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1

Rotary upgrading method and its experimental study of an inertially stabilized platform

Guo Rong, Wang Xueyun, Zhang Jingjuan, Song Tianxiao

Metrology and Measurement Systems

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2019

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Vol. 26, nr 4

617--629

EN

Rotation modulation can significantly improve the navigation accuracies of an inertial navigation system (INS) and a strap-down configuration dominating in this type of INS. However, this style of construction is not a good scheme since it has no servo loop to counteract a vehicle manoeuvre. This paper proposes a rotary upgrading method for a rotational INS based on an inertially stabilized platform. The servo control loop is reconstructed on a four-gimbal platform, and it has the functions of providing both a level stability relative to the navigation frame and an azimuth rotation at a speed of 1.2°/s. With the platform’s rotation, the observability and the convergence speed of the estimation for the initial alignment can be improved, as well as the biases of the gyroscopes and accelerometers be modulated into zero-mean periodic values. An open-loop initial alignment method is designed, and its detailed algorithms are delivered. The experiment result shows that the newly designed rotational INS has reached an accuracy of 0.38 n mile/h (CEP, circular error probable). The feasibility and engineering applicability of the designed scheme have been validated.

2

Adaptive motion control with state constraints using barrier Lyapunov functions

Jastrzębski M., Kabziński J., Mosiołek P.

Przegląd Elektrotechniczny

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2016

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R. 92, nr 4

112--119

EN

A servo control with unknown system parameters and the constraints imposed on the maximal position and velocity is considered. The barrier Lyapunov functions approach is applied to assure the preservation of bounds in any conditions. The system performance is compared for three cases of the controller design: based on quadratic Lyapunov functions, based on barrier Lyapunov functions if only position constraints are imposed and based on barrier Lyapunov functions if both position and velocity bounds are present. The tuning rules are discussed and several numerical experiments demonstrating features of the proposed control and the influence of the parameters are presented.

PL

Opisano problem sterowania napędowym układem nadążnym z nieznanymi parametrami i ograniczeniami nałożonymi na maksymalne wartości położenia i prędkości. Porównano właściwości trzech układów regulacji: ze sterowaniem zaprojektowanym na podstawie kwadratowych funkcji Lapunowa, ze sterowaniem zaprojektowanym na podstawie barierowych funkcji Lapunowa i ograniczeniem na położenie, oraz ze sterowaniem zaprojektowanym na podstawie barierowych funkcji Lapunowa przy ograniczeniach na położenie i prędkość. Opisano szereg eksperymentów, które ilustrują charakterystyczne właściwości układu regulacji i dostarczają wniosków co do wyboru parametrów algorytmu sterowania.

3

Adaptive Servo Control with Polynomial Approximation of Stribeck Curve

Kabziński J.

Przegląd Elektrotechniczny

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2014

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R. 90, nr 5

20--24

EN

We consider a servo dynamics with friction modeled by static, memoryless nonlinear function of velocity, with strong influence of Stribeck effect. We consider approximation of the Stribeck curve by a polynomial. The approximating polynomial coefficients become control parameters modified by the adaptive loop. We formulate the control algorithm and prove its stability by Lyapunov function approach, and finally we describe several numerical experiments demonstrating features of the proposed control and the influence of the parameters.

PL

Przedstawiony niżej tekst opisuje problem sterowania napędowym układem nadążnym z tarciem, które może być modelowane przez statyczną, nieliniową funkcję prędkości z silnie zaznaczonym efektem Stribeck’a. Badamy możliwość aproksymacji krzywej Stribecka przez wielomian, którego współczynniki będą zmieniane w pętli sterowania adaptacyjnego. Wyprowadzamy algorytm sterowania i formułujemy warunki jego stabilności poprzez użycie odpowiedniej funkcji Lapunowa. Opisujemy szereg eksperymentów, które ilustrują charakterystyczne właściwości układu regulacji i dostarczają wniosków co do wyboru parametrów algorytmu sterowania.

4

Fuzzy logic gain scheduling for non-linear servo tracking

Brdyś M. A., Littler J. J.

International Journal of Applied Mathematics and Computer Science

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2002

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Vol. 12, no 2

209-219

EN

This paper proposes the use of gain scheduling as a method of controlling a servo system with hard non-linear elements. The servo controls two elements of a tracker mounted on a ship at sea. There is stiction at the zero velocity point and non-linear friction against the motion of each tracker axis. A dual feedback loop control structure is employed. Fuzzy logic is used to provide smoothly varying non-linear scheduling functions to map the velocity of the servo relevant to the deck of the ship onto the rate loop controller parameters. Consideration is given to the use of a derivative signal as a secondary input to the fuzzy inference system. Results are presented which demonstrate that this method of controlling the servo system gives a dramatic improvement over the traditional linear control methodology for low velocity tracking performance. A linear PID controller is used in the outer loop and its design is also given some consideration.