Abstract:
A sensor interface is disclosed including a flexible substrate in which are embedded sensors for measuring physical parameters such as temperature, displacement, velocity, acceleration, stress, strain, pressure and force present between objects such as a railcar bearing and a truck side frame. The substrate is positioned between the objects of interest Electronic components such as a data processing unit, a data storage device, a communication device and a power source may also be embedded within the substrate. The electronic devices communicate with one another and the sensors to process signals generated by the sensors indicative of the parameters being measured.
Abstract:
A microelectromechanical system (MEMS) strain gauge includes at least one flexible arm that can be caused to oscillate. Transverse strain on the arm changes the resonant frequency of the arm. A detector communicating with the flexible arm may detect the frequency of oscillation to provide, an indication of the transverse strain of the substrate.
Abstract:
A force transducer having a semiconductor substrate including a surface defining a recess, such that the recess has a peripheral boundary and a flexible diaphragm connected to the surface along the peripheral boundary to enclose the recess so that the diaphragm moves in response to changes in a force applied thereto. The force transducer also includes a resonant beam connected to the surface adjacent the peripheral boundary. The resonant beam has a frequency of resonation. Movement of the diaphragm in response to changes in the force applied to the diaphragm changes the frequency of resonation of the resonant beam.
Abstract:
At least one microbeam situated on a substrate, having a resonant frequency dependent on the strain on the microbeam which may be affected by the bending of the substrate. The beam or beams have sense and drive electrodes proximate to the beam or beams and form capacitors with a beam being the other electrode. The capacitance varies as the beam moves in vibration. The sense electrode is connected to an input of a transistor, such as the gate or base, and the drive electrode is connected to an output of the transistor. The transistor has a load impedance with a capacitive component to aid in the sustaining of vibration of the beam at a resonant frequency. A high ohm resistor is connected between the gate and the drain of the transistor to appropriately bias the gate. The bending of the substrate may be caused by a magnitude of a physical stimulus being measured. However, the bending of the substrate is not utilized nor desired in the filter and temperature sensing configurations of the invention. The frequency of resonance is an indication of the magnitude of the physical parameter. Variants of the sensor may be implemented with different placements of the sense and drive electrodes, and additional electronics as needed to implement the various configurations and microbeam geometry. Additional sense and/or drive electrodes and beams also may be incorporated in the transistor resonant microbeam sensor.
Abstract:
A combined transducer that measures force or displacement and temperature utilizes a pair of vibrating tines to provide a simultaneous output representative of temperature and force or displacement whereby the sum or average of the vibrating frequencies of the two tines is representative of temperature and the difference is representative of force or displacement.
Abstract:
A vibratory transducer comprising a vibratory beam composed of an n-type layer and having at least one end fixed. The vibratory beam is formed by selectively etching an n-type layer formed by adding impurities locally to a single silicon crystal. The vibratory transducer also comprises means for vibrating the vibratory beam and means for detecting vibration of the vibratory beam. The vibratory transducer measures pressure, temperature, density, etc, by detecting change in the resonant frequency of the vibratory beam. The vibratory beam can be finely etched irrespective of the density of the impurities therein by forming the vibratory beam in an alkaline aqueous solution while applying a negative DC or pulsed voltage to a p-type layer and a positive DC or pulsed voltage to an n-type layer. The vibrating and detecting means for the vibratory beam can be easily provided by making a diode and a transistor including the vibratory beam in the transducer.
Abstract:
A system for performing force sensing with an electromagnetic load may include a signal generator configured to generate a signal for driving an electromagnetic load and a processing subsystem configured to monitor at least one operating parameter of the electromagnetic load and determine a force applied to the electromagnetic load based on a variation of the at least one operating parameter.
Abstract:
A vibration sensor includes at least one piezoelectric crystal having an upper surface and a lower surface; a base having an attachment section defining an attachment surface and an at least one calibration mass; wherein a one of the at least one piezoelectric crystal upper surface and lower surface attaches to the attachment surface of the base; and wherein the at least one calibration mass is external to the piezoelectric crystal.