A vibrotactile device including a first actuator channel having a vibrotactile actuator and a resistor with a predetermined resistance positioned at an input of the vibrotactile actuator, a processor configured to output a driving signal for driving the vibrotactile actuator, and a voltage sensor configured to measure a voltage drop across the resistor. A current drawn by the vibrotactile actuator varies according to a load applied to the vibrotactile actuator and passes through the resistor. The processor is configured to receive voltage drop measurement data from the voltage sensor, detect a load applied to the vibrotactile actuator based on the measured voltage drop, and control the driving signal based on the detected load.

This disclosure is related to marine seismic sources, for example marine seismic sources known in the art as benders. Some embodiments of this disclosure use magnetic reluctance forces to produce seismic energy. For example, pole pieces may be attached to one or more plates of a marine seismic source, and a wire coil may induce an attractive force between the pole pieces to cause deformation of the plates to produce seismic energy. Such marine seismic sources may be components of a marine seismic survey system, and may be used in a method of marine seismic surveying. Methods of making marine seismic sources are also disclosed.

This disclosure is related to marine seismic sources, for example marine seismic sources known in the art as benders. Some embodiments of this disclosure use magnetic reluctance forces to produce seismic energy. For example, pole pieces may be attached to one or more plates of a marine seismic source, and a wire coil may induce an attractive force between the pole pieces to cause deformation of the plates to produce seismic energy. Such marine seismic sources may be components of a marine seismic survey system, and may be used in a method of marine seismic surveying. Methods of making marine seismic sources are also disclosed.

Embodiments provide methods for controlling an actuator based on closed-loop feedback of capacitance measured between a rotor plate attached to a rotor and a stator plate attached to a stator. The methods involve measuring capacitance at a predetermined sampling rate using a capacitance sensing unit operationally connected to an actuator. The capacitance measurement is made between the rotor plate and the stator plate of the actuator and is subsequently stored. The methods further include calculating the capacitance change between two consecutive capacitance measurements using a processing unit operationally connected to an actuator. Based on calculated capacitance changes, a control signal is generated to regulate the operation of the actuator.

A pump contains a pump unit for suctioning and discharging fluid due to electromagnetic drive of a vibration actuator. The vibration actuator includes a fixed body containing one of a coil core portion and a magnet, a movable body containing another one of the coil core portion and the magnet, and a shaft portion for supporting the movable body so that the movable body can perform reciprocating rotation. The pump unit includes a movable wall, and a sealed chamber whose volume can be changed by displacement of the movable wall. The movable body has a pressing portion which can abut against the movable wall to press the movable wall when the movable body performs the reciprocating rotation.

A method of controlling a vibrational transducer, the method comprising: tracking a temperature metric of the vibrational transducer; and controlling a drive signal for the vibrational transducer, where the drive signal is limited to a value to protect the vibrational transducer from over excursion, and where said value is a function of the tracked temperature metric.

Provided is a control device controlling an electromagnetic actuator that drives an operation device, supported in an elastically vibratable manner by an elastic support part, in one direction of a vibration direction of the operation device to vibrate the operation device. The control device includes a circuit that applies a main driving signal to a coil of the electromagnetic actuator to start vibration of the operation device in response to a touch operation on the operation device, then applies a sub-driving signal to the coil to adjust an attenuation period of the vibration. The sub-driving signal has a variable voltage varying with an offset voltage, as a center value, offset from a zero voltage, and a waveform that indicates a variation in the variable voltage is a sine function curve or a cosine function curve.

A mass positioning system includes a first end portion separated from a second end portion, a mechanical spring coupled to the first end portion, control circuitry configured to generate a first control signal and a second control signal, a first conductive coil proximate to the first end portion and configured to generate a first magnetic field in response to the first control signal, a second conductive coil proximate to the second end portion and configured to generate a second magnetic field in response to the second control signal, and a magnetic mass coupled to the mechanical spring and having a displacement that is responsive to the first magnetic field and the second magnetic field. The mass positioning system has an oscillation frequency that is controllable by the first control signal or the second control signal.