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Date 19-21 June 1985

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Displaying Results 1 - 25 of 331
  • Proceedings of the 1985 American Control Conference

    Page(s): 1
    Save to Project icon | PDF file iconPDF (26 KB)  
    Freely Available from IEEE
  • Copyright page

    Page(s): 2
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    Freely Available from IEEE
  • Forward [sic]

    Page(s): 3
    Save to Project icon | Request Permissions | PDF file iconPDF (55 KB)  
    Freely Available from IEEE
  • Dedication [to Howard Elliot]

    Save to Project icon | PDF file iconPDF (98 KB)  
    Freely Available from IEEE
  • AACC Awards

    Page(s): 6
    Save to Project icon | Request Permissions | PDF file iconPDF (127 KB)  
    Freely Available from IEEE
  • Operating Committee

    Page(s): 7
    Save to Project icon | PDF file iconPDF (46 KB)  
    Freely Available from IEEE
  • Program Committee

    Page(s): 7
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    Freely Available from IEEE
  • CC 1985 Program at a Glance

    Page(s): 8
    Save to Project icon | PDF file iconPDF (63 KB)  
    Freely Available from IEEE
  • Table of contents and Program

    Page(s): 9 - 32
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    Freely Available from IEEE
  • Optimal Missile Midcourse and Terminal Guidance and Control Law Design

    Page(s): 1 - 6
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (344 KB)  

    This paper summarizes a combined midcourse and terminal guidance and control law design of missiles to achieve range enhancement and stability with excellent intercept performance. We derive analytic solutions of a closed loop, nonlinear optimal guidance law for three dimensional flight for both the midcourse and terminal phases. Since this combined guidance law contains the proportional navigation feature, it can quickly modify the missile trajectory in the case when the target position changes drastically during midcourse guidance. This results in zero heading error at handover from midcourse to terminal guidance. To design the autopilot for this missile, a unique modern autopilot synthesis technique is employed. The resulting guidance and control algorithm is sufficiently simple for onboard implementation and has been applied successfully for on-line operation. This has led to large overall performance improvement in missiles. Although a surface-to-air missile model is used in the guidance and control law design, analysis, and simulation, the guidance law can also be applied to surface-to-surface. air-to-air, and air-to-surface type missiles. View full abstract»

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  • Time-Varying Smoothing for Proportional Navigation

    Page(s): 7 - 17
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (730 KB)  

    Variable smoothing in proportional navigation is implemented by modern homing guidance with time-varying state estimation followed by time-varying control. This system is examined by the techniques associated with classical homing guidance, normalized adjoints and idealized trajectory responses. View full abstract»

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  • Identification of Parameters and Model Structure for Missile Aerodynamics

    Page(s): 18 - 26
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (850 KB)  

    In this paper, current work on the Aerodynamic Coefficient Estimation (ACES) program for guided missiles is reviewed. A fundamental statistical approach to the problem is taken, and recent developments in the identification of model structure are used including: initial comparison of parametric model structures by subset regression using a leaps and bounds algorithm, refined comparison of different parametric model structures using the Akaike information criterion (AIC), and estimation of parameters within a model structure using batch and recursive maximum likelihood parameter estimation algorithms. Detailed numerical results of the parameter estimation procedures are presented using simulated measurement data. Batch maximum likelihood (BML) and recursive maximum likelihood (RML) parameter estimation algorithms are compared to the original ACES program using the Extended Kalman Filter (EKFP) algorithm with the unknown parameters augmenting the states. It is found that the BML is about 100 times more accurate than the EKF, and that the RML is almost as accurate as the BML with considerably less computation. View full abstract»

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  • PDF Not Yet Available In IEEE Xplore

    Page(s): 27
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (65 KB)  

    The document that should appear here is not currently available. IEEE Xplore® is working to obtain a replacement PDF. That PDF will be posted as soon as it is available. View full abstract»

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  • New Controller Designs for Robot Manipulator Systems

    Page(s): 38 - 43
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (405 KB)  

    Several different controllers for robot manipulator systems based on the general adaptive control theory using Lyapunov direct method are designed. Simplicities and/or complexities of these designs are described by simulation to indicate the relative importance and advantage of each design with respect to the others. A way of improving the transient response and convergence speed of a multivariable system in conjunction with this controller is established. View full abstract»

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  • Decentralized Model Reference Adaptive Control of Robotic Manipulators

    Page(s): 44 - 49
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (447 KB)  

    This paper presents a class of decentralized adaptive control schemes based on a model reference approach for a multi-jointed robotic manipulator. An integrated model for the combined dynamics of the manipulator and the joint actuators is developed which provides an ideal framework for the design of decentralized controllers. The adaptive control schemes obtained consist of an on-line recursive estimation of model parameters which are then used to compute the feedback controller gains. To account for the dynamic coupling that exists between the joint motions appropriate feedforward compensation signals are used. Simulation results performed on a VAX 11/780 computer have demonstrated the tracking performance of the adaptive controllers and have illustrated the important connections that exist between the representation of joint motion coupling effects and the controller performance under different tasks and demanded motions. Major strong points of the present schemes are: (i) possibility of implementation by distributed processing techniques and to meet independent joint control objectives, (ii) insensitivity to drift in motor parameters and (iii) possibility of making appropriate selection of control schemes based on specific representations of joint coupling effects and demanded motion characteristics to realize improved performance. View full abstract»

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  • Dynamics of a Closed Chain Manipulator

    Page(s): 50 - 54
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (286 KB)  

    In many manipulator configurations, where the end effector of the manipulator is in contact with a fixed object, a complete mathematical model for the manipulator dynamics should include the effects of the resulting contact force between the end effector and the fixed object. Equations for such a closed chain manipulator are developed, where the end effector constraint is defined by a smooth manifold. These equations are shown to be complete in the sense that the direct dynamics problem and the inverse dynamics problem are well-posed. This formulation suggests a new approach to planning and tracking control for manipulators in a constrained environment. View full abstract»

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  • A Control-Configured End Effector for a Visual Servoing Algorithm

    Page(s): 55 - 60
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (494 KB)  

    An algorithm is presented for using a robot system with a single camera to position in three-dimensional space a slender object for insertion into a hole; for example, an electrical pin-type termination into a connector hole. The algorithm relies on a control-configured end effector to achieve the required horizontal translations and rotational motion, and it does not require camera calibration. A force sensor in each fingertip is integrated with the vision system to allow the robot to teach itself new reference points when different connectors and pins are used. Variability in the grasped orientation and position of the pin can be accommodated with the sensor system. Performance tests show that the system is feasible. More work is needed to determine more precisely the effects of lighting levels and lighting direction. View full abstract»

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  • Sub-Optimal Control Strategies for Manipulators with Actuator Constraints: The Near Minimum Time Problem

    Page(s): 61 - 62
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (128 KB)  

    In this paper, we investigate the feasibility of employing a sub-optimal control strategy which results in "near minimum time" motion for a robotic manipulator along any pre-determined path in 3-D space. A computationally simple algorithm based on Optimal Aiming Strategies is presented. The applicability of the proposed algorithm is demonstrated through a two-link manipulator example. View full abstract»

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  • Control, Performance and Applications of Antagonist Actuated Manipulator Joints

    Page(s): 63 - 64
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (119 KB)  

    Antagonist actuated joints are defined as being driven by a pair of opposing actuators, as in the arrangement of muscles in human joints. A simple method of controlling the motion and varying the compliance of the joint is presented, along with examples of the performance of a prototype joint. The use of antagonist actuators to reduce the size, inertia and backlash of manipulator arm joints is discussed. An antagonist actuated joint is one that is driven by a pair of opposing uni-directional actuators rather than by a single bi-directional actuator. This arrangement is necessary in human limbs since muscles can apply force in contraction only. View full abstract»

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  • Compliance Analysis and Tool Holder Design for Grinding with Robots

    Page(s): 65 - 68
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (230 KB)  

    Grinding robots must hold and guide a grinding tool in the face of large vibratory loads. This paper presents an optimal compliance design for grinding tool suspension systems, with the objective of reducing vibrations and maximizing material removal rate. First, the endpoint compliance matrix of the main robot is utilized to determines the optimal workpiece position and orientation. Then a method for determining the optimal end-effector compliance matrix for a given workpiece position and orientation is presented. View full abstract»

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  • On the Control of Robots with Elastic Joints

    Page(s): 69 - 70
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (179 KB)  

    The problem of controlling robots with flexible joints is considered. After recalling the exact nonlinear model it is shown that the model is singularly perturbed if joints are nearly stiff. Singular perturbation techniques are used to add a stabilizing control signal to well established control laws obtained under the assumption of stiff joints. View full abstract»

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  • A Proof of Global Stability of a Direct Adaptive Pole Placement Scheme for Multivariable Systems

    Page(s): 71 - 76
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (327 KB)  

    A proof of global stability of a specific direct adaptive pole placement scheme for linear multivariable systems is presented here. It is based upon the idea of block processing of input-output data. The global stability result is established under the assumption that the external reference signal consists of a sum of at least a specificied minimum number of distinct sinusoids. View full abstract»

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  • A Smooth Algorithm for Adaptive Stabilization of a Discrete Linear System with an Unknown High Frequency Gain

    Page(s): 77 - 80
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (228 KB)  

    This paper presents a simple algorithm for adaptively stabilizing a linear one-dimensional discrete time process. Prior knowledge of the sign of the process high frequency gain is not required, and the adaptive control law is a continuous function of its arguments. Performance of the algorithm is considered and a simple modification is suggested to improve algorithm convergence rate while preserving system stability. View full abstract»

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  • An Investigation of Adaptive Control Techniques for Space Stations

    Page(s): 81 - 94
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (800 KB)  

    Of all large space structural systems, space stations present a unique challenge and requirement to advanced control technology. Their operations require control system stability over an extremely broad range of parameter changes and high level of disturbances. During shuttle docking the system mass may suddenly increase by more than 100% and during station assembly the mass may vary even more drastically. This coupled with dynamic model uncertainties require highly sophisticated controller and control architectures. An adaptive control algorithm along with the proposed inner-loop plant augmentation for controlling the space station under severe conditions of shuttle docking, mass and inertia change and modal truncation are investigated in this paper. Simulation results with a simplified Initial Operation Center model show that the controller is robust and the plant dynamics closely follows that of the reference model. Reasonable results have been observed even with the constraints of excessive control hardware saturation. View full abstract»

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  • Uncertainty in Sampled Systems

    Page(s): 95 - 97
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (149 KB)  

    The recently obtained evidence of the need for a positive real element in an adaptive system leaves us with a disturbing gap in adaptive control theory. It is a fact that in some applications adaptive controllers are performing well in practice. How can these systems behave well in practical situations which must contain modeling error? This paper introduces a preliminary result which indicates that it may be possible to maintain the needed positive real system in the presence of modeling error. The result shows that if a continuous-time system with large high frequency uncertainty is treated appropriately with antialiasing filters and sampled slowly enough, the resulting discrete-time system may contain very little uncertainty. With small enough uncertainty in the plant, a positive real system in the adaptive loop is possible. View full abstract»

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