Abstract: We describe a way of detecting delamination of a laminated structure that is heated by DC powered heaters by passing the source and return wires that supply current to the heaters through a toroidal transformer core. Should there be a breakdown in the laminations, current flowing through the heater will flow into the structure, resulting in less current being present in the return wire than in the source wire. The current imbalance between the source and return wires causes the transformer core to saturate. Using the core saturation, caused by the DC current imbalance, the delamination (or imminent delamination) of the laminated structure can be detected.

Abstract: We describe a way of detecting delamination of a laminated structure that is heated by DC powered heaters by passing the source and return wires that supply current to the heaters through a toroidal transformer core. Should there be a breakdown in the laminations, current flowing through the heater will flow into the structure, resulting in less current being present in the return wire than in the source wire. The current imbalance between the source and return wires causes the transformer core to saturate. Using the core saturation, caused by the DC current imbalance, the delamination (or imminent delamination) of the laminated structure can be detected.

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: 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 provides an apparatus and method for vibration isolation. The invention may be conceptualized as a vibration isolation mount. The vibration isolation mount mounts a first member to a second member for reducing the transmission of vibrations from the first member to the second member. The vibration isolation mount comprises a first mounting means for mounting to the first member, and a second mounting means for mounting to the second member. A spring means is arranged between the first and second mounting means, wherein said spring means is coupled to the first mounting means and provides a spring force between said first and second mounting means. The invention may also be conceptualized as a vibration isolation method. The method controls vibrations transmitted from a first member to a second member when the second member is mounted on the first member using a spring arrangement. The spring arrangement provides a delay in transmission of an impulse between the first and second members.

Abstract: An active vibration absorber is provided for absorbing vibrations in a member. An inertial mass is mounted on the member with a stiffness between the member and the mass. A force actuator arrangement applies a force between the inertial mass and the member. A damping arrangement provides for damping of a resonance of the active vibration absorber. A first sensor arrangement provides at least one first signal indicative of at least one movement and/or stress related parameter for the member and a second sensor arrangement provides for at least one second signal indicative of a reaction of the inertial mass. A control arrangement is provided for controlling the force actuator arrangement using the at least one first signal and the at least one second signal.

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: An active vibration absorber is provided for absorbing vibrations in a member. An inertial mass is mounted on the member with a stiffness between the member and the mass. A force actuator arrangement applies a force between the inertial mass and the member. A damping arrangement provides for damping of a resonance of the active vibration absorber. A first sensor arrangement provides at least one first signal indicative of at least one movement and/or stress related parameter for the member and a second sensor arrangement provides for at least one second signal indicative of a reaction of the inertial mass. A control arrangement is provided for controlling the force actuator arrangement using the at least one first signal and the at least one second signal.

Abstract: The present invention provides an apparatus and method for vibration isolation. The invention may be conceptualized as a vibration isolation mount. The vibration isolation mount mounts a first member to a second member for reducing the transmission of vibrations from the first member to the second member. The vibration isolation mount comprises a first mounting means for mounting to the first member, and a second mounting means for mounting to the second member. A spring means is arranged between the first and second mounting means, wherein said spring means is coupled to the first mounting means and provides a spring force between said first and second mounting means. The invention may also be conceptualized as a vibration isolation method. The method controls vibrations transmitted from a first member to a second member when the second member is mounted on the first member using a spring arrangement. The spring arrangement provides a delay in transmission of an impulse between the first and second members.

Abstract: A system for attenuating noise in a cabin of a vehicle is provided in which the vehicle has an interior wall defining the cabin and an exterior wall defining a cavity between the interior wall and the exterior wall. A plurality of actuators are arranged within the cavity, on the interior wall or on the exterior wall for providing a physical actuation resulting in an acoustic disturbance. A plurality of sensors are arranged in the cavity on the interior wall, or on the exterior wall to provide indications of acoustic disturbances. A control system uses the indications from the sensors to generate control signals for the actuators. In one arrangement the sensors are arranged in an array interspersed between the actuators which are also arranged in an array. A drive signal for each actuator is then generated using the signals from sensors adjacent to the actuators.