Abstract: A look-ahead detection system (LADS) that actively controls the suspension of at least some of the seats in a watercraft to drastically reduce the shock and/or vibrations experienced by passengers within the seats caused by waves, other water conditions and/or the bending of the craft as it travels through the water. The look-ahead detection system utilizes downward-looking sensors to help the system predict when the craft will strike the water and how strong the impact will be. That is, the look-ahead detection system uses the sensors to look forward in time and down in space.

Abstract: A dynamic degaussing system includes a magnetic field sensor for generating a sensor signal in response to a sensed magnetic field. The magnetic sensor is coupled to a controller that produces an output signal based on the sensor signal. The controller may include feedforward and feedback control loops. The output signal of the controller controls a magnetic field generator which generates a magnetic field so as to attenuate the sensed magnetic field. According to one aspect of the invention, a vessel is provided with a reduced magnetic signature and a control system for controlling magnetic fields about a podded electric motor. The control system employs feed-forward and feedback control in tandem. The control system may be dynamically adapted to changing physical characteristics of the motor. Control signals are generated in response to sensed or predicted magnetic fields internal to, or external to, the motor.

Abstract: An active suspension system is used to control the motion of a passenger seat in a high speed watercraft. A forward looking wave sensor is used in connection with a feed-forward wave impact shock predictor to determine characteristics of impending dynamic forces applied via the impact of the watercraft on waves. Information concerning the impending dynamic forces is used by a passenger seat suspension and control system to attenuate the shock effects on passengers, where such effects are characterized by large-amplitude, short-duration accelerations recurring at a low frequency and/or irregularly.

Abstract: A multi-sensor, multi-actuator control system for controlling vibration in a mechanical structure. The system employs feedforward and feedback control strategies in tandem. Outputs from adaptive feedforward and modal feedback control loops are added to each other. The control system may be dynamically adapted to the changing physical characteristics of the controlled structure. For example, the plant transfer function estimates for the feedforward unit and the gain for the feedback unit may be calculated as functions of sensed physical parameters (location, mass, etc.), and the plant transfer function estimates may be dynamically modified to reflect time-varying feedback control gains. If desired, the control system may be used to cancel low frequency vibrations (<20 Hz) in industrial processes. The actuators may be formed of electromagnets, fixed armatures and interposed flux sensors. In a preferred embodiment of the invention, the robust actuators are sealed so as to be impervious to fluids and dust.