This paper presents a design technique for the two degree of freedom (2-DOF) controlsystem using PID (Proportional-Integral-Derivative)×(n-2) stage PD as a cascade controller for a class of nth order plant. It i...
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This paper presents a design technique for the two degree of freedom (2-DOF) controlsystem using PID (Proportional-Integral-Derivative)×(n-2) stage PD as a cascade controller for a class of nth order plant. It is intended to satisfy both transient and steady state response specifications based on the root locus approach. This controller can be used instead of the conventional PID controller for the higher order plant to obtain better performance. The transfer function of a class of nth order plant should not include zeros, the poles of the plant should have negative real part. The overall system is approximated as a stable and robust second order system. The performances of the controlled system are satisfied by this design technique. Moreover, this technique can also be applied to the plant with small dead time. The cascade controller gain can be adjusted to meet faster responses with a little or no overshoot. Robustness properties given by this controller proposed in this paper have also been demonstrated by numerical examples.
In this paper we investigate the interaction between window based flow control and a recently proposed packet scheduling discipline designed for real-time services. The scheduling discipline, called the Dual Queue dis...
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In this paper we investigate the interaction between window based flow control and a recently proposed packet scheduling discipline designed for real-time services. The scheduling discipline, called the Dual Queue discipline, has been shown to provide greater flexibility than other scheduling disciplines such as fair queueing. However, its performance on non real-time services has not been previously investigated. We show that the Dual Queue's performance for non real-time services is again better than that of alternative approaches, which indicates that it will perform well in an environment of mixed real-time and non real-time traffic, such as the current internet.
Magnetic levitation systems have recently become the focus of many research interests not only because they are most suitable for high precision engineering applications but also due to the fact that they represent a ...
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Magnetic levitation systems have recently become the focus of many research interests not only because they are most suitable for high precision engineering applications but also due to the fact that they represent a difficult challenge to control engineers. As a result, most previous studies have focused on the control stabilization problem. In this paper, we address the issue of performance with respect to uncertainty in order to achieve a desired rigidity. The proposed controller is an adaptive backstepping controller. The adaptive backstepping controller provides system stability under model uncertainty, and achieves the desired servo performance. The experiments show that the proposed control achieves a superior behavior than other control.
The traditional MDP deals with the cost function which only depends on the state, and the corresponding action. In the real world, however, there are many applications where the cost incurred depends on the particular...
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The traditional MDP deals with the cost function which only depends on the state, and the corresponding action. In the real world, however, there are many applications where the cost incurred depends on the particular transition as well, which makes the traditional MDP solution infeasible for these problems. In this paper, we apply the performance potential theory as an optimization tool for MDP. In particular, the notion of the expanded Markov chain is introduced to map this problem to a general form. Both computation-based and sample-path-based algorithms are developed for potential derivation. We address ourselves to the complexity-reduction techniques. Finally, we apply these techniques to the `Join the Shortest Queue' application, which is a significant component in the analysis of communication system.
Residual vibration of flexible structures can be greatly reduced by generating specially-shaped command signals. Input shaping is a type of command generation scheme that is implemented by convolving a sequence of imp...
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Residual vibration of flexible structures can be greatly reduced by generating specially-shaped command signals. Input shaping is a type of command generation scheme that is implemented by convolving a sequence of impulses with any desired system command. The resulting shaped input is used as the reference command. Many types of useful impulse sequences have been proposed. Most of these have contained only positively valued impulses. However, when some of the impulses are allowed to have negative amplitudes, the system rise time can be improved. The improved rise time comes with the potential drawback of actuator saturation. New types of impulse sequences containing negative impulses are proposed. These sequences allow the designer to specify the swing in amplitude between successive impulses. This in turn allows the actuator effort to be controlled.
The state-dependent Riccati equation (SDRE) method is used to control the nonlinear nonminimum-phase dynamics of a continuously stirred tank reactor (CSTR). The benefits of using the SDRE method are that it can be dir...
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The state-dependent Riccati equation (SDRE) method is used to control the nonlinear nonminimum-phase dynamics of a continuously stirred tank reactor (CSTR). The benefits of using the SDRE method are that it can be directly applied to the nonminimum-phase system and hard bounds can be imposed on the control activity. From simulation analysis, it is determined that a complicated state-dependent state weighting matrix Q(x) would be required in order to produce satisfactory responses to changes in the set point of the reactor. To avoid the problem of finding such a state weighting matrix, an asymmetric solution of the SDRE is used instead of the symmetric positive-definite solution. Since there are an infinite number of asymmetric solutions, the paper discusses the process that was used in obtaining the selected asymmetric solution. Simulations are performed which produce a level of confidence that the closed loop system is asymptotically stable and is robust to parameter variations in the chemical concentration level in the educt flow.
In this paper an automotive MacPherson suspension unit is identified and modeled using a radial basis function network with local linear weighting functions (LOLIMOT). The output of the network represents the nonlinea...
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In this paper an automotive MacPherson suspension unit is identified and modeled using a radial basis function network with local linear weighting functions (LOLIMOT). The output of the network represents the nonlinear force characteristic of the spring-and-damper unit in dependency of the measured spring travels at the front axle and the corresponding spring travel velocities. The network parameters are interpreted physically by comparing the five local linear models identified with the network to a physical second-order model of the wheel suspension unit. Implemented in an overall vehicle model the network or its look-up table representation represents an adaptable model of the nonlinear vehicle suspension characteristics.
The precision and micro assembly requires special tools in order to fulfill the high demands in accuracy and control of the assembly process. Our new precise gripper tool with 2dof, the micro positioning system (MPS),...
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The precision and micro assembly requires special tools in order to fulfill the high demands in accuracy and control of the assembly process. Our new precise gripper tool with 2dof, the micro positioning system (MPS), enables micro assembly with standard industrial robots by compensating for vibrations and inaccuracies of the handling device. The new developed controlsystem combines data of three diverse sensors to perform the corrective movement. The designed controlsystem of the MPS consists of two closed-loop and one open-loop regulator. A classical controldesign with pole-zero cancellation is used to linearize the hysteresis of the piezo actuator. An H2-regulator using only acceleration feedback is the main part of the controlsystem and generates a control signal proportional to the position for the actuator's corrective movement. The third regulator handles the reference input. The realized controlsystem reduces vibrations to less than 30%, the position accuracy without disturbances is better than 2 microns according to experimental results.
The models that describe the dynamics of reaction systems are usually complex and uncertain. To simplify their description it is useful to identify the states which are dependent/independent of the reactions and flows...
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The models that describe the dynamics of reaction systems are usually complex and uncertain. To simplify their description it is useful to identify the states which are dependent/independent of the reactions and flows. This allows us, for instance, to design observers which are independent of the (highly uncertain) reaction functions and, in principle, simplify the controller design. The main contribution of this paper is to show the utility of nonlinear state-dependent time-scaling to carry out these objectives. First, we prove the existence of attractive invariant manifolds, which allows us to reduce the dimension of the system under study. Second, we design reaction-independent observers, which are simpler than the existing ones, and have a guaranteed convergence rate in all operating regimes. As an application we study a fifth order baker's yeast fed-batch fermentation process model, for which we reduce the essential dynamics to the plane. A simple input-output feedback linearizing controller is designed and its asymptotic stability established.
Flexible manipulators provide significant advantages over commonly used rigid robots, such as high operation speed and high power efficiency. However, the controller design for these manipulators is very complicated b...
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ISBN:
(纸本)078035446X
Flexible manipulators provide significant advantages over commonly used rigid robots, such as high operation speed and high power efficiency. However, the controller design for these manipulators is very complicated because of the nonlinear vibration dynamics. In this paper, a rule-based scheme for implementing a fuzzy logic controller to drive a flexible manipulator is proposed. The phase portrait plane has been adopted to build the rules based on mathematical reasoning rather than the conventional trial and error method, which is dependent on the operator's experience. In order to improve the performance of the fuzzy logic controller, an adjustable weight parameter has been introduced to build the control table. A set of variable width triangular membership functions is used to improve the resolution of the controller. The effectiveness of the control law has been demonstrated with numerical simulation.
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