Unconstrained and Constrained Control for a Tentacle Manipulator

2004 ◽  
Author(s):  
Mircea Ivanescu
Keyword(s):  
Control Problem ◽  
Numerical Simulations ◽  
Potential Method ◽  
Constrained Control ◽  
Constrained Motion ◽  
Controlled System ◽  
Differential Model

The control problem of the spatial tentacle manipulator is presented. In order to avoid the difficulties generated by the complexity of the nonlinear integral - differential model, the control problem is based by the artificial potential method. It is shown that the control of a tentacle robot to a desired position it is possible if the artificial potential is a potential functional whose point of minimum is attractor of this dissipative controlled system. Then, the method is used for constrained motion in an environment with obstacles. Numerical simulations for spatial and planar tentacle models are presented in order to illustrate the efficiency of the method.

scholarly journals Reducing Response Time in Fork-Join Systems under Heavy Traffic Via Imbalance Control

2013 ◽  
Vol 45 (4) ◽  
pp. 1137-1156
Author(s):  
Saul C. Leite ◽  
Marcelo D. Fragoso
Keyword(s):  
Optimal Control ◽  
Response Time ◽  
Control Problem ◽  
Stochastic Optimal Control ◽  
Numerical Experiments ◽  
Heavy Traffic ◽  
Controlled System ◽  
Reflected Diffusion ◽  
Stochastic Optimal Control Problem ◽  
Workload Imbalance

We consider the problem of reducing the response time of fork-join systems by maintaining the workload balanced among the processing stations. The general problem of modeling and finding an optimal policy that reduces imbalance is quite difficult. In order to circumvent this difficulty, the heavy traffic approach is taken, and the system dynamics are approximated by a reflected diffusion process. This way, the problem of finding an optimal balancing policy that reduces workload imbalance is set as a stochastic optimal control problem, for which numerical methods are available. Some numerical experiments are presented, where the control problem is solved numerically and applied to a simulation. The results indicate that the response time of the controlled system is reduced significantly using the devised control.

scholarly journals Dynamic Analysis of a Two-Language Competitive Model with Control Strategies

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Lin-Fei Nie ◽  
Zhi-Dong Teng ◽  
Juan J. Nieto ◽  
Il Hyo Jung
Keyword(s):  
Optimal Control ◽  
Optimal Control Problem ◽  
Control Problem ◽  
Numerical Simulations ◽  
Control Strategy ◽  
Sufficient Conditions ◽  
Positive Order ◽  
State Dependent ◽  
Competitive Model ◽  
The Impact

The dynamic behavior of a two-language competitive model is analyzed systemically in this paper. By the linearization and the Bendixson-Dulac theorem on dynamical system, some sufficient conditions on the globally asymptotical stability of the trivial equilibria and the existence and the stability of the positive equilibrium of this model are presented. Nextly, in order to protect the endangered language, an optimal control problem relative to this model is explored. We derive some necessary conditions to solve the optimal control problem and present some numerical simulations using a Runge-Kutta fourth-order method. Finally, the languages competitive model is extended to this model assessing the impact of state-dependent pulse control strategy. Using the Poincaré map, differential inequality, and method of qualitative analysis, we prove the existence and stability of positive order-1 periodic solution for this control model. Numerical simulations are carried out to illustrate the main results and the feasibility of state-dependent impulsive control strategy.

scholarly journals Wear Processes in a Mechanical Friction Clutch: Theoretical, Numerical, and Experimental Studies

2015 ◽  
Vol 2015 ◽  
pp. 1-28 ◽  
Author(s):  
Dariusz Grzelczyk ◽  
Jan Awrejcewicz
Keyword(s):  
Mathematical Modeling ◽  
Experimental Data ◽  
Numerical Analysis ◽  
Numerical Simulations ◽  
Experimental Studies ◽  
Friction Torque ◽  
Wear Properties ◽  
Wear Model ◽  
Differential Model ◽  
Friction Clutch

Mathematical modeling, theoretical/numerical analysis, and experimental verification of wear processes occurring on the contact surface of friction linings of a mechanical friction clutch are studied. In contrast to many earlier papers we take into consideration wear properties and flexibility of friction materials being in friction contact. During mathematical modeling and numerical simulations we consider a general nonlinear differential model of wear (differential wear model) and a model of wear in the integral form (integral wear model). Equations governing contact pressure and wear distributions of individual friction linings, decrease of distance between clutch shields, and friction torque transmitted by the clutch are derived and compared with experimental data. Both analytical and numerical analyses are carried out with the qualitative and quantitative theories of differential and integral equations, including the Laplace transform approach to ODEs. We show that theoretical results and numerical simulations agree with the experimental data. Finally, a numerical analysis of the proposed mathematical models was carried out in a wider range of parameters of the considered system.

Modeling of the Stress-Dependent Hysteretic Dynamics of Ferroelectric Materials

2014 ◽  
Vol 941-944 ◽  
pp. 606-609 ◽  
Author(s):  
Wei Feng Chen ◽  
Lin Xiang Wang ◽  
Fu Zai Lv
Keyword(s):  
Numerical Simulations ◽  
Hysteresis Loops ◽  
Ferroelectric Materials ◽  
Engineering Applications ◽  
Differential Model ◽  
Polarization Orientation ◽  
Stress Dependent ◽  
Theoretical Results ◽  
Combined Loadings

In the most of its engineering applications, ferroelectric materials are often subjected to combined loadings in the electric and mechanical fields. To simulate the influence of the biased stresses on the hysteretic dynamics of the materials, a macroscopic differential model is proposed to model the hysteresis loops and butterfly-shaped behaviors caused by the polarization orientation switching with biased stresses. A group of numerical simulations are presented, and the comparison of theoretical results with its experimental counterparts is also presented.

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