Abstract: Systems and methods are described for governing the speed of a propeller on a propeller-based engine in an aircraft. The method comprises obtaining a synthesized or estimated blade angle for the propeller of the engine, determining one or more gain for a controller of the propeller based on the synthesized or estimated blade angle and one or more engine or aircraft parameter, determining a difference between a reference propeller speed and an actual propeller speed, applying the one or more gain to the difference via the controller in order to generate a command signal for controlling the propeller, and governing the propeller of the engine using the command signal.

Abstract: Methods and systems for governing an aircraft propeller of an engine are described. The method comprises obtaining a fluid flow command for speed control of the propeller, determining pulse parameters of a pulse width modulated valve control signal for actuating a two-position solenoid valve in accordance with the fluid flow command based on an average fluid flow through the solenoid valve and an opening and closing time of the solenoid valve, generating the valve control signal with the pulse parameters as determined, and transmitting the valve control signal to the solenoid valve for actuating the solenoid valve, thereby controlling the speed of the propeller.

Abstract: Methods and systems relating to the design and testing of systems that include hinged flight control surfaces of aircraft are disclosed. The systems and methods disclosed herein make use of a structural model representing a structural environment of the system in a relatively simple manner. In various embodiments, the structural model comprises one or more actuation branches having a common linear actuation direction, a load mass, and a massless connector representative of a hinge line of the flight control surface. The massless connector is connected to and disposed between the one or more actuation branches and the load mass and is movable along the common linear actuation direction so that linear movement of the massless connector is correlated to rotational movement of the hinged flight control surface.

Abstract: A method and system of controlling a turboprop engine are described. The method comprises obtaining a propeller speed and a pressure-based measurement signal from a torque pressure transducer coupled to the turboprop engine, determining an output power of the turboprop engine from the pressure-based measurement and the propeller speed, calculating a gas generator speed request based on an error between the output power and a reference power, determining a fuel flow command based on the gas generator speed request, and issuing the fuel.

Abstract: Methods and system for operating a gas turbine engine are described. The method comprises determining an actual engine output power based on a torque of the gas turbine engine, comparing the actual engine output power to an estimated engine output power to obtain an error, obtaining an actual engine speed and biasing the actual engine speed using the error to produce a biased engine speed, determining the estimated engine output power using a model-based estimator having the biased engine speed as input, detecting a torque-related fault based on the error and a first threshold, and accommodating the torque-related fault in response to detecting the torque-related fault.

Abstract: A method for controlling an aircraft propeller is provided that comprises obtaining a measurement of a speed of the propeller, comparing the propeller speed to a first threshold, responsive to determining that the propeller speed exceeds the speed threshold, outputting a valve control signal for opening a two-position solenoid valve coupled to the propeller, the two-position solenoid valve configured for controlling fluid flow to and from the propeller to control propeller blade angle, computing a rate of change of the propeller speed, comparing the rate of change of the propeller speed to a second threshold, and responsive to determining that the rate of change of the propeller speed is below the second threshold, outputting the valve control signal for closing the two-position solenoid valve. A system for controlling an aircraft propeller and an aircraft propeller control assembly are also provided.

Abstract: Systems and methods are described for governing the speed of a propeller on a propeller-based engine in an aircraft. The method comprises obtaining a synthesized or estimated blade angle for the propeller of the engine, determining one or more gain for a controller of the propeller based on the synthesized or estimated blade angle and one or more engine or aircraft parameter, determining a difference between a reference propeller speed and an actual propeller speed, applying the one or more gain to the difference via the controller in order to generate a command signal for controlling the propeller, and governing the propeller of the engine using the command signal.

Abstract: Systems and methods for controlling a gas turbine engine are provided. The system comprises an interface to a fuel flow metering valve for controlling a fuel flow to the engine in response to a fuel flow command and a controller connected to the interface and configured for outputting the fuel flow command to the fuel flow metering valve in accordance with a required fuel flow. The controller comprises a feedforward controller configured for receiving a requested engine speed and acceleration, obtaining a steady-state fuel flow for the requested engine speed and a relationship between fuel flow and gas generator speed, and determining the required fuel flow to obtain the requested engine acceleration as a function of the requested engine speed, the steady-state fuel flow, and the relationship between fuel flow and gas generator speed.

Abstract: A method for controlling an aircraft propeller is provided that comprises obtaining a measurement of a speed of the propeller, comparing the propeller speed to a first threshold, responsive to determining that the propeller speed exceeds the speed threshold, outputting a valve control signal for opening a two-position solenoid valve coupled to the propeller, the two-position solenoid valve configured for controlling fluid flow to and from the propeller to control propeller blade angle, computing a rate of change of the propeller speed, comparing the rate of change of the propeller speed to a second threshold, and responsive to determining that the rate of change of the propeller speed is below the second threshold, outputting the valve control signal for closing the two-position solenoid valve. A system for controlling an aircraft propeller and an aircraft propeller control assembly are also provided.

Abstract: Methods and systems for governing an aircraft propeller of an engine are described. The method comprises obtaining a fluid flow command for speed control of the propeller, determining pulse parameters of a pulse width modulated valve control signal for actuating a two-position solenoid valve in accordance with the fluid flow command based on an average fluid flow through the solenoid valve and an opening and closing time of the solenoid valve, generating the valve control signal with the pulse parameters as determined, and transmitting the valve control signal to the solenoid valve for actuating the solenoid valve, thereby controlling the speed of the propeller.

Abstract: Methods and systems relating to the design and testing of systems that include hinged flight control surfaces of aircraft are disclosed. The systems and methods disclosed herein make use of a structural model representing a structural environment of the system in a relatively simple manner. In various embodiments, the structural model comprises one or more actuation branches having a common linear actuation direction, a load mass, and a massless connector representative of a hinge line of the flight control surface. The massless connector is connected to and disposed between the one or more actuation branches and the load mass and is movable along the common linear actuation direction so that linear movement of the massless connector is correlated to rotational movement of the hinged flight control surface.

Abstract: A system and computer-implemented method of determining an acceleration of an engine are provided. The system comprises a processor and a memory comprising instructions stored thereon which when executed by the processor cause the system to perform a method of determining an acceleration of an engine. The method comprises obtaining and storing zero-crossing timestamps in a buffer, determining angular displacement times of the shaft based on the timestamps, applying a conversion factor to the angular displacement times, determining an acceleration of a shaft based on the angular displacement, and causing a fuel flow to the engine to be adjusted as a function of the acceleration as determined. The zero-crossing timestamps correspond to an angular displacement of a shaft associated with the engine. The zero-crossing timestamps are obtained using an angular displacement measurement device. The conversion factor corresponds to an angular displacement of the shaft.

Abstract: Systems and methods for regulating fuel flow to a gas turbine engine are provided. Power for the engine is governed using a control structure having an inner control loop and an outer control loop, the outer control loop comprising a feedback controller that outputs a feedback command based on a power error determined as a function of a shaft horsepower, the feedback command used to determine a gas generator speed error, the gas generator speed error used by the inner control loop for outputting a fuel flow command. The shaft horsepower is determined from a torque measurement of the engine using a torque pressure transducer. When a momentary loss of the torque measurement from the torque pressure transducer is detected, power fluctuations due to the loss of torque measurement are limited by maintaining the feedback command from the feedback controller constant during the momentary loss of torque measurement.

Abstract: A method and system of controlling a turboprop engine are described.

Abstract: Systems and methods for controlling an gas turbine engine are provided. The method comprises receiving a requested engine speed and obtaining a shaft inertia of the engine, a steady state fuel flow for the requested engine speed, and a relationship between fuel flow and acceleration power generated by the fuel flow. A required fuel flow to obtain an engine acceleration is determined as a function of the requested engine speed, the shaft inertia of the engine, the steady state fuel flow for the requested engine speed, and the relationship between fuel flow and acceleration power generated by the fuel flow. A command to a fuel flow metering valve is output in accordance with the required fuel flow.

Abstract: Systems and methods for controlling a gas turbine engine are provided. The system comprises an interface to a fuel flow metering valve for controlling a fuel flow to the engine in response to a fuel flow command and a controller connected to the interface and configured for outputting the fuel flow command to the fuel flow metering valve in accordance with a required fuel flow. The controller comprises a feedforward controller configured for receiving a requested engine speed and acceleration, obtaining a steady-state fuel flow for the requested engine speed and a relationship between fuel flow and gas generator speed, and determining the required fuel flow to obtain the requested engine acceleration as a function of the requested engine speed, the steady-state fuel flow, and the relationship between fuel flow and gas generator speed.

Abstract: Herein provided are methods and systems for operating a gas-turbine engine comprising a gearbox and a power turbine coupled to the gearbox. A first torque at the gearbox is obtained via a sensor. A second torque at the power turbine is determined based on the first torque. A power at the power turbine is determined based on the second torque. Operation of the engine is controlled based on the power.

Abstract: Systems and methods for controlling a gas turbine engine are provided. The system comprises an interface to a fuel flow metering valve for controlling a fuel flow to the engine in response to a fuel flow command and a controller connected to the interface and configured for outputting the fuel flow command to the fuel flow metering valve in accordance with a required fuel flow. The controller comprises a feedforward controller configured for receiving a requested engine speed, obtaining a steady-state fuel flow for the requested engine speed as a function of the requested engine speed, the steady-state fuel flow, and the relationship between fuel flow and gas generator speed, and determining the required fuel flow to obtain the requested engine speed and the relationship between fuel flow and gas generator speed.

Abstract: Systems and methods for controlling an gas turbine engine are provided. The method comprises receiving a requested engine speed and obtaining a shaft inertia of the engine, a steady state fuel flow for the requested engine speed, and a relationship between fuel flow and acceleration power generated by the fuel flow. A required fuel flow to obtain the requested engine speed is determined as a function of the requested engine speed, the shaft inertia of the engine, the steady state fuel flow for the requested engine speed, and the relationship between fuel flow and acceleration power generated by the fuel flow. A command to a fuel flow metering valve is output in accordance with the required fuel flow.

Abstract: Systems and methods for controlling a gas turbine engine are provided. The system comprises an interface to a fuel flow metering valve for controlling a fuel flow to the engine in response to a fuel flow command and a controller connected to the interface and configured for outputting the fuel flow command to the fuel flow metering valve in accordance with a required fuel flow. The controller comprises a feedforward controller configured for receiving a requested engine speed, obtaining a steady-state fuel flow for the requested engine speed as a function of the requested engine speed, the steady-state fuel flow, and the relationship between fuel flow and gas generator speed, and determining the required fuel flow to obtain the requested engine speed and the relationship between fuel flow and gas generator speed.