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American Control Conference, 2001. Proceedings of the 2001

Date 25-27 June 2001

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  • Proceedings of the 2001 American Control Conference [front matter]

    Page(s): i - xx
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    Freely Available from IEEE
  • Communication and control of distributed hybrid systems

    Page(s): 4968 - 4983 vol.6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1742 KB) |  | HTML iconHTML  

    The rich and exciting research over the past decade concerning the description, analysis, controller design, simulation, and implementation of distributed systems is reviewed. From control engineering, this research has inherited the concepts and theories of optimality, stability, controlled differential equation models, and the motivation to improve the performance of increasingly complex physical processes. From computer science, the research has incorporated the theories of logical specification and verification, event-driven state machine models, concurrent processes and object-oriented approaches. The review is organized in the framework of dynamic networks of hybrid automata. The case study of an automated highway system is used to illustrate the challenges posed by a complex distributed system, and the research contributions that address different challenges. There is an equal emphasis on the conceptual and theoretical contributions and on tools and techniques that yield more immediately practical benefits. View full abstract»

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  • Index of authors, chairpersons, and organizers

    Page(s): 5070 - 5082
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    Presents an index of the authors whose papers are published in the conference. View full abstract»

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  • Discrete event systems approach to fixtureless peg-in-hole assembly

    Page(s): 4962 - 4967 vol.6
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    Assembly tasks are normally performed with one robot and fixtures. Fixtures reduce the flexibility of the system and increase the cost of assembly. This paper addresses assembly without fixtures using two-manipulator robot. An active method using force feedback is proposed for the peg-in-hole assembly in highly uncertain environment. Assembly states are described by extended contact relations. Qualitative models for event evolution are easily derived from the marking of the Petri net model. The states are recognized through identification of the events using two 6-DOF force and moment sensors. The proposed method is verified and evaluated through experiments with round peg-in-hole assembly View full abstract»

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  • Application of shared control strategy in the design of a robotic device

    Page(s): 4532 - 4536 vol.6
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    A new paradigm in the design and control of assistive robotic devices is the notion of Shared Control. Shared control devices can be categorized as a class of robotics where both the human and mechanism are in direct cooperation in accomplishing a given task. The information and power are distributed and interconnected between the agents. This way one may be able to accomplish tasks which takes advantage of the information and power capabilities of both agents. This paper presents an application of the above concept in the design of a surgical tool which is used in the minimally-invasive surgery. The paper presents a summary of the design integration and performance analysis of such concept View full abstract»

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  • Backlash compensation of systems using fuzzy logic

    Page(s): 4788 - 4789 vol.6
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    A backlash compensator is designed for systems using the fuzzy logic. The classification property of fuzzy logic systems makes them a natural candidate for the rejection of errors induced by the backlash, which has regions in which it behaves differently. A tuning algorithm is given for the fuzzy logic parameters, so that the backlash compensation scheme becomes adaptive, guaranteeing small tracking errors and bounded parameter estimates. Formal nonlinear stability proofs are given to show that the tracking error is small. The fuzzy logic backlash compensator is simulated on a system to show its efficacy View full abstract»

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  • Worst-case identification of Hammerstein models based on l gain

    Page(s): 5022 - 5027 vol.6
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    We propose a new model set identification method for nonlinear systems described by the generalized Hammerstein model. While the existing method evaluates the parametric error based on the assumption that the true plant and the nominal model have the same structure, the proposed method evaluates the non-parametric error due to the unmodeled dynamics by l gain compatible with robust l1 control, and gives a local model set near an equilibrium point for the given input level. Although it is generally quite difficult to evaluate the non-parametric error bound of the nonlinear systems based on finite experimental data, the upper bound of l gain can be obtained based on the impulse response estimates and their error bounds by taking account of a special property of l gain. Also, this method gives less conservative model sets with more experimental data by using the noise set which consists of hard-bounded noises, taking into account of a low correlation property of noise signals, simultaneously. Moreover, the effectiveness of this method is shown by a numerical example View full abstract»

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  • Optimal filtering for polynomial measurement nonlinearities with additive non-Gaussian noise

    Page(s): 5028 - 5033 vol.6
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    We consider the problem of estimating the n-dimensional state of a dynamic system based on m-dimensional discrete-time measurements. The measurements depend nonlinearly on the state and are corrupted by white non-Gaussian noise. The problem is solved by recursively calculating the complete posterior density of the state given the measurements. For that purpose, a new exponential type density is introduced, the so called pseudo Gaussian density, which is used to represent the complicated non-Gaussian posterior densities resulting from the recursion. For polynomial measurement nonlinearities and pseudo Gaussian noise densities, it is shown that the result of the optimal Bayesian measurement update is exactly obtained by a Kalman filter operating in a higher dimensional space. The resulting filtering algorithms are easy to implement and always guarantee valid posterior densities View full abstract»

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  • Neuro-fuzzy networks-dynamic modeling and performance enhancement incorporating process knowledge

    Page(s): 4796 - 4801 vol.6
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    A study of the mapping capabilities of neuro-fuzzy networks in relation to conventional neural nets is carried out. Two representative systems, a time series model and an actual chemical process, are studied to analyze the ability of the empirical structure to capture complex nonlinear dynamics. The superiority of the neuro-fuzzy network in terms of its mapping ability is demonstrated. Performance enhancement of the empirical model is sought through incorporation of process knowledge into the identification procedure. The importance of appropriate choice of identification experiments and their role in model enhancement is highlighted through simulation studies. A nonlinear model predictive control scheme employing the neuro-fuzzy models is designed. The utility of this scheme in terms of its wide range of applicability is discussed View full abstract»

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  • A gain shaped sliding mode control scheme using filtering techniques with applications to multi-link robotic manipulators

    Page(s): 4363 - 4368 vol.6
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    A gain shaped sliding mode control scheme is proposed for tracking control tasks of multi-link robotic manipulators. In the new scheme, filtering techniques play the key role in acquiring equivalent control signals and shaping the switching control gain automatically. Once the system entering the sliding motion, two classes of low-pass filters are introduced to work concurrently for the purpose of acquiring equivalent control, reducing the switching gain effectively and in the sequel eliminating chattering. By virtue of equivalent control theory, one class of filters is designed to capture the "average" profile of the switching quantity which is in proportion to the desired control input. Meanwhile, another class of low-pass filters is added to scale down the gain of the switching control. The convergence property of the proposed control scheme is rigorously analyzed in time domain, and the frequency domain knowledge can be easily incorporated into the construction of the two classes of filters. Excellent tracking performance is achieved with the direct manipulation of switching control input using the filtering technology and with the integration of both time domain and frequency domain system knowledge in the controller design View full abstract»

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  • Passive control of bilateral teleoperated manipulators: robust control and experiments

    Page(s): 4612 - 4618 vol.6
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    In a previous paper, a control law was developed for a passive bilateral teleoperator to achieve theoretically perfect coordination in the presence of arbitrary environment forcing, and to enable the teleoperator to behave like a passive rigid mechanical tool. In this paper, the authors develop an adaptive control law to relax the need for the precise knowledge of inertia parameters, and a robust control law to eliminate the need for expensive force sensors. In addition, a novel experiment, that mimics the dynamics of piano playing is used to evaluate the efficacies of the various controllers to provide kinesthetic coupling View full abstract»

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  • Stability regions for systems with mode transitions

    Page(s): 4834 - 4839 vol.6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (464 KB) |  | HTML iconHTML  

    This paper concerns the problem of guaranteeing the stability of dynamic systems that can undergo mode transitions caused by external events. The mode transitions can include a finite-duration transient phase. Assuming the system is designed to be stable in each mode, with associated regions of stability, the problem is to compute the region of states in the pre-transition mode for which it can be guaranteed the system will be in the region of stability in the post-transition mode. We call this region in the pre-transition mode the virtual stability region. Methods for computing the virtual stability region are discussed and illustrated for a small power system example View full abstract»

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  • A robust nonlinear controller design for a pneumatic actuator

    Page(s): 4490 - 4495 vol.6
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    This paper presents a feedback linearization based variable structure controller for a pneumatically actuated system utilizing sliding mode observers. Using the robustness implications of the sliding mode control theory and the structural properties of pneumatically actuated systems, a nonlinear controller is designed to drive the output tracking error to zero in finite time. Strong robustness with respect to bounded modeling and parameter uncertainties is attained through compensation of the friction effect of the piston in the cylinder body. The controller and the observer are based on a third-order nonlinear state-space model of a pneumatic system which was developed, validated numerically with experimental data and presented by Acarman et al. (SAE, 2000-01). Simulation results are included to demonstrate the effectiveness of the designed observer and the good performance of the designed tracking controller View full abstract»

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  • Active sensing and control of vibration of circular saws-a comparison of optimal and variable structure control

    Page(s): 4294 - 4299 vol.6
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    This paper discusses the modeling, sensing, estimation of vibration modes, and the development of two types of active vibration control strategies-optimal state feedback control based on on-line estimation of vibration characteristics, and a modified variable structure controller. The discussion is based on results of a research project for active vibration control of circular saws for wood cutting, using magnetic actuators. The purpose of the research is to develop an active control system to increase wood recovery by reducing saw blade vibration View full abstract»

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  • Financial benefits of advanced control. Benchmarking and optimization of a crude oil production platform

    Page(s): 4330 - 4331 vol.6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (232 KB) |  | HTML iconHTML  

    Advanced control and optimization techniques provide an effective technique for increasing productivity and reducing operational cost. Petrochemical processes provide good examples in demonstrating the applicability of advanced systems control for revenue optimization. This paper presents the results of an integrated process control and revenue optimization audit technique applied to an oil production platform to assess the potential benefits of advanced control systems View full abstract»

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  • Dynamic performance of mini-scale servomechanisms with mini servomotors controlled by IC drivers in automotive applications

    Page(s): 5010 - 5015 vol.6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (368 KB) |  | HTML iconHTML  

    To significantly simplify the hardware solution, mini-scale electric machines are controlled using power amplifiers and controllers which are designed and fabricated as the monolithic integrated circuit (IC) drivers. This paper designs closed-loop mini-scale servomechanisms, compares different control algorithms, performs assessment analysis, and validates the results. The problems to be solved are very challenging because a number of long-standing issues in modeling, control, analysis, stability, robustness, and hardware-software co-design must be solved. The major emphasizes are placed in the analysis and design of robust mini-scale servomechanisms as well as the performance analysis and optimization. We synthesize and verify PID linear quadratic, relay, and sliding mode tracking controllers. It is illustrated that the sliding mode controllers with soft switching guarantee superior performance View full abstract»

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  • Asymptotic tracking for linear systems with actuator saturation by output feedback control

    Page(s): 4920 - 4925 vol.6
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    This paper is concerned with asymptotic tracking for linear systems with actuator saturation by output feedback control. Both reference inputs and disturbances are represented as zero-input responses of linear systems. The controller includes the internal model with an anti-windup term for the reference and disturbance signals and a state observer for the system to allow output feedback control. The overall system is shown to be asymptotically stable for any initial condition of the system as long as the magnitudes of the reference and disturbance signals are sized such that the asymptotic tracking of the reference signal can be achieved without saturating the actuator. A simulation example is presented to verify the effectiveness of the proposed approach View full abstract»

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  • Multi-model adaptive control for discrete time systems

    Page(s): 4820 - 4825 vol.6
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    A multi-model adaptive control approach is proposed to improve the performance of adaptive control of discrete time invariant plant or time variant plant with jumping parameters and bounded disturbances. Multiple models of the plant are set up to cover the uncertainties of the plant dynamics. The localization method is used to reduce the computation burden of the multiple model algorithm. It is proved that the closed loop system is stable when multi-model pole assignment controller is used to a linear time-invariant plant with unknown parameters. The simulation results are given to show the usefulness of the proposed method View full abstract»

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  • On the stability and instability of a class of nonlinear nonautonomous ordinary differential equations

    Page(s): 4858 - 4861 vol.6
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    This paper presents sufficient conditions for Lyapunov's stability and instability of a class of nonlinear nonautonomous, second-order ordinary differential equations. Such a class includes, as particular cases, a remarkably large number of differential equations with specific physical applications. Two successive nonlinear transformations are applied to the original differential equation in order to convert it into a more convenient form for stability analysis purposes. The obtained stability/instability conditions depend closely on the parametrization of the original differential equation View full abstract»

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  • The effect of uncertain time variant delays in ATM networks with explicit rate feedback

    Page(s): 4537 - 4543 vol.6
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    A new, more realistic model for the ABR traffic class in ATM network congestion control is introduced and analyzed. The new discrete time model takes into account the effect of time-variant buffer occupancy levels of ATM switches, thus treating the case of time-variant delays between a single congested node and the connected sources. For highly dynamic situations, such a model is crucial for a valid analysis of the resulting feedback system. The new model also handles the effects of the mismatch between the RM cell rates and the variable bit rate controller sampling rate as well as buffer and rate nonlinearities. A stability study is presented, that shows an equilibrium in the buffer occupancy level is not possible if time-variant delays are present in the forward path. Stability conditions for the case of time-variant delays in the return path axe derived. Finally, illustrating examples are provided View full abstract»

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  • Extracting fault subspaces for fault identification of a polyester film process

    Page(s): 4466 - 4471 vol.6
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    Although fault detection has been well studied in process monitoring under stationary conditions, the identification of faults in chemical processes is a difficult task. We present a new approach in the use of a fault identification index to identify faults based on fault directions extracted from abnormal data using singular value decomposition. The proposed method is demonstrated on an industrial polyester film process which is characterized by frequent set-point changes and multiple grade changes. Further, a comparison between the fault identification index and the contribution plot method is given View full abstract»

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  • Engine modeling and exhaust gas estimation for DI-diesel engines

    Page(s): 4585 - 4590 vol.6
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    Engine models are a basis for better controlling combustion process and the exhaust emissions resulting from it. Currently the zero- and quasi-dimensional models are mostly used. These types of model are also addressed in this article. Zero-dimensional models are computationally efficient but they are not able to describe fuel efficiency or the generation of pollutants. It is therefore necessary to enhance combustion process models with phenomenological fuel spray and vaporization models, with a local resolution of at least two zones. The chemical model for calculating emissions is based on the two-zone model. The amount of mass, which is transferred from the unburned to the burned zone, is the input for a chemical model based on the equilibrium for the OCH-system (oxygen/carbon/hydrogen). The nitrogen-oxide emissions are calculated by using the advanced Zeldovich-mechanism which uses the reaction-kinetic approach rather than the less accurate chemical equilibrium assumption. The NOx-emissions (nitrogen-oxides) can be influenced by changing the exhaust-gas recirculation (EGR) rate View full abstract»

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  • Robustness of disturbance observers in the presence of structured real parametric uncertainty

    Page(s): 4222 - 4227 vol.6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (352 KB) |  | HTML iconHTML  

    The disturbance observer is a widely used form of a two degree of freedom control architecture which reduces sensitivity to modeling error while enhancing disturbance rejection properties. While standard robust stability analysis of the disturbance observer in the presence of unstructured modeling error is well known and results in a simple design guideline, similar results are lacking for the case of structured, real parametric uncertainty in the plant. Considering the case in which the plant has real parametric uncertainty, the real structured singular value method is applied to stability and performance robustness analysis, resulting in less conservative results. The model of an electrohydraulic positioning system with large parametric variation especially in its damping ratio is used to illustrate the concept. The results are extended to the case in which the plant under disturbance observer regulation is also under feedback control, as is usually the case in applications View full abstract»

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  • Controller synthesis using bond graphs

    Page(s): 4765 - 4770 vol.6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (448 KB) |  | HTML iconHTML  

    The physical characteristics of the bond-graph representation are exploited for controller synthesis purpose. When the system under control possesses a specific cascaded structure, the theoretical results developed allow one to physically visualize the closed-loop system from the open-loop bond-graph model. With this visualization, it is possible to employ physical intuition to determine the desired closed-loop behavior that meets the performance requirement. Then the associated control law can be derived using a recursive backstepping procedure in a straightforward manner. Different from conventional controller synthesis procedure, in which systems are dealt with in mathematical domain, the approach proposed follows closely the physical aspect of system properties and control performance View full abstract»

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  • Output feedback robust stabilization of jump linear system with mode-dependent time-delays

    Page(s): 4683 - 4688 vol.6
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    This paper studies the class of uncertain dynamical time-delay linear systems with Markovian jumps. The time-delay is assumed to be dependent on the system mode. LMI-based sufficient conditions for the robust stability and output feedback stabilization axe developed. To illustrate the validness of the theoretic results, many numerical examples axe worked out View full abstract»

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