Abstract:
A temperature and static pressure compensated differential pressure sensor includes a semiconductor substrate in which a flexible, pressure responsive diaphragm is formed. A pressure responsive resonant microbeam is fabricated at the diaphragm periphery. For temperature compensation, a secondary resonant microbeam sensor is fabricated on the substrate at a peripheral location beyond the point of substrate attachment to a pressure tube or other support. For static pressure compensation, another secondary resonant microbeam can be positioned remote from the diaphragm and at a location of maximum substrate response to static pressure. A further resonant microbeam can be mounted at the diaphragm center to augment the signal due to diaphragm deflections. Also disclosed is an accelerometer including a proof mass, a rigid rim surrounding the proof mass, and a series of narrow, flexible bridges supporting the proof mass relative to the rim. The bridges flex responsive to accelerations, thus to allow the proof mass to move relative to the rim. At least one of the bridges incorporates a resonant microbeam for measuring acceleration by virtue of the induced strain from flexure of its associated bridge. For temperature compensation, a secondary resonant microbeam is fabricated along the rim.
Abstract:
A method of creating a star database (38). From a star catalog which contains known features of stars which appear in the celestial sphere, bi-directional data links are created between the individual star entries which provide search paths according to the relative magnitudes of the predetermined features. The links are created in such a fashion that searches can be done in circular fashion through the database (38) according to the predetermined feature being search. Bi-directional also provided between each star and its neighbours to provide for quick searches of a particular portion of the celestial sphere.
Abstract:
A method of star acquisition and identification for a spacecraft. A star database is established which has data links between individual star entries according to set of predetermined features such as brightness and adjacent location. A star camera aboard the spacecraft (12) identifies the brightest star in its field of view (FOV) (20) as well as select portion of adjacent stars. Information gathered from the relation of the brightest star to the adjacent stars is then compared to the relation of the star entries in the star database.
Abstract:
A ceiling mounted air purifier that provides a high velocity, multi-directional air exhaust pattern that distributes filtered air to all areas of a room which includes a plurality of filters and centrifugal fans. The centrifugal fans are substantially surrounded by baffles which form generally equally spaced exhaust outlets.
Abstract:
A control moment gyroscope (10) including a rotor (16) extending along a rotor axis (18). The rotor includes a first and second rotor end. A gimbal housing (12) includes a magnetic suspension system for magnetically suspending the rotor (16) within the gimbal housing (12) to allow rotation of the rotor about the rotor axis. A first and second conical clutch (22, 24) positioned adjacent to the first and second rotor end, respectively, and connected to the gimbal housing couples the rotor to the gimbal housing if the magnetic suspension system is inoperative. The gyroscope (10) also includes an apparatus for forcing the first and second clutches (22, 24) to couple the rotor (16) to the gimbal housing (12).
Abstract:
A safety circuit for monitoring computer hardware that can create an unsafe condition if a failure occurs. The circuit includes a microprocessor, a keyword decoder, and a dynamic safety relay drive circuit. The microprocessor runs a set of internal tests which create a keyword made up of a series of bits. A particular series of bits indicates the desired operation of the microprocessor. On alternate generations of the keyword one bit in the series is inverted. The keyword decoder receives the keywords and outputs a "true" signal if the keyword indicates the desired operation of the microprocessor, and "false" signal if the keyword indicates otherwise. The output of the keyword decoder is transmitted to the dynamic safety relay drive circuit, and this signal will keep the circuit energized as long as its alternating. The position of the bit which is inverted is rotated through the keyword so that different bit paths through the keyword decoder may be tested.
Abstract:
A half-tone liquid crystal display panel having half-tone pixels (50), each comprising a plurality of sub-pixels including first (31) and second (33) sub-pixels. Activation voltage is supplied to the first sub-pixel (31) from a TFT switch (18) and to the second sub-pixel (33) from the TFT switch through a coupling capacitor (39, 42). The second sub-pixel includes a storage capacitor (51, 53). Sensitivity of the activation voltage applied to the second sub-pixel resulting from capacitance non-uniformity across the panel is reduced by forming the coupling capacitor (39, 42) and the storage capacitor (51, 53) of the second sub-pixel with the same depositions utilizing a common dielectric layer (41). The capacitance (53) of the storage capacitor of the second sub-pixel is designed large compared to the capacitance (36) of the second sub-pixel.
Abstract:
A latching relay control circuit comprising a latching relay pulse generator circuit and a relay coil drive circuit, the latching relay pulse generator circuit receiving relay control signals and relay reset signals. When a relay control signal changes states, the latching relay pulse generator provides a pulsed signal to the relay and coil drive circuit, the relay and coil drive circuit then changing the state of a latching relay. The relay reset signal is provided during power-up or just before power is lost to the system, the relay reset signal being provided to the latching relay pulse generator circuit wherein the latching relay pulse generator circuit provides a reset signal to the relay and coil driver circuit, and the relay and coil driver circuit opens all of the latching relays it controls.
Abstract:
A process control system which includes at least one manipulated variable and at least one controlled variable, provides a method for robust control of a process. Predetermined constraints of the manipulated variables and the controlled variables, and the present values of the manipulated variables are obtained. New values are calculated for the controlled variables for a predetermined number of points in the future, such that the values of the controlled variables are within the predetermined range, thereby obtaining an optimal robustness of the resultant controller. The manipulated variables are also calculated to be within predetermined constraints, and the controlled variables to fall within a predetermined range when controllable. From a plurality of solutions, a most robust solution is selected. Then the manipulated variables are adjusted to cause the process control system to drive the values of the controlled variables to the calculated values.
Abstract:
A method for decoding an encoded non-return to zero (NRZ) signal without the use of external clock. Transitions within the encoded NRZ signal cause a differential voltage signal to be output. This differential voltage increases at a constant rate between two transitions. At the second transition the magnitude of the differential voltage is compared to a preset value to determine a number of consecutive like bits. These consecutive bits can then be transmitted in one step to a storage means.