Ponderomotive stabilization of flute modes in mirrors: Feedback control and numerical results

1987 ◽  
Vol 58 (5) ◽  
pp. 495-498 ◽  
Author(s):  
P. L. Similon
Keyword(s):  
Feedback Control ◽  
Numerical Results

scholarly journals The Dubins Traveling Salesperson Problem With Stochastic Dynamics

2013 ◽  
Author(s):  
Ross P. Anderson ◽  
Dejan Milutinović
Keyword(s):  
Feedback Control ◽  
Bellman Equation ◽  
Stochastic Dynamics ◽  
Numerical Results ◽  
Traveling Salesperson Problem ◽  
Expected Time ◽  
Hamilton Jacobi Bellman Equation ◽  
Dubins Vehicle ◽  
Robotic Vehicle ◽  
Hamilton Jacobi Bellman

Motivated by applications in which a nonholonomic robotic vehicle should sequentially hit a series of waypoints in the presence of stochastic drift, we formulate a new version of the Dubins vehicle traveling salesperson problem. In our approach, we first compute the minimum expected time feedback control to hit one waypoint based on the Hamilton-Jacobi-Bellman equation. Next, minimum expected times associated with the control are used to construct a traveling salesperson problem based on a waypoint hitting angle discretization. We provide numerical results illustrating our solution and analyze how the stochastic drift affects the solution.

On the Construction of Minimum-Time Tours for a Dubins Vehicle in the Presence of Uncertainties

2014 ◽  
Vol 137 (3) ◽  
Author(s):  
Ross P. Anderson ◽  
Dejan Milutinović
Keyword(s):  
Feedback Control ◽  
Numerical Results ◽  
Minimum Time ◽  
Receding Horizon ◽  
Stochastic Motion ◽  
Traveling Salesperson Problem ◽  
Expected Time ◽  
Dubins Vehicle ◽  
On Line ◽  
Hamilton Jacobi Bellman

We propose an approach to the problem of computing a minimum-time tour through a series of waypoints for a Dubins vehicle in the presence of stochasticity. In this paper, we explicitly account for kinematic nonlinearities, the stochastic drift of the vehicle, the stochastic motion of the targets, and the possibility for the vehicle to service each of the targets or waypoints, leading to a new version of the Dubins vehicle traveling salesperson problem (TSP). Based on the Hamilton–Jacobi–Bellman (HJB) equation, we first compute the minimum expected time feedback control to reach one waypoint. Next, minimum expected times associated with the feedback control are used to construct and solve a TSP. We provide numerical results illustrating our solution, analyze how the stochasticity affects the solution, and consider the possibility for on-line recomputation of the waypoint ordering in a receding-horizon manner.

Dynamics of a Duffing Oscillator With Two Time Delays in Feedback Control Under Narrow-Band Random Excitation

2008 ◽  
Vol 3 (2) ◽  
Author(s):  
Yanfei Jin ◽  
Haiyan Hu
Keyword(s):  
Feedback Control ◽  
Time Delays ◽  
Multiple Scales ◽  
Narrow Band ◽  
Duffing Oscillator ◽  
Primary Resonance ◽  
Random Excitation ◽  
Numerical Results ◽  
Linear Feedback ◽  
The Difference

The paper presents analytical and numerical results of the primary resonance of a Duffing oscillator with two distinct time delays in the linear feedback control under narrow-band random excitation. Using the method of multiple scales, the first-order and the second-order steady-state moments of the primary resonance are derived. For the case of two distinct time delays, the appropriate choices of the combinations of the feedback gains and the difference between two time delays are discussed from the viewpoint of vibration control and stability. The analytical results are in well agreement with the numerical results.

Linear Stability Analysis for the Wall Temperature Feedback Control of Planar Poiseuille Flows

2002 ◽  
Vol 124 (4) ◽  
pp. 617-624
Author(s):  
Herve´ Pabiou ◽  
Jun Liu ◽  
Christine Be´nard
Keyword(s):  
Stability Analysis ◽  
Feedback Control ◽  
Flow Control ◽  
Linear Stability ◽  
Wall Temperature ◽  
Linear Stability Analysis ◽  
Poiseuille Flow ◽  
Numerical Results ◽  
Coupled Equations ◽  
Linear Loss

Active control of a planar Poiseuille flow can be performed by increasing or decreasing the wall temperature in proportion to the observed wall shear stress perturbation. In continuation with the work of H. H. Hu and H. H. Bau (1994, Feedback Control to Delay or Advance Linear Loss of Stability in Planar Poiseuille Flow, Proc. R. Soc. London A, 447, pp. 299–312), a linear stability analysis of such a feedback control is developed in this paper. The Poiseuille flow control problem is reduced to a modified Orr-Sommerfeld equation coupled with a heat equation. By solving numerically the coupled equations with a finite element method, many numerical results about the stability of the flow control are obtained. We focus our attention on the interpretation of the numerical results. In particular, the role of two essential parameters—the Prandtl number Pr and the control gain K—is investigated in detail. When Pr>1.31, stabilizing K is negative; while, when Pr<1.31, stabilizing K is positive. And when Pr=1.31, the flow cannot be stabilized by a real K. A comparison between symmetric two-wall control and non-symmetric one-wall control is also made.

scholarly journals Nonlinear feedback control of spatiotemporal chaos in coupled map lattices

1998 ◽  
Vol 1 (4) ◽  
pp. 283-305 ◽  
Author(s):  
Jin-Qing Fang ◽  
M. K. Ali
Keyword(s):  
Dynamical Systems ◽  
Feedback Control ◽  
Nonlinear Control ◽  
Functional Method ◽  
Spatiotemporal Chaos ◽  
Numerical Results ◽  
Coupled Map Lattices ◽  
Nonlinear Feedback Control ◽  
Nonlinear Feedback ◽  
Control And Synchronization

We describe a nonlinear feedback functional method for study both of control and synchronization of spatiotemporal chaos. The method is illustrated by the coupled map lattices with five different connection forms. A key issue addressed is to find nonlinear feedback functions. Two large types of nonlinear feedback functions are introduced. The efficient and robustness of the method based on the flexibility of choices of nonlinear feedback functions are discussed. Various numerical results of nonlinear control are given. We have not found any difficulty for study both of control and synchronization using nonlinear feedback functional method. The method can also be extended to time continuous dynamical systems as well as to society problems.

Use of vent stack temperature as a feedforward variable for dissolver total titratable alkali (TTA) control

TAPPI Journal ◽  
2018 ◽  
Vol 17 (05) ◽  
pp. 261-269
Author(s):  
Wei Ren ◽  
Brennan Dubord ◽  
Jason Johnson ◽  
Bruce Allison
Keyword(s):  
Feedback Control ◽  
Current Practice ◽  
Feedforward Control ◽  
Control Variable ◽  
Indirect Measurement ◽  
Tight Control ◽  
Transfer Lines ◽  
Green Liquor ◽  
Process Dynamics ◽  
Downstream Processes

Tight control of raw green liquor total titratable alkali (TTA) may be considered an important first step towards improving the overall economic performance of the causticizing process. Dissolving tank control is made difficult by the fact that the unknown smelt flow is highly variable and subject to runoff. High TTA variability negatively impacts operational costs through increased scaling in the dissolver and transfer lines, increased deadload in the liquor cycle, under- and over-liming, increased energy consumption, and increased maintenance. Current practice is to use feedback control to regulate the TTA to a target value through manipulation of weak wash flow while simultaneously keeping dissolver density within acceptable limits. Unfortunately, the amount of variability reduction that can be achieved by feedback control alone is fundamentally limited by the process dynamics. One way to improve upon the situation would be to measure the smelt flow and use it as a feedforward control variable. Direct measurement of smelt flow is not yet possible. The use of an indirect measurement, the dissolver vent stack temperature, is investigated in this paper as a surrogate feedforward variable for dissolving tank TTA control. Mill trials indicate that significant variability reduction in the raw green liquor TTA is possible and that the control improvements carry through to the downstream processes.

Sign in / Sign up

Export Citation Format

Share Document