Optimal thrust control of an aircraft engine

A method for controlling a gas turbine engine, the gas turbine engine including, at least, an exhaust nozzle, the exhaust nozzle changing positions to change dimensions of an exhaust section with respect to a tail cone, the method comprising:

• determining a nozzle schedule of exhaust nozzle positions related to flight conditions;
• determining an exhaust nozzle position goal (A8 GOAL) based on the nozzle schedule;
• determining sensor signals using system sensors;
• estimating synthesis signals (FN) using an engine model and input from the sensor signals;
• determining, with a goal generator module, auxiliary goals and actuator goals;
• the auxiliary goals based on engine states that are related to engine thrust during transient engine operations;
• and
• the actuator goals based on positions for high pressure compressor stator vanes (HPCSV), low pressure compressor stator vanes (LPCSV) and/or engine stability bleeds (BLD);
• electronically receiving information by a control module, being a hybrid model predictive control (HMPC), the received information including:
• the exhaust nozzle position goal (A8 GOAL);
• the sensor signals;
• the synthesis signals (FN) signals;
• and
• the auxiliary and actuator goals;
• and
• determining and outputting, by the control module based on the received information, a control command for the gas turbine engine, the control command including:
• a fuel flow (WF) command;
• a stability bleeds (BLD) position command;
• an exhaust nozzle position command;
• a high pressure compressor stator vanes (HPCSV) position command;
• and
• a low pressure compressor stator vanes (LPCSV) position command;
• and
• controlling the gas turbine engine based on the control command.

A gas turbine engine comprising:

• a compressor section;
• a combustor section downstream of the compressor section;
• a turbine section downstream of the combustor section;
• an exhaust nozzle, the exhaust nozzle changing positions to change dimensions of an exhaust section with respect to a tail cone;
• and
• a control system comprising:
• a nozzle scheduler for determining an exhaust nozzle position goal (A8 GOAL) based on a nozzle schedule of exhaust nozzle positions related to flight conditions;
• a plurality of system sensors for determining sensor signals;
• an engine model for estimating synthesis signals (FN) using the sensor signals;
• a goal generator module for determining auxiliary goals and actuator goals;
• the auxiliary goals based on engine states that are related to engine thrust during transient engine operations;
• and
• the actuator goals based on positions for high pressure compressor stator vanes (HPCSV), low pressure compressor stator vanes (LPCSV) and/or engine stability bleeds (BLD);
• a control module, being a hybrid model predictive control (HMPC), electronically receiving information, including:
• the exhaust nozzle position goal (A8 GOAL);
• the sensor signals;
• the synthesis signals (FN);
• and
• the auxiliary and actuator goals;
• based on the received information, the control module determining and outputting a control command for the gas turbine engine, the control command including:
• a fuel flow (WF) command;
• a stability bleeds (BLD) position command;
• an exhaust nozzle position command;
• a high pressure compressor stator vanes (HPCSV) position command;
• and
• a low pressure compressor stator vanes (LPCSV) position command.