This paper deals with the adaptive suboptimal control of linear, discrete-time, time-invariant, minimum phase, scalar plants in the presence of nonstochastic bounded unmeasurable disturbances whose upper and lower bounds, which may be asymmetric, are assumed to be unknown a priori. Additional assumption is that an order of the difference equation describing the plant is known a priori. The distinguishing feature of the problem stated in this paper is that neither bounds on the unmeasured disturbances, nor bounds on an allowable region to which the unknown plant parameters belong are assumed to be known a priori. To solve this problem, adaptation procedures for the point and membership set estimation are utilized. The standard recursive procedure with adjustable dead zone is employed in order to derive the point estimates of unknown plant parameters together with the point estimate of time-invariant disturbance component. The size of this dead zone depends on the previous point estimate of the bounds on the time-varying disturbance component and also on a fixed suboptimality index chosen by the designer. The estimates generated by the point estimation procedure are directly exploited to derive the adaptive control law. The main idea advanced in this paper is that, instead of unknown a priori membership set of these parameters, their peculiar hypothetical a posteriori membership sets are designed via the use of the measured system’s signals together with the current point estimate of bounds on the time-varying disturbance component. Contrary to the usual membership set estimation approach, this set is updated if only it is discovered that the unknown parameter vector does not belong in reality to this set. To this end, a remarkable property of the point estimation procedure is utilized. Such an approach makes it possible to reconstruct this set and to update the previous estimate of the bounds on the time-varying disturbance component. The finite convergence of the adaptation procedures and also the ultimate boundedness of system’s signals are established. To demonstrate an efficiency of the adaptive controller and support the theoretical study, simulation results are presented.

The synthesis of control laws for an inertial stabilized platform (ISP) designed for stabilizing the image of an observed target in observer’s field of view and tracking the position of this target from an airborne vehicle is considered. Such a system consists of a stabilization loop for controlling the outer stabilizing frame of the double gimbal suspension, and a target tracking loop for controlling the inner frame of this suspension where the observer is located. One of the new proposals is to use a combined control in the stabilization loop, which consists of disturbance-based feedforward and error-based feedback controls and provides for the direct measurement of external disturbance with the help of high-speed PINS gyros. The synthesis of a stabilizing control law is based on the invariance theory as background for the feedforward control design and the robust control theory for the feedback control one. The robust control theory is also used for designing the feedback control for the tracking loop. The results of the design procedures are verified by simulating ISP operation in the stabilizing and tracking modes. These results prove the efficiency of the proposed design algorithms and obtained control laws.

This paper analyses errors compensation ability of differential mode of operation implemented in MEMS gyros based on planar micro-rings and micro-3D resonators such as micro-hemisphere, micro hemi-toroid and other micro shells which are bodies of rotation. It is shown when standing wave disposition is in between the electrodes there appear two angle rate measurement channels with different signs. With this, it turns out to be possible to compensate for errors caused by both external and internal destabilizing factors.

Introduction.The paper deals with nonzero set-point regulating the first-order linear discrete-time multivariable system.The case where the number of outputs exceeds the number of control inputs is considered.It is assumed that arbitrary but bounded unmeasurable disturbances are present.The assumption that the elements of the matricies arising in the system equation are unknown.However, their bounds are assumed to be known a priori.From practical point of view, it is important to design a simple controller similar to reduced-order or static output feedback (SOF) controllers.A difficulty associated with this problem is in establishing the existence of SOF control to be able to cope with a given system.The three different problems concerning the optimality, ultimate boundedness and robustness features are stated and solved.The purpose of the paper is to answer the question: is there the SOF control based on the pseudoinverse concept to stabilize some first-order multivariable system with nonsquare gain matrix?33

The design of the control systems of the inertially stabilized platforms (ISPs) as part of airborne equipment for the majority of aircraft has its peculiarity. The presence of rate gyros in the inertial measurement unit gives the possibility to measure the rotation rate of the ISP base, which is the main disturbance interfering with the ISP accuracy. Inclusion of the feedforward disturbance gain in the control law with the simplest PI feedback significantly improves the accuracy of stabilization by the invariance theory. A combination of feedback and feedforward controllers produces a synergetic effect, thus, improving ISP accuracy. This article deals with the design of the airborne ISP control systems consisting of two stages: the parametric optimization of the PI feedback control based on composite “performance-robustness” criterion and the augmentation of the obtained system with feedforward gain. To prove the efficiency of the proposed control laws, the simulation of the ISP was undertaken. We have used a simulation of the heading-hold system of the commuter aircraft Beaver and the yaw rate output of this closed-loop system we have used as a source of the disturbance. The results of modeling proved the efficiency of the proposed design method.

The robustness analysis of a digital autopilot for controlling the longitudinal motion of some UAV with time-varying parameters is addressed in this paper. As an example of such UAV, the guided missile controlled by an internal guidance system is considered. The autopilot represents the two-circuit feedback discrete-time control system containing the conventional P and PI type controllers. They are needed to stabilize the pith attitude and pith rate of an UAV whose flight conditions (the altitude and the airspeed) change in time. It is assumed that its parameters are known for each fixed flight condition. Using the so-called l1-optimization approach, the three parameters of P and PI controllers for different conditions are determined. The performance of the closed-loop control system with these controllers having time-invariant parameters are chosen for one of fixed flight conditions is studied by exploiting the numerical tool. It is established that the longitudinal autopilot which is the l1-optimal for some fixed flight condition can also be robust stable in a situation where they become time-varying.

Introduction.The adaptive stabilization of some classes of uncertain multivariable static plants with arbitrary unmeasurable bounded disturbances is addressed in this article.The cases where the number of the control inputs does not exceed the number of the outputs are studied.It is assumed that the plant parameters defining the elements of its gain matrix are unknown.Again, the rank of this matrix may be arbitrary.Meanwhile, bounds on external disturbances are supposed to be known.The problem stated and solved in this work is to design adaptive controllers to be able to ensure the boundedness of the all input and output system's signals in the presence of parameter uncertainties.The purpose of the paper is to show that it is possible to stabilize any uncertain multivariable static plant which gain matrix may be either square or nonsquare and may have an arbitrary rank remaining unknown for the designer.Methods.The methods based on recursive point estimation of unknown plant parameters are utilized to design the adaptive inverse model-based controller.Results.The asymptotic properties of the adaptive controllers have been established.Simulation results have been presented to support the theoretic studies.

The structure of the laser Doppler velocimeter, which uses the powerful laser diode. Using the laser diode, photodiode, and optic elements with small dimensions and mass will allow using such a device for measuring two vector components of the true airspeed of heavy unmanned aerial vehicles.

The article presents a model of a signal generated by microparticles moving in an aerodynamic flow.This model is based on the Lorentz-Mie scattering theory.It is shown that the visibility and the signal/noise ratio of the Doppler signal are determined by the degree of amplitude and polarization matching of the scattered waves.These parameters also depend on the degree of phase matching of "elementary" Doppler signals.Using this signal model, it is possible to calculate the shape of the aperture of the receiving optics for a specific type of laser Doppler anemometer.The use of such an aperture will increase the visibility, the signal-to-noise ratio and the measurement accuracy of the aerodynamic flow velocity using a laser Doppler anemometer.

This paper deals with deriving the properties of updated neural network model that is exploited to identify an unknown nonlinear system via the standard gradient learning algorithm. The convergence of this algorithm for online training the three-layer neural networks in stochastic environment is studied. A special case where an unknown nonlinearity can exactly be approximated by some neural network with a nonlinear activation function for its output layer is considered. To analyze the asymptotic behavior of the learning processes, the so-called Lyapunov-like approach is utilized. As the Lyapunov function, the expected value of the square of approximation error depending on network parameters is chosen. Within this approach, sufficient conditions guaranteeing the convergence of learning algorithm with probability 1 are derived. Simulation results are presented to support the theoretical analysis.

In this paper it is proposed the methodology of analytic design of the optimum structure for stochastic control system used on multi-degree-of-freedom stand simulator of spacecraft motion in the presence of deterministic and stochastic disturbances acting on it.

This paper deals with controlling the in-process inventories for the manufacturing system of a typical machine-building enterprise which includes the machining, the transport, the storage bunker and the assembly line. The decision-making is implemented under uncertainty associated with the absence of exact machining model assuming that machine failures are also possible. To cope with this uncertainty, the adaptive control approach is proposed. Within this approach, a new adaptive reorder policy which makes it possible to improve the performance of the inventory control system is developed. Simulation experiments are conducted to demonstrate the advantage of this policy.

Пропонується алгоритм ідентифікації моделей динаміки нелінійної системи «рухомий об’єкт-сервопривод» при врахуванні впливів на неї стохастичних збурюючих факторів в реальних умовах експлуатації.

The ℓ 1 -optimal digital autopilot needed to control of the roll for an aircraft under an arbitrary unmeasured disturbances is addressed in this paper. This autopilot has to achieve a desired lateral motion control via minimizing the upper bound on the absolute value of the difference between the given and true roll angles. It is ensured by means of the two digital ℓ 1 -optimal controllers of PI type The main result consists in establishing the fact that this controller can be robust in the presence of parametric and nonparametric uncertainties.

In the paper methodology of analytic design of the optimized and optimum structures of the regulator is considered. Procedure of regulator synthesis is implemented for the closed-loop system of stochastic motion control of the stand simulator of the aircraft angular motion under different types of influences.

Пропонується алгоритм ідентифікації моделей динаміки нелінійної системи «рухомий об’єкт-сервопривод» при врахуванні впливів на неї стохастичних збурюючих факторів в реальних умовах експлуатації.

This paper deals with the design of the l1-optimal digital autopilot needed to control of the roll for an aircraft under an arbitrary unmeasured disturbances. This autopilot has to achieve a desired lateral motion control via minimizing the upper bound on the absolute value of the difference between the given and true roll angles. It is ensured by means of the two digital l1-optimal controllers of PI type. The main result consists in establishing the fact that the autopilot can be robust in the presence of parametric and nonparametric uncertainties.

Запропоновано алгоритм оцінювання стану лінійних інваріантних у часі систем з довільними динамічними характеристиками об’єкта управління і системи вимірювання з урахуванням реальних експлуатаційних умов

Розглядається постановка етапу ідентифікації моделей дій пілота в контурі управління, методика, алгоритми й деякі результати його проведення на комплексі імітації польоту. Запропоновано новий підхід до ідентифікації моделей динаміки оператора в контурі управління рухомим об’єктом. Відмінності в основному пов’язані з багатоканальним розширенням традиційних моделей, що дозволяє значно більше враховувати саме біологічні властивості оператора.