A system includes sensing modules positioned along a length of a drill string. Each sensing module includes a structure arrangement composed of an outer structure body having a cavity and an inner structure body rotatably supported within the cavity. The structure arrangement is coupled to the drill string such that rotation of the drill string produces a relative rotation between the structure bodies. Ball elements are disposed in a gap between the structure bodies and move along a predetermined path defined in the gap in response to relative rotation between the structure bodies. Movable elements are positioned to physically interact with the ball elements as the ball elements move along the predetermined path. Energy harvesters in the sensor modules generate electrical energy from the mechanical energy produced by physical interaction between the ball elements and movable elements. The sensing modules include sensors to measure parameters in the drill string environment.

A strain sensor having an active area that includes a magnetoelastic resonator and spring configured so that the spring undergoes a greater amount of strain than the resonator when the sensor is under load. The sensor is anchored at opposite ends of the active area to a substrate for which strain is to be measured. An interrogating coil is used for wireless sensor readout. A biasing magnet may be included to provide a desired sensor response for the particular application of the sensor. The strain sensor may be implemented as a differential strain sensor that includes a second, strain-independent reference resonator.

To reduce the construction effort and also to make it smaller, the detector coil (6) is formed in the detector head (7) of a magnetostrictive position sensor (100) in a semiconductor chip (2), in which at the same time also the evaluation circuit (16) is formed and—if biased electrically and by means of direct current—also the then necessary separate bias coil (18).

The disclosure describes new apparatus, systems and methods utilizing magnetoelectric neural stimulators with tunable amplitude and waveform. Specific embodiments of the present disclosure include a magnetoelectric film, a magnetic field generator and an electrical circuit coupled to the magnetoelectric film, in particular embodiments, the electrical circuit comprises components configured modify an electrical output signal produced by the magnetoelectric film. In certain embodiments, the electrical circuit is configured to modify the electric signal to charge a charge storage element, to transmit data to an implantable wireless neural stimulator, and to provide a stimulation output to electrodes.

A gap compensated stress sensing system and methods for using the same are provided. The system can include a sensor head in communication with a controller. The sensor head can contain a stress sensor configured to generate a stress signal representing stress applied to a target based upon measurement of generated magnetic fluxes passing through the target. The system can also include a drive circuit configured to provide a current for generation of the magnetic fluxes, and to measure signals characterizing a gap between the sensor head and the target. The controller can analyze these signals to determine a gap-dependent reference signal that is relatively insensitive to electrical runout. The controller can further adjust the stress signal based upon the gap-dependent reference signal to determine an improved stress signal that has reduced sensitivity to gap changes.

An assembly measures a bending torque on a machine element extending on an axis using the inverse magnetostrictive effect. The machine element has a cavity and at least one magnetization region, extending circumferentially around the axis. A magnetic sensor is arranged in the cavity to measure a directional component of a magnetic field which is brought about by the magnetization and by the bending torque. A second directional component of the magnetic field may be measured by the magnetic sensor or by another magnetic sensor.

Disclosed herein is a device for measuring mechanical stress. The device comprises a magnetostrictive body enclosing a remanent magnetization. The magnetostrictive body comprises first and second end surfaces that are arranged opposite to each other. At least one of the first and second end surfaces is configured to receive a mechanical stress. The magnetostrictive body further comprises a first recess formed at the first end surface towards the second end surface and a second recess formed at the second end surface towards the first end surface. In a projection perpendicular to the first end surface, the first recess overlaps the second recess and extends beyond the second recess. Further disclosed are a method of manufacturing such a device and a method of measuring mechanical stress using such a device.

A magnetostrictive alternator configured to convert pressure waves into electrical energy is provided. It should be appreciated that the magnetostrictive alternator may be combined in some embodiments with a Stirling engine to produce electrical power. The Stirling engine creates the oscillating pressure wave and the magnetostrictive alternator converts the pressure wave into electricity. In some embodiments, the magnetostrictive alternator may include aerogel material and magnetostrictive material. The aerogel material may be configured to convert a higher amplitude pressure wave into a lower amplitude pressure wave. The magnetostrictive material may be configured to generate an oscillating magnetic field when the magnetostrictive material is compressed by the lower amplitude pressure wave.

A first torque detection part and a second torque detection part are stacked so that a first energizing circuit and a third energizing circuit as well as a second energizing circuit and a fourth energizing circuit are arranged in mirror symmetry with respect to a symmetry plane orthogonal to an axial center direction of an object to be detected, and a plurality of magnetic paths are respectively formed between teeth having inclinations of ±45 degrees in the first torque detection part and the second torque detection part.

A power generation element and an actuator for vibration power generation is provided that can be mass-produced at low cost while achieving increase in electromotive force. A power generation element includes a main series magnetic circuit having a frame yoke made of magnetic material and provided with a fixed portion that is one end and a free portion that is the other end across a U-shaped bent portion, a main magnet that applies a magnetic bias to the frame yoke, and a first gap formed at a position in contact with the free portion; and an auxiliary series magnetic circuit having an auxiliary yoke made of magnetic material and attached to the frame yoke, an auxiliary magnet that gives a magnetic bias to the auxiliary yoke, a second gap formed at a position facing the first gap across the free portion, the frame yoke, the main magnet, and the first gap. The amount of change in a main magnetic flux passing in a coil wound around the frame yoke increases when the free portion vibrates due to application of an external force and a magnetic resistance of the first gap and a magnetic resistance of the second gap increase or decrease reciprocally.