Moog Inc.

Abstract: Impact technologies have developed a robust modeling paradigm for actuator fault detection and failure prediction. This model-based approach to prognostics and health management (PHM) applies physical modeling and advanced parametric identification techniques, along with fault detection and failure prediction algorithms, in order to predict the time-to-failure for each of the critical, competitive failure modes within the system. Advanced probabilistic fusion strategies are also leveraged to combine both collaborative and competitive sources of evidence, thus producing more reliable health state information. These algorithms operate only on flight control command/response data. This approach for condition-based maintenance provides reliable early detection of developing faults. As an advantage over 'black-box' health-monitoring schemes, faults and failure modes are traced back to physically meaningful system parameters, providing the maintainer with invaluable diagnostic and prognostic information. The developed model-based reasoner was validated and demonstrated on an electromechanical actuator (EMA) provided by Moog, Inc.

Abstract: Sensor faults continue to be a major hurdle for systems health management to reach its full potential. At the same time, few recorded instances of sensor faults exist. It is equally difficult to seed particular sensor faults. Therefore, research is underway to better understand the different fault modes seen in sensors and to model the faults. The fault models can then be used in simulated sensor fault scenarios to ensure that algorithms can distinguish between sensor faults and system faults. The paper illustrates the work with data collected from an electromechanical actuator in an aerospace setting, equipped with temperature, vibration, current, and position sensors. The most common sensor faults, such as bias, drift, scaling, and dropout were simulated and injected into the experimental data, with the goal of making these simulations as realistic as feasible. A neural network-based classifier was then created and tested on both experimental data and the more challenging randomized data sequences. Additional studies were also conducted to determine sensitivity of detection and disambiguation efficacy with respect to severity of fault conditions.

Abstract: Current phacoemulsification handpieces require rigorous cleaning after each procedure because the aspiration and irrigation pathways for fluids are integral to the handpiece. According to the present invention, a removable horn extension and nosecone may be used with a phacoemulsification handpiece to allow for disposable fluid pathways exterior to the handpiece. This will reduce the cleaning time and effort, reduce cross-contamination, and increase the lifespan of the handpiece. Furthermore, the current invention allows different horn extensions to be used to excite different motions at the tip of the handpiece, depending on the preference of the surgeon.

Abstract: Measurements of the temperature and distortion evolution during laser powder bed fusion (LPBF) are taken as a function of time In situ measurements have proven vital to the development and validation of FE (finite element) models for alternate forms of additive manufacturing Due to powder obscuring all but the top layer of the part in LPBF, many non-contact measurement techniques used for in situ measurement of additive manufacturing processes are impossible Therefore, an enclosed instrumented system is designed to allow for the in situ measurement of temperature and distortion in an LPBF machine without the need for altering the machine or the build process By instrumenting a substrate from underneath, the spread powder does not affect measurements Default processing parameters for the EOS M280 machine prescribe a rotating scan pattern of 67° for each layer One test is completed using the default rotating scan pattern and a second is completed using a constant scan pattern Experimental observations for the build geometry tested showed that for Inconel ® 718 and a constant scan pattern produce results in a 376% increase in distortion as compared with a rotated scan pattern The in situ measurements also show that the thermal cycles caused by the processing of a layer can impact the distortion accumulated during the deposition of the previous layers The amount of distortion built per layer between the rotating and constant scan pattern cases highlights inter-layer effects not previously discovered in LPBF The demonstrated inter-layer effects in the LPBF process should be considered in the development of thermo-mechanical models of the LPBF process