A device (2) for demagnetizing and for measuring the magnetic signature of a stationary hull (4) and for simulating a magnetic field, including a demagnetization coil assembly (8), a magnetic field sensor assembly (10) and a simulation coil assembly (12a, 12b, 12c), which can be positioned next to the hull (4) in a horizontal manner on one side and the cross-sectional areas of the demagnetization coils (8) and of the simulation coils (12a, 12b, 12c) being disposed in the longitudinal direction of the hull (4) with horizontally oriented surface normals. The demagnetization coils (8) produce an alternating magnetic field; the simulation coils (12a, 12b, 12c) produce a stationary simulated magnetic field in all three dimensions.

A material defect detection device that detects a material defect in a predetermined region of metallic equipment using a magnetic field distribution in the predetermined region measured by a magnetic sensor array including a plurality of magnetic sensors, the material defect detection device including: a processor that calculates a density distribution of magnetic dipoles in the predetermined region based on the magnetic field distribution and calculates a depth distribution of material defect in the predetermined region based on the density distribution of the magnetic dipoles.

A device (2) for demagnetizing and for measuring the magnetic signature of a stationary hull (4) and for simulating a magnetic field, including a demagnetization coil assembly (8), a magnetic field sensor assembly (10) and a simulation coil assembly (12a, 12b, 12c), which can be positioned next to the hull (4) in a horizontal manner on one side and the cross-sectional areas of the demagnetization coils (8) and of the simulation coils (12a, 12b, 12c) being disposed in the longitudinal direction of the hull (4) with horizontally oriented surface normals. The demagnetization coils (8) produce an alternating magnetic field; the simulation coils (12a, 12b, 12c) produce a stationary simulated magnetic field in all three dimensions.

A measurement apparatus acquires actually-measured closed magnetic path curve data, actually-measured open magnetic path curve data, and a surface magnetic property value; calculates, for each divided region obtained by sectioning and dividing the permanent magnet, by using a function including a parameter that determines distribution of magnetic property of the permanent magnet, a magnetic property value of the divided region based on an internal magnetic property value extracted from the actually-measured closed magnetic path curve data and the surface magnetic property value; calculates estimated open magnetic path curve data indicating a magnetization curve of the permanent magnet, based on a magnetic property value and the actually-measured closed magnetic path curve data; changes a value of the parameter to minimize a magnetization difference between the actually-measured open magnetic path curve data and the estimated open magnetic path curve data; and outputs a magnetic property value of each of the divided regions.

A motor demagnetization detection method includes the following steps. The speed of a motor is calculated according to the rotation angle of the motor. When determining that the motor respectively maintains a first and second steady state according to the speed, the three-phase current values of the motor are received to obtain first and second steady-state data. An equivalent magnetic flux is calculated according to the first and second steady-state data. The motor is repeatedly driven to maintain the first and second steady states, the first and second steady-state data are updated according to the three-phase current values, and the equivalent magnetic flux is again calculated to generate equivalent magnetic fluxes. A magnetic flux change is calculated according to equivalent magnetic fluxes. A demagnetization warning is issued according to a comparison of the magnetic flux change and a demagnetization warning value.

A motor demagnetization detection method includes the following steps. The speed of a motor is calculated according to the rotation angle of the motor. When determining that the motor respectively maintains a first and second steady state according to the speed, the three-phase current values of the motor are received to obtain first and second steady-state data. An equivalent magnetic flux is calculated according to the first and second steady-state data. The motor is repeatedly driven to maintain the first and second steady states, the first and second steady-state data are updated according to the three-phase current values, and the equivalent magnetic flux is again calculated to generate equivalent magnetic fluxes. A magnetic flux change is calculated according to equivalent magnetic fluxes. A demagnetization warning is issued according to a comparison of the magnetic flux change and a demagnetization warning value.

A rapid demagnetization method based on characteristics of magnetic media. In the method, basic information is obtained by a recognition module of magnetic media by means of multi-source sensing collaboration. The magnetic medium is identified by using a data processing technology and a magnetic medium identification algorithm, and then the characteristic information is extracted. Optimized set values of demagnetization parameters are obtained by a demagnetization parameter optimizing and setting module based on a demagnetization optimizing model. Demagnetization parameter set values are tracked by a closed-loop control module of a demagnetization magnetic field in combination with domain expert knowledge by using a closed-loop control mechanism integrated with a magnetic field control algorithm, a charging-discharging device, a magnetic field generating device, a magnetic field sensor and an environmental sensor, completing the rapid demagnetization of the magnetic medium.

Disclosed is a magnetizing pulse detector that detects magnetizing pulses produced by a magnetizing coil; the magnetizing pulse detector comprising: a measuring coil configured to generate a measuring pulse in response to a magnetizing pulse produced by the magnetizing coil; a measuring pulse detection circuit configured to generate a detection signal based on the measuring pulse generated by the measuring coil; and a duration extension circuit configured to generate an extended detection signal based on the detection signal generated by the measuring pulse detection circuit.

A method for initializing a sensor array comprises executing a statistical test on a set consisting of first measurements measured by the sensors of the array, the statistical test being able to detect in the first measurements at least one aberrant measurement caused by a presence of an object, called a disruptor, this disruptor modifying the measured physical quantity nonuniformly, wherein if the execution of the statistical test detects at least one aberrant measurement, then the method comprises signaling the presence of the disruptor, and if the execution of the statistical test does not detect at least one aberrant measurement, then the method comprises acquiring second measurements of the physical quantity, the second measurements being measured by the sensors.

The inspection device includes: a conveyance route that conveys an inspection object at moving speed v; a first magnetic detector and a second magnetic detector that detect a magnetic field of a magnetic foreign object contained in the inspection object; an amplifying unit that amplifies detection signals of the first magnetic detector and the second magnetic detector; and a computation processing unit that performs processing of multiplying the detection signal of the second magnetic detector by a signal obtained by delaying the detection signal of the first magnetic detector. The first magnetic detector and the second magnetic detector each include one magnetic sensor and the magnetic sensors form a pair.