Robust Feedback Control of a Baffled Plate via Open-Loop Optimization

2001 ◽  
Vol 124 (1) ◽  
pp. 154-157 ◽  
Author(s):  
P. De Man ◽  
A. Franc¸ois ◽  
A. Preumont

A SISO control system is built by using a volume displacement sensor and a set of actuators driven in parallel with a single amplifier. The actuators location is optimized to achieve an open-loop transfer function which exhibits alternating poles and zeros, as for systems with collocated actuators and sensors; the search procedure uses a genetic algorithm. The ability of a simple lead compensator to control this SISO system is numerically demonstrated.

Climate control for livestock building is of considerable significance but it is additionally a difficult and convoluted task. The chickens are mainly affected by the variation of temperature and relative humidity. The arrangement of these parameters is accomplished by selecting proper control techniques. In this paper, an optimized controller for the stabilization of the poultry house system has been designed in order to reduce the heat stress of broilers and to achieve the preservation of chickens’ health and comfort. A hygro-thermal model describing the behavior of the poultry house is decomposed into two single loops based on the theory of the effective open-loop transfer function. Adopting a model reduction technique, the equivalent transfer function of each loop is then designed by developing an independent multi-loop PID controller. The initial stability of the reduced model is assured via the Hermite-Biehler theorem. Then, the Genetic Algorithm is adopted to search the optimal gain values that contribute to the desired indoor climate monitoring. An extensive numerical simulation is tested with original experiments measures to show the effectiveness of the design control and the results are compared to those of the ant colony optimization and Ziegler-Nichols methods.


2012 ◽  
Vol 235 ◽  
pp. 186-191
Author(s):  
Gui Ying Lu ◽  
Yuan Sheng Wang ◽  
Bo Li ◽  
Juan Yu

The structure and its function about a dual-axis rate turntable has been elaborated, its principle block diagram of control system is given. And its electromechanical system’s transfer function of the dual-axis rate table has been calculated and simplified reasonably based on experiments and practical situation, then a double loop control system constituted with a speed loop and a stabilization loop is got. Its’ correction link of the stabilization loop is calculated, which has a 2-order open loop transfer function. In order to achieve a suitable stability margin, the corresponding digital controller is designed, and its’ pulse transfer function response and the three-step iterative simulation results to a same sinusoidal excitation are got and compared, the same results verified the correctness of the design to the correction link.


1990 ◽  
Vol 112 (3) ◽  
pp. 337-345 ◽  
Author(s):  
C. A. Tan ◽  
B. Yang ◽  
C. D. Mote

The vibration of a translating string, controlled through hydrodynamic bearing forces, is analyzed by the transfer function method. Interactions between the string response and the bearing film are described by the bearing impedance function. This function depends on the string translation speed, the frequency of the film thickness variation, and the spatial location of the bearings. The control system consists of the translating string, bearings, actuators and sensors, and feedback elements. An integral formulation of the controlled system response is proposed that leads to the closed-loop transfer function. The frequency response of the control system is studied in the system parameter space. The feasibility of adding active control to improve the bearing force control is also considered.


Author(s):  
Aimee S. Morgans ◽  
Ann P. Dowling

Model-based control has been successfully implemented on an atmospheric pressure lean premixed combustion rig. The rig incorporated a pressure transducer in the combustor to provide a sensor measurement, with actuation provided by a fuel valve. Controller design was based on experimental measurement of the open loop transfer function. This was achieved using a valve input signal which was the sum of an identification signal and a control signal from an empirical controller to eliminate the non-linear limit cycle. The transfer function was measured for the main instability occurring at a variety of operating conditions, and was found to be fairly similar in all cases. Using Nyquist and H∞-loop shaping techniques, several robust controllers were designed, based on a mathematical approximation to the measured transfer function. These were implemented experimentally on the rig, and were found to stabilise it under a variety of operating conditions, with a greater reduction in the pressure spectrum than had been achieved by the empirical controller.


Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Zhiguo Wang ◽  
Peng Wei

In this paper, a new design method with performance improvements of multiloop controllers for multivariable systems is proposed. Precise expression is developed to show the relationship between the dynamic- and steady-state characteristics of the multiloop control system and its parameters. First, an equivalent transfer function (ETF) is introduced to decompose the multivariable system, based on which the multiloop controller parameters are calculated. According to the ETF matrix property, an analytical expression for the PI controller for multivariable systems is derived in terms of substituting the ETF matrix for the inverse open-loop transfer function. In the proposed controller design method, no approximation of the inverse of the process model is needed, implying that this method can be applied to some multivariable systems with high dimensions. The simulation results obtained from several examples demonstrate the effectiveness of the proposed method.


Author(s):  
Song Zhang ◽  
Daisuke Iba ◽  
Akira Sone ◽  
Arata Masuda

This paper proposes a new method that is an optimization design of a passive vibration system based on linear control theory. A Force generated by spring and damper that are the design parameters of the passive vibration system have the same properties with a PD controller. So it is possible to apply a method that shapes an open-loop transfer function of the PD controller based on the GKYP lemma. By using the method, the gain and the phase of the transfer function can be designed with respect to each frequency band. As a result, it is not necessary to solve a difficult problem that is a bilinear matrix inequality problem obtained by an ordinary formulation.


Author(s):  
Meng-Sang Chew ◽  
Theeraphong Wongratanaphisan

Abstract This paper presents the analysis of the kinematics, dynamics and controls of tendon-driven mechanism under the framework of signal flow graphs. For decades, the signal flow graphs have been applied in many areas, particularly in controls, for determining the closed-loop transfer function of a control system. The tendon-driven mechanism considered here consists of several subsystems including actuator-controller dynamics, mechanism kinematics and mechanism dynamics. Each subsystem will be derived and represented by signal flow graphs. The representation of the whole system can be carried out by connecting the graphs of subsystems at the corresponding nodes. Transfer functions can then be obtained by using Mason’s rules. A 3-DOF robot finger utilizing tendon-driven mechanism is used as an illustrative example.


2004 ◽  
Vol 126 (4) ◽  
pp. 899-904 ◽  
Author(s):  
O. Yaniv ◽  
M. Nagurka

This paper presents performance limitations and a control design methodology for nonminimum phase plants of the pure delay type subject to robustness constraints. Of interest is the design of a set of controllers, for which the open-loop transfer function is a proportional-integral (PI) controller plus delay, meeting constraints on the magnitude of the closed-loop transfer function and on the plant gain uncertainty. These two specifications are used to characterize the robustness, and are a recommended alternative to the gain and phase margin constraints. A control design plot is presented which allows for selection of controller parameters including those for the lowest sensitivity controller, and graphically highlights gain and phase margin tradeoffs. The paper discusses limitations of performance of such systems in terms of crossover frequency and sensitivity. In addition, expressions and design plots are provided for a simplified approximate solution.


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