A method of controlling at least one of a first robot and a second robot to collaborate within a system, the first robot and the second robot being physically separate to one another, the method including: receiving sensed data associated with the second robot; determining position and/or orientation of the second robot using the received sensed data; determining an action for the second robot using the determined position and/or orientation of the second robot; and providing a control signal to the second robot to cause the second robot to perform the determined action to collaborate with the first robot.

A method of delivering fuel to an engine during operation of the engine, that includes, sensing the speed of sound in the fuel, determining a density or property of the fuel, and based on that density or fuel property adjusting the flow rate of the fuel. Further, an established fuel profile or determined energy density value can also be used to adjust the flow rate of the fuel.

A method of inspecting the fan track liner of a gas turbine engine of a type having a rotatable propulsive fan circumscribed by a fan track liner and having a plurality of fan blades extending radially outwardly from a central hub. The method comprises the steps of: affixing at least part of an inspecting device to the fan so as to be directed towards the fan track liner; and rotating the fan within the fan track liner to move the at least part of the inspecting device circumferentially relative to at least a region of the fan track liner to thereby scan the region of the fan track liner with the at least part of the inspecting device.

A turbomachine having an air flow measurement system. The system comprises a plurality of acoustic sensors upstream of a compressor of the turbomachine. The acoustic sensors are configured to transmit acoustic waveforms through an intake airflow to further acoustic sensors. The acoustic sensors are located in a single plane and mounted at angular spacing about a central axis of an intake.

A turbofan gas turbine engine having a bypass duct, and a bypass airflow measurement system. The bypass airflow measurement system comprises: at least one acoustic transmitter configured to transmit an acoustic waveform across the bypass duct of the gas turbine engine though which a bypass airflow passes to at least one acoustic receiver; where the at least one acoustic transmitter and the at least one acoustic receiver are located on an axial plane that is substantially perpendicular to the bypass flow. A method of measuring bypass airflow properties of a turbofan gas turbine engine is also described.

A turbofan gas turbine engine having a bypass duct, and a bypass airflow measurement system. The bypass airflow measurement system comprises: at least one acoustic transmitter configured to transmit an acoustic waveform across the bypass duct of the gas turbine engine though which a bypass airflow passes to at least one acoustic receiver; where the at least one acoustic transmitter and the at least one acoustic receiver are located on an axial plane that is substantially perpendicular to the bypass flow. A method of measuring bypass airflow properties of a turbofan gas turbine engine is also described.

A turbomachine having an air flow measurement system. The system comprises a plurality of acoustic sensors upstream a compressor of the turbomachine. The acoustic sensors comprise at least one acoustic transmitter configured to transmit an acoustic waveform through an intake airflow to an acoustic receiver. The acoustic sensors are located in a single plane and mounted at angular spacing about a central axis of an intake.

A flow machine having a flow passage and an air flow measurement system comprising a plurality of acoustic sensors. The acoustic sensors comprise at least one acoustic transmitter configured to transmit an acoustic waveform through the airflow passing through the flow passage to an acoustic receiver. At least one of the acoustic sensors is rotatable relative to one or more other acoustic sensor.

A method of thermodynamic assessment of flow through a turbomachine having a compressor, comprising: receiving sensor readings from a plurality of acoustic sensors located about an intake for the turbomachine upstream of the compressor; and receiving pressure and stagnation temperature readings for the flow into the intake. A static temperature is determined for the flow into the intake and an average velocity of the flow over a flow area of the intake upstream of the compressor using the acoustic sensor readings. A mass flow rate of the flow through the intake is determined using the average velocity of the flow and the stagnation pressure.

A method of delivering fuel to an engine during operation of the engine, that includes, sensing the speed of sound in the fuel, determining a density or property of the fuel, and based on that density or fuel property adjusting the flow rate of the fuel. Further, an established fuel profile or determined energy density value can also be used to adjust the flow rate of the fuel.