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Articles 1 - 12 of 12
Full-Text Articles in Mechanical Engineering
Research And Development Of A Hybrid Rapid Manufacturing Process, Frank W. Liou, J. Choi, Robert G. Landers, Vijayakumar Janardhan, S. N. Balakrishnan, Sanjeev Agarwal
Research And Development Of A Hybrid Rapid Manufacturing Process, Frank W. Liou, J. Choi, Robert G. Landers, Vijayakumar Janardhan, S. N. Balakrishnan, Sanjeev Agarwal
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper presents the research and development of a hybrid rapid manufacturing process being developed at the University of Missouri--Rolla. This process includes a laser deposition and a 5- axis CNC milling system. By combining laser deposition and machining processes, the resulting hybrid process can provide greater build capability and better accuracy and surface finish. The hybrid process can build some features that are difficult to build in using a purely deposition processes. The issues and related approaches in the research and development of the hybrid deposition-machining process, including laser deposition process, system design and integration, process planning, and sensor …
Skeleton-Based Geometric Reasoning For Adaptive Slicing In A Five-Axis Laser Aided Manufacturing Process System, Kunnayut Eiamsa-Ard, Jun Zhang, Frank W. Liou
Skeleton-Based Geometric Reasoning For Adaptive Slicing In A Five-Axis Laser Aided Manufacturing Process System, Kunnayut Eiamsa-Ard, Jun Zhang, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Multi-axis Laser Aided Manufacturing Process (LAMP) is an additive manufacturing process similar to laser cladding. This process can produce full functional parts [1]. Traditional Layered Manufacturing processes produce parts with limited surface quality; and also the build time is often long due to the deposition of sacrificial support structure. The multiple degrees of freedom endow the LAMP system a capability to build parts without support structure. An algorithm for adaptive slicing based on skeleton is presented in this paper. The skeleton is useful for many applications such as feature recognition, robot path planning, shape analysis, and etc [2]. The near …
Empirical Modeling And Vision Based Control For Laser Aided Metal Deposition Process, Mallikharjuna R. Boddu, Srinivas Musti, Robert G. Landers, Sanjeev Agarwal, Frank W. Liou
Empirical Modeling And Vision Based Control For Laser Aided Metal Deposition Process, Mallikharjuna R. Boddu, Srinivas Musti, Robert G. Landers, Sanjeev Agarwal, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper gives a brief description of the laser aided manufacturing process. Empirical models describing the process dynamics of the laser aided metal deposition process is developed based on some of the models found in the literature. These models provide the basis for process planning and real time control. An embedded vision system, a two color temperature sensor, and a laser displacement sensor are incorporated for real time monitoring and control of the deposition process. The temperature profile of the surface and geometric characteristics of the melt pool are studied to ensure consistent operation of the process.
Control Of Laser Cladding For Rapid Prototyping -- A Review, Mallikharjuna R. Boddu, Robert G. Landers, Frank W. Liou
Control Of Laser Cladding For Rapid Prototyping -- A Review, Mallikharjuna R. Boddu, Robert G. Landers, Frank W. Liou
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Lasers have wide-ranging applications in the manufacturing field (e.g., cladding, welding, cutting, machining, drilling). Extensive work is being conducted to apply laser cladding as a Rapid Prototyping (RP) process. In this paper the authors illustrate various principles of laser cladding in rapid prototyping. Important process parameters for the control of the laser cladding process are discussed as well as the experimental methods adopted, and results obtained by, various authors.
Ingaasnsb/Gaas Quantum Wells For 1.55 Μm Lasers Grown By Molecular-Beam Epitaxy, Xiaodong Yang, J. B. Heroux, L. F. Mei, W. I. Wang
Ingaasnsb/Gaas Quantum Wells For 1.55 Μm Lasers Grown By Molecular-Beam Epitaxy, Xiaodong Yang, J. B. Heroux, L. F. Mei, W. I. Wang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
InGaAsNSb/GaAs quantum wells (QWs) were grown by solid-source molecular-beam epitaxy using a N2 radio frequency plasma source. The effect of adding Sb during growth of InGaAsN/GaAs QWs was studied. X-ray diffraction, reflection high-energy electron diffraction and transmission electron microscopy studies indicate that Sb suppresses the three-dimensional growth and improves the interface of the QWs. X-ray diffraction and secondary ion mass spectroscopy analysis show that Sb gets incorporated into the quantum well, which becomes a quinternary compound that was previously unexplored. The introduction of Sb during growth of InGaAsN/GaAs QWs significantly enhances the optical properties of the QWs. 1.53 /spl …
Membrane Electrostatic Precipitator, Hajrudin Pasic, M. Khairul Alam, David J. Bayless
Membrane Electrostatic Precipitator, Hajrudin Pasic, M. Khairul Alam, David J. Bayless
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A membrane is used as a collection substrate in an electrostatic precipitator (ESP). Possible material choices include fibers in the form of woven mats, screens made from stainless steel wires or fiber reinforced polymer composite membranes. The membranes have a tensile bias applied during operation, and have impulse tensile force applied during a dust removal step. By combining a dry ESP membrane field with wet-film cleaning field, it may be possible to improve collection efficiencies both by reducing turbulence and eliminating re-entrainment losses due to rapping. Through implementation of new materials that resist hostile ESP environments, the invention enhances the …
Adaptive Critic Based Neuro-Observer, Xin Liu, S. N. Balakrishnan
Adaptive Critic Based Neuro-Observer, Xin Liu, S. N. Balakrishnan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A new Neural Network (NN) based observer design method for nonlinear systems represented by nonlinear dynamics and linear/nonlinear measurement is proposed in this paper. In this new approach, as the first step, the observer design problem is changed into a "controller" design problem by establishing the error dynamics, and then the Adaptive Critic (AC) based approach is applied on this error dynamics to design a 'controller', such that the errors are driven to zero. The resulting observer has inherent robustness from the AC based design approach. Some simulations are presented to illustrate the effectiveness of this approach.
High Precision Solder Droplet Printing Technology: Principle And Applications, Qingbin Liu, M. Orme, Ming-Chuan Leu
High Precision Solder Droplet Printing Technology: Principle And Applications, Qingbin Liu, M. Orme, Ming-Chuan Leu
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Solder droplet printing technology, which is low-cost, noncontact, flexible, data-driven, and environmentally friendly, has emerged as an enabling technology for precisely placing fine solder deposits on a variety of small substrates. It is suitable for a variety of applications including direct chip attach site preparation, 3D substrates, fine line interconnect, substrate via fill, optoelectronics and many others. It enables manufacturing techniques that are impossible or unfeasible with current technology, such as localized replacement of solder on board, depositing solder in different thicknesses on the same board, or using more than one type of solder on the same board. This makes …
Amplitude Modulated Droplet Formation In High Precision Solder Droplet Printing, Qingbin Liu, M. Orme, Ming-Chuan Leu
Amplitude Modulated Droplet Formation In High Precision Solder Droplet Printing, Qingbin Liu, M. Orme, Ming-Chuan Leu
Mechanical and Aerospace Engineering Faculty Research & Creative Works
There are many methods used at present to apply solder to wafers, ceramics, laminate and flex circuit boards, and other substrates. Among these, high-precision solder droplet printing technology, which is noncontact, data driven, flexible and environmentally friendly, is a key enabling technology. This technology selectively deposits solder droplets only where required, and therefore needs no mask or secondary resist removal, uses materials more efficiently and creates less waste than other methods. Currently, continuous droplet formation from capillary streams is mainly achieved by application of the well-known Rayleigh instability in which a sinusoidal disturbance is applied to the stream, resulting in …
Robust State Dependent Riccati Equation Based Guidance Laws, S. N. Balakrishnan, Ming Xin
Robust State Dependent Riccati Equation Based Guidance Laws, S. N. Balakrishnan, Ming Xin
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A robust state dependent Riccati equation based guidance/control is investigated in this study. In order to have a better design tool in terms of required interceptor accelerations, the target intercept geometry is formulated in a set of polar coordinates. With this formulation, we formulate a cost function with state dependent weights. In this study, we investigate the effects of such cost functions on the levels of interceptor accelerations. We also synthesize a neural network based extra controller to achieve the robustness in the presence of the target acceleration. In this manner, we will not need target acceleration estimation explicitly in …
An Optimal Control Based Treatment Strategy For Parturient Paresis Using Neural Networks, Radhakant Padhi, S. N. Balakrishnan
An Optimal Control Based Treatment Strategy For Parturient Paresis Using Neural Networks, Radhakant Padhi, S. N. Balakrishnan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
An optimal online feedback treatment strategy is developed for the parturient paresis of cows, based on nonlinear optimal control theory. A limitation in the development of an existing mathematical model for calcium homeostasis is addressed and the model is extended to incorporate control inputs. An optimal feedback controller is synthesized for the nonlinear system using neural networks. Though the main aim of this paper is to solve the biomedical control problem, the methodology presented in this paper is a general computational tool, which can be applied to solve a fairly general class nonlinear optimal control problems.
Robust State Dependent Riccati Equation Based Robot Manipulator Control, Ming Xin, S. N. Balakrishnan, Zhongwu Huang
Robust State Dependent Riccati Equation Based Robot Manipulator Control, Ming Xin, S. N. Balakrishnan, Zhongwu Huang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
We present a new optimal control approach to robust control of robot manipulators in the framework of state dependent Riccati equation (SDRE) technique. To treat this highly nonlinear control system, we formulate it as a nonlinear optimal regulator problem. SDRE technique was used to synthesize an optimal controller to this class of robot control problem. We also synthesize a neural network based extra controller to achieve the robustness in the presence of the parameter uncertainties. A typical two-link robot position control problem was studied to show the effectiveness of SDRE approach and robust extra control design to robotic application.