LIM Control Strategy Supported by Genetic Algorithm with Unbalanced AC Source

Author(s):  
Matheus Garcia Soares ◽  
Afonso Bernardino Almeida Junior ◽  
Thiago Berger Canuto Alves ◽  
Luciano Martins Neto

AbstractThis work presents the improvement of an open loop control strategy for linear induction motors operating at low speeds. The improvement is provided through the application of genetic algorithms in determining unbalance factors of the supply voltages of the linear motor. For this, a computational model of the linear motor was used as the evaluation function. The computational model was developed based on the equations of the linearized induction motor. The proposed methodology is validated through the comparison between computational results and experimental data performed in a linear motor prototype. This methodology allows to evaluate the influence of the unbalance of the supply voltages for linear motors working at low speeds.

Author(s):  
H. Jammoussi ◽  
S. Choura ◽  
E. M. Abdel-Rahman ◽  
H. Arafat ◽  
A. Nayfeh ◽  
...  

In this paper, an open-loop control strategy is proposed for maneuvering the angular motion of a Digital Micromirror Device (DMD). The control law is based on a micromirror model that accounts for both bending and torsion motions. The model characterizes two DMD configurations: with and without contact with the substrate. The device is actuated using an electrostatic field which is a nonlinear function of the states and input voltage. The proposed control strategy is a Zero Vibration (ZV) shaper. It overshoots the DMD to its desired final angle by appropriately varying two independent input voltages. Actuating voltages and switching times are determined to maneuver the DMD from −10° to +10° tilt angles while reducing the residual vibrations.


Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 132 ◽  
Author(s):  
Javier Velasco ◽  
Oscar Barambones ◽  
Isidro Calvo ◽  
Joseba Zubia ◽  
Idurre Saez de Ocariz ◽  
...  

In piezoelectric actuators (PEAs), which suffer from inherent nonlinearities, sliding mode control (SMC) has proven to be a successful control strategy. Nonetheless, in micropositioning systems with time delay, integral proportional control (PI), and SMC, feedback control schemes have a tendency to overcompensate and, consequently, high controller gains must be rejected. This may produce a slow and inaccurate response. This paper presents a novel control strategy that deals with time-delay micropositioning systems aimed at achieving precise positioning by combining an open-loop control with a modified SMC scheme. The proposed SMC with dynamical correction (SMC-WDC) uses the dynamical system model to adapt the SMC inputs and avoid undesirable control response caused by delays. In order to develop the SMC-WDC scheme, an exhaustive analysis on the micropositioning system was first performed. Then, a mixed control strategy, combining inverse open-loop control and SMC-WDC, was developed. The performance of the presented control scheme was analyzed and compared experimentally with other control strategies (i.e., PI and SMC with saturation and hyperbolic functions) using different reference signals. It was found that the SMC-WDC strategy presents the best performance, that is, the fastest response and highest accuracy, especially against sudden changes of reference setpoints (frequencies >10 Hz). Additionally, if the setpoint reference frequencies are higher than 10 Hz, high integral gains are counterproductive (since the control response increases the delay), although if frequencies are below 1 Hz the integral control delay does not affect the system’s accuracy. The SMC-WDC proved to be an effective strategy for micropositioning systems, dealing with time delay and other uncertainties to achieve the setpoint command fast and precisely without chattering.


1997 ◽  
Vol 119 (2) ◽  
pp. 298-300 ◽  
Author(s):  
C. R. Knospe ◽  
S. M. Tamer ◽  
S. J. Fedigan

Experimental results have recently demonstrated that an adaptive open-loop control strategy can be highly effective in the suppression of the unbalance induced vibration of rotors supported in active magnetic bearings. A synthesis method is presented for determining the adaptive law’s gain matrix such that the adaptation’s stability and steady-state performance are robust with respect to structured uncertainty.


Micromachines ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 421 ◽  
Author(s):  
Lucía Díaz Pérez ◽  
Marta Torralba Gracia ◽  
José Albajez García ◽  
José Yagüe Fabra

A two-dimensional (2D) nanopositioning platform stage (NanoPla) is in development at the University of Zaragoza. To provide a long travel range, the actuators of the NanoPla are four Halbach linear motors. These motors present many advantages in precision engineering, and they are custom made for this application. In this work, a one-dimensional (1D) control strategy for positioning a Halbach linear motor has been developed, implemented, and experimentally validated. The chosen control hardware is a commercial Digital Motor Control (DMC) Kit from Texas Instruments that has been designed to control the torque or the rotational speed of rotative motors. Using a commercial control hardware facilitates the applicability of the developed control system. Nevertheless, it constrains the design, which needs to be adapted to the hardware and optimized. Firstly, a dynamic characterization of the linear motor has been performed. By leveraging the dynamic properties of the motor, a sensorless controller is proposed. Then, a closed-loop control strategy is developed. Finally, this control strategy is implemented in the control hardware. It was verified that the control system achieves the working requirements of the NanoPla. It is able to work in a range of 50 mm and perform a minimum incremental motion of 1 μm.


1991 ◽  
Vol 113 (1) ◽  
pp. 26-33 ◽  
Author(s):  
S. Choura ◽  
S. Jayasuriya ◽  
M. A. Medick

A set of governing differential equations is derived for the inplane motion of a rotating thin flexible beam. The beam is assumed to be linearly elastic and is connected to a rigid hub driven by a torque motor. Both flexural and extensional effects are included in the derivation. This coupling due to flexure and extension is usually neglected in studies dealing with the control of such a system. Models for typical control studies are often derived by utilizing an assumed mode approach where the mode shapes are obtained by solving the Euler-Bernoulli beam equation for flexural vibrations, with clamped-free or pinned-free boundary conditions. The coupled equations developed in this paper are used to demonstrate that typical models in control studies give satisfactory results up to a critical rotational speed. For the case where these coupled equations are specialized to simple flexure only, valid for low angular speeds, a unique feedforward control strategy can be derived. This is an open-loop control strategy that enables total elimination of an a priori specified vibratory mode from the gross motion in a finite critical time.


2013 ◽  
Vol 316-317 ◽  
pp. 1183-1187
Author(s):  
Qian Wang ◽  
Shuo Li ◽  
Jing Wang ◽  
Ping Qi

Open-loop control strategy of SCR urea injection system for MD/HD vehicle diesel engine is established firstly in this paper. Then the emission test is performed for a domestic diesel engine in test bench. Test results show that NOX emissions of ESC and ETC are much lower than the limit values of National-IV emission regulation under a simple injection strategy. The results also show that the urea solution consumption accounts for only 5.8% of the fuel consumption. What’s more, the tests have been accumulated for achieving accurate matching between urea injection and diesel engine.


Author(s):  
Yang Wang ◽  
Cle´ment M. Gosselin

Because wear, clearance and backlash can be reduced or eliminated, one of the important advantages of compliant mechanisms is their potential to increase the mechanism precision dramatically. In this paper, a spatial compliant mechanism based on the 3-PRRR parallel mechanism driven by linear motors is presented. The design methodology is described and the kinematic and static models are developed. Using the “transmission ratio”, an effective and simple compensation method is designed. The performances of this mechanism are studied with the help of the structure simulation module in Pro-Mechanica. Using an open-loop control with compensation, measurements over a 20×20×20 mm3 workspace show that the position accuracy is smaller than 1 μm, i.e., 0.05% of the full range of motion and that the orientation error is less than 1 μradian.


2019 ◽  
Vol 2 (1) ◽  
pp. 1-11
Author(s):  
Jerzy Dajka

We study the Quantum Cheshire Cat effect in an open system coupled to a finite environment. We consider a very special type of coupling—pure dephasing—and show that there is a scattering-like mechanism which can be utilized to construct an open-loop control strategy for the weak values of the Cat and its grin.


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