scholarly journals Passing through resonance of the unbalanced rotor with self-balancing device

2021 ◽  
Author(s):  
Olga Drozdetskaya ◽  
Alexander Fidlin
Keyword(s):  
Mechanical System ◽  
Stationary System ◽  
Slow Dynamics ◽  
Averaging Technique ◽  
Unbalanced Rotor ◽  
Different Types ◽  
Limited Power ◽  
Damped Systems ◽  
System Configurations ◽  
Strongly Damped

AbstractThe slow dynamics of unbalanced rotors with a passive self-balancing system are investigated considering the interaction of the mechanical system with a limited power engine. The slow dynamics equations are obtained using the averaging technique for partially strongly damped systems. Stationary system configurations, different types of nonstationary solutions while passing through resonance, and areas of stability and attraction are investigated.

Hopf Bifurcation in PD Controlled Pendulum or Manipulator

2002 ◽  
Vol 124 (2) ◽  
pp. 327-332 ◽  
Author(s):  
Tom Bucklaew ◽  
Ching-Shi Liu
Keyword(s):  
Steady State ◽  
Hopf Bifurcation ◽  
Dynamic Behavior ◽  
Limit Cycle ◽  
Initial Conditions ◽  
Pendulum System ◽  
Periodic Attractors ◽  
Control Failure ◽  
Damped Systems ◽  
Strongly Damped

In this brief the dynamic behavior of a parametrically forced manipulator, or pendulum, system with PD control is examined. For an excitation of sufficient amplitude or frequency a Hopf bifurcation to a steady-state limit cycle is shown to result, appearing as a precursor to instability. The parameter space is mapped in order to illustrate regions where control failure will likely occur, even in the strongly damped case. For weakly damped systems, the Hopf bifurcation can additionally exhibit a dependence on initial conditions. The resulting case of competing point and periodic attractors is discussed.

A Testbed for Human-Robot Interactions

2004 ◽  
Author(s):  
Kai Wei Ong ◽  
Gerald Seet ◽  
Siang Kok Sim ◽  
William Teoh ◽  
Kean Hee Lim ◽  
...  
Keyword(s):  
Human Interaction ◽  
Multiple Robots ◽  
Safe Operation ◽  
Robot System ◽  
Manufacturing Automation ◽  
Current State ◽  
Simple Machines ◽  
Different Types ◽  
Robot Task ◽  
System Configurations

This paper describes the design and implementation of a testbed for facilitating the study of human-robot interactions (HRI). HRI has long been a part of robotics research, where humans were typically required to guide the robot task in progress and to ensure safe operation. The current state of human interaction with robots, versus simple “machines” (e.g. in manufacturing automation) is quite different. This called for the need to look into different interaction roles between humans and robots. Robots differ from simple machines in that they are mobile, some may be autonomous and hence not as predictable in their actions. To facilitate the research in this domain, the aim is to develop an easy to use and safe front-end human-robot system for human users to interact with physical mobile robots. This testbed provides different types of system configurations (i.e. one human to one robot, one human to multiple robots, etc.) and interfaces for conducting experiments under different HRI scenarios.

Influence of Mooring Lines and Risers on the Trim, Heel and Displacement on FPUs

2015 ◽  
Author(s):  
Cecília Coelho ◽  
Bruna Nabuco
Keyword(s):  
Water Depth ◽  
Mooring System ◽  
Mooring Lines ◽  
Different Types ◽  
Zero Degree ◽  
Displacement Based ◽  
System Configurations ◽  
And Behavior ◽  
Seabed Bathymetry ◽  
Water Depths

By monitoring the variation of weights of floating production units (FPUs), the sum of total weight computed by load calculators on board very often does not match the actual displacement based on the current drafts. Differences can also be observed in the trim and heel of FPUs, which present values different from zero degree in the calculations, but in fact they are frequently kept near zero by ballast control. The mooring lines and risers tensions are one of the most uncertain weight items in loading conditions reported by the crew on board, therefore, this paper aims to assess the influence and behavior of these systems to a variety of situations in which FPUs operate. Analyses were performed for semi-submersibles and FPSOs considering two configurations of mooring system: catenary and taut-leg. The purpose is to evaluate how the magnitude of the resulting force varies — and hence how the trim and heel change — for a range of offsets caused by environmental conditions. The effect of mooring lines and risers is also discussed regarding the water depth by means of case studies considering a range of water depths. Actual lines properties and seabed bathymetry from mooring system models of platforms located offshore Brazil have been taken as reference. In short, the mooring lines and risers loads will be calculated for different types of floating production units, mooring system configurations and water depths in order to evaluate their influence on the trim, heel and displacement of FPUs.

INFLUENCE OF INITIAL STATES ON TWO-TIME DEPENDENCE OF MAGNETORESISANCE IN MULTILAYER STRUCTURES WITH DIFFERENT TYPES OF ANISOTROPY

2020 ◽  
Vol 25 (2) ◽  
pp. 24-33
Author(s):  
Marina Mamonova ◽  
Vladimir Prudnikov ◽  
Pavel Prudnikov ◽  
Anna Samoshilova
Keyword(s):  
Monte Carlo ◽  
Time Dependence ◽  
Monte Carlo Study ◽  
Multilayer Structures ◽  
Aging Effects ◽  
Slow Dynamics ◽  
Magnetic Structures ◽  
Different Types ◽  
Initial States ◽  
Non Equilibrium

The Monte Carlo study of initial states influence on non-equilibrium slow dynamics and two-time dependence of magnetoresistance in multilayer magnetic structures Co/Cu(100)/Co и Pt/Co/Cu(100)/Co/Pt with different types of anisotropy is presented. It was revealed nontrivial aging effects in the magnetoresistance and essential influence of initial states on the magnetoresistance.

Parametric Representation for Geometry Variation in Digital Mechanical System

2014 ◽  
Vol 686 ◽  
pp. 507-512
Author(s):  
Wei Dong Liu ◽  
Yuan Sun
Keyword(s):  
Mechanical System ◽  
Parametric Representation ◽  
Location Error ◽  
Orientation Error ◽  
Cad System ◽  
Different Types ◽  
Geometry Error

Ideal geometry is mainly represented by several parameters in traditional CAD system. Based on these parameters, ideal geometry can be dynamically constructed to build the entire CAD entity; however, the modeling of variated geometry by parameters is not included, and parametric representation for variated geometry is introduced in this paper; sets of parameters for different types of geometry variation are discussed. Based on parametric representation for variated geometry, the translation and orientation error of part that affected by the variation of geometry is calculated, the process for converting geometry error to parametric part location error is introduced.

scholarly journals Realizing brachistochronic planar motion of a variable mass nonholonomic mechanical system by an ideal holonomic constraint with restricted reaction

Filomat ◽  
2019 ◽  
Vol 33 (14) ◽  
pp. 4387-4401
Author(s):  
Bojan Jeremic ◽  
Radoslav Radulovic ◽  
Nemanja Zoric ◽  
Milan Drazic
Keyword(s):  
Mechanical System ◽  
Degrees Of Freedom ◽  
Variable Mass ◽  
Planar Motion ◽  
Arbitrary Field ◽  
Mass Variation ◽  
Singular Optimal Control ◽  
Control Structures ◽  
Holonomic Constraint ◽  
Different Types

The paper considers realization of the brachistochronic motion of a nonholonomic mechanical system, composed of variable mass particles, by means of an ideal holonomic constraint with restricted reaction. It is assumed that the system performs planar motion in an arbitrary field of forces and that it has two degrees of freedom. In addition, the laws of the time-rate of mass variation of the particles, as well as relative velocities of the expelled and gained particles, respectively, are known. Restricted reaction of the holonomic constraint is taken for the scalar control. Applying Pontryagin?s maximum principle and singular optimal control theory, the problem of brachistochronic motion is solved as a two-point boundary value problem (TPBVP). Since the reaction of the constraint is restricted, different types of control structures are examined, from singular to totally nonsingular. The considerations are illustrated via an example.

scholarly journals Sound Over-Approximation of Probabilities

2020 ◽  
Vol 24 (3) ◽  
pp. 269-285
Author(s):  
Eugenio Moggi ◽  
Walid Taha ◽  
Johan Thunberg
Keyword(s):  
General Framework ◽  
General Setting ◽  
High Confidence ◽  
Transition Systems ◽  
Complete Lattices ◽  
Discrete Time Systems ◽  
Finite Lattices ◽  
Different Types ◽  
System Configurations ◽  
Time Systems

Safety analysis of high confidence systems requires guaranteed bounds on the probability of events of interest. Establishing the correctness of algorithms that compute such bounds is challenging. We address this problem in three steps. First, we use monadic transition systems (MTS) in the category of sets as a general framework for modeling discrete time systems. MTS can capture different types of system behaviors, but here we focus on a combination of non-deterministic and probabilistic behaviors that arises often when modeling complex systems. Second, we use the category of posets and monotonic maps as general setting to define and compare approximations. In particular, for the MTS of interest, we consider approximations of their configurations based on complete lattices of interval probabilities. Third, we obtain an algorithm that computes over-approximations of system configurations after a finite number of steps, by restricting to finite lattices.

A Computational Environment for Dextrous Workspace Analysis

1992 ◽  
Author(s):  
J. Y. Wang ◽  
J. K. Wu
Keyword(s):  
Mechanical System ◽  
Automatic Differentiation ◽  
System Modeling ◽  
Necessary Condition ◽  
Dimensional Solution ◽  
Computational Environment ◽  
Kinematic Behavior ◽  
Workspace Analysis ◽  
Engineering Environment ◽  
System Configurations

Abstract This paper presents an interactive engineering environment for dextrous workspace analysis of manipulators. The environment contains a mechanical system modeling tool, an automatic differentiation package, and numerical solvers that map one-dimensional and two-dimensional solution sets of nonlinear parametrized kinematic constraint equations. Row-rank deficiency of constraint sub-Jacobian matrices is used as a necessary condition for characterizing the boundaries of the workspaces and dextrous workspaces of manipulators. A cursor driven animation capability, developed in an interactive graphics environment allows the user to retrieve system configurations by dragging the cursor along solution branches. An animation of the assembled configuration along that solution branch is then displayed. Thus, a better understanding of the kinematic behavior of mechanical systems that limits their dexterity can be obtained. A construction backhoe mechanical system is used to demonstrate the capability of the method developed.

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