摘要:
Guard bands which reduce or eliminate force and sensitivity associated with proof mass motion normal to the substrate as a result of voltage transients is disclosed. The guard bands are biased to reduce the coupling ratio to zero and thereby enable starting and improved performance. Various configurations of guard bands may be employed including distinct inner and outer guard bands, distinct inner guard bands only, extended sense electrodes below inner sensing combs with no outer guards, distinct outer guard bands with extended sense electrodes, and sense electrodes extended beneath both drive and sensing combs.
摘要:
A microfabricated, tuning fork rate sensitive structure and drive electronics in which vibrational forces are communicated through a set of meshing drive and driven finger electrodes associated with each of two vibrating elements. The vibrating elements are supported in a rotatable assembly between first and second support electrodes which are in turn suspended by flexures for rotation about an axis passing through the flexures and through a point midway between the vibrating elements. Additional masses are formed onto the vibrating elements to improve overall sensor sensitivity. Sense electrodes for detecting capacitive changes between the support beams and the substrate are positioned on the substrate beneath each end of the support beams. In an alternative embodiment, piezoelectric sense capacitors are disposed on the flexures for detecting rotation of the support electrodes. Drive electronics are connected between the driven fingers of the vibrating elements and the drive electrode fingers which mesh with them to cause vibration. Excitation is provided between the support electrodes and the sense electrodes. Any change in signal resulting from rotation of the assembly and the resulting variation in capacitance between the support electrodes and the sense electrodes or within the piezoelectric capacitors is sensed as a measure of inertial rate. A torque loop may be additionally formed using the sense electrodes in order to re-torque the assembly to a neutral position in a torque-to-balance loop.
摘要:
A resonantly vibrating or tuning fork rate sensor in which a quartz beam is instrumented with electrodes in first and second regions forming respective sense and drive electrodes wherein the piezoelectric resonance affect of the quartz material between the drive electrodes is used as a tuning element for an oscillator circuit. The electrodes are driven in a balanced voltage mode and sensed in a common mode rejection differential amplifier while leads running to the electrodes along the quartz beam are placed at positions of minimal field strength for improving the signal to noise ratio of the device. The rate sensor utilizes a multi-electrode pattern in order to make such lead placement possible. The sense pattern and drive pattern may be either in one orientation with the drive electrodes proximate to the body of the quartz resonator or in a second pattern with the sense electrodes proximate to the body. Both the drive electrodes and the sense electrodes operate on the piezoelectric principal, utilizing constriction to induce vibration from the drive electrodes and sensing the current generated from piezoelectric effect resulting from the vibrational compression which occurs out of the plane of vibration during inertial rate input. Alternatively, a capacitive electrode structure may be utilized as a pick-off.
摘要:
A single vibration sensor having the capability of sensing vibration along three rotational axes as well as three translational axes and exhibiting consistent dynamics over a wide frequency range. The sensor includes an elongated mass formed of a generally rigid material suspended in a fluid within a housing. The exterior surface of the mass is spaced from the interior surface of the housing to permit limited freedom of motion of the mass within the housing. The mass is provided with multiaxial radial and axial electromagnetic suspensions, and is typically supported by a fluid within the housing. Rotational positioning is provided by a signal generator, torque generator combination. Vibration is sensed by additive or differential measurements of current changes in the coils of different axes of the suspensions or electromagnetic signal and torque generator combinations. The sensor is conveniently implemented as a single degree of freedom inertial gyroscope without the gyroscope wheel and adapted to permit sensing of current changes in coils provided to achieve suspension or suspension and signal and torque generation functions.
摘要:
Among other things, a vestibular prosthesis includes a wearable motion sensing system, the motion sensing system generating a motion signal indicative of a motion thereof, wherein the motion includes rotation about two distinct axes; a signal processor in communication with the motion sensing system, the signal processor being configured to generate an estimate of a tilt of the motion sensing system; and an actuator responsive to the estimate of the tilt made by the signal processor.
摘要:
In one embodiment, a rotary device includes a multiwall nanotube that extends substantially perpendicularly from a substrate. A rotor may be coupled to an outer wall of the multiwall nanotube, be spaced apart from the substrate, and be free to rotate around an elongate axis of the multiwall nanotube.
摘要:
A thermoelectric device transfers heat away from or toward an object using the Peltier effect. In some embodiments, the length of at least one thermoelectric element is at least ten times greater than a combined average cross-sectional dimension, orthogonal to the length, of two thermoelectric elements.
摘要:
A sensor may include a substrate that has a cavity formed in a surface thereof. A diaphragm, having a conductive portion, may be suspended over the cavity, a selective coating may be present on a face of the diaphragm outside of the cavity, and a counterelectrode may be spaced from and in opposition to the diaphragm. The diaphragm may deform upon interaction of the selective coating with an analyte and thereby alter a capacitance of the sensor in a manner indicative of a degree of interaction.
摘要:
A system and method for compensating for gradients in a dual cavity device such as but not limited to an accelerometer. A first source drives a first cavity at least two different modes, at least one mode varying with changes in cavity length. A second source drives a second cavity at least two different modes, at least one mode varying with changes in cavity length. A processor determines changes in cavity length as a function of both modes in both cavities to compensate for non-uniform behavior between the cavities.