Abstract: Interruption in supervisory position control signals can cause problems with respect to actuators which upon loss of such control signals for the actuator will generally slew to a fixed idle position. In such circumstances a machine such as a gas turbine engine in which an actuator is associated will not sustain performance even though there is continued local power supply to the actuator. By utilizing a local controller which stores actuator response profiles for certain machine status stages through perturbation or marginal activation of the actuator an appropriate actuator response profile can be chosen and therefore sustaining control signals presented to the actuator to maintain machine operation.

Abstract: A method of controlling turbine case cooling in a gas turbine engine, the method including monitoring the present state of the engine 32 and using a predictive model based system 44, 46 to predict the future thermal expansion of the turbine case 12 and turbine blades 28, and controlling cooling of the turbine case 12 in response to said prediction to provide a required gap 30 over time.

Abstract: Interruption in supervisory position control signals can cause problems with respect to actuators which upon loss of such control signals for the actuator will generally slew to a fixed idle position. In such circumstances a machine such as a gas turbine engine in which an actuator is associated will not sustain performance even though there is continued local power supply to the actuator. By utilising a local controller which stores actuator response profiles for certain machine status stages through perturbation or marginal activation of the actuator an appropriate actuator response profile can be chosen and therefore sustaining control signals presented to the actuator to maintain machine operation.

Abstract: A control system for a gas turbine engine provides a combined power and data bus that connects a Electrical Engine Controller with electrically actuated pumps, actuators and valves. A scheduler within the Electrical Engine Controller divides the information to be sent out into minor time frames. Each electrically actuated component reads and acts on data from a predetermined minor time frame.

Abstract: Four actuators are instructed to move to a condition indicated by a demand line 81. Their actual conditions are indicated by four arrows. The method determines if the range 84 of actual conditions exceeds a threshold value, representing an unacceptable mismatch of actuator positions. This comparison is used to establish further demand instructions. For example, if the range is too great, and the average 82 is below the demand line 81, the devices are instructed to move to the upper extreme position at 88. If the average position 82 is above the demand line 81, the devices are instructed to move to the lower end of the range, at 90. This results in the actuator positions moving together, as they also move toward the demand line 81, reducing risks associated with actuator mismatches.

Abstract: A method of controlling turbine case cooling in a gas turbine engine, the method including monitoring the present state of the engine 32 and using a predictive model based system 44, 46 to predict the future thermal expansion of the turbine case 12 and turbine blades 28, and controlling cooling of the turbine case 12 in response to said prediction to provide a required gap 30 over time.

Abstract: Four actuators are instructed to move to a condition indicated by a demand line 81. Their actual conditions are indicated by four arrows. The method determines if the range 84 of actual conditions exceeds a threshold value, representing an unacceptable mismatch of actuator positions. This comparison is used to establish further demand instructions. For example, if the range is too great, and the average 82 is below the demand line 81, the devices are instructed to move to the upper extreme position at 88. If the average position 82 is above the demand line 81, the devices are instructed to move to the lower end of the range, at 90. This results in the actuator positions moving together, as they also move toward the demand line 81, reducing risks associated with actuator mismatches.