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 ...
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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.
In this paper, two theorems are quoted which, when applied together, provide much information about the robustness of adaptive control schemes. From these two theorems, another theorem is developed which can explain w...
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In this paper, two theorems are quoted which, when applied together, provide much information about the robustness of adaptive control schemes. From these two theorems, another theorem is developed which can explain why adaptive controllers can perform robustly in certain practical situations, while possibly failing in other situations. In particular, if the bandwidth constraints on a controlsystems are lenient enough to allow the use of a sampling frequency which is smaller than the frequency at which unstructured uncertainty becomes significant, an adaptive controller can behave robustly. Many, if not all, of the applications of adaptive control which have been successful employ relatively slow sampling of the process. Thus, the results of this paper provide a theoretical explanation of how certain adaptive controllers are performing robustly in practice. In addition, the final theorem is of a form which provides insight into what a priori knowledge is required to achieve robust adaptive control and how this knowledge say be used.
作者:
MALKOFF, DBMOY, MCWILLIAMS, HLDr. Donald B. Malkoff majored in physics as an undergraduate at Harvard University. He received an M.D. degree from the University of Pittsburgh School of Medicine in 1960. This was followed by an internship and residency in neurology at University Hospital in Ann Arbor
Michigan. He spent several years at the National Institutes of Health engaged in gerontology research has practiced and taught clinical neurology and in 1983 received an M.S. degree in computer science at the University of California San Diego. Currently Dr. Malkoff is employed by the Navy Personnel Research and Development Center in San Diego California where he is senior investigator in a human factor/computer display-and-control project involving the DDG-51 gas turbine propulsion unit. He is a member of the American Academy of Neurology the Society for Neuroscience the American Association for Artificial Intelligence and the Association for Computing Machinery. Dr. Malkoff is certified by the American Board of Psychiatry and Neurology has taught computer science at UCSD and published in several research areas including magnetoencephalography and electron microscopy. His basic interests are in the areas of artificial intelligence and learning expert systems particularly as they apply to the problems of fault-detection and control. Dr. Melvyn C. Moy received his undergraduate training in mathematics and chemistry at the University of Texas
Austin. He studied experimental psychology at the University of Wisconsin Madison receiving his M.S. in 1970 and Ph.D. in 1972. He served as an assistant professor at the University of South Dakota where he taught experimental design and methodology for a year before joining the Navy Personnel Research and Development Center in 1973. His work and research since then spans across many application areas such as the development of manpower planning models for the Navy the design of operational decision aids the human engineering of interactive large-scale war gaming systems and the evaluation o
The ship fire main has undergone considerable development throughout the past 2,000 years, resulting in a system that is critical both for normal ship function and for ship survivability in emergencies. Because of its...
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The ship fire main has undergone considerable development throughout the past 2,000 years, resulting in a system that is critical both for normal ship function and for ship survivability in emergencies. Because of its complexity, the modern firemain system is highly vulnerable to malfunction and to damage during combat. Firemain fault detection and fault recovery are currently conducted manually by damage control teams. The advantages and disadvantages of this method are discussed, and alternative methods of fault detection and recovery are explored. An interactive computer program is introduced which uses central control over remotely situated valves to facilitate fault detection and recovery, significantly reducing recovery-time and manpower requirements. These reductions may result in savings of lives, ship systems, and ships themselves. The computer program is based upon an algorithm which is, in effect, a prescription that can be followed manually by the operator or be completely automated. The color graphic display which is used for monitoring can also be utilized for the training of damage control operators or for the evaluation of other algorithms for firemain control. Alternative firemain hardware and configurations could lead to even more efficient methods of fault detection and recovery as well as improved firemain water supply management in general.
作者:
GILBERT, EGHA, IJDepartment of AeroSpace Engineering
Robot Systems Division University of Michigan Ann Arbor MI USA Computer
Information and Control Engineering Program Robot Systems Division College of Engineering University of Michigan Ann Arbor MI USA
A control problem involving a mechanical system with generalized coordinates q ∈ R m is considered. The error in tracking a desired input y d ∈ R p is e = E (q,y d )∈ R m . If E satisfies simple conditions, ...
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A control problem involving a mechanical system with generalized coordinates q ∈ R m is considered. The error in tracking a desired input y d ∈ R p is e = E (q,y d )∈ R m . If E satisfies simple conditions, it leads to a nonlinear control law that assures e (t)→0 as t →∞. The law is robust in that small changes in it do not produce large steady-state errors or loss of stability. In this theory a unified framework is presented for treating a number of problems in the control of mechanical manipulators.
The pole placement self-tuning control method is applied to the control of the manipulators directly in the task coordinate system, which results in highly desirable task-oriented performance characteristics. In the t...
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A new iterative adaptive image restoration algorithm is developed. It is composed of a sub-optimal filter and a least squares based identifier. To account for nonstationarity, a moving window technique has been incorp...
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A new iterative adaptive image restoration algorithm is developed. It is composed of a sub-optimal filter and a least squares based identifier. To account for nonstationarity, a moving window technique has been incorporated. Based upon computational results on two noisy images and a comparison with three other adaptive image restoration algorithms, it was concluded that the proposed adaptive image estimation algorithm is highly competitive.
The pole placement self-tuning control method is applied to the control of the manipulators directly in the task coordinate system, which results in highly desirable task-oriented performance characteristics. In the t...
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The pole placement self-tuning control method is applied to the control of the manipulators directly in the task coordinate system, which results in highly desirable task-oriented performance characteristics. In the task coordinate, the position control axes and force control axes are orthogonal, therefore, hybrid control can be achieved without degradation in performance of the control system. With the learning mechanism at the task location, dynamic friction and compliant effects are automatically compensated. Simulation results for both position control and hybrid control using the JPL-Stanford Arm demonstrate the effectiveness of the proposed method.
An overview of system applications using large-scale modelling, optlmlsation and control methods is presented. The method used includes both hierarchical and dec entralised control. The applications are drawn from the...
An overview of system applications using large-scale modelling, optlmlsation and control methods is presented. The method used includes both hierarchical and dec entralised control. The applications are drawn from the fields of power systems, biological processes, water distribution networks, urban traffic control, telecommunication networks, river pollution control and a ship system.
A ship design methodology is presented for developing hull forms that attain improved performance in both seakeeping and resistance. Contrary to traditional practice, the methodology starts with developing a seakeepin...
A ship design methodology is presented for developing hull forms that attain improved performance in both seakeeping and resistance. Contrary to traditional practice, the methodology starts with developing a seakeeping-optimized hull form without making concessions to other performance considerations, such as resistance. The seakeeping-optimized hull is then modified to improve other performance characteristics without degrading the seakeeping. Presented is a point-design example produced by this methodology. Merits of the methodology and the point design are assessed on the basis of theoretical calculations and model experiments. This methodology is an integral part of the Hull Form Design System (HFDS) being developed for computer-supported naval ship design. The modularized character of HFDS and its application to hull form development are discussed.
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