This paper presents a study of the control of a fluidized bed catalytic reactor using the model reference adaptive control algorithm with independent tracking and regulation objectives as presented by Landau and Lozan...
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This paper presents a study of the control of a fluidized bed catalytic reactor using the model reference adaptive control algorithm with independent tracking and regulation objectives as presented by Landau and Lozano (1981). The purpose of the control is to maintain the temperature of the reactor as near as possible to a desired set value (490°C). Some of the heat produced by the exothermal reaction taking place between propylene, ammonia and oxygen is carried away by a ventilator. The control action is based on a low order mathematical model with time varying parameters. This method of control results in a significantly improved control for both servo and regulatory control.
In the literature to date there is a dichotomy between results on continuous- and discrete-time modelreferencecontrol. This is highlighted in the case of continuous-time systems having relative degree greater than o...
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In the literature to date there is a dichotomy between results on continuous- and discrete-time modelreferencecontrol. This is highlighted in the case of continuous-time systems having relative degree greater than one. It is known that, for rapid sampling, these systems always give rise to a non-stably invertible discrete-time system and thus discrete modelreferencecontrol is ruled out. On the other hand, there are many results pertaining to continuous-time modelreferencecontrol of such systems. This apparent paradox can be resolved by a slight modification to the discrete-time model format as shown later. This alternative model is used to develop a new discrete model reference adaptive control law and a convergence analysis for the algorithm is presented.
An industrial robot is composed of a multidegree-of-freedom mechanism, associated actuator subsystems, and a computer based control system. In general, it is difficult to accurately control the motion of mechanical ma...
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An industrial robot is composed of a multidegree-of-freedom mechanism, associated actuator subsystems, and a computer based control system. In general, it is difficult to accurately control the motion of mechanical manipulators by the usual linear control methods, because of the complex nonlinearities of mechanical dynamics and parameter uncertainty. Strong coupling among the actuator subsystems occurs, due to the influence of the inertial forces in the mechanical parts which causes interaction between links. Thus, when the nonlinearities are essential, linear approximations give poor results and the complete dynamic models have to be considered. In the present work the complete nonlinear dynamic model of the robotic manipulator is considered together with its joint actuator (i.e. d.c. motor) dynamics. A control law of the robotic system is developed based on the well known”model reference adaptive control” (MRAC) approach. An exhaustive study of a decoupled referencemodel of the who1 e robotic system is proposed which possesses strong stability properties. The paper is completed by sane simulation results on trajectory following control of a 3-link manipulator.
The design of a multivariable sliding mode controller based on the equations of motion of an unmanned aircraft or remotely piloted vehicle (RPV)is described and an emphasis on robust eigenstructure assignment is given...
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The design of a multivariable sliding mode controller based on the equations of motion of an unmanned aircraft or remotely piloted vehicle (RPV)is described and an emphasis on robust eigenstructure assignment is given. The linear and nonlinear model responses are compared when subjected to the same variable-structure control design. The ability of the controller to cope with uncertain parameter variations is investigated as a problem of robustness assessment. It is shown that after sliding has commenced, the response of the objective system is tracked by the corresponding nonlinear or perturbed system. A measure of sensitivity is defined as the proximity of the actual system modal structure and response to that of the designed objective. The nonlinear system with variable- structure controller is also shown to be robust in the sense that this objective response is always recovered after a disturbance or parameter variation. (Author)
Damping of synchronous generator oscillations has been investigated by using three types of controllers, i.e., the PI (proportional-integral) controller, the model reference adaptive controller (MRAC) and the variable...
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Damping of synchronous generator oscillations has been investigated by using three types of controllers, i.e., the PI (proportional-integral) controller, the model reference adaptive controller (MRAC) and the variable-structure model-following controller (VSMFC). It was found that the PI controller fails to accommodate itself to the situation where there is a significant change in generator loading conditions. The MRAC greatly improves the dynamic responses of the generator over a wide range of operating conditions by minimizing the error in the responses obtained from the plant with a specified referencemodel. The damping of the generator is further improved by the VSMFC, which reduces the sensitivity of generator responses relative to plant parameter variations by providing sliding-mode operations.
A cascade speed control strategy for a thyristor driven DC motor subjected to parameter variations is proposed. A dual mode adaptive inner current loop is cascaded with a modelreferenceadaptive speed control loop. T...
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A cascade speed control strategy for a thyristor driven DC motor subjected to parameter variations is proposed. A dual mode adaptive inner current loop is cascaded with a modelreferenceadaptive speed control loop. The scheme is implemented in a 16 bit microcomputer using a floating point coprocessor. Tests on a DC machine have been conducted. The proposed solution guarantees a stable and predefined performance under all operating conditions. Comparisons with a conventional analog speed control are made.
It is shown that the strict positive realness (SPR) condition for asymptotic stability of the continuous-time parallel modelreferenceadaptive system (MRAS) can be removed provided that the parameter adaption law inc...
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It is shown that the strict positive realness (SPR) condition for asymptotic stability of the continuous-time parallel modelreferenceadaptive system (MRAS) can be removed provided that the parameter adaption law includes a proportional term and the information matrix is made sufficiently large. The present result a continuous-time counterpart of an earlier result (M. Tomizuka, ibid., vol.27, no.4, p.505-6, 1982) on the discrete-time parallel MRAS.
A novel control approach for a robust induction motor drive system supplied from avoltage source inverter is developed. In the scheme, the inverter gating signal is controlled based on the Decoupling control Theory. I...
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The requirements placed on modern robot control applications are presented. These include speed and changing parameters such as load. Against these requirements recent advances in adaptivecontrol in general are short...
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The requirements placed on modern robot control applications are presented. These include speed and changing parameters such as load. Against these requirements recent advances in adaptivecontrol in general are shortly presented. The exposition confines itself to rigid mechanical structures and focuses on issues arising in general nonlinear dynamical robot models. Proposed algorithms are investigated, especially those developed in connection to the Esprit program. These include self-tuning adaptive, modelreferenceadaptive (MRAC) and variable structure controllers. Emphasis is placed on the possibility of controlling independently each link by handling the coupling of the differential equations through the inherent adaptibility of the investigated methods.
A more efficient way of implementing robust adaptivecontrol than that proposed in an earlier work by the authors is considered for the same electrohydraulic system. In certain cases, some of the control parameters ar...
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A more efficient way of implementing robust adaptivecontrol than that proposed in an earlier work by the authors is considered for the same electrohydraulic system. In certain cases, some of the control parameters are independent of the unknown plant parameters and, therefore, can be eliminated from parameter identification. Since parameter identification takes much of the computation time, even a reduction of one parameter can be beneficial. The simplification of the parameter identification method is achieved by using the knowledge of the structure of a plant model and carrying out the design procedure for modelreferencecontrol, treating the plant parameters is unknown coefficients. This procedure is explained for the electrohydraulic system used in the study.< >
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