Interactive Modeling and Analysis of Open or Closed Loop Dynamic Systems with Redundant Actuators

1979 ◽  
Vol 101 (3) ◽  
pp. 407-416 ◽  
Author(s):  
R. J. Williams ◽  
A. Seireg
Keyword(s):  
Dynamic Systems ◽  
Closed Loop ◽  
Open Loop ◽  
Rigid Bodies ◽  
Dynamic Activity ◽  
Modeling And Analysis ◽  
Closed Loop Systems ◽  
Redundant Actuators ◽  
Machine Systems ◽  
Input Motion

This paper deals with the development of a computer-based procedure for the modeling and analysis of large displacement dynamic systems of the open or closed loop types. The procedure facilitates the construction of the model for such systems, automatically formulates the dynamic equations and provides the solution for any given input motion. The program is capable of analyzing complex systems with redundant force actuators utilizing a linear programming optimization scheme. It incorporates an interactive graphic capability which is invaluable in the construction, modification and visual checking of a model. The modeling procedure is general in nature and is applicable to systems of many connected rigid bodies. Its capabilities are illustrated in this paper by evaluating muscle forces and joint reactions of the musculoskeletal structure during dynamic activity. The system is readily applicable to the analysis of the actuation schemes in human and animal locomotion, many classes of machine systems, as well as robots and manipulators. Although only applications to open loop mechanisms are presented in this paper, the program can be readily extended to treat closed loop systems as well.

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.

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.

On the Comparison of the Dynamic Performance of Open-Loop and Closed-Loop Mechanisms

2014 ◽  
Author(s):  
Jahangir Rastegar ◽  
Dake Feng
Keyword(s):  
Dynamic Response ◽  
Dynamic Systems ◽  
Closed Loop ◽  
Dynamic Performance ◽  
Mechanical Systems ◽  
Open Loop ◽  
Actuation Devices

In general, mechanical systems with closed-loop mechanisms can achieve significantly higher operating speeds as compared to open-loop mechanisms such as robots performing identical tasks. In this brief paper, the reason for the superior dynamic performance of closed-loop mechanisms as compared to open-loop mechanisms performing identical tasks is shown to be the inherent dynamic response limitations of the actuation devices in open-loop dynamic systems. Several examples are provided.

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.

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>

scholarly journals On finite-time consensus objectives in time-varying interconnected discrete linear dynamic systems under internal and external delays

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401878484 ◽  
Author(s):  
Manuel De la Sen ◽  
Santiago Alonso-Quesada
Keyword(s):  
Dynamic Systems ◽  
Finite Time ◽  
Closed Loop ◽  
Discrete Systems ◽  
Open Loop ◽  
Time Varying ◽  
Common Error ◽  
Linear Dynamic Systems ◽  
External Point ◽  
Point Delays

This article formulates the properties of achievable consensus of linear interconnected discrete systems with multiple internal and external point delays. The formulation is stated in an algebraic generic context as the ability of achievement of (a non-necessarily zero) finite-time common error between the various subsystems. The consensus signals are generically defined so that they can be, in general, distinct of the output or state components. However, the consensus signals of all the interconnected subsystems have the same dimension for coherency reasons. A particular attention is paid to the case of weak interconnection couplings in both the open-loop case and the closed-loop one under, in general, linear output feedback. Some further extensions are given related to consensus over intervals and related to consensus of positive interconnected systems.

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.

MODELING AND ANALYSIS OF SWITCHING-MODE DC–DC REGULATORS

2000 ◽  
Vol 10 (02) ◽  
pp. 373-390 ◽  
Author(s):  
M. ALFAYYOUMI ◽  
A. H. NAYFEH ◽  
D. BOROJEVIC
Keyword(s):  
Closed Loop ◽  
Period Doubling ◽  
Input Voltage ◽  
Open Loop ◽  
Domain Model ◽  
Equilibrium Solutions ◽  
Modeling And Analysis ◽  
Proportional Integral ◽  
Switching Regulators ◽  
Switching Mode

The nonlinear dynamics of PWM DC–DC switching regulators operating in the continuous conduction mode are investigated. A quick review of the existing analysis techniques and their limitations are first presented. A discrete nonlinear time-domain model is then derived for open-loop DC–DC converters. This model is then extended for closed-loop regulator systems implementing any type of compensation scheme. The equilibrium solutions of the closed-loop system are then identified. The eigenvalues of the Jacobian matrix evaluated at the equilibrium solution are used to assess its stability. The methods developed are used to study the dynamic behavior of a DC–DC buck regulator implementing different types of compensation design: proportional, integral, proportional–integral, and proportional–integral–derivative type feedback control. A detailed bifurcation analysis of the dynamic solutions as a design or a control parameter is changed is presented. A period-doubling route to chaos is shown to exist in voltage-mode regulators, depending on the values of the parameters of the compensator and the input voltage. A further investigation of the behavior of the converter in the instability regions was carried out to improve the understanding of this interesting behavior.

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:

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