Offset-Free Economic MPC Based on Modifier Adaptation: Investigation of Several Gradient-Estimation Techniques

Various offset-free economic model predictive control schemes that include a disturbance model and the modifier-adaptation principle have been proposed in recent years. These schemes are able to reach plant optimality asymptotically even in the presence of plant–model mismatch. All schemes are affected by a major issue that is common to all modifier-adaptation formulations, namely, plant optimality (note that convergence per se does not require perfect plant gradients) requires perfect knowledge of static plant gradients, which is a piece of information not known in most practical applications. To address this issue, we present two gradient-estimation techniques, one based on Broyden’s update and the other one on linear regression. We apply these techniques for the estimation of either the plant gradients or the modifiers directly. The resulting economic MPC schemes are tested in a simulation and compared on two benchmark examples of different complexity with respect to both convergence speed and robustness to measurement noise.

Dynamic Disturbance and Error Analysis of Flexible Support System for Large Optical Mirror Processing

To improve the accuracy of a flexible support system (FSS) used for optical mirror processing, the influence of air content in the working medium and ambient temperature change on the FSS is analyzed and studied. First, the disturbance model of the FSS and single support cylinder affected by different air contents in the working medium and ambient temperature is established, and the mapping relationship between the influencing factors and the affected factors is analyzed. Then, the effects of ambient temperature change on volume, support height, and support pressure for different air contents are simulated and analyzed separately. The results of the simulation obtained show that when the working medium is mixed with different volume fractions of air and the ambient temperature changes, upper and lower chamber volumes, support rigidity, and support height of the support cylinder are also changed. Finally, an experimental study of pressure changes in the upper and lower chambers, support height, and support rigidity changes at different ambient temperatures and air contents are carried out. By measuring the support height, support pressure, and support rigidity error, the effectiveness of the established mathematical disturbance model of FSS is further verified. It not only provides a theoretical basis for improving the support accuracy of the FSS but also provides a foundation for the application of the FSS in the processing stage of large optical mirrors.

Development and research of selectively invariant electromechanical systems with elastic kinematic units based on the separation of the harmonic disturbance model

Currently there is a big variety of structure solutions of the selective invariant electromechanical systems with different layout schemes of disturbance internal model for electric drives with robust kinematic units. However, methods of structural parametric synthesis for controllers with combined triggering model only were developed selective invariant systems with “robust” kinematic of mechanical part. Consequently, further improvement of the structure variety of systems for special effects of elastic kinematic units of mechanical part is of current interest. It can be performed by including the distributed model of harmonic disturbance into the synthesis process. Structural parametric synthesis is based on the methods of modal control theory, regulators reduction, selective invariant principals, velocity separation in local sub-systems, regulation by coordinates of state and by output, cascade and slaved coordinates regulation, splitting of disturbance model to separate elements in managing contours. Investigation was performed by specified computing experiments with synthesized electromechanical system models. Now, new structure solutions of selective invariant electromechanical systems with elastic mechanical elements are developed. They are created by using the additional separation principle for disturbance model into separate parts and moving them in to the contours of “fast” and “slow” sub-systems. Acquired models of synthesized systems were compared upon the complex of main quality indicators, the comparison was based on the performed computing experiments. The acquired results of complex performance of set requirements demonstrate main pros and cons for each variant of selective invariant electromechanical systems with elastic elements, determine areas of their preferred usage and allow the developers to simplify the solution of structure optimization based on selected schema of compromises.

On the Accuracy of an Analytical Solution to Model Wave-Induced Loads on an Underwater Vehicle in Real-Time

The accuracy of an existing analytical solution for modeling the linear, first-order wave- induced loads on a fully submerged body is investigated. The accuracy is assessed for the situation where the underlying theoretical assumptions are met and the sensitivity of the accuracy to these assumptions is also explored. The accuracy was quantified by comparing the analytical solutions to experimental measurements from a tow tank with wave generation capability. The assessment showed that when all the assumptions are met, the heave and surge forces are predicted quite accurately but the pitch moment is over predicted. The results also showed that the deeply submerged assumption is met as long as the body does not cause a disruption of the passing wave on the free surface. The slenderness and end face curvature assumptions are also quite relaxed and the curvature assumption only affects the pitch moment accuracy. The most stringent assumption appears to be the body-of revolution assumption which can cause all three loads to be predicted poorly. The analytical solution appears to be accurate over a large parameter space and could be incorporated as a wave disturbance model into a virtual environment used to develop control and autonomy of unmanned underwater vehicles.

Inspection of Centrifugal Blower by Varying Different Blade Configuration using CFD

This examination points towards the advancement of an enhanced plan of a radiating blower comprising of different fan ribs, in light of execution appraisals looking like its inside parts. Different segments, for example, the outside cases and the turning fan ribs set in an assortment of working conditions, for example, fluctuating impeller speed and number of edges, are assessed mathematically and tentatively. Assessment depends on execution boundaries, including the delta and outlet pressures, stream rate, force, and intensity of the radial fan. The mathematical examination recommends that the blend of the different pivoting outline strategy and the standard k-ε disturbance model was suitable for recreation of the inside stream qualities and for power forecast. The mathematical outcomes were contrasted and tests under deliberately planned trial conditions. Plan and displaying of Impeller and packaging has been completed in CATIA V5R21 and then the Calculation was imported to Ansys 16.0. By differing the quantity of fan ribs, the exhibition fluctuates practically nothing. Nonetheless, the FC fan ribs display the best exhibition in regards to their stream rate reaction and are related with most reduced force. The weight at the exit is diminished as the stream rate is expanded. Among all the fans, the FC fan would yield the most noteworthy stream rate.

Effect of Short-Term Weather Predictions on Model Predictive Trajectory Tracking Performance of Unmanned Surface Vessels

For mobile robots, such as Autonomous Surface Vessels (ASVs), limiting error from a target trajectory is necessary for effective and safe operation. This can be difficult when subjected to environmental disturbances like wind, waves, and currents. This work compares the tracking performance of an ASV using a Model Predictive Controller that includes a model of these disturbances. Two disturbance models are compared. One prediction model assumes the current disturbance measurements are constant over the entire prediction horizon. The other uses a statistical model of the disturbances over the prediction horizon. The Model Predictive Controller performance is also compared to a PI-controlled system under the same disturbance conditions. Including a disturbance model in the prediction of the dynamics decreases the trajectory tracking error over the entire disturbance spectrum, especially for longer horizon lengths.

Assessment of Alcohol Consumption and Anxiety as Predictors of Risk of Anorexia and Bulimia in Non-Clinicals Samples

The objective of this study is to assess the effect of alcohol consumption, anxiety, and food restriction before and after consuming alcohol and body image on the risk of anorexia and bulimia in college students from Tijuana, Baja California, through predictive statistical models. A quantitative, descriptive, and cross-sectional design and a non-probabilistic sample of 526 college students from Tijuana, Baja California, México were used. Application of the scales (with acceptable psychometric properties) was conducted in classrooms. Through path analyses, four models were found with adequate indicators of goodness of fit: (1) risk of anorexia in women [Chi Square (X2) = 5.34, p = 0.376, Adjusted Determination Coefficient (R2)= 0.250]; (2) anorexia risk for men (X2 = 13.067, p = 0.192, R2 = 0.058); (3) risk of bulimia in women (X2 = 3.358, p = 0.645, R2 = 0.202); and bulimia risk for men (X2 = 14.256, p = 0.075, R2 = 0.284). The findings provide empirical evidence for the food and alcohol disturbance model.

Conservation-Theory-Based Analysis Method About Effect of External Wind Disturbance on Small Civilian UAV

In the future civilian UAV market, low-altitude low-speed small UAV will obtain a dominant position. In order to achieve small UAV accurate navigation, researchers have devoted lots of efforts on disturbance-model-reference controllers to reject the external wind disturbance. As we all know, accurate modeling helps the efficiency of controller’s parameters. However, almost all the design processes of disturbance-model-reference controllers are based on speed triangle theory which fails to adequately explain the effect of external wind field disturbances on UAV. First, conservation of energy and momentum theory is used to prove that the traditional speed triangle theory is unreasonable to analyze the influence of external wind field on UAV. Then, a more accurate method based on the conservation of energy and momentum theory is proposed to correctly illustrate the effect of wind disturbance on UAV. Finally, two external wind disturbance UAV flight simulation platforms based on speed triangle theory and conservation of energy and momentum theory are implemented separately, showing the big difference between these two types of methods about presenting effect of external wind field on UAV.