A5074761929- Structural Health Monitoring Techniques
- Advanced machining processes and optimization
- Iterative Learning Control Systems
- Advanced Surface Polishing Techniques
- Fault Detection and Control Systems
- Stability and Controllability of Differential Equations
- Dynamics and Control of Mechanical Systems
- Ultrasonics and Acoustic Wave Propagation
- Control Systems and Identification
- Extremum Seeking Control Systems
- Advanced Measurement and Detection Methods
- Numerical methods for differential equations
- Non-Destructive Testing Techniques
- Sensor Technology and Measurement Systems
- Computational Fluid Dynamics and Aerodynamics
- Advanced Numerical Methods in Computational Mathematics
- Adaptive Control of Nonlinear Systems
- Advanced Machining and Optimization Techniques
- Scientific Computing and Data Management
- Gear and Bearing Dynamics Analysis
- Target Tracking and Data Fusion in Sensor Networks
- Bladed Disk Vibration Dynamics
- Advanced Control Systems Optimization
- Advanced Data Storage Technologies
- Vibration and Dynamic Analysis
Oak Ridge National Laboratory
2022-2023
Los Alamos National Laboratory
2007-2017
Computational Physics (United States)
2014
Texas A&M University
1998-2002
A means of obtaining a nonovershooting output tracking response for single-input-single-output (SISO) strict-feedback nonlinear systems is introduced. With the proposed method, arbitrary reference trajectories can be tracked "from below" initial conditions (as long as value plant strictly below trajectory). In addition, design presented "approximately" control in presence disturbances, where amount overshoot made arbitrarily small by appropriately choosing gains. Finally, an output-feedback...
Abstract Purpose – This paper aims to investigate methods of implementing in‐process fault avoidance in robotic friction stir welding (FSW). Design/methodology/approach Investigations into the possibilities for automatically detecting gap‐faults a lap weld were conducted. Force signals collected from number welds containing differing degrees gap faults. Statistical analysis was carried out determine whether these could be used develop an automatic detector/classifier. Findings The results...
The problem of tracking a known reference without overshooting is great practical importance in number applications. However, nonminimum phase systems have received little attention connection with obtaining nonovershooting response. Using state feedback, this paper develops an eigenvector placement technique to construct invariant set which guarantees step response for class SISO systems.
We present the stability analysis and numerical results for our controller observer designs slender Timoshenko beam with Kelvin-Voigt (internal material) damping. Our designs, introduced in a companion ACC '06 paper, use combination of classical "damping boundary feedback" ideas backstepping. The main advantage techniques over previous damping is that they apply to readily implementable "anti-collocated" architecture, which uses actuation only at beam's base sensing tip
The primal and adjoint, time-dependent fluid—structure interaction (FSI) formulations are presented. A simple control strategy for FSI problems is formulated based on the information provided by solution of adjoint problem. well-known benchmark problem computed to demonstrate effectiveness proposed technique. Such strategies as in this paper useful computational steering or so-called Dynamics Data Driven Application System (DDDAS) simulations, which model adjusted include coming from...
Abstract The machining process is very important in many engineering applications. In high precision machining, surface finish strongly correlated with vibrations and the dynamic interactions between part cutting tool. Parameters affecting these interactions, such as spindle speed, cut depth, feed rate, part’s material properties can vary real time, resulting unexpected or undesirable effects on of product. focus this research development an improved through use active vibration damping....
Abstract Explicit motion-planning reference solutions are presented for flexible beams with Kelvin–Voigt (KV) damping. The goal is to generate periodic signals the displacement and deflection angle at free-end of beam using only actuation base. explicit solution found as a result writing shear model in strict-feedback form. Special “partial differential equation (PDE) backstepping” transformations relate “target system,” governed by an exponentially stable wave KV damping, whose relatively...
The problem of tracking a known reference without overshooting is great practical importance in number applications. However, nonminimum phase systems and with inputs other than steps have received very little attention. This paper proposes two different techniques for obtaining continuous time, nonovershooting, feedback controller wide variety linear single input, output (SISO) systems, including whose input something step function. These are then used to generate an initial nonovershooting...
Metal additive manufacturing (AM) is a disruptive technology that opens the design space for parts outside those possible from traditional methods. In order to accelerate industry and R&D needs certify AM parts, Exascale Additive Manufacturing project (ExaAM) has developed suite of exascale-ready computational tools model process-to-structure-to-properties (PSP) relationship additively manufactured metal components. One such tool an uncertainty quantification (UQ) pipeline quantify effect in...
This article is the last of a set four companion articles. In these articles, hybrid parameter multiple body system (HPMBS) methodology utilized to model frictional contact/impact loose bolted joint between two sections cantilever beam undergoing planar slewing motion. this preliminary model, “rigid” utilized, which allows members be rigid, each attached elastic sections. Frictional modeled at contact points. The constraints and momentum transfer are with idea instantly applied nonholonomic...
Abstract We present a control design method for nonlinear partial differential equations (PDEs) based on combination of gain scheduling and backstepping theory linear PDEs. A benchmark first-order hyperbolic system with an in-domain nonlinearity is considered first. For this feedback law, scheduling, derived explicitly, proof local exponential stability, estimate the region attraction, presented closed-loop system. Control designs (without proofs) are then string PDE shear beam PDE, both...
Nonlinear systems have received little attention in conjunction with the problem of achieving a non-overshooting tracking response. This paper demonstrates means obtaining response for single- input/single-output strict-feedback nonlinear systems. With proposed method, arbitrary reference trajectories can be tracked "from below" initial conditions (as long as value plant output is strictly below trajectory). In addition, design presented "approximately" control presence disturbances, where...
Heat transfer simulations play an important role in predicting solidification conditions that determine microstructure properties of additive manufactured products. High-fidelity heat models, e.g., Truchas [1], provide a numerical framework capable resolving many desired physics (e.g., thermal radiation, elemental vaporization, gas-solid-liquid interactions, etc.), but they are often too computationally expensive to simulate the at AM process-scale. Recently, Stump et al. [2] proposed...
Nowadays, many scientific workflows from different domains, such as Remote Sensing, Astronomy, and Bioinformatics, are executed on large computing infrastructures managed by resource managers. Scientific workflow management systems (SWMS) support the execution communicate with infrastructures' However, communication between SWMS managers is complicated a) inconsistent interfaces SMWS b) lack of for dependencies workflow-specific properties. To tackle these issues, we developed Common...