Abstract: The present invention relates to an apparatus and method for detecting the presence of water or ice on a structure, for example on the surface of an aircraft. A plurality of heaters (202-214) are thermally coupled to a structure (for example on the back of a wing) (104) in order to detect the presence of water or ice on the structure. The heaters are arranged adjacent one another from a GC region of a leading edge (106) of the structure (that is exposable to an impinging airflow) and extending aft of the leading edge of the structure. The heaters, which may be controlled individually, are supplied power that is sufficient to heat the surface of the structure to substantially the same temperature. A controller senses the power required for the heaters to achieve the same surface temperature at the respective regions.

Abstract: We describe an ice protection system used for removing ice and/or other accretions from a structure. An actuator, coupled to a structure, is driven to generate vibrations in the structure. A controller drives the actuator using a signal that comprises a frequency chirp over a first period of time, and the controller controls the frequency chirp and the first period such that vibrations generated in the structure by the actuator propagate through the structure to coincide at a desired area of the structure remote from the actuator to remove ice and/or other accretions from the desired area of the structure.

Abstract: We describe an ice protection system used for removing ice and/or other accretions from a structure. An actuator, coupled to a structure, is driven to generate vibrations in the structure. A controller drives the actuator using a signal that comprises a frequency chirp over a first period of time, and the controller controls the frequency chirp and the first period such that vibrations generated in the structure by the actuator propagate through the structure to coincide at a desired area of the structure remote from the actuator to remove ice and/or other accretions from the desired area of the structure.

Abstract: A circuit for simulating a capacitance fuel probe, the circuit comprising: an input for receiving an alternating current (AC) excitation signal; an output for outputting an output signal representing a capacitance of the simulated fuel probe; a single reference capacitance; a first amplifier connected to the reference capacitance, the first amplifier being configured to cause a current flow through the reference capacitance; a second, variable gain, amplifier, the second, variable gain amplifier being configured to output an AC signal representing a multiple of the current flow through the reference capacitance, wherein the AC signal output by the second amplifier is used to generate the output signal.

Abstract: A filter for use with a brushless DC motor to filter a signal received from a floating terminal of the brushless DC motor, wherein the filter is configured such that a time delay introduced by the filter to the signal received from the floating terminal is equal to the time taken for a rotor of the motor to rotate through an angle equal to half of a commutation step of the motor.

Abstract: The present invention relates to an apparatus and method for detecting the presence of water or ice on a structure, for example on the surface of an aircraft. One or more separate heaters are thermally coupled to a structure (for example on the back of wing leading edge skins). A controller applies power to the heaters to heat the different regions of the surface of the structure. The controller detects the presence of water or ice by comparing the power required to achieve the desired surface temperature, and a reference power, where the reference power is the power required to heat the surface of the structure to the same temperature if the structure were in a dry air environment (i.e. an environment devoid of water). If the power consumed by the heater is greater than the reference power, the presence of water or ice is inferred.

Abstract: A proximity sensor core for a proximity sensor is provided. The core has a head portion extending across a width of the sheet of material and the head has a first length. First and second leg portions extend for a second length from the same edge of the head portion. Each of the first and second leg portions extend across a portion of the width of the head portion. First and second foot portions extend for a third length from the respective first and second leg portions. The first and second foot portions have the same width as the respective leg portions. The core has a first bend between each of the first and second foot portions and the respective first and second leg portions so that the first and second foot portions extend generally perpendicular to the respective first and second leg portions.

Abstract: A circuit for simulating a capacitance fuel probe, the circuit comprising: an input for receiving an alternating current (AC) excitation signal; an output for outputting an output signal representing a capacitance of the simulated fuel probe; a single reference capacitance; a first amplifier connected to the reference capacitance, the first amplifier being configured to cause a current flow through the reference capacitance; a second, variable gain, amplifier, the second, variable gain amplifier being configured to output an AC signal representing a multiple of the current flow through the reference capacitance, wherein the AC signal output by the second amplifier is used to generate the output signal.

Abstract: A filter for use with a brushless DC motor to filter a signal received from a floating terminal of the brushless DC motor, wherein the filter is configured such that a time delay introduced by the filter to the signal received from the floating terminal is equal to the time taken for a rotor of the motor to rotate through an angle equal to half of a commutation step of the motor.

Abstract: The present invention generally relates to proximity sensor monitors and proximity monitor systems incorporating proximity sensor monitors. A proximity sensor monitor measures the impedance or other electrical characteristics of a proximity sensor component to determine the presence of a target. The proximity sensor monitor performs this measurement independently of a separate proximity sensor. The proximity sensor monitor is configured to compensate for differences between the measurement frequency of the proximity sensor monitor and the driving frequency of the proximity sensor.

Abstract: An ice detection system, in particular a method, apparatus and controller for detecting icing conditions and the presence of ice formed on a structure. Also, a method, apparatus and controller to detect the prevailing environmental conditions to determine whether or not ice may form on a structure. Two heaters of an ice protection system (experiencing substantially the same environmental conditions) are driven to different temperatures (the first greater than or equal to 0° C., and the second less than 0° C.). A difference in the powers required to drive the two heaters indicates the prevailing environmental conditions. In another embodiment, a heater of an ice protection system is driven and the rate of change of surface temperature is measured over several periods. A substantial deviation from a rate of change of surface temperature, which indicates the presence of ice on the surface of the structure, is detected.

Abstract: Each of a plurality of acoustic sensors (acoustically coupled to a structure for monitoring) is connected to a network bus system via a preamplifier for capturing, processing and reporting acoustic events in a structure, for example aircraft structures. Each of the preamplifiers processes the acoustic event signals received from the sensors when an acoustic emission resulting from an acoustic event (defect in a structure, impact on the structure etc), and passes digital processed signal data relating to the detected acoustic event to a Remote Data Concentrator over the network for collation. The collated data is then stored and/or further processed (at a later time or in near real-time) to determine the source and/or location of detected acoustic emissions in the structure.

Abstract: The present invention relates to an apparatus and method for detecting the presence of water or ice on a structure, for example on the surface of an aircraft. One or more separate heaters are thermally coupled to a structure (for example on the back of wing leading edge skins). A controller applies power to the heaters to heat the different regions of the surface of the structure. The controller detects the presence of water or ice by comparing the power required to achieve the desired surface temperature, and a reference power, where the reference power is the power required to heat the surface of the structure to the same temperature if the structure were in a dry air environment (i.e. an environment devoid of water). If the power consumed by the heater is greater than the reference power, the presence of water or ice is inferred.

Abstract: An adaptive control unit is described for receiving an analog input signal containing at least an indication of a parameter to be controlled to generate an analog output signal for control of the parameter. The analog input signal contains a fed back component resulting from the analog output signal. The adaptive control unit comprises an analog filter having an adjustable gain, a gain adjuster for adjusting the gain of the analog filter using a feedforward adjustment method, and a filter for compensating for the fed back component in the analog input signal.

Abstract: The present invention generally relates to proximity sensor monitors and proximity monitor systems incorporating proximity sensor monitors. A proximity sensor monitor measures the impedance or other electrical characteristics of a proximity sensor component to determine the presence of a target. The proximity sensor monitor performs this measurement independently of a separate proximity sensor. The proximity sensor monitor is configured to compensate for differences between the measurement frequency of the proximity sensor monitor and the driving frequency of the proximity sensor.

Abstract: A cable (7) is routed between a pair of links (1, 2) that are pivotally connected about a lateral pivot axis (4). A wound section (8) is provided in the cable with the winding axis coincident with the pivot axis of the links. The wound section (8) may be preformed. A cable protector (10, 11) is provided each end of the wound section (8) along the pivot axis (4) so as to constrain the adjacent end of the wound section (8) to be keyed with it and the adjacent link.

Abstract: An active tuned vibration absorber (100) is disclosed for reducing vibrations in a structure, the vibration absorber comprising: a mount (104) for attachment to the structure; a moveable mass (106); a spring arrangement (108) connected between the mass and the mount; an actuator arrangement (110) for applying a force between the mass and the mount; a first sensor (112) for providing a first measurement indicative of a force exerted between the structure and the mount; a second sensor (114) for providing a second measurement indicative of an acceleration of the structure at or proximate to the mount; and a control system (116) for generating an actuator driving signal for driving the actuator using the first and second measurement, wherein the control system is operable to generate the actuator driving signal to cause the first measurement and second measurement to conform to a target relationship.

Abstract: A method is disclosed for controlling the distribution of power to a plurality of devices, the method being carried out during a plurality of time periods, and the method during each time period after the first comprising: determining (S700) an energy or power deficit for each device based on the difference between a target amount of energy or power and a measured amount of energy or power supplied to the device prior to the current time period; selecting (S702) at least one device in decreasing order of energy or power deficit, whereby priority is given to devices having the largest energy or power deficit or the smallest energy or power surplus, until the selection of any further devices will cause a total estimated power consumption of the selected devices during the time period to exceed a predetermined maximum power consumption; and supplying (S704) power to the or each selected device during the time period.

Abstract: A method of calibrating a heater system for heating a surface of a structure, the heater system including a heater element, a temperature sensor proximate the heater element for outputting a signal indicative of the temperature of the heater element, and a controller for controlling the supply of power to the heater element in dependence on the signal to maintain the temperature of the heater element at a first substantially constant temperature. The method comprises: immersing the structure in a fluid for maintaining the surface of the structure at a second substantially constant temperature; supplying an amount of power to the heater element; receiving the signal from the temperature sensor and determining a temperature at the temperature sensor; and determining a setpoint temperature for controlling the heater element in dependence on the signal and the second substantially constant temperature.

Abstract: An ice detection system, in particular a method, apparatus and controller for detecting icing conditions and the presence of ice formed on a structure. Also, a method, apparatus and controller to detect the prevailing environmental conditions to determine whether or not ice may form on a structure. Two heaters of an ice protection system (experiencing substantially the same environmental conditions) are driven to different temperatures (the first greater than or equal to 0° C., and the second less than 0° C.). A difference in the powers required to drive the two heaters indicates the prevailing environmental conditions. In another embodiment, a heater of an ice protection system is driven and the rate of change of surface temperature is measured over several periods. A substantial deviation from a rate of change of surface temperature, which indicates the presence of ice on the surface of the structure, is detected.