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Control Systems, IEEE

Issue 2 • Date Apr 1998

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Displaying Results 1 - 7 of 7
  • A software environment for gain scheduled controller design

    Publication Year: 1998 , Page(s): 48 - 60
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1644 KB)  

    Theoretical developments have improved the understanding of gain scheduled control and suggested new methods for design, analysis, and implementation of such nonlinear control systems. An integrated software environment for gain scheduled local controller network design and analysis, including computer-aided modeling and system identification, is described. Some background theory is included, and a speed control design problem for an experimental vehicle-a Mercedes-Benz truck called OTTO-illustrates the application of the approach View full abstract»

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  • Low velocity friction compensation

    Publication Year: 1998 , Page(s): 61 - 69
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1048 KB)  

    A model-free design methodology is reported for identification and stable adaptive control of a class of systems with state dependent parasitic effects such as friction. The methodology is constructive, incorporates modeling error bound information, and ensures stable and convergent performance. The identifier and control designs are applicable to a class of low-dimensional dynamic systems with the cited parasitic effects. Validation of the designs is provided using two hardware example cases View full abstract»

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  • Experimental results in robust lateral control of highway vehicles

    Publication Year: 1998 , Page(s): 70 - 76
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (708 KB)  

    Vehicle lateral dynamics are affected by vehicle mass, longitudinal velocity, vehicle inertia, and the cornering stiffness of the tires. All of these parameters are subject to variation, even over the course of a single trip. Therefore, a practical lateral control system must guarantee stability, and hopefully ride comfort, over a wide range of parameter changes. This article describes a robust controller that theoretically guarantees stability over a wide range of parameter changes. The performance of the robust controller is then evaluated in simulation as well as on a test vehicle. Test results for experiments conducted on an instrumented track are presented, comparing the robust controller to a PID controller that was tuned on the vehicle View full abstract»

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  • Distributed intelligent control for a mine refrigeration system

    Publication Year: 1998 , Page(s): 31 - 38
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1016 KB)  

    One way to construct intelligent controllers is to use an agent-centered approach in which the agents themselves determine the global structure of the controller and the inter-agent cooperation methods. To assess this approach, the design and testing of a distributed intelligent controller for a laboratory-scale mine refrigeration plant is discussed. Underlying theoretical concepts are briefly reviewed, and experimental results are presented. Important findings are that the approach supports the use of multiple knowledge representations, the use of partial results, and dynamic structuring of the distributed controller. The results presented indicate that development for practical, supervisory-level control applications is worthy of further investigation View full abstract»

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  • Control experiments and what I learned from them: a personal journey

    Publication Year: 1998 , Page(s): 81 - 88
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1764 KB)  

    This article is a personal account of my experiences in developing control experiments for the purpose of control research. The article does not address the important questions surrounding the development of control experiments for undergraduate education. Rather, the emphasis is on research, specifically, the role that control experiments can play in motivating new theoretical ideas. To stimulate discussion about these issues I organized a session for the 1997 American Control Conference entitled “Control Experiments: What Do We Learn From Them?” The reader is invited to peruse the various papers that were contributed to that session for further insights into this question View full abstract»

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  • H control for suppressing stick-slip in oil well drillstrings

    Publication Year: 1998 , Page(s): 19 - 30
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1360 KB)  

    We show, applying the linear H control design technique, that the suppression of stick-slip oscillations and transient behavior can be largely improved over a PD-like control system currently applied in oil well drilling. Using rough knowledge (e.g. size and induced oscillation frequency) of the friction disturbance, the appropriate choice of dynamic weighting functions can make the closed loop system robust toward the substantial uncertainty in the knowledge of the nonlinear friction. After an introduction to drilling engineering and a description of the drilling system, a condensed analysis of the stick-slip phenomenon in drillstrings and a brief history of control solutions for the drillstring problem are given, and H control solutions for allied systems are described. Then, the general principles of linear H control design are sketched. Subsequently, the H control design technique is applied to design a controller for the system under study. Next, the improved closed-loop behavior toward stick-slip oscillations is shown in simulations and experiments. Conclusions with respect to the results are drawn View full abstract»

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  • Experimental evaluation of nonlinear adaptive controllers

    Publication Year: 1998 , Page(s): 39 - 47
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (948 KB)  

    Attractive methods for learning the dynamics and improving the control of robot manipulators during movements have been proposed for more than 10 years, but they still await applications. This article investigates practical issues for the implementation of these methods, Two nonlinear adaptive controllers, selected for their simplicity and efficiency, are tested on 2-DOF and 3-DOF manipulators. The experimental results show that the adaptive feedforward controller (AFFC) is well suited for learning the parameters of the dynamic equation, even in the presence of friction and noise. The control performance along the learning trajectory and other test trajectories are also better than when measured parameters are used. However, when the task consists of driving a repeated trajectory, the adaptive lookup table MEMory is simpler to implement. It also provides a robust and stable control, and results in even better performance View full abstract»

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