A semiactive mechanism, called a VDSA (variable damping semiactive device), is proposed to reduce the seismic response of structures. It is composed of two fixed-orifice viscous fluid dampers installed in the form of ...
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A semiactive mechanism, called a VDSA (variable damping semiactive device), is proposed to reduce the seismic response of structures. It is composed of two fixed-orifice viscous fluid dampers installed in the form of a V whose top ends are attached to a floor and their lower ends to a collar that moves along a vertical rod. By varying the VDSA position one obtains an optimal instantaneous damping added to the structure. The position of the moving end is calculated with an algorithm based on a variation of the instantaneous optimal control theory which includes a generalized LQR (linear quadratic regulator) scheme. This modified algorithm, referred to as Qv, is based on the minimization of a performance index J quadratic in the state vector, the control force vector, and an absolute velocity vector. Two variants of the algorithm are used to present numerical simulations of the controlled seismic response of a single and a MDOF (multi-degree-of-freedom) structure.
We present a new algorithm of the two-level control for a singularly perturbed system. If the mathematical model of the controllable dynamic system has a singular perturbation, it can be reduce with the help of hierar...
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We present a new algorithm of the two-level control for a singularly perturbed system. If the mathematical model of the controllable dynamic system has a singular perturbation, it can be reduce with the help of hierarchical controls that can be obtained with Tikhonov's theorem. This is the stabilization of the adjoining system around an equilibrium point and to stabilize the desired movement through the use of a simplified system. In this paper, we present the application of the stabilization and the control algorithm of an aeronautics problem.
Pléiades High Resolution Programme aims at realising a new class of optical observation system, characterised by imaging performances in the range of one meter resolution, large image fields and increased agility...
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Pléiades High Resolution Programme aims at realising a new class of optical observation system, characterised by imaging performances in the range of one meter resolution, large image fields and increased agility. The main feature of the Attitude control System (ACS) is to rely on a new type of actuator: a cluster of 4 control Moment Gyros (CMGs). The use of CMGs allows to reach high agility performances to meet the requirements induced by demanding imaging missions. This paper presents the design, development status and performances of the Pléiades-HR ACS based on a CMGs-cluster.
The Galileo In Orbit Verification (IOV) program, consisting of 4 spacecrafts, is the first step towards an European satellite-based navigation system. The main objective of the IOV phase is to verify the proper functi...
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The Galileo In Orbit Verification (IOV) program, consisting of 4 spacecrafts, is the first step towards an European satellite-based navigation system. The main objective of the IOV phase is to verify the proper functioning of the overall system before starting the next step - Galileo Full Operational Capability (FOC) - where the full deployment of 30 Galileo satellites will be performed. This paper gives an overview of the Galileo IOV Attitude and Orbit control (AOC) function with the focus being put on the spacecraft attitude control. The AOC is a part of the Avionics subsystem, manufacturing of which has been subcontracted to Astrium. The article also describes the overall requirements on the control system, the AOC hardware and operational architecture as well as selected details on the AOC algorithms with corresponding test results.
Two suboptimum control methods are compared. One is the currently popular state-dependent Riccati equation (SDRE) method and the other is based on the quasi-optimum control method developed by the author in the 1960&#...
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Two suboptimum control methods are compared. One is the currently popular state-dependent Riccati equation (SDRE) method and the other is based on the quasi-optimum control method developed by the author in the 1960's. Both methods are applied to a nonlinear dynamic system with a quadratic performance criterion. Both methods include the special case of a “mildly” nonlinear process, giving rise to 4 methods to be compared. After presenting a brief summary of the theory, two applications are developed in which each of the variations of the two methods are applied and the results compared. It is concluded that has advantages and disadvantages, but most problems are amenable to treatment by at least one of them.
The paper intends to present goals and preliminary results of the ARFLEX Project (Adaptive Robots for Flexible Manufacturing Systems), a three-year project funded by the European Commission aiming at applying the most...
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The paper intends to present goals and preliminary results of the ARFLEX Project (Adaptive Robots for Flexible Manufacturing Systems), a three-year project funded by the European Commission aiming at applying the most advanced control technologies to radically innovate a class of products – industrial robots – where these technologies did not yet find full application. The system concept, the optical system and of the new superior level of tool pose control are presented. Calibration issues are discussed in details as well as the development of an embedded solution to be standardized and flexible enough for exploitation and adoption in different robotic applications.
This paper describes approach based on active scripts models that controls and restrict personnel activities on controlling technological processes. Script provides sharing personnel control roles by their decision ma...
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This paper describes approach based on active scripts models that controls and restrict personnel activities on controlling technological processes. Script provides sharing personnel control roles by their decision making level, it makes selection of control cases, coordinates different executors and controls task achievement. The development of the scheme controls with application of active technological scripts is presented. A description of HEPS (Human Error Protection System) application package is given, that is developed on the basis of suggested approach and traditional SCAD A.
A three leveled event production model and scheme of control elaborated on that model is proposed in this paper. Scheme of control is presented as a flow of events and commands in structure of technologically controll...
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A three leveled event production model and scheme of control elaborated on that model is proposed in this paper. Scheme of control is presented as a flow of events and commands in structure of technologically controlled object, automation system, SCAD A, event model, human - operator. Abilities of system's protection from human errors are shown that are provided by personnel action restrictions which introduced as dialog schemes. Dialog of operator with agent is proposed. Solver of the agent is based on ontology of object domain; it allows to execute coordination of processes using logical analysis of the experience accumulated in ontology.
Researchers have proposed the use of adaptation to reduce the energy consumption of different hardware components, such as the processor, memory, disk, and display for general-purpose applications. Previous algorithms...
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Researchers have proposed the use of adaptation to reduce the energy consumption of different hardware components, such as the processor, memory, disk, and display for general-purpose applications. Previous algorithms to control these adaptations, however, have focused on a single component. This work takes the first step toward developing algorithms that can jointly control adaptations in multiple interacting components for general-purpose applications, with the goal of minimizing the total energy consumed within a specified performance loss. Specifically, we develop a joint-adaptation, algorithm for processor and memory adaptations. We identify two properties that enable per-component algorithms to be easily used in a cross-component context-the algorithms' performance impact must be guaranteed and composable. We then modify a current processor and a memory algorithm to obey these properties. This allows the cross-component problem to be reduced to determine an appropriate (energy-optimal.) allocation of the target performance loss (slack) between the two components. We develop such an optimal slack allocation algorithm that exploits the above properties. The result is an efficient cross-component adaptation framework that minimizes the total energy of the processor and memory without exceeding the target performance loss, while substantially leveraging current per-component algorithms. Our experiments show that joint processor and memory adaptation provides significantly more energy savings than adapting either component, alone;intelligent slack distribution is specifically effective for highly compute-or memory-intensive applications;and the performance slowdown never exceeds the specification.
In this paper, a new method is proposed to design optimized control fields with desired temporal and/or spectral properties. The method is based on penalizing the difference between an optimized field obtained from an...
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In this paper, a new method is proposed to design optimized control fields with desired temporal and/or spectral properties. The method is based on penalizing the difference between an optimized field obtained from an iterative scheme and a reference field with desired temporal and/or spectral properties. Compared with the standard optimal control theory, the current method allows a simple, experimentally accessible field be found on the fly;while compared with parameter space searching optimization, the iterative nature of this method allows automatic exploration of the intrinsic mechanism of the population transfer. The method is illustrated by examing the optimal control of vibrational excitation of the Cl-O bond with both temporally and spectrally restricted pulses. (c) 2006 American Institute of Physics.
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