Method and system for model based control for variable pitch fan engines and turbo-shaft, turbo-propeller engines

Patent metadata

Field	Value
Publication number	US-2016159461-A1
Application number	US-201514830914-A
Country	US
Kind code	A1
Filing date	Aug 20, 2015
Priority date	Sep 30, 2014
Publication date	Jun 9, 2016
Grant date	—

Abstract

A method and control system for an aircraft engine comprising a gas turbine driving a fan propeller with a mechanical gear-train and a dedicated pitch change mechanism for the fan propeller includes a fuel flow signal input; a pitch change mechanism signal input; a controlled plant for relating a pitch change mechanism pitch angle (BetaP) and a fuel flow (Wf) to at least two controlled outputs and a set of constraints. A decoupling control decoupling the controlled plant and/or the constraints into two separate single-input single-output (SISO) control loops for the first and second controlled outputs and a decoupling control decoupling the constraints from the decoupled controlled outputs and the constraints from one another provide gas turbine and fan propeller coordinate control while coordinately controlling constraints and outputs. A feedforward control can compensate the load change effect on engine speed and fan propeller rotor speed control.

First claim

What is claimed is:

1 . A control system for an aircraft engine comprising a gas turbine driving a fan propeller with a mechanical gear-train and a dedicated pitch change mechanism for the fan propeller, the control system comprising:
a fuel flow signal input; a pitch change mechanism signal input; at least one constraint input; a controlled plant for relating a pitch change mechanism pitch angle (BetaP) from the pitch change mechanism signal input and a fuel flow (Wf) from the fuel flow signal input and a constraint from the at least one constraint input to at least two controlled outputs, wherein a first one of the controlled outputs is either propeller speed (Nr) or power turbine shaft speed (N1) and a second one of the controlled outputs is engine core speed (N2), engine pressure ratio (EPR) or engine torque (Tq); and a decoupling control for decoupling one of the controlled plant and the at last one constraint into two separate single-input single-output (SISO) control loops for the first and second controlled outputs; a decoupling control for decoupling constraints from the decoupled controlled outputs and the constraints from one another such that each of constraints is separated into a SISO control loop; wherein the gas turbine and the fan propeller are coordinately controlled while coordinately controlling the constraints and the outputs.

2 . The control system of claim 1 wherein the fan propeller is parallel to the axis of the gas turbine.

3 . The control system of claim 2 wherein the aircraft engine is an unducted single fan engine.

4 . The control system of claim 1 wherein the aircraft engine is a turbo shaft, turbo propeller engine.

5 . The control system of claim 1 further comprising a control for measuring a propeller speed phase to be transmitted to a speed phase synchronization and a control for receiving and adding a speed reference bias to a propeller speed reference to synchronize the aircraft engine with a second aircraft engine.

6 . The control system of claim 1 wherein the decoupling control includes at least one known disturbance input.

7 . The control system of claim 6 wherein the pitch change mechanism pitch angle (BetaP) is treated as a known disturbance input and the decoupling control is reconfigured to have a single controlled input based on the fuel flow (Wf).

8 . The control system of claim 1 wherein the fan propeller is variable pitch.

9 . A method of controlling an aircraft engine comprising a gas turbine driving a fan propeller with mechanical gear-train, and a fuel actuator, a pitch change mechanism actuator, the method comprising:
receiving a fuel flow signal; receiving a pitch change mechanism signal; relating in a controlled plant a pitch change mechanism pitch angle (BetaP) from the pitch change mechanism signal and a fuel flow (Wf) fuel flow signal to at least two controlled outputs, wherein a first one of the controlled outputs is either propeller speed (Nr) or power turbine shaft speed (N1) and a second one of the controlled outputs is engine core speed (N2), engine pressure ratio (EPR) or engine torque (Tq); decoupling the controlled plant into two separate single-input single-output (SISO) control loops for the first and second controlled outputs; and decoupling the constraints from the decoupled controlled outputs and the constraints from one another for coordinately controlling the constraints and the outputs.

10 . The method of claim 9 wherein the aircraft engine comprises a pitch change mechanism actuator, and further including receiving a pitch change mechanism signal and relating in the controlled plant a pitch change mechanism pitch angle (BetaP) from the pitch change mechanism signal to at least two controlled outputs, wherein a first one of the controlled outputs is either propeller speed (Nr) or power turbine shaft speed (N1) and a second one of the controlled outputs is engine core speed (N2), engine pressure ratio (EPR) or engine torque (Tq).

11 . The method of claim 9 further including a step of rejecting known disturbances in the decoupling step.

12 . The method of claim 11 further including a step of reconfiguring a decoupling control to have a single controlled input based on the fuel flow (Wf) and treating the pitch change mechanism pitch angle (BetaP) as a known disturbance input.

13 . The method of claim 9 further including at least a feedforward control action of compensating the load change effect on engine speed and fan propeller rotor speed control based on load change indication or load change estimation.

Assignees

• Gen Electric

Inventors

• Lu Manxue
• Carpenter R Sheldon

Classifications

• B64C11/305 Primary

  characterised by being influenced by other control systems, e.g. fuel supply · CPC title

• B64D27/10

  of gas-turbine type  (jet aircraft B64D27/16) · CPC title

• F02C9/58 Primary

  with control of a variable-pitch propeller · CPC title

• F05D2270/052

  Torque · CPC title

• F05D2220/32

  in gas turbines · CPC title