Several distributed power control algorithms that can achieve carrier-to-interference ratio (CIR) balancing with probability one have been proposed recently for cellular mobile systems [5]-[8], In these algorithms, on...
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Several distributed power control algorithms that can achieve carrier-to-interference ratio (CIR) balancing with probability one have been proposed recently for cellular mobile systems [5]-[8], In these algorithms, only local information is used to adjust transmitting power, However, a normalization procedure is required in each iteration to determine transmitting power and, thus, these algorithms are not fully distributed, In this paper, we present a distributed power control algorithm which does not need the normalization procedure, We show that the proposed algorithm can achieve CIR balancing with probability one, Moreover, numerical results reveal our proposed scheme performs better than the algorithm presented in [7], which has the best performance among the distributed power control algorithms studied in [5]-[8], The excellent performance and the fully distributed property make our proposed algorithm a good choice for cellular mobile systems.
This paper is a study on the hybrid position/force control of a two-fingered miniature gripper driven by piezoelectric bimoph cells. The system is composed of the flexible cantilevers and a compact force sensor attach...
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This paper is a study on the hybrid position/force control of a two-fingered miniature gripper driven by piezoelectric bimoph cells. The system is composed of the flexible cantilevers and a compact force sensor attached to the tip of one finger. Control action is applied by two piezoelectric bimorph strips placed at the base of each finger. The theoretical model of the electro-mechanical system is developed and applied to the study of a control problem where the gripper is commanded to grasp its object with a time-constant force 0.01 N at a prescribed commanded fingertip position. The PID control algorithm is introduced to drive the gripper. The system control behaviour is examined both theoretically and experimentally.
In the last decade, chaos theory has become a popular method for approaching the analysis of nonlinear data for which most mathematical models produce intractable solutions. The concept of chaos was first introduced w...
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In the last decade, chaos theory has become a popular method for approaching the analysis of nonlinear data for which most mathematical models produce intractable solutions. The concept of chaos was first introduced with applications in meteorology. Since then, considerable work has been done in the theoretical aspects of chaos. Applications have abounded, especially in medicine and biology. A particularly active area for the application of chaos theory has been cardiology. Many aspects of heart disease have been addressed, including whether chaos represents the healthy or diseased state. Most approaches to chaotic modeling rely on discrete models of continuous problems, which are represented by computer algorithms. Due to the nature of chaotic models, both the discretization and the computer simulation can lead to propagation of errors that may overtake the actual solution. This article describes an approach to chaotic modeling in which a continuous model is developed based on a conjectured solution to the logistic equation. As a result of this approach, two practical methods for quantifying variability in data sets have been derived. The first is a graphical representation obtained by using second-order difference plots of time series data. The second is a central tendency measure (CTM) that quantifies this degree of variability. The CTM can then be used as a parameter in decision models, such as neural networks. It appears that measuring the degree of variability is a more useful measure of chaos, as demonstrated by the application of this work to the analysis of congestive heart failure patients as compared to normal controls.
Vibration isolation of mechanical systems is achieved through either passive or active vibration control systems. Although a passive vibration isolation system offers simple and reliable means to protect mechanical sy...
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Vibration isolation of mechanical systems is achieved through either passive or active vibration control systems. Although a passive vibration isolation system offers simple and reliable means to protect mechanical systems from a vibration environment, it has inherent performance limitations, that is, its controllable frequency range is limited and the shape of its transmissibility does not change. Recently, in some applications, such as active suspensions or precise vibration systems, active vibration isolation systems have been employed to overcome the limitations of the passive systems. In this paper, a hybrid-type active vibration isolation system that uses electromagnetic and pneumatic force is developed, and a new control algorithm adopting neural networks is proposed. The characteristics of the hybrid system proposed in the paper were investigated via computer simulation and experiments. It was shown that the transmissibility of the vibration isolation system could be kept below 0.63 over the entire frequency range, including the resonance frequency. (C) 1996 Academic Press Limited
This article presents a new approach for the hybrid position/force control of a manipulator by using self-tuning regulators (STR). For this purpose, the discrete-time stochastic multi-input multi-output (MIMO) and sin...
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This article presents a new approach for the hybrid position/force control of a manipulator by using self-tuning regulators (STR). For this purpose, the discrete-time stochastic multi-input multi-output (MIMO) and single-input single-output (SISO) models are introduced. The MIMO model's output vector has the positions and velocities of the gripper expressed in the world (xyz) coordinate system as the components. The SISO model outputs are the hybrid errors consisting of the derivatives of the position and force errors at the joints. The inputs of both models are the joint torques. The unknown parameters of those models can be calculated recursively on-line by the square-root estimation algorithm (SQR). An adaptive MIMO and SISO self-tuning type controllers are then designed by minimizing the expected value of a quadratic criterion. This performance index penalizes the deviations of the actual position and force path of the gripper from the desired values expressed in the Cartesian coordinate system. An integrating effect is also included in the performance index to remove the steady-state errors. Digital simulation results using the parameter estimation and the control algorithms are presented and the performances of those two controllers are discussed. (C) 1996 John Wiley & Sons, Inc.
Active control of noise and vibration in large dimensional complex systems is generally accomplished with adaptive feedforward control algorithms based on the steepest descent optimization approach. This paper examine...
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Active control of noise and vibration in large dimensional complex systems is generally accomplished with adaptive feedforward control algorithms based on the steepest descent optimization approach. This paper examines the effects of incorporating control effort weighting into the cost function that is minimized by an adaptive control algorithm. When the plant matrix is rank-deficient, the least-squares solution to which the control algorithm converges is nonunique. In such situations, the control signals can drift with no change in performance. Small amounts of uniform control effort weighting can enforce a unique solution at the expense of decreased performance. A nonuniform form of control effort weighting is introduced that yields a unique solution without a performance penalty. With ill-conditioned systems, small amounts of effort weighting can provide significant reductions in the control signals with only a very small increase in residual error. A form of effort weighting is introduced for ill-conditioned systems based on the results for the rank-deficient case. Stability and robustness issues are examined for each form of weighting. It is shown that the nonuniform forms of control effort weighting can significantly diminish the trade-off between performance and robustness in the presence of plant model error. (C) 1996 Acoustical Society of America.
In this letter, an efficient, rapid-convergent, control algorithm will be developed and compared with finite impulse response (FIR), filtered-x, LMS [Widrow et al., Proc. IEEE 63, 1692-1711 (1975)], and a modified ver...
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In this letter, an efficient, rapid-convergent, control algorithm will be developed and compared with finite impulse response (FIR), filtered-x, LMS [Widrow et al., Proc. IEEE 63, 1692-1711 (1975)], and a modified version of Godard's algorithm [D. Godard, IBM J. Res. Develop., pp. 267-273 (1974)]. The experiments will be performed on an active noise control (ANC) system. Comparisons of the random noise attenuation capability, transient and convergence performance, and computational requirements of each algorithm will be made as the order of the controller and relevant convergence parameters are varied. The ANC system used for these experiments is a test bed of noise suppression technology for expendable launch vehicles, It consists of a flexible plate backed by a rigid cavity. Piezoelectric actuators are mounted on the plate and polyvinylidene fluoride (PVDF) microphones are used to sense the reference and error signals. The plate is bombarded with an amplified random noise signal, and the control system is used to suppress the cavity noise generated by the sound source. (C) 1995 Acoustical Society of America.
An adaptive, sliding control algorithm is developed for automated throttle control of an I.C. engine to be used in drive-by-H ire applications such as coordinated engine/transmission gear shiftings, traction control a...
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An adaptive, sliding control algorithm is developed for automated throttle control of an I.C. engine to be used in drive-by-H ire applications such as coordinated engine/transmission gear shiftings, traction control and autonomous vehicle control (NHS). The paper presents a new sliding control formulation that includes combustion transport delays and a simplified adapation law to account for slowly varying engine parameters. The new technique is evaluated by computer simulation and laboratory dynamometer tests.
作者：
Cash, GGEnvironmental Effects Branch
Health & Environmental Review Division Office of Pollution Prevention & Toxics U.S. Environmental Protection Agency SW USA
A fast computer algorithm is described which brings computation of the permanents of sparse matrices, specifically, chemical adjacency matrices, within the reach of a desktop computer. Examples and results are present...
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A fast computer algorithm is described which brings computation of the permanents of sparse matrices, specifically, chemical adjacency matrices, within the reach of a desktop computer. Examples and results are presented, along with a discussion of the relationship of the permanent to the Kekule structure count. Also presented is a C-language implementation which was deliberately written for ease of translation into other high-level languages.
We designed, implemented, and tested a real-time flexible controller for manipulating different types of robots and control algorithms. The robot-independent, IBM PC-based multiprocessor system contains a DSP56001 mas...
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We designed, implemented, and tested a real-time flexible controller for manipulating different types of robots and control algorithms. The robot-independent, IBM PC-based multiprocessor system contains a DSP56001 master controller, six independent HCTL-1100 joint processors for accurate robotic joint control, and an interface computer board for processor communication, The joint processors operate in four user-defined modes and can be connected directly to an incremental optical encoder, which accommodates specialized applications and eliminates extra hardware.
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