A Mechanical Filter Concept to Suppress Crane Load Oscillations

1997 ◽  
Author(s):  
B. Balachandran ◽  
Y.-Y. Li
Keyword(s):  
Nonlinear Dynamics ◽  
Dynamical Systems ◽  
Control Parameters ◽  
Pivot Point ◽  
Preliminary Results ◽  
Scalar Control ◽  
Load Response ◽  
Mechanical Filter ◽  
Circular Track ◽  
Ship Roll

Abstract In this article, preliminary results obtained in the exploration of a mechanical filter concept for suppressing crane-load oscillations on a ship vessel are presented. The pivot point about which the load oscillates is constrained to follow a circular track in the considered filter. The governing dynamical systems for the cases with and without the filter are presented, and the nonlinear dynamics of these systems is studied with respect to quasi-static variation of different scalar control parameters. It is shown that the presence of the filter helps in eliminating some of the sub-critical bifurcations that may arise in the crane-load response during periodic ship-roll excitations.

Active Control of Nonlinear Dynamics of Crane Loads

2000 ◽  
Author(s):  
Y.-Y. Li ◽  
B. Balachandran ◽  
K. V. Krishna
Keyword(s):  
Nonlinear Dynamics ◽  
Active Control ◽  
Mechanical Filter ◽  
Ship Roll ◽  
Present Effort

Abstract In order to suppress crane-load oscillations on ship vessels, a novel mechanism called a mechanical filter was introduced recently. This system is further numerically studied in the present effort. With the aid of active control, it is illustrated as to how the suppression bandwidth can be tailored and bifurcations in the response of the crane load can be eliminated from the considered range of disturbance parameters. Suppression of crane-load oscillations in the presence of aperiodic ship-roll motions is also addressed.

Suppression of Crane-Load Oscillations Using Shape-Controlled Mechanical Filters

2002 ◽  
Vol 8 (2) ◽  
pp. 121-134 ◽  
Author(s):  
K. V. Kaipa ◽  
B. Balachandran
Keyword(s):  
System Dynamics ◽  
Equilibrium Position ◽  
Shape Control ◽  
State Feedback ◽  
Pivot Point ◽  
Mechanical Filter ◽  
Ship Roll ◽  
Shape Controlled ◽  
Persistent Disturbances ◽  
Insight Into

In the present study, control of ship board crane-load oscillations using a shape-controlled mechanical filter is investigated. The pivot point about which the load oscillations occur is constrained to follow an actively controlled surface, which is referred to as the mechanical filter. Planar load oscillations in the presence of ship roll motions are considered, and a nonlinear system with nonautonomous terms is used to describe the motions. For the case without shape control, it is shown that with only state feedback applied to the pivot point, it is not possible to stabilize the equilibrium position (i.e., absence of load oscillations and pivot motions). In the presence of shape control, it is shown that it is possible to have an equilibrium position even in the presence of persistent disturbances. A Lyapunov function-based analysis conducted to gain insight into the system dynamics is also presented. Through numerical simulations, it is verified that the equilibrium position is stable over a range of excitation frequencies. Efforts undertaken to examine the system dynamics in the presence of both state feedback applied to the pivot and shape control are also discussed.

scholarly journals Theory of hybrid dynamical systems and its applications to biological and medical systems

2010 ◽  
Vol 368 (1930) ◽  
pp. 4893-4914 ◽  
Author(s):  
Kazuyuki Aihara ◽  
Hideyuki Suzuki
Keyword(s):  
Nonlinear Dynamics ◽  
Dynamical Systems ◽  
Mathematical Modelling ◽  
Systems Theory ◽  
Control Systems ◽  
Hybrid Systems ◽  
Hybrid Dynamical Systems ◽  
Medical Systems ◽  
Theme Issue ◽  
And Control

In this introductory article, we survey the contents of this Theme Issue. This Theme Issue deals with a fertile region of hybrid dynamical systems that are characterized by the coexistence of continuous and discrete dynamics. It is now well known that there exist many hybrid dynamical systems with discontinuities such as impact, switching, friction and sliding. The first aim of this Issue is to discuss recent developments in understanding nonlinear dynamics of hybrid dynamical systems in the two main theoretical fields of dynamical systems theory and control systems theory. A combined study of the hybrid systems dynamics in the two theoretical fields might contribute to a more comprehensive understanding of hybrid dynamical systems. In addition, mathematical modelling by hybrid dynamical systems is particularly important for understanding the nonlinear dynamics of biological and medical systems as they have many discontinuities such as threshold-triggered firing in neurons, on–off switching of gene expression by a transcription factor, division in cells and certain types of chronotherapy for prostate cancer. Hence, the second aim is to discuss recent applications of hybrid dynamical systems in biology and medicine. Thus, this Issue is not only general to serve as a survey of recent progress in hybrid systems theory but also specific to introduce interesting and stimulating applications of hybrid systems in biology and medicine. As the introduction to the topics in this Theme Issue, we provide a brief history of nonlinear dynamics and mathematical modelling, different mathematical models of hybrid dynamical systems, the relationship between dynamical systems theory and control systems theory, examples of complex behaviour in a simple neuron model and its variants, applications of hybrid dynamical systems in biology and medicine as a road map of articles in this Theme Issue and future directions of hybrid systems modelling.

PANS Turbulence Model for Seamless Transition Between RANS and LES: Fixed-Point Analysis and Preliminary Results

2003 ◽  
Author(s):  
Sharath S. Girimaji ◽  
Ravi Srinivasan ◽  
Euhwan Jeong
Keyword(s):  
Fixed Point ◽  
Navier Stokes ◽  
Control Parameters ◽  
Preliminary Results ◽  
Point Analysis ◽  
Large Eddy ◽  
Seamless Transition ◽  
Bridging Model ◽  
Reynolds Averaged Navier Stokes ◽  
Initial Results

Partially-averaged Navier-Stokes (PANS) approach has been recently developed as a possible bridging model between Reynolds-averaged Navier-Stokes (RANS) method and large-eddy simulations (LES). The resolution control parameters in PANS are the fractions of unresolved kinetic energy (fk) and unresolved dissipation (fε). We investigate the fixed-point behavior of PANS and present some preliminary results obtained using this model. By comparing the fixed-point behavior of PANS and URANS (unsteady Reynolds-averaged Navier-Stokes) methods, the possible advantage of the former over the latter is explained. Initial results from two-dimensional simulations of flow past square results are also presented.

Next step, synergetics?

2001 ◽  
Vol 24 (1) ◽  
pp. 66-67
Author(s):  
Wolfgang Tschacher ◽  
Ulrich M. Junghan
Keyword(s):  
Field Theory ◽  
Dynamical Systems ◽  
Systems Theory ◽  
Organization Theory ◽  
Field Model ◽  
Environmental Control ◽  
Clinical Applications ◽  
Self Organization ◽  
Control Parameters ◽  
Cognitive Problem

Thelen et al. offer an inspiring behavior-based theory of a long-standing cognitive problem. They demonstrate how joining traditions, old (the Gestaltist field theory) and new (dynamical systems theory) may open up the path towards embodied cognition. We discuss possible next steps. Self-organization theory (synergetics) could be used to address the formation of gaze/reach attractors and their optimality, given environmental control parameters. Finally, some clinical applications of the field model are advocated.

scholarly journals Multiconsensus of Nonlinear Multiagent Systems with Intermittent Communication

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Jie Chen ◽  
Guang-Hui Xu ◽  
Liang Geng
Keyword(s):  
Nonlinear Dynamics ◽  
Lyapunov Function ◽  
Multiagent Systems ◽  
Closed Loop ◽  
Sufficient Conditions ◽  
Control Parameters ◽  
Numerical Examples ◽  
Relative Information ◽  
Loop Dynamics ◽  
Intermittent Communication

Compared with single consensus, the multiconsensus of multiagent systems with nonlinear dynamics can reflect some real-world cases. This paper proposes a novel distributed law based only on intermittent relative information to achieve the multiconsensus. By constructing an appropriate Lyapunov function, sufficient conditions on control parameters are derived to undertake the reliability of closed-loop dynamics. Ultimately, the availability of results is completely validated by these numerical examples.

Chaotic Vibrations of Sector-Type Spherical Shells

2008 ◽  
Vol 3 (4) ◽  
Author(s):  
A. V. Krysko ◽  
J. Awrejcewicz ◽  
I. V. Papkova
Keyword(s):  
Nonlinear Dynamics ◽  
Chaotic Dynamics ◽  
Static Stability ◽  
Control Parameters ◽  
Spherical Shells ◽  
Spherical Cap ◽  
Chaotic Vibrations ◽  
Novel Method ◽  
Sector Type ◽  
Mechanical Objects

In this work, chaotic vibrations of shallow sector-type spherical shells are studied. A sector-type shallow shell is understood as a shell defined by a sector with associated boundary conditions and obtained by cutting a spherical shell for a given angle θk, or it is a sector of a shallow spherical cap associated with the mentioned angle. Both static stability and complex nonlinear dynamics of the mentioned mechanical objects subjected to transversal uniformly distributed sign-changeable load are analyzed, and the so-called vibration charts and scales regarding the chosen control parameters are reported. In particular, scenarios of transition from regular to chaotic dynamics of the mentioned shells are investigated. A novel method to control chaotic dynamics of the studied flexible spherical shells driven by transversal sign-changeable load via synchronized action of the sign-changeable antitorque is proposed and applied. All investigations are carried out within the fields of qualitative theory of differential equations and nonlinear dynamics.

Nonlinear Dynamics of Upright Human Balance While Using a Passive-Cane

2016 ◽  
Author(s):  
James R. Chagdes ◽  
Joao P. Freire ◽  
Amit Shukla
Keyword(s):  
Nonlinear Dynamics ◽  
Mathematical Model ◽  
Assistive Technology ◽  
Treatment Plan ◽  
Assistive Technologies ◽  
Feedback Gain ◽  
Control Parameters ◽  
Human Posture ◽  
Inverted Pendulum Model ◽  
Potential Applications

Recent mathematical models of human posture have been explored to better understand the space of control parameters that result in stable upright balance. These models have demonstrated that there are two types of instabilities — a leaning instability and an instability leading to excessive oscillation. While these models provide insight into the stability of upright bipedal stance, they are not sufficient for individuals that require the aid of assistive technologies, such as a passive-cane or a walker. Without a valid model one is unable to understand the control parameters required for maintain upright posture or if similar instabilities even exist when assistive technologies are used. Therefore in this study, we developed a mathematical model of human posture while using a passive-cane to examine the nonlinear dynamics of stance. First, we developed a simple mathematical model of cane assisted human stance by adapting the inverted pendulum model of Chagdes et al., [1]. We modeled the human body, upper arm, forearm, cane, and ground as a two-degree-of-freedom, five-bar-linkage with pin joints representing the ankle, shoulder, elbow, and wrist joints. Second, we investigate upright stability in the parameter space of feedback gain and time-delay. We hypothesize that the analysis will show similar instabilities compared to that of a human standing without assistive technology. We also hypothesize that the space of control parameters which stabilize upright equilibrium posture will increase when a cane is incorporated. This study has two potential applications. First, the developed mathematical model could allow clinicians to better assess technology assisted balance and if needed help clinicians to customize a treatment plan for an individual that allows them to avoid unstable postural dynamics. Second, the mathematical model can be used to design customized assistive technology for people of difference physical properties and impairments.

Sign in / Sign up

Export Citation Format

Share Document