2018 (vol. 28) - Number 1

*I. Duleba, I. Karcz-Duleba:*

A comparison of methods solving repeatable inverse kinematics for robot manipulators

*A. Niederliński:*

A new approach for modelling uncertainty in expert systems knowledge bases

*T.T. Tuan, L.D. Tufa, M.I.A. Mutalib, N.M. Ramli :*

Optimal operation of a process by integrating dynamic economic optimization and model predictive control formulated with empirical model

*M. Kaleta:*

Network winner determination problem

*A. Kowalewski:*

Extremal problems for parabolic systems with time-varying lags

*T. Rybus, K. Seweryn, J.Z. S±siadek:*

Application of predictive control for manipulator mounted on a satellite

*T. Kaczorek:*

Reachability and observability of positive discrete-time linear systems with integer positive and negative powers of the state Frobenius matrices

*G. Grassi, A. Ouannas, V-T. Pham:*

A general unified approach to chaos synchronization in~continuous-time systems (with or without equilibrium points) as well as in discrete-time systems

*D. Pazderski:*

A robust smooth controller for a unicycle-like robot

ACS Abstract:

**2003 (Volume 13)**

Number 4

**Robot controller with a self-measurement capability enabling the identification of friction**

Adam Wozniak, Wojciech Szynkiewicz and Cezary Zielinski(Warsaw University of Technology, Poland) |

**keywords:** robot controller, servomechanism, friction model, identification.

**The interval parabolic system**

Krzysztof Oprzedkiewicz(University of Mining and Metallurgy, Poland) |

**keywords:** interval systems, parabolic systems,the exponential stability.

**On controllability and minimum energy control of linear positive systems with delays**

Beata Sikora(Silesian University of Technology, Poland) |

**keywords:** positive dynamical systems, delay systems, relative controllability, admissible control, minimum energy control.

**Active control of circular plate vibration by using piezoceramic actuators**

Lucyna Leniowska and Ryszard Leniowski(University of Rzesz?w, Poland) |

**keywords:** active vibration control, feedback control, piezoceramic transducers, identification methods.

**Multivariable robust control applied to steering of three ship's velocities**

Witold Gierusz(Gdynia Maritime University, Poland) |

**keywords:** training ship, simulation model, multivariable system, robust control, real-time steering.

**Hierarchical control in a large scale stochastic system with nonclassical information structure**

Zdzislaw Duda and Witold Brandys(Silesian University of Technology, Poland) |

**keywords:** large scale system, stochastic system, decentralized control, optimal control.

**Errors of elementary floating-point operations in control algorithms**

Zbigniew Swider(Technical University of Rzeszow, Poland) |

*b*denotes the number of mantissa bits. Error of Euler rectangular integrator , commonly used in digital controllers, is evaluated as well. For small sampling step the error depends primarily on precision of the addition executed by the integrator. Increase of the precision used in some small controllers is also considered. The results are verified for first-order transfer function subject to white noise, sinusoidal and constant-plus-noise inputs.

**keywords:** floating-point arithmetic, roundoff errors, delta-operator, stochastic systems.

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