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Control Systems Magazine, IEEE

Issue 1 • Date Jan. 1990

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Displaying Results 1 - 7 of 7
  • Real-time computer control of a flexible spacecraft emulator

    Publication Year: 1990 , Page(s): 3 - 8
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (569 KB)  

    A description is given of a ground-based test facility named Daisy, which was established to study control issues for large flexible spacecraft. The validation of modern algorithms for system identification and shape and attitude control and the development of new control devices can be performed using Daisy. The experimental structure consists of a radial mesh of ribs attached flexibly to a rigid hub. The structure is instrumented with position and rate sensors and controlled by a real-time computer and data acquisition system by means of torque actuators. The more important aspects of these subsystems and their integration are presented along with experimental results for a baseline controller, consisting of a simple integral-derivative feedback control on the position of the hub.<> View full abstract»

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  • Feedforward and feedback control of a flexible robotic arm

    Publication Year: 1990 , Page(s): 9 - 15
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (633 KB)  

    Feedforward and feedback control strategies are applied to a servo-driven flexible structure and studied by time-domain computer simulations. Simulation results are compared to the results of experimental runs on a flexible arm apparatus. The most accurate and stable responses of the arm are obtained by adding corrective terms to the command signals when position feedback is taken only from the servo. Full conditioning of the command signal, which involves compensating for the dynamics of both the servo and the arm, produced the best response. Simulations and experiments show that positional and accelerometric feedback, combined with a proportional-derivative element acting on the position error, is a viable solution in the less stable situation when feedback is being taken only from the manipulator.<> View full abstract»

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  • Digital control of repetitive errors in disk drive systems

    Publication Year: 1990 , Page(s): 16 - 20
    Cited by:  Papers (127)  |  Patents (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (525 KB)  

    Tracking errors in disk drive systems have a significant repetitive component that is not explicitly taken into account in conventional servo controllers. A modified prototype repetitive controller is applied as a plug-in module to a Winchester disk drive with a preexisting analog feedback controller to demonstrate its efficacy in the reduction of this periodic component. A review of the Winchester disk drive system is included.<> View full abstract»

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  • Robust design of cascade control

    Publication Year: 1990 , Page(s): 21 - 25
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (558 KB)  

    A design concept for cascade control that ensures enhanced robustness by minimizing the mutual influence among the cascaded loops is proposed. This is achieved by complete decoupling of the design and performance of two (or more) cascaded control loops. The decoupling applies not only to static aspects (windup and saturations) but also to possible degradation of dynamic performance. The practical impact of the design is illustrated by both analytic and numerical examples.<> View full abstract»

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  • Computer-aided design and analysis for a class of nonlinear systems

    Publication Year: 1990 , Page(s): 26 - 33
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (811 KB)  

    A description is given of a computer-aided control system design package, NLCON, that supports analysis and design functions for single-input/single-output nonlinear control systems with a single nonlinearity. The single nonlinearity can be one of seven nonlinearities commonly encountered in mechanical systems, and its location within the system is not restricted. The controller design benefits from designer experience, but it is facilitated by the software package, since program operation is highly interactive and the interface is user friendly. The analysis functions supported include sinusoidal-input describing functions and limit-cycle analysis, frequency-response determination, and jump-resonance analysis. Design functions include procedures for compensator modification to modify limit-cycle and jump-resonance behavior. A design advisory is provided for some simple design situations. Examples to illustrate various facets of program operation are presented.<> View full abstract»

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  • Automatic tuning of commercial PID controllers for single-loop and multiloop applications

    Publication Year: 1990 , Page(s): 34 - 42
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (977 KB)  

    Certain continuous-time self-tuning algorithms are shown to be capable of generating tuning parameters for commercial proportional-integral-derivative (PID) controllers. They are also shown to be capable of generating a feedforward signal that decouples the disturbance from the interaction from adjacent loops in a multivariable situation. The approach is verified using a standard Atari personal computer supervising Eurotherm 820 PID controllers. Two systems are used to test the method: a laboratory water tank system under level control and an industrial multizone plastics extruder under temperature control.<> View full abstract»

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  • Applications of the linear algebraic method for control system design

    Publication Year: 1990 , Page(s): 43 - 47
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (494 KB)  

    It is shown how to apply the linear algebraic method to the design of control systems with specific characteristics. The method is applied to pole-zero assignment with disturbance rejection and to tracking of a reference input. The problem of choosing overall transfer functions is discussed. In general, the examples show that the method is systematic and general and yields good results.<> View full abstract»

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Aims & Scope

This Magazine ceased publication in 1990. The current retitled publication is IEEE Control Systems.

Full Aims & Scope