity of the aircraft and the reference flight path angle of the aircraft, by simultaneously generating a commanded thrust of the pusher-propeller and a commanded thrust of the co-axial main rotor assembly using a multiple input, multiple output algorithm applying dynamic inversion.

Example implementations provide fluid-borne vehicles comprising a body and a plurality of thrust vectoring modules, each thrust vectoring module comprising a set of thrust producing means, wherein a first thrust producing means, mounted on a first mounting bar having a first mounting bar axis, is rotatable about the mounting bar axis and the mounting bar axis is rotatable about an arm having an arm axis that is nonparallel to the mounting bar axis; and a second thrust producing means, mounted on a second mounting bar having a second mounting bar axis, is rotatable about the second mounting bar axis and the second mounting bar axis is rotatable about the arm axis that is nonparallel to the second mounting bar axis.