1. A method for detecting and isolating intermittently observable fault modes in a system having models describing its behavior and one or more measurements that are sampled regularly, said method comprising:
(a) said models and computing capacity to calculate past and present measurements that would result from said system with no faults, as well as from said system with one or more potential fault mode candidates;
(b) algorithms to calculate and store deviations between said calculated measurements and either actual measurements or an abstraction of said actual measurements as returned by a filtering function;
(c) detection algorithms using said calculated deviations at times or states comprising present and historical data to declare when one of said fault mode candidates or anomalies in the data un-related to said fault modes becomes possible;
(d) exoneration algorithms using said calculated deviations to remove certain fault mode candidates from consideration as a potential fault mode, thereby making the decision making in the final step simpler and more robust; and
(e) isolation algorithms using said calculated deviations to declare which one of remaining said potential fault mode candidates is the true fault mode.
2. The method of claim 1, wherein the system is controlled with on-off actuators and the fault modes are hard-off or hard-on actuator faults.
3. The method of claim 1, wherein the system is a thruster-controlled spacecraft, and the fault modes are thruster faults.
4. The method of claim 3, wherein the method is implemented on-board said spacecraft using the main spacecraft processor.
5. The method of claim 3, wherein the method is implemented on-board said spacecraft using a secondary processor communicating with said main spacecraft processor.
6. The method of claim 3, wherein the method is implemented off-board said spacecraft, including at a ground station, performing said calculations based on telemetry from said spacecraft, and communicating the results back to said spacecraft.
7. The method of claim 3, wherein said measurements are obtained from one or more of the following sensors: gyroscopes of all varieties, accelerometers, star trackers, sun sensors, horizon sensors, video cameras, directional antennae, radar, and other measurements that directly or indirectly relate to spacecraft motions.
8. The method of claim 1, wherein said model or models are adapted to match system outputs during periods where no failures are present, as with a neural network.
9. The method of claim 1, further including the case where it is implemented sequentially, whereby once a fault mode is correctly detected and isolated, said method is re-initialized with this information to enable detection and isolation of any subsequently occurring faults.
10. The method of claim 1, wherein the application is to a system where a real-time controller exists, to be implemented either on the real-time processor, on a secondary processor as part of the system, on a processor that is separate from the system, or by manual implementation of said method, where communication of required signals and results would occur for the latter two instances.
11. The method of claim 1, further including the case where excitation logic is used to dynamically adjust system inputs to improve the ability of said method to discern between a plurality of candidate fault modes, with said adjustments made as to minimize any negative impact on overall system performance.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A spray nozzle comprising:
a nozzle body,
a nozzle ently orifice through which a material to be sprayed can enter,
a nozzle bore through which a material to be sprayed can pass,
a nozzle exit orifice through which a material to be sprayed can exit,
a sintered polycrystalline diamond compact bore liner in said bore for providing low wear, durable and long-lasting service in the nozzle,
interstitial spaces in said diamond compact,
solvent-catalyst metal in said interstitial spaces,
chemical bonds in the sintered polycrystalline diamond compact bore liner, said chemical bonds including diamond-to-diamond bonds, diamond-to-metal bonds, and metal-to-metal bonds.
2. The spray nozzle as recited in claim 1 wherein the nozzle entry orifice, nozzle bore and nozzle exit orifice each have an internal diameter.
3. The spray nozzle as recited in claim 2 wherein the internal diameter of the entry orifice is greater than the internal diameter of the exit orifice.
4. The spray nozzle of claim 3 wherein the internal diameter of the nozzle bore is reverse conical.
5. The spray nozzle as recited in claim 2 wherein the internal diameter of the entry orifice is less than the internal diameter of the exit orifice.
6. The spray nozzle as recited in claim 5 wherein the internal diameter of the nozzle bore is conical.
7. The spray nozzle as recited in claim 1 wherein said diamond compact comprises diamond feedstock that has diamond particles that have a dimension in the range of less than about 1 nanometer to more than about 100 microns.
8. The spray nozzle as recited in claim 1 further comprising CoCr solvent-catalyst metal in said interstitial spaces.
9. The spray nozzle as recited in claim 1 further comprising tungsten carbide solvent-catalyst metal in said interstitial spaces.
10. The spray nozzle as recited in claim 1 wherein at least some of said bonds are sp3 carbon bonds.
11. The spray nozzle as recited in claim 1 wherein said diamond compact includes diamond sintered to a substrate.
12. The spray nozzle as recited in claim 1 wherein said diamond compact is constructed from free standing diamond that is not sintered to a substrate.
13. A spray nozzle comprising:
a nozzle body,
a nozzle ently orifice through which a material to be sprayed can enter,
a nozzle bore through which a material to be sprayed can pass,
a nozzle exit orifice through which a material to be sprayed can exit,
a sintered polyciystalline diamond compact nozzle tip at said exit orifice,
interstitial spaces in said diamond compact,
solvent-catalyst metal located in said interstitial spaces, chemical bonds in the sintered polycyrstalline diamond compact nozzle tip, said chemical bonds including diamond-to-diamond bonds, diamond-to-metal bonds, and metal-to-metal bonds, and
wherein material to be sprayed travels fiom said bore, through said sintered polycrystalline diamond compact nozzle tip and out said exit orifice.
14. The spray nozzle as recited in claim 13 wherein said diamond compact comprises diamond feedstock that has diamond particles that have a dimension in the range of less than about 1 nanometer to more than about 100 microns.
15. The spray nozzle as recited in claim 13 further comprising CoCr solvent-catalyst metal in said interstitial spaces.
16. The spray nozzle as recited in claim 13 further comprising tungsten carbide solvent-catalyst metal in said interstitial spaces.
17. The spray nozzle as recited in claim 13 wherein at least some of said bonds are sp3 carbon bonds.
18. The spray nozzle as recited in claim 13 wherein said diamond compact includes diamond sintered to a substrate.
19. The spray nozzle as recited in claim 13 wherein said diamond compact is constructed from free standing diamond that is not sintered to a substrate.
20. The spray nozzle as recited in claim 13 wherein the nozzle tip at said exit orifice is a hemispherical cup.
21. The spray nozzle as recited in claim 20 wherein the nozzle tip at said exit orifice further comprises an elongated member extending fiom said hemispherical cup.
22. The spray nozzle as recited in claim 20 wherein the nozzle tip further comprises a concave relief surrounding said exit orifice.