A reliable, straightforward technique for generating Bode and Nyquist diagrams

SIMULATION ◽  
1967 ◽  
Vol 8 (5) ◽  
pp. 255-257 ◽  
Author(s):  
Willard A. Gilly
Keyword(s):  
Input Signal ◽  
Closed Loop ◽  
Analog Computer ◽  
Open Loop ◽  
Closed Loop System ◽  
Closed Loop Systems ◽  
Graphical Comparison ◽  
Analog Logic ◽  
Computer Operator ◽  
Chart Recording

Several methods have been devised for generating Bode diagrams on an analog computer. All of them, or at least all of them that we are familiar with, are either imprecise or they are excessively laborious. And the method most commonly used by analog pro grammers -graphical comparison of variables on a strip chart recording-combines both disadvantages. These can be largely avoided by a method we have found quite convenient, using analog logic and memory equipment. Our method yields phase and gain information directly and requires no manual adjustments by the computer operator other than to change the frequency of the input signal and to adjust the abscissa of the X-Y plotter. The method can be used for both open-loop and closed-loop systems and is especially useful for obtaining the open-loop response of a closed-loop system, as in figure 1. Here is how it works:

Water Hammer Pressure Transients in a Closed Loop System

Volume 3 ◽  
2004 ◽  
Author(s):  
Robert A. Leishear ◽  
Jeffrey H. Morehouse
Keyword(s):  
Method Of Characteristics ◽  
Closed Loop ◽  
Water Hammer ◽  
Open Loop ◽  
Loop System ◽  
Closed Loop System ◽  
Open Loop System ◽  
Trapped Air ◽  
Closed Loop Systems ◽  
Fluid Transients

The effects of fluid transients, or water hammer, in closed loop systems are somewhat different than those observed in open ended systems. The open loop system has received much attention in the literature, not so for the closed system. The generally accepted method of characteristics (MOC) technique was applied herein to investigate closed loop systems. The magnitudes of the pressures during fluid transients were investigated for examples of rapid valve closures, and the operations of parallel pumps. The effects of trapped air in the system were also considered for these examples. To reduce the pressures caused by the transients, the installation of slow closing valves were evaluated for different conditions.

scholarly journals A System View on Iterative MIMO Detection: Dynamic Sphere Detection versus Fixed Effort List Detection

VLSI Design ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Christina Gimmler-Dumont ◽  
Frank Kienle ◽  
Bin Wu ◽  
Guido Masera
Keyword(s):  
Communication Systems ◽  
Closed Loop ◽  
Mimo Systems ◽  
Open Loop ◽  
Spatial Multiplexing ◽  
Loop System ◽  
Mimo Detection ◽  
Closed Loop System ◽  
Closed Loop Systems ◽  
Sphere Detection

Multiple-antenna systems are a promising approach to increase the data rate of wireless communication systems. One efficient possibility is spatial multiplexing of the transmitted symbols over several antennas. Many different MIMO detector algorithms exist for this spatial multiplexing. The major difference between different MIMO detectors is the resulting communications performance and implementation complexity, respectively. Particularly closed-loop MIMO systems have attained a lot of attention in the last years. In a closed-loop system, reliability information is fed back from the channel decoder to the MIMO detector. In this paper, we derive a basic framework to compare different soft-input soft-output MIMO detectors in open- and closed-loop systems. Within this framework, we analyze a depth-first sphere detector and a breadth-first fixed effort detector for different application scenarios and their effects on area and energy efficiency on the whole system. We present all system components under open- and closed-loop system aspects and determine the overall implementation cost for changing an open-loop system in a closed-loop system.

Impedance Reduction Controller Design for Mechanical Systems

2013 ◽  
Author(s):  
Hanseung Woo ◽  
Kyoungchul Kong
Keyword(s):  
Case Studies ◽  
Closed Loop ◽  
Controller Design ◽  
Mechanical Impedance ◽  
Open Loop ◽  
Mechatronic Systems ◽  
Closed Loop Systems ◽  
Guaranteed Stability ◽  
Reaction Forces ◽  
Definition Of

Safety is one of important factors in control of mechatronic systems interacting with humans. In order to evaluate the safety of such systems, mechanical impedance is often utilized as it indicates the magnitude of reaction forces when the systems are subjected to motions. Namely, the mechatronic systems should have low mechanical impedance for improved safety. In this paper, a methodology to design controllers for reduction of mechanical impedance is proposed. For the proposed controller design, the mathematical definition of the mechanical impedance for open-loop and closed-loop systems is introduced. Then the controllers are designed for stable and unstable systems such that they effectively lower the magnitude of mechanical impedance with guaranteed stability. The proposed method is verified through case studies including simulations.

scholarly journals Equivalence of Open-Loop and Closed-Loop Operation of SAW Resonators and Delay Lines

Sensors ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 185 ◽  
Author(s):  
Phillip Durdaut ◽  
Michael Höft ◽  
Jean-Michel Friedt ◽  
Enrico Rubiola
Keyword(s):  
Closed Loop ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Noise Analysis ◽  
Open Loop ◽  
Sensor System ◽  
Electronic Systems ◽  
Delay Lines ◽  
Resonant Sensors ◽  
Closed Loop Systems

Surface acoustic wave (SAW) sensors in the form of two-port resonators or delay lines are widely used in various fields of application. The readout of such sensors is achieved by electronic systems operating either in an open-loop or in a closed-loop configuration. The mode of operation of the sensor system is usually chosen based on requirements like, e.g., bandwidth, dynamic range, linearity, costs, and immunity against environmental influences. Because the limit of detection (LOD) at the output of a sensor system is often one of the most important figures of merit, both readout structures, i.e., open-loop and closed-loop systems, are analyzed in terms of the minimum achievable LOD. Based on a comprehensive phase noise analysis of these structures for both resonant sensors and delay line sensors, expressions for the various limits of detection are derived. Under generally valid conditions, the equivalence of open-loop and closed-loop operation is shown for both types of sensors. These results are not only valid for SAW devices, but are also applicable to all kinds of phase-sensitive sensors.

scholarly journals Formulation and Simulations of the Conserving Algorithm for Feedback Stabilization on Rigid Body Rotations

2014 ◽  
Vol 2014 ◽  
pp. 1-11
Author(s):  
Yong-Ren Pu ◽  
Thomas A. Posbergh
Keyword(s):  
Rigid Body ◽  
Closed Loop ◽  
Numerical Algorithms ◽  
Open Loop ◽  
Rigid Bodies ◽  
Feedback Stabilization ◽  
Conserved Quantities ◽  
Control Laws ◽  
Loop Control ◽  
Closed Loop Systems

The problem of stabilization of rigid bodies has received a great deal of attention for many years. People have developed a variety of feedback control laws to meet their design requirements and have formulated various but mostly open loop numerical algorithms for the dynamics of the corresponding closed loop systems. Since the conserved quantities such as energy, momentum, and symmetry play an important role in the dynamics, we investigate the conserved quantities for the closed loop control systems which formally or asymptotically stabilize rigid body rotation and modify the open loop numerical algorithms so that they preserve these important properties. Using several examples, the authors first use the open loop algorithm to simulate the tumbling rigid body actions and then use the resulting closed loop one to stabilize them.

Modeling and Simulation of Closed Loop Controlled Parallel Cascaded Buck Boost Converter Inverter Based Solar System

2015 ◽  
Vol 6 (3) ◽  
pp. 648 ◽  
Author(s):  
T. Sundar ◽  
S. Sankar
Keyword(s):  
Solar System ◽  
Modeling And Simulation ◽  
Single Phase ◽  
Closed Loop ◽  
Boost Converter ◽  
Open Loop ◽  
Boost Converters ◽  
Closed Loop Systems ◽  
Simulink Model ◽  
Simulation Results

<p>This Work deals with design, modeling and simulation of parallel cascaded buck boost converter inverter based closed loop controlled solar system. Two buck boost converters are cascaded in parallel to reduce the ripple in DC output. The DC from the solar cell is stepped up using boost converter. The output of the boost converter is converted to 50Hz AC using single phase full bridge inverter. The simulation results of open loop and closed loop systems are compared. This paper has presented a simulink model for closed loop controlled solar system.  Parallel cascaded buck boost converter is proposed for solar system.</p>

Application of Anytime Control to an Inherently Unstable Physical System

2015 ◽  
Author(s):  
Wayne Maxwell ◽  
Al Ferri ◽  
Bonnie Ferri
Keyword(s):  
Closed Loop ◽  
Initial Conditions ◽  
Transient Behavior ◽  
Open Loop ◽  
Loop System ◽  
Closed Loop System ◽  
Pendulum System ◽  
Inverted Pendulum System ◽  
Lqr Controller ◽  
Two Stages

This paper extends the use of closed-loop anytime control to systems that are inherently unstable in the open-loop. Previous work has shown that anytime control is very effective in compensating for occasional missed deadlines in the computer processor. When misses occur, the control law is truncated or partially executed. However, the previous work assumed that the open-loop system was stable. In this paper, the anytime strategy is applied to an inverted pendulum system. An LQR controller with estimated state feedback is designed and decomposed into two stages. Both stages are implemented most of the time, but in a small percentage of time, only the first stage is applied, with the resulting closed-loop system being unstable for short periods of time. The statistical performance of the closed-loop system is studied using Monte-Carlo simulations. It is seen that, on average, the closed-loop performance is very close to that of the full-order controller as long as the miss rate is relatively small. However, the variance of the response shows much higher dependence on the miss rate, suggesting that the response becomes more unpredictable. At a critical value of miss rate, the closed-loop system is unstable. The critical miss rate found through simulation is seen to correlate well with the results of a deterministic stability analysis. The statistics on the settling time are also studied, and shown to grow longer as the miss rate increases. The transient behavior of the system is studied for a range of initial conditions.

Analysis of loading effect of systems in a bond graph approach with application to a synchronous machine

2011 ◽  
Vol 226 (2) ◽  
pp. 243-255
Author(s):  
G Gonzalez
Keyword(s):  
Transfer Function ◽  
Closed Loop ◽  
Bond Graph ◽  
Physical Domain ◽  
Closed Loop System ◽  
Graph Models ◽  
Loading Effect ◽  
Closed Loop Systems ◽  
New Type ◽  
Feedback Connections

A new type of bond designed as an adapted bond is proposed. This bond can be considered in the transition from an active bond to a bond. This approach makes it possible to know the loading effect of the controller–plant and the feedback connections. In order to determine the loading effect of the closed-loop system, the transfer function using causal paths and causal loops of the system in the physical domain is presented. However, this proposed adapted bond should be used in fault cases. Finally, some examples of bond graph models in open- and closed-loop systems are given.

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