Abstract: An electrode assembly for electrochemically machining a cavity of a component is disclosed. The electrode assembly comprises: an electrode, a mounting body, and an urging means. The electrode comprises a plurality of conductive elements, including an outermost conductive element. The mounting body is coupled to the electrode and engageable with the component to align the electrode within the cavity. The urging means is configured to transition the electrode from a movable configuration to a conforming configuration. In the movable configuration the conductive elements are moveable relative to one another. In the conforming configuration adjacent conductive elements align to define a substantially continuous outer electrode surface.

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: 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: 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.