Mechanical devices usually come with undesirable nonlinearities such as frictions, backlashes and saturation. Under the assumption of linear systems, the commonly seen identification schemes utilize sinusoidal excitat...
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Mechanical devices usually come with undesirable nonlinearities such as frictions, backlashes and saturation. Under the assumption of linear systems, the commonly seen identification schemes utilize sinusoidal excitation signals for parameter identifications. However, the data for identification are unavoidably distorted by the fore-mentioned nonlinearities and the identification result is not satisfactory. In this paper, a method based on binary excitation signals is proposed. The method does not suffer from the problem of nonlinear distortions in signal shape and is able to determine the bias term for asymmetric frictions such that an accurate model can be derived. A 0.01 μm high precision ballscrew table with asymmetric frictions is utilized as a test plant for this approach. The result proves to be very successful.
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.
controller synthesis for protecting the vehicle from spin is described as a robust stabilization problem against perturbations of rear cornering force. The controller is designed by gain-scheduled H∞ control theory s...
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controller synthesis for protecting the vehicle from spin is described as a robust stabilization problem against perturbations of rear cornering force. The controller is designed by gain-scheduled H∞ control theory so that the closed-loop system satisfies an H∞ norm condition guaranteeing the stability of the vehicle. The controller adjusts the braking force distribution to the right and the left wheels. The result has been tested by executing experiment. The experimental results showed that the designed controller can robustly stabilizes the vehicle and protects it from spin under the presence of large perturbations of rear cornering force.
The results of analysis using a reduced-order model of combustion instability derived at UTRC and experiments with active control using fuel modulation motivated a study of what performance is achievable using active ...
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The results of analysis using a reduced-order model of combustion instability derived at UTRC and experiments with active control using fuel modulation motivated a study of what performance is achievable using active control. Limitations due to lightly damped or unstable eigenvalues, delay, disturbances, and limited actuator authority and bandwidth are studied. In this part of the paper we focus on linear analysis of a combustion model and study effect of delay in the model and limited actuator bandwidth.
A novel capturing method of tumbling objects in non-gravitational field is proposed, aiming for the future on-orbit service missions such as capturing failed satellites or manned vehicle which loses control, or removi...
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A novel capturing method of tumbling objects in non-gravitational field is proposed, aiming for the future on-orbit service missions such as capturing failed satellites or manned vehicle which loses control, or removing debris. The key technology for this capture is how to compensate for the difference of rotational motions between the chaser and the target at the moment of capture. Most conventional methods use manipulator movement for this objective while keeping the position and attitude of the chaser body constant, which limits the allowable rotational velocity and patterns of the tumbling motion of the target. In the proposed method, the chaser aligns its rotational motion with the target's one by appropriate control before capturing the target, which is expected to enlarge the allowable target rotational motion range. Technical issues to realize it are discussed and our approach to them are proposed, which is verified with some computer simulations and hardware experiments.
The defining characteristic of a networked controlsystem (NCS) is having a feedback loop that passes through a local area computer network. This paper considers nonlinear systems controlled in this manner, and demons...
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The defining characteristic of a networked controlsystem (NCS) is having a feedback loop that passes through a local area computer network. This paper considers nonlinear systems controlled in this manner, and demonstrates that for sufficiently high transmission rates, the network may be considered transparent. Three methods of scheduling data packets are compared: a static scheduler (token ring), the Try-Once-Discard (maximum-error-first) scheduler with continuous priority levels, and the Try-Once-Discard scheduler with discrete priority levels. The third method is of particular interest when only a small number of bits are available for collision resolution. Asymptotic stability is guaranteed in the first two cases, and ultimate uniform boundedness in the third. In the final section, simulations demonstrate the theoretical results. The contributions of this paper are two-fold: first, it extends the earlier results on NCS to nonlinear systems, and second, it allows for finite word-length message identifiers.
By adding an electronic throttle and a torque sensor to an engine equipped with variable cam timing, it is potentially possible to vary cam phasing to improve emissions and fuel economy while preserving the torque res...
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By adding an electronic throttle and a torque sensor to an engine equipped with variable cam timing, it is potentially possible to vary cam phasing to improve emissions and fuel economy while preserving the torque response of a conventional non-VCT engine. To do so effectively, however, requires the use of multivariable control. A controller consisting of decentralized individual control loops will not yield satisfactory performance because such a controller cannot compensate for system interactions. Yet, a fully multivariable controller may not prove necessary in order to achieve the desired performance. In this paper, we design linear multivariable controllers at a number of operating points and simplify the resulting controllers by eliminating cross-coupling terms that do not affect the closed loop response. Doing so provides insight useful in tuning controller parameters.
This paper aims at proposing a new integrated design method of structure-control combined system: such as several types of mechanical systems equipped with vibration controlsystem in order to suppress the structural ...
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This paper aims at proposing a new integrated design method of structure-control combined system: such as several types of mechanical systems equipped with vibration controlsystem in order to suppress the structural vibration. When the proposed method is applied to the design of a structure-control combined system, the closed loop pole placement of the reduced order model of the combined system is specified in advance as a design requirement. The proposed method is constructed from two steps: in the first step, output feedback controlsystem is designed for the initial closed loop system in order to realize the specified closed loop pole placement;and next step, structural and vibration controlsystemdesign parameters are simultaneously optimized to minimize the objective function subject to constraints on the pole placement. Scalar objective function is defined as a linear combination of several measures of the optimality of the structure design and the vibration controlsystemdesign. According to the proposed method, the closed loop pole placement of the reduced order model is preserved through the iterative optimum design process. The effect of the proposed method is shown by the numerical example. Not only structural design parameters but also vibration controlsystemdesign parameters are successfully optimized under the objective function minimization.
The major objectives of this paper are to analyze and model, control and optimize advanced diesels with optimal electronic fuel systems in order to improve fuel economy and reduce emission, guarantee the desired perfo...
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The major objectives of this paper are to analyze and model, control and optimize advanced diesels with optimal electronic fuel systems in order to improve fuel economy and reduce emission, guarantee the desired performance and increase service life, etc. Using a nonlinear mathematical model developed, a spectrum of problems in nonlinear analysis, control, and optimization are solved. In particular, using a complete mathematical model, the torque production features are studied. To inject the fuel into the cylinders, advanced fuel systems should be used to guarantee a spectrum of requirements to optimize the diesel performance. Thorough analytical results are performed, and novel control algorithms are designed and tested.
The concept of Plug & Play has become increasingly popular in consumer electronics because of the ease of use and low maintenance, it now appears possible to apply this concept to the motor drive design. New gener...
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The concept of Plug & Play has become increasingly popular in consumer electronics because of the ease of use and low maintenance, it now appears possible to apply this concept to the motor drive design. New generations of DSP controllers, such as the Texas Instruments TMS320C240 ('C240) DSP controller, by integrating the high performance of a DSP core and the powerful on-chip peripherals of a microcontroller into a single-chip solution, have made this possible. This paper describes the practical implementation of a linear induction motor drive, which consists of power module and a single DSP controller, which will both reduce the cost and the complexity of the design. In order to save space and enable continuous operation, a linear induction motor has been specifically built for this study. Experimental results will be presented by a videotape in the conference.
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