scholarly journals Modelling of autoresonant control of ultrasonic transducer for machining applications

2008 ◽  
Vol 222 (10) ◽  
pp. 1957-1974 ◽  
Author(s):  
S Voronina ◽  
V Babitsky ◽  
A Meadows
Keyword(s):  
Numerical Model ◽  
Computer Model ◽  
Positive Feedback ◽  
Piezoelectric Transducer ◽  
Control Strategies ◽  
Ultrasonic Transducer ◽  
Machining Process ◽  
Identification Process ◽  
Electromechanical Model ◽  
Control Signals

A computer model of a non-linear ultrasonic vibrating system with the possibility of autoresonant control is presented in this paper. The system controlled consists of two modules, the first of which is an electromechanical model of an ultrasonic transducer comprising a piezoelectric transducer and a step concentrator. The second module simulates an influence from the machining process. Coefficients of the electromechanical model and its validity were estimated through an identification process based on the experiments with a real ultrasonic transducer. Further, a numerical model of the autoresonant control of this system has been developed. The autoresonant control maintains the resonant regime of oscillation by means of positive feedback, which provides transformation and amplification of the control signal. The model allows the use and comparison of three control strategies depending on the different electrical and mechanical feedback control signals. The results from simulation and from real machining experiments under different control strategies are compared and discussed.

Lyapunov Control Strategy for Thermoelectric Cooler Activating an Ice-Clamping System

2018 ◽  
Vol 10 (4) ◽  
Author(s):  
Alexandra Mironova ◽  
Paolo Mercorelli ◽  
Andreas Zedler
Keyword(s):  
Manufacturing Systems ◽  
Control Strategies ◽  
Industrial Applications ◽  
Machining Process ◽  
Free Form ◽  
Cooling Power ◽  
Machining Processes ◽  
Clamping System ◽  
Ice Strength ◽  
Free Form Surfaces

Deformation-free clamping plays an important role in manufacturing systems helping to ensure zero-defect production. The fixture of workpieces during machining processes poses challenges not only for microparts but also for thin-walled pieces or free-form surfaces in macromanufacturing. To address this challenge, a nontraditional adhesive technique, using frozen water to clamp, is introduced in this paper. By increasing the cooling power and thus reducing the temperature of the clamping plate, higher adhesive ice strength and, therefore, a safer clamping system during machining process, can be achieved. The objective of this investigation is to ensure a stable low temperature and to compensate for thermal disturbances. Thanks to their structural robustness, Lyapunov-based control strategies demonstrate an appropriate capability to achieve these results in real industrial applications. Model design of the clamping system as well as simulation and experimental results are shown and discussed.

scholarly journals Some Problems of Feedback Control Strategies and It’s Treatment

2017 ◽  
Vol 9 (1) ◽  
pp. 39 ◽  
Author(s):  
Maysoon M. Aziz ◽  
Saad Fawzi AL-Azzawi
Keyword(s):  
Dynamical Systems ◽  
Feedback Control ◽  
Numerical Simulations ◽  
Positive Feedback ◽  
Control Strategies ◽  
Novel Approach

This paper extends and improves the feedback control strategies. In detailed, the ordinary feedback, dislocated feedback, speed feedback and enhancing feedback control for a several dynamical systems are discussed here. It is noticed that there some problems by these strategies. For this reason, this Letter proposes a novel approach for treating these problems. The results obtained in this paper show that the strategies with positive feedback coefficients can be controlled in two cases and failed in another two cases. Theoretical and numerical simulations are given to illustrate and verify the results.

scholarly journals Electromechanical Dynamics Model of Ultrasonic Transducer in Ultrasonic Machining Based on Equivalent Circuit Approach

Sensors ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1405
Author(s):  
Jian-Guo Zhang ◽  
Zhi-Li Long ◽  
Wen-Ju Ma ◽  
Guang-Hao Hu ◽  
Yang-Min Li
Keyword(s):  
Removal Rate ◽  
Ultrasonic Transducer ◽  
Mechanical Vibration ◽  
Electrical Energy ◽  
Structure Design ◽  
Machining Process ◽  
Ultrasonic Machining ◽  
Impedance Model ◽  
Impedance Characteristics ◽  
Electromechanical Dynamics

Ultrasonic transducer is a piezoelectric actuator that converts AC electrical energy into ultrasonic mechanical vibration to accelerate the material removal rate of workpiece in rotary ultrasonic machining (RUM). In this study, an impedance model of the ultrasonic transducer is established by the electromechanical equivalent approach. The impedance model not only facilitates the structure design of the ultrasonic transducer, but also predicts the effects of different mechanical structural dimensions on the impedance characteristics of the ultrasonic transducer. Moreover, the effects of extension length of the machining tool and the tightening torque of the clamping nut on the impedance characteristics of the ultrasonic transducer are investigated. Finally, through experimental analysis, the impedance transfer function with external force is established to analyze the dynamic characteristics of machining process.

Control Method for Elimination of Self–Excited Oscillations during Turning

2010 ◽  
Vol 164 ◽  
pp. 171-176 ◽  
Author(s):  
Tomáš Březina ◽  
Jan Vetiška ◽  
Petr Blecha ◽  
Pavel Houška
Keyword(s):  
Tool Wear ◽  
Computer Model ◽  
Pid Controller ◽  
Control Method ◽  
The Self ◽  
Machining Process ◽  
Geometric Accuracy ◽  
Turning Process ◽  
Machined Surface ◽  
Excited Oscillation

The oscillations occurring between the tool and the machined area during the turning process lead to degradation of the machined surface, cause poor geometric accuracy, accelerate tool wear and generate noise. This paper deals with the possibility of elimination of these self-excited oscillations by changing the parameters of the turning process. On the basis of the regenerative principle of self-excited oscillation generation, a computer model of the machining process was developed. Furthermore, a PID controller was proposed to control the compensation of the vibrations and its suitability for elimination of the self-excited oscillations was verified experimentally.

scholarly journals Description of nymphs and ontogenetic morphometry of Triatoma ryckmani Zeledón & Ponce, 1972 (Hemiptera: Heteroptera: Reduviidae: Triatominae)

2020 ◽  
Vol 13 ◽  
pp. e899
Author(s):  
Dayse da Silva Rocha ◽  
Carolina Dale ◽  
João Aristeu Da Rosa ◽  
Cleber Galvão
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Central America ◽  
Control Strategies ◽  
Postembryonic Development ◽  
Disease Vectors ◽  
Immature Stages ◽  
Identification Process ◽  
The Past ◽  
Scanning Electron

Triatoma ryckmani Zeledón & Ponce, 1972 is a species found in sylvatic habitat at Central America. Considered rare in the past and poorly studied, nowadays can be found inside houses with potential of dispersal and colonization. All five instars of T. ryckmani are described based on optical and scanning electron microscopy. The postembryonic development of the head analyzed by ontogenetic morphometry showed the largest changes occur in the first three instars. Information about morphology of the immature stages of disease vectors can be helpful in the identification process increasing speed and efficiency of control strategies.

Numerical Model Development and Validation for the WECCCOMP Control Competition

2018 ◽  
Author(s):  
Nathan Tom ◽  
Kelley Ruehl ◽  
Francesco Ferri
Keyword(s):  
Experimental Data ◽  
Numerical Model ◽  
Control Strategies ◽  
Model Development ◽  
Control Algorithms ◽  
Numerical Implementation ◽  
Energy Converter ◽  
Experimental Implementation ◽  
Two Stages ◽  
Development And Validation

This paper details the development and validation of a numerical model of the Wavestar wave energy converter (WEC) developed in WEC-Sim. This numerical model was developed in support of the WEC Control Competition (WECCCOMP), a competition with the objective of maximizing WEC performance over costs through innovative control strategies. WECCCOMP has two stages: numerical implementation of control strategies, and experimental implementation. The work presented in this paper is for support of the numerical implementation, where contestants are provided a WEC-Sim model of the 1:20 scale Wavestar device to develop their control algorithms. This paper details the development of the numerical model in WEC-Sim and of its validation through comparison to experimental data.

Testing and Evaluation of Control Strategies for a Prototype Hydraulic Press

2003 ◽  
Author(s):  
J. M. Cruz ◽  
J. A. Ferreira
Keyword(s):  
Computer Model ◽  
Control Strategies ◽  
Hydraulic Press ◽  
Hydraulic Systems ◽  
The Press ◽  
Testing And Evaluation

The work that this paper describes is the attempt to safely optimize, test and evaluate the performance of advanced strategies for the control of hydraulic systems. The method proposed is to use a computer model of a prototype hydraulic press to develop, optimize and test various controllers. The same tests are then repeated on the actual prototype of the press. The results of the experiments are compared to evaluate the accuracy of the model, the performance of the controllers, and the validity of the method.

scholarly journals A computer model designed to evaluate the firefighting effectiveness of solid jet produced by water nozzle

2018 ◽  
Vol 24 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Jerzy GAŁAJ ◽  
Tomasz DRZYMAŁA ◽  
Ritoldas ŠUKYS ◽  
Piotr TOFIŁO
Keyword(s):  
Mathematical Model ◽  
Numerical Model ◽  
Computer Model ◽  
International Research ◽  
Input Data ◽  
General Concept ◽  
Main Program ◽  
Jet Streams ◽  
Input And Output ◽  
Water Nozzle

The paper begins with a brief introduction and review of international research in the area of water jet streams and their effectiveness in firefighting. Then a general concept of a new numerical model for firefighting process using solid jet produced by water nozzle is presented. The provided description of the model includes main assumptions for extinguishing process and a set of relationships representing a mathematical model. The paper also includes block diagrams of the main program algorithms and procedures designed to determine the value of the surface and sprinkling intensity depending on the input data like nozzle dimensions, position etc. Input parameters which are necessary for the calculation are discussed, together with a general concept of the users input and output interfaces and simulation tests that can be performed using the developed model. Some selected simulation tests in tabular and graphical forms are included. Summary and general conclusions can be found at the end.

Influence of Unsteadiness on the Control of a Hub-Corner Separation Within a Radial Vaned Diffuser

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
Aurélien Marsan ◽  
Isabelle Trébinjac ◽  
Sylvain Coste ◽  
Gilles Leroy
Keyword(s):  
Boundary Layer ◽  
Steady State ◽  
Numerical Model ◽  
Flow Field ◽  
Centrifugal Compressor ◽  
Control Strategies ◽  
Boundary Layer Separation ◽  
Pressure Waves ◽  
Vaned Diffuser ◽  
Corner Separation

The present work aims at evaluating the effect of the impeller–diffuser interaction on the control of a hub corner separation, which develops in the radial vaned diffuser of a centrifugal compressor designed and built by Turbomeca, Safran group. Unsteady numerical simulations of the flow in the aspirated centrifugal compressor are then performed. Numerical results are validated by comparison with the available experimental results. The analysis of the numerical flow field shows that the hub-corner separation is not completely removed by the suction, on the contrary to the steady-state results that were obtained in previous work. The boundary layer separation is only translated downstream. Its location is explained by the scrolling of the pressure waves generated by the impeller–diffuser interaction, which strengthen when crossing the diffuser throat. This result highlights the major role played by the impeller–diffuser interaction, which should be taken into account for developing control strategies in radial vaned diffusers, and stresses the shortcoming of the steady-state numerical model when suction is applied.

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