In this paper we consider the model reference adaptive control (MRAC) problem of a class of linear time-varying (LTV) plants. The plant parameters are assumed to be smooth, bounded functions of time which satisfy the ...
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In this paper we consider the model reference adaptive control (MRAC) problem of a class of linear time-varying (LTV) plants. The plant parameters are assumed to be smooth, bounded functions of time which satisfy the usual assumptions of MRAC for time-invariant plants, at each frozen time instant. We first show that if the plant parameters are sufficiently slowly-varying with time, a control parameter vector with smooth elements exists, such that the closed loop plant behaves almost like a linear time invariant referencemodel. We then use the robust adaptive law proposed in Ioannou and Tsakalis (1985) to adjust the controller parameters and establish boundedness for all signals in the adaptive loop for any bounded initial conditions. The bound for the residual tracking error depends on the speed of the plant parameter variations in such a way that as these parameters become constant the bound reduces to zero.
The complete dynamic model of a 6-degrees-of-freedom (DOF) robotic manipulator is very complicated, having a large number of nonlinear terms, and so it is very difficult to be used for actual on-line control. The purp...
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The complete dynamic model of a 6-degrees-of-freedom (DOF) robotic manipulator is very complicated, having a large number of nonlinear terms, and so it is very difficult to be used for actual on-line control. The purpose of this paper is to provide a method for decomposing the dynamical model of such a 6-IDOF manipulator in two 3-DOF submodels (one for the arm and one for the wrist) which can be successfully used both for simulation and control purposes. The arm submodel takes into account the effect of the wrist and of the manipulator task requirements, in the form of an external force/ torque pair expressed in tool coordinates. The influence of the robot task is similarly included in the wrist dynamic model. Then the paper shows how the model reference adaptive control (MRAC) technique can be used on this two-part robot model. As a simulator of the 6-DOF robot, the exact dynamic model, based on the Newton Euler method, is employed. Computational experimental results are included which show the effectiveness of the approach.
A model reference adaptive controller proposed by Morse is studied. It is shown to be exponentially convergent when the high frequency gain is known and when the reference inputs satisfy a persistence of excitation as...
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A model reference adaptive controller proposed by Morse is studied. It is shown to be exponentially convergent when the high frequency gain is known and when the reference inputs satisfy a persistence of excitation assumption, which allows the inputs to be other than a linear combination of sinusoids.
In this paper some problems concerning the control of multifunctional manipulators (industrial robots) with high speed continuous movements are investigated. Although deterministic approaches to the control of robots,...
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In this paper some problems concerning the control of multifunctional manipulators (industrial robots) with high speed continuous movements are investigated. Although deterministic approaches to the control of robots, whose model are highly interconnected and non-linear, are known alternative approaches based on the modelreferenceadaptive System (MRAS) method of control are possible and useful. In the paper it is proved that a generalized MRAS control assures the convergence to a suitable referencemodel for a class of processes: the manipulator is shown to belong to such a class. The paper is completed by some applications evaluated by simulation.
The role of model reference adaptive control is under consideration for a computer based feedback system which will regulate the infusion rate of a drug (nitroprusside) in order to maintain desired blood pressure. Bec...
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The role of model reference adaptive control is under consideration for a computer based feedback system which will regulate the infusion rate of a drug (nitroprusside) in order to maintain desired blood pressure. Because the transfer function parameters are different for each patient and furthermore are variable with time, an adaptive algorithm is desirable for maintaining both steady-state and transient specifications. To this effect, computer simulation has shown that direct (or implicit) modelreference procedures might be successfully applied to the control of blood pressure despite the uncertainty in the delays, time constant and gains. Additional efforts concerned with the actual demonstration of these concepts on dogs have further supported the role of adaptivecontrol for blood pressure regulation.
This paper deals with the design of a model reference adaptive controller for a distributed parameter system generated by a self-adjoint operator. The space of inputs and the space of outputs are both one dimensional....
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This paper deals with the design of a model reference adaptive controller for a distributed parameter system generated by a self-adjoint operator. The space of inputs and the space of outputs are both one dimensional. After introducing input-output representations, an adaptivecontrol system is designed for the system with unknown input function and unknown output function. The input-output equations can be expressed using filtered values generated from the inputs and outputs
The paper tries to present a state-of-the art of recent applications of adaptive systems to process control. A broad scope of practical applications in different fields of process industries is given, where stress is ...
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The paper tries to present a state-of-the art of recent applications of adaptive systems to process control. A broad scope of practical applications in different fields of process industries is given, where stress is laid on the necessity of adaptivecontrol. It will be shown, that the applications are not only devoted to pilot plants, but also to industrial units. It seems that industry has accepted the application of these schemes, which have fulfilled the expected improvements. The demands for a broad industrial application of adaptive approaches are discussed.
The dynamic control of industrial robots is one of the most important issues in today's advanced robotics research. This paper first illustrates a new control algorithm and some relative schemes in order to guaran...
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The dynamic control of industrial robots is one of the most important issues in today's advanced robotics research. This paper first illustrates a new control algorithm and some relative schemes in order to guarantee perfect trajectory tracking both in thr-task space, usually the Cartesian one, and in the joint space. Such control allows joint servoing decoupling and proves so robust that practical implementation is realizable without requiring on-line accurate evaluation of robot model and load. The kinematic control, that is the coordinate transformation problem, is then faced up and a very general solution algorithm which only makes use of direct kinematics is derived.
Systems which automatically adjust their controller parameters to compensate for changes in the controlled process or its environment are referred to as adaptivecontrol systems. This survey of adaptivecontrol theory...
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Systems which automatically adjust their controller parameters to compensate for changes in the controlled process or its environment are referred to as adaptivecontrol systems. This survey of adaptivecontrol theory and its applications reviews the progress during the years 1980 till 1984. Different basic structures of adaptivecontrol systems, including model reference adaptive control self-tuning regulators and parameter scheduling control are discussed. It is shown that carefully designed adaptivecontrol systems have been used successfully in a broad variety of application areas.
This paper presents an overview of the current status of convergence theory for adaptivecontrol algorithms. Rather than giving a comprehensive survey, the paper aims to emphasize the conceptual common ground between ...
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This paper presents an overview of the current status of convergence theory for adaptivecontrol algorithms. Rather than giving a comprehensive survey, the paper aims to emphasize the conceptual common ground between different approaches. Possible areas for future research are also discussed.
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