In this paper, we consider the vibration suppression control of flexible arms by using sliding mode method. The vibration motion of the flexible arm has infinite number of modes. The higher order modes of the flexible...
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In this paper, we consider the vibration suppression control of flexible arms by using sliding mode method. The vibration motion of the flexible arm has infinite number of modes. The higher order modes of the flexible arm are considered as the disturbances. Since the payload mass is usually unknown, the model uncertainties usually exist. The sliding surface is designed such that the dynamics on the surface is stable under the sliding mode control. The robustness of sliding mode control is effectively employed to compensate the model uncertainties and the disturbances. For different payloads, experimental results show that the robustness of the proposed method is superior to that of the traditional pole-placement methods.
This paper utilizes robust modeling and control techniques to solve the problem of synthesizing a controller that ensures closed loop stability as well as maintaining the desired performance of large space structures ...
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This paper utilizes robust modeling and control techniques to solve the problem of synthesizing a controller that ensures closed loop stability as well as maintaining the desired performance of large space structures under various predicted failure conditions. The approach is divided into two parts. First, we develop a family of MIMO models that includes various predicted failure states in the structures. Then a controller that guarantees robust stability and performance of the entire closed loop family is designed by using the μ-synthesis technique. The key ingredients of this approach are 1) use of the interval transfer function to model the structures with predicted damage and 2) utilization of the properties of interval transfer functions to simplify the μ-synthesis procedure. Steps to validate the proposed approach are carried out by simulation.
An alternative approach to identify suspension system models using neuro-fuzzy technique is presented in this paper. Structure and design scheme based on this approach will be briefly discussed, which includes an adap...
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An alternative approach to identify suspension system models using neuro-fuzzy technique is presented in this paper. Structure and design scheme based on this approach will be briefly discussed, which includes an adaptive network employed as a building block, and the back-propagation gradient method as well as least square estimator as a hybrid learning rule. The objective is to represent the suspension dynamics by a set of fuzzy rules representation. By using this approach, the nonlinear characteristics of the suspension system can also be accommodated. Experimental evaluation of the proposed technique has been conducted using an input-output data collected from a running test vehicle. Observations by comparing the model responses with the actual output measurements revealed that satisfactory model matching were obtained which means that the models have captured the real basic features of the vehicle suspension dynamic characteristics.
This paper presents experimental results of the first-stage implementation of a new generation of longitudinal controllers for commercial heavy vehicles. The experimental vehicle used is a Class-8 18-wheel tractor-tra...
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This paper presents experimental results of the first-stage implementation of a new generation of longitudinal controllers for commercial heavy vehicles. The experimental vehicle used is a Class-8 18-wheel tractor-trailer combination vehicle, equipped with electronic throttle, brake, and steering actuators, and the corresponding sensors for automated operation. In the first stage of the experiments we tested two of our speed control algorithms: fixed-gain PID and PIQ controllers. The verification of our theoretical predictions by the experimental results provides the basis for investigating further control performance improvement with more advanced controllers.
Bifurcation control deals with the modification of the bifurcation characteristics of a parameterized nonlinear system by a judiciously designed control input. In this paper, we investigate the problem of active contr...
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Bifurcation control deals with the modification of the bifurcation characteristics of a parameterized nonlinear system by a judiciously designed control input. In this paper, we investigate the problem of active control of Rayleigh-Benard convection (RBC) via a bifurcation control approach. Active control of Rayleigh-Benard convection is a problem of importance to both theoretical research and industrial applications. Several forms of bifurcation control laws are designed based on the mathematical analysis of the governing partial differential equations for RBC. Simulations as well as experimental studies have been carried out to validate the controldesigns. A composite bifurcation control law combining a linear control law and a cubic control law is found to be most effective and flexible for this problem.
The major goal of this paper is to perform the comprehensive and thorough studies of current developments in nonlinear analysis, design, control, and deployment of advanced electromechanical systems with synchronous m...
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The major goal of this paper is to perform the comprehensive and thorough studies of current developments in nonlinear analysis, design, control, and deployment of advanced electromechanical systems with synchronous machines (motors and generators). The integration of power converters, sensors, and microprocessors depicts the realistic situation encountered in engineering practice, and this realism has stimulated the industry and academia interest in advanced analysis and design to provide a means for developing newest systems to reduce the current drawbacks and satisfy industry needs. This paper approaches and solves extremely challenging nonlinear analysis and control problems for highly nonlinear electromechanical dynamic systems without placing the problem studied into the scope of pure theoretical research. Our goal is to derive mathematical models, develop innovative design methods, synthesize novel nonlinear controllers, implement control algorithms, and perform experimental studies.
In this paper an adaptive controller known as the self-tuning regulator (STR) is employed for actively controlling an actuator for vibration isolation. Numerical simulations of the developed STR for active vibration i...
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In this paper an adaptive controller known as the self-tuning regulator (STR) is employed for actively controlling an actuator for vibration isolation. Numerical simulations of the developed STR for active vibration isolation of a simple mass-spring-damper system of two-degree-of-freedom subject to external disturbances are carried out. Experimental studies of vibration isolation by using magnetostrictive actuator with Terfenol-D rod are also presented. Both studies demonstrate the validity and effectiveness of the STR for active vibration isolation when the system is disturbed by a pure harmonic, two-modes harmonic, random, or even band-limited white noise excitation. In addition, the results are shown to be superior in terms of faster convergence and more vibration attenuation to those obtained by using previously developed adaptive plant disturbance canceler.
In this paper, we extend the observer/control strategies previously published in [18] to an n-link, serially connected, direct drive, rigid link, revolute robot operating in the presence of nonlinear friction effects ...
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In this paper, we extend the observer/control strategies previously published in [18] to an n-link, serially connected, direct drive, rigid link, revolute robot operating in the presence of nonlinear friction effects modeled by the Lu-Gre model. In addition, we also present a new adaptive control technique for compensating for the nonlinear parameterizabIe Stribeck effects. Specifically, an adaptive observer/controller scheme is developed which contains a feedforward approximation of the Stribeck effects. This feedforward approximation is used in a composite controller/observer strategy which forces the average square integral of the position tracking error to an arbitrarily small value.
Experimental testing is an important step in the verification of control strategies. In the case of civil engineering structural controlsystems, small scale testing is commonly used to demonstrate key concepts and me...
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Experimental testing is an important step in the verification of control strategies. In the case of civil engineering structural controlsystems, small scale testing is commonly used to demonstrate key concepts and methods. Large or full scale testing is expensive and only a handful of facilities exist in the world. Thus, some researchers have considered experimental techniques which focus on the control device itself, and emulate the behavior of the structure with a simulator. The concern is that these techniques do not account for the interaction between the control device and the structure. This issue will be examined herein. In a numerical example, the behavior of the control device when tested independently will be compared to that of the device when it is used to control a structure.
In this paper, first, the structure of the trial production of the mechanical system of the noncontact hold and transfer controlsystem consisting of a magnetic robot hand and a mobile robot with two independent drive...
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In this paper, first, the structure of the trial production of the mechanical system of the noncontact hold and transfer controlsystem consisting of a magnetic robot hand and a mobile robot with two independent drive wheels is expressed. Then, the state equation of the magnetic robot hand attached to the mobile robot is derived, and the robust noncontact hold controlsystem with the magnetic levitation control is designed by use of the mixed sensitivity method based on the H∞ control theory. On the other hand, the disturbance observer for the mobile robot is designed using the equation of motion of the mobile robot, and the trajectory tracking controlsystem of the mobile robot is constructed by use of the PD control and the disturbance observer. Furthermore, the experimental results concerning the noncontact hold and transfer control of a steel sphere are demonstrated, and the usefulness of the present noncontact hold and transfer controlsystem with the magnetic robot hand attached to the mobile robot is confirmed.
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