Synthesis of Robust Gain Matrices for Adaptive Rotor Vibration Control

1997 ◽  
Vol 119 (2) ◽  
pp. 298-300 ◽  
Author(s):  
C. R. Knospe ◽  
S. M. Tamer ◽  
S. J. Fedigan
Keyword(s):  
Steady State ◽  
Control Strategy ◽  
Synthesis Method ◽  
Open Loop ◽  
Active Magnetic Bearings ◽  
Open Loop Control ◽  
Rotor Vibration ◽  
Loop Control ◽  
Structured Uncertainty ◽  
Steady State Performance

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.

Control of a Digital Micromirror Device Using Input Shaping

2007 ◽  
Author(s):  
H. Jammoussi ◽  
S. Choura ◽  
E. M. Abdel-Rahman ◽  
H. Arafat ◽  
A. Nayfeh ◽  
...  
Keyword(s):  
Electrostatic Field ◽  
Control Strategy ◽  
Nonlinear Function ◽  
Input Voltage ◽  
Open Loop ◽  
Input Shaping ◽  
Control Law ◽  
Digital Micromirror Device ◽  
Open Loop Control ◽  
Loop Control

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.

scholarly journals Sliding Mode Control with Dynamical Correction for Time-Delay Piezoelectric Actuator Systems

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 132 ◽  
Author(s):  
Javier Velasco ◽  
Oscar Barambones ◽  
Isidro Calvo ◽  
Joseba Zubia ◽  
Idurre Saez de Ocariz ◽  
...  
Keyword(s):  
Time Delay ◽  
Sliding Mode Control ◽  
Control Strategy ◽  
Sliding Mode ◽  
Open Loop ◽  
Open Loop Control ◽  
Loop Control ◽  
Mode Control ◽  
Control Response ◽  
Dynamical Correction

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.

LIM Control Strategy Supported by Genetic Algorithm with Unbalanced AC Source

2018 ◽  
Vol 19 (4) ◽  
Author(s):  
Matheus Garcia Soares ◽  
Afonso Bernardino Almeida Junior ◽  
Thiago Berger Canuto Alves ◽  
Luciano Martins Neto
Keyword(s):  
Computational Model ◽  
Control Strategy ◽  
Induction Motors ◽  
Linear Motor ◽  
Open Loop ◽  
Open Loop Control ◽  
Loop Control ◽  
Linear Motors ◽  
Low Speeds ◽  
Supply Voltages

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.

Computer Simulation of a Variable Fill Hydraulic Dynamometer: Part 2: Steady State and Dynamic Open-Loop Performance

1992 ◽  
Vol 206 (1) ◽  
pp. 49-56 ◽  
Author(s):  
P G Hodgson ◽  
J K Raine
Keyword(s):  
Steady State ◽  
Closed Loop ◽  
Open Loop ◽  
Stable Set ◽  
Open Loop Control ◽  
Test Bed ◽  
Loop Control ◽  
Transient Phenomena ◽  
Absorption Performance ◽  
Dissipation Processes

Part 1 of this paper presented a theoretical model for the torque absorption and energy dissipation processes in a variable fill Froude-type hydraulic dynamometer. Effects of working compartment geometry changes on steady state running full torque absorption performance were also shown. Part 2 presents both steady state and dynamic computer simulations of an engine-dynamometer system under open-loop control. Comparisons between model simulations and test bed data show that the dynamic model reproduces both the negative torque-speed dynamometer characteristics and other transient phenomena that occur under real open-loop partial fill conditions. Requirements of control systems to modify this behaviour and ensure stable set point holding are introduced. Part 3 of the paper will deal with the simulation of the engine-dynamometer system under closed-loop control.

On the Modeling, and Open-Loop Control of a Rotating Thin Flexible Beam

1991 ◽  
Vol 113 (1) ◽  
pp. 26-33 ◽  
Author(s):  
S. Choura ◽  
S. Jayasuriya ◽  
M. A. Medick
Keyword(s):  
Control Strategy ◽  
Critical Time ◽  
Open Loop ◽  
Mode Shapes ◽  
Beam Equation ◽  
Flexible Beam ◽  
Open Loop Control ◽  
Loop Control ◽  
Coupled Equations ◽  
Critical Rotational Speed

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.

Experimental Study of Urea-SCR System Under Open-Loop Control Strategy

2013 ◽  
Vol 316-317 ◽  
pp. 1183-1187
Author(s):  
Qian Wang ◽  
Shuo Li ◽  
Jing Wang ◽  
Ping Qi
Keyword(s):  
Diesel Engine ◽  
Control Strategy ◽  
Open Loop ◽  
Injection System ◽  
Urea Solution ◽  
Bench Test ◽  
Open Loop Control ◽  
Limit Values ◽  
Loop Control ◽  
Emission Regulation

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.

scholarly journals Scattering–Like Control of the Cheshire Cat Effect in Open Quantum Systems

2019 ◽  
Vol 2 (1) ◽  
pp. 1-11
Author(s):  
Jerzy Dajka
Keyword(s):  
Open System ◽  
Control Strategy ◽  
Open Quantum Systems ◽  
Quantum Systems ◽  
Open Loop ◽  
Weak Values ◽  
Open Loop Control ◽  
Loop Control ◽  
Open Quantum ◽  
Pure Dephasing

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.

scholarly journals Effect of EGR and Fuel Injection Strategies on the Heavy-Duty Diesel Engine Emission Performance under Transient Operation

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 566 ◽  
Author(s):  
Fangyuan Zhang ◽  
Zhongshu Wang ◽  
Jing Tian ◽  
Linlin Li ◽  
Kaibo Yu ◽  
...  
Keyword(s):  
Control Strategy ◽  
Fuel Injection ◽  
Open Loop ◽  
Point Load ◽  
Injection Timing ◽  
Open Loop Control ◽  
Loop Control ◽  
Smoke Opacity ◽  
Engine Emission ◽  
Close Loop Control

To reduce the smoke and nitrogen oxide (NOx) emissions; a detailed study concerned with exhaust gas recirculation (EGR) and diesel injection strategy was conducted on a two-stage series turbocharging diesel engine under transient operating condition. One transient process based on the constant speed of 1650 r/min and load increases linearly from 10% to 100% within 5 s was tested in this study. The effect of the EGR valve control strategy on engine transient performance was examined. The results show that better air-fuel mixing quality can be obtained with the optimized the EGR valve open loop control strategy and the smoke opacity peak decreased more than 64%. Under the EGR valve close loop control strategy; the smoke opacity peak was lower than with open loop control strategy; but higher than without EGR. The effect of fuel injection strategy on engine transient performance was examined with the EGR valve close loop control. The results show that sectional-stage rail pressure (SSRP) strategy (increasing injection pressure from a turning point load to 100% load) and optimizing fuel injection timing can improve the engine emission performance. The satisfactory results can be obtained with lower NOx (382 ppm) emissions and the smoke opacity peak (3.8%), when the turning point load is set to 60% with the injection timing delay 6° CA.

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