System and method for combined propeller speed and propeller pitch control for a turbopropeller engine

Patent metadata

Field	Value
Publication number	US-11780600-B2
Application number	US-201916982334-A
Country	US
Kind code	B2
Filing date	Mar 22, 2019
Priority date	Mar 23, 2018
Publication date	Oct 10, 2023
Grant date	Oct 10, 2023

Abstract

An electronic control system ( 30 ) for a turbopropeller engine ( 12 ) having a gas turbine ( 20 ) and a propeller assembly ( 13 ) coupled to the gas turbine ( 20 ), controls propeller operation based on a pilot input request, via generation of a driving quantity (Ip) for an actuation assembly ( 29 ) designed to adjust a pitch angle (β) of propeller blades ( 2 ) of the propeller assembly ( 13 ). The control system ( 30 ) envisages: a propeller speed regulator ( 39 ), receiving at its input a propeller speed error (ep), indicative of a difference between a propeller speed measure (Nr) and a propeller speed demand (Nrref), and generating at its output, based on the propeller speed error (ep), a first control quantity (Outi); a propeller pitch regulator ( 42 ), receiving at its input a propeller pitch error (ep), indicative of a difference between a propeller pitch demand ( ) and a pitch position measure (β), and generating at its output, based on the propeller pitch error (ep), a first control quantity (Out 2 ); and a priority selection stage ( 45 ), configured to implement a priority selection between the first and the second control quantities, for providing at the output the driving quantity (IP), based on the priority selection between the first and the second control quantities.

First claim

The invention claimed is:

1. An electronic control system for a turbopropeller engine having a gas turbine and a propeller assembly coupled to the gas turbine, the control system being configured to control propeller operation based on a pilot input request, via generation of a driving quantity for an actuation assembly designed to adjust a pitch angle of propeller blades of the propeller assembly, the electronic control system comprising:
a propeller speed regulator configured to receive at its input a propeller speed error indicative of a difference between a propeller speed measure and a propeller speed demand, and to generate at its output, based on the propeller speed error, a first control quantity;
a propeller pitch regulator configured to receive at its input a propeller pitch error indicative of a difference between a propeller pitch demand and a pitch position measure, and to generate at its output, based on the propeller pitch error, a second control quantity; and
a priority selection stage coupled to the output of the propeller speed regulator and the output of the propeller pitch regulator to receive the first and the second control quantities, and configured to implement a priority selection between the first and the second control quantities, for providing at an output of the priority selection stage the driving quantity, based on the priority selection between the first and the second control quantities.

2. The system according to claim 1 , wherein the electronic control system is configured to receive an input signal indicative of an angular position of an input lever determining the pilot input request; wherein the priority selection stage is configured to select the first control quantity at the output of the propeller speed regulator, when the input signal is indicative of the angular position of the input lever being in a first range, comprised between an idle position up to a full-forward position; and to select the second control quantity at the output of the propeller pitch regulator when the input signal is indicative of the angular position of the input lever being in a second range, distinct from the first range, comprised between the idle position down to a full-reverse position.

3. The system according to claim 1 , wherein the priority selection stage is configured to implement a maximum selection between the first and the second control quantities, to select at the output of the priority selection stage the greater between the first and second control quantities, for providing the driving quantity.

4. The system according to claim 3 , wherein a positive value of the driving quantity is designed to determine an increase of the pitch angle by the actuation assembly.

5. The system according to claim 1 , wherein the electronic control system is configured to engage a mechanical lock, determining a minimum flight pitch value for the pitch angle during a flight operating mode; wherein the propeller pitch demand is equal to a minimum ground pitch value, lower than the minimum flight pitch value, when an angular position of an input lever is in a first range, comprised between an idle position up to a full-forward position.

6. The system according to claim 1 , wherein the propeller pitch demand is equal to a feather position value, corresponding to a maximum pitch value, upon receiving a feather command indicative of a feathering request.

7. The system according to claim 1 , further comprising:
a first reference generator configured to receive an input signal indicative of an angular position of an input lever and to determine a value of the propeller speed demand corresponding to the input signal;
a first adder block configured to receive at a negative input the propeller speed demand and at a positive input the propeller speed measure, and to provide at its output the propeller speed error.

8. The system according to claim 1 , further comprising:
a second reference generator configured to receive an input signal indicative of an angular position of an input lever and to determine a value of the propeller pitch demand corresponding to the input signal;
a second adder block configured to receive at a positive input the propeller pitch demand and at a negative input the pitch position measure, and to provide at the its output the propeller pitch error.

9. The system according to claim 8 , wherein the second reference generator comprises:
a scheduler configured to receive the input signal and to determine a first reference value for the pitch angle, corresponding to the angular position of the input lever;
a first switch selector having a first switching input coupled to the scheduler to receive the first reference value and a second switching input to receive a minimum ground pitch value, lower than a minimum flight pitch value that is determined by a hydraulic lock, and providing at its output either the first reference value or the minimum ground pitch value, as a second reference value, depending on the angular position of the input lever being lower than an idle position or, respectively, higher than the idle position;
a second switch selector, having a respective first switching input coupled to the output of the first switch selector to receive the second reference value and a respective second switching input to receive a feather position value, corresponding to a maximum pitch value, and providing at its output either the second reference value or the feather position value, as the propeller pitch demand based on a feather command indicative of a feathering request.

10. The system according to claim 1 , wherein the propeller speed regulator and the propeller pitch regulator comprise a respective lead compensator, implementing a proportional gain and a lead/lag function.

11. A turbopropeller engine for an aircraft, comprising: a gas turbine; a propeller assembly, coupled to the gas turbine via a gearbox assembly; and the electronic control system according to claim 1 .

12. An aircraft comprising the turbopropeller engine according to claim 11 .

13. A control method for a turbopropeller engine having a gas turbine and a propeller assembly coupled to the gas turbine, configured to control propeller operation based on a pilot input request, via generation of a driving quantity for an actuation assembly designed to adjust a pitch angle of propeller blades of the propeller assembly,
wherein the control method comprises:
generating, by a propeller speed regulator, a first control quantity, based on a propeller speed error, indicative of a difference between a propeller speed measure and a propeller speed demand;
generating, by a propeller pitch regulator, a second control quantity, based on a propeller pitch error, indicative of a difference between a propeller pitch demand and a pitch position measure; and
implementing a priority selection between the first and the second control quantities, for providing the driving quantity, based on the priority selection between the first and the second control quantities.

14. The method according to claim 13 , further comprising:
receiving an input signal indicative of an angular position of an input lever; wherein implementing the priority selection comprises selecting the first control quantity, when the input signal is indicative of the angular position of the input lever being in a first range, comprised between an idle position up to a full-forward position; and
selecting the second control quantity generated by of the propeller pitch regulator when the input signal is indicative of the angular position of the input lever being in a second range, distinct from the fi

Assignees

• Ge Avio Srl

Inventors

• Forte Pierpaolo
• Ettorre Stefano
• Donini Giuseppe

Classifications

• B64C11/44

  electric · CPC title

• B64D31/06 Primary

  actuated automatically · CPC title

• B64C11/301 Primary

  characterised by blade position indicating means · CPC title

• B64C11/305

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

• F02C9/58

  with control of a variable-pitch propeller · CPC title