In the paper multiobjective robust controller synthesis problem for nonlinear mechanical system described by Lagrange’s equations of the second kind is considered. Such tasks have numerous practical applications, for example in controller design of robotic systems and gyro-stabilized platforms. In practice, we often have to use uncertain mathematical plant models in controller design. Therefore, ensuring robustness in presence of parameters perturbations and unknown external disturbances is an important requirement for designed systems. Much of modern robust control theory is linear. When the actual system exhibits nonlinear behavior, nonlinearities are usually included in the uncertainty set of the plant. A disadvantage of this approach is that resulting controllers may be too conservative especially when nonlinearities are significant. The nonlinear H∞ optimal control theory developed on the basis of differential game theory is a natural extension of the linear robust control theory. Nonlinear theory methods ensure robust stability of designed control systems. However, to determine nonlinear H∞-control law, the partial differential equation have to be solved which is a rather complicated task. In addition, it is difficult to ensure robust performance of controlled processes when using this method. In this paper, methods of linear parameter-varying (LPV) systems are used to synthesize robust control law. It is shown, that Lagrange system may be adequately represented in the form of quasi-LPV model. From the computational point of view, the synthesis procedure is reduced to convex optimization techniques under constraints expressed in the form of linear matrix inequalities (LMIs). Measured parameters are incorporated in the control law, thus ensuring continuous adjustment of the controller parameters to the current plant dynamics and better performance of control processes in comparison with H∞-regulators. Furthermore, the use of the LMIs allows to take into account the transient performance requirements in the controller synthesis. Since the quasi-LPV system depends continuously on the parameter vector, the LMI system is infinite-dimensional. This infinitedimensional system is reduced to a finite set of LMIs by introducing a polytopic LPV representation. The example of multiobjective robust control synthesis for electro-optical device’s line of sight pointing and stabilization system suspended in two-axes inertially stabilized platform is given.

At the present, there are no satisfactory engineering solutions related to the synthesis of robust regulators taking into account the constraints on control. In this connection, it is important to study the influence of saturation effect of the controller on the robust properties of systems. In this paper, this problem is considered in connection with K∞-robust control systems with a high gain. It is shown that in control limit systems, in particular, K∞-robust systems at the initial instant of time, the control assumes an excessively large value. This ensures the robustness of the dynamic mode. The reason for this feature is related to the fact that at the initial instant of time the initial conditions has a great importance. The main reason for the deterioration of robust properties is due to the tight control in the initial time interval. Provision of robustness of the static mode does not require great control efforts. For the first time, using computer graphics in a three-dimensional coordinate system, taking into account the time, a visual representation of the sections of phase trajectories pertaining to different types of movements is given: rapid motion from an arbitrary initial state that ensures hitting the imaging point into the degenerate trajectory; slow motion along this trajectory; steady-state motion within the specified accuracy. For the limit control systems, an integral robustness estimate is proposed, which consists in calculating the integral of the absolute value of the slow motion trajectory. This indicator characterizes the discrepancy (dispersion) of the real trajectory with respect to the limiting trajectory. The reliability of theoretical reasoning is confirmed by solving a model problem in the block-vision environment of Matlab/Simulink.

In this paper, we consider the problem of the development of an algorithm of the adaptive cruise control functioning operating in the conditions of powertrain gear ratio varying in a wide range and vehicle velocity changing. The functioning of a classical cruise control system is generally based on the usage of a PID-controller with constant coefficients. However, despite the easiness of its tuning and physical realization and also its relatively high robustness this class of control devices cannot guarantee the cruise control system optimal functioning in all driving conditions because the plant is not timeinvariant and linear. To overcome the above shortcomings, in this research we consider the possibility of neural network realization of a commercial vehicle adaptive cruise control algorithm.

In this paper, we propose the mathematical model of a commercial vehicle longitudinal motion designed for the control system analysis and synthesis. We carry out the PI-controller coefficients tuning to control the vehicle longitudinal velocity in various driving conditions of a commercial vehicle. We show that the controller coefficients vary according to a rather complex law. Therefore, we propose the algorithm of the adaptive cruise control functioning based on the approximation of the controller coefficients by the artificial neural network. The network used is the multilayer perceptron and it has ten neurons in the hidden layer to provide the high quality of the approximation. We carry out the training of the neural network by the Levenberg-Marquardt method with a sample of a total volume of 500 points, obtained using standard methods of controller synthesis. We verify the correctness of the obtained results through the computer simulations of the vehicle acceleration from 0 to 100 km/h, proving that the PI-controller coefficients, providing the required transient responses, significantly vary depending on the current state of the vehicle. The approach of the PI-controller coefficients approximation presented in this paper may be further used in the design of adaptive control systems able to function effectively in various operating modes.

This paper focuses on the real-time kinematics solution of an aerial manipulator mounted on an aerial vehicle, the vehicle’s motion isn’t considered in this study. Robot kinematics using Denavit-Hartenberg model  was presented. The fundamental scope of this paper is to obtain a global online solution of design configurations with a weighted specific objective function and imposed constraints are fulfilled. Acknowledging the forward kinematics equations of the manipulator; the trajectory planning issue is consequently assigned to on an optimization issue. Several types of computing methods are documented in the literature and are well-known for solving complicated nonlinear functions. Accordingly, this study suggests two kinds of artificial intelligent techniques which are regarded as search methods; they are differential evolution (DE) method and modified shuffled frog-leaping algorithm (MSFLA). These algorithms are constrained metaheuristic and population-based approaches. moreover, they are able to solve the inverse kinematics problem taking into account the mobile platform additionally avoiding singularities since it doesn’t demand the inversion of a Jacobian matrix. Simulation results are carried out for trajectory planning of 6 degree-of-freedom (DOF) kinematically aerial manipulator and confirmed the feasibility and effectiveness of the supposed methods.

The task was to develop an automatic landing system (ALS) for a passenger carrier that can be externally activated and excludes the possibility of the crew’s interference into the landing process, for example, when a carrier alters its nominal course or there is no contact with the crew. The air crush history saw a lot of cases that could have been prevented if the planes had had an ALS system and airports had had possibilities to activate that system and suspend the crew from flight control. One of such unforgettable examples is the New-York tragedy of September 11, 2001. State-of-the-art technology allows solving the problem of automatic carrier landing. The most remarkable example demonstrating solution of this problem is the automatic landing of the Buran orbiter 30 years ago on November 15, 1988. The article consists of two sections. The first section of the article deals with conditions of effective solution of autoland problem. It describes in short, the flight modes during automatic landing control. To solve the problem of automatic longitudinal control in the most crucial final landing mode, the author proposes an energy-saving control algorithm that provides control in the mode of negative feedback. The system status vector comprises six parameters: range, altitude, pitch angle, and their first-order derivatives. The control algorithm is developed for the Tupolev TU-154M airliner. In development of the algorithm, the following assumptions were used: a) a linear model of dependence of aerodynamic data on the angle of attack; b) a linear model of programmed switch of engine thrust to the idle mode on the interval of 3 seconds from the beginning of the flareout; c) a pitch angular acceleration, occurring at elevator rate reversal, as a control signal; d) the frequency of the control algorithm operation equal to 200 Hz. The second section further analyzes characteristics of the energy-saving algorithm of automatic control of compulsory passenger carrier landing during the final landing phase, which was developed in the first section. The author developed a model program of control and mathematically modeled the carrier landing phases. When switching from one phase to another, the motion parameters were concatenated so that the final motion parameters of the previous phase became the initial motion parameters of the next phase. The author also studied the influence of errors in aerodynamic data on the landing conditions. The modeling revealed that if a pitch deflection direction is used for the determination of phases, then in a general case, the landing mode consists not of two traditionally determined phases, but of the following three: pitch angle increase (flareout), pitch angle decrease (float), and again, pitch angle increase (this phase is called ‘maintenance’). The necessity to introduce the third phase is determined by the presence of errors in the aerodynamic data of the airplane. On the whole, it is confirmed that the energy saving control algorithm provides successful solution of the problem of automatic landing of a passenger carrier at its final flight phase. At that, it is determined that the landing mode does not exceed 5s.

In order to fulfill the corresponding task successfully, a crucial issue should be addressed is the path planning for the exploration of the Mars surface owing to the environmental features of the tough terrain. Traditional path planning algorithms, such as the A* algorithm and the improved A* algorithm — the algorithm D* and the Field D*, which have been successfully implemented on the planetary rover during the expeditions of the Moon and Mars, have the problem of finding the shortest optimal path. One of the more effective algorithms derived from the modified A* refers to the Basic Theta* or the Lazy Theta* algorithms, which are faster any-angle path planning. Additionally, the algorithms can find shorter routes. In this paper, derived from a comprehensive comparison of the existing algorithms (A*, Basic Theta* and Lazy Theta*), a novel modification of the Lazy AT methodology is proposed to reduce the calculation time and obtain a shorter path. Based on the analysis of the surface feature of the Mars topography, the corresponding safety indicator is discussed. The principal hazards of the wheeled vehicles during the exploration on the surface of the Mars are the slopes and the obstacles. According to the requirements for avoiding obstacles as well as the exploration stability of the Mars rover in the period of the exploration, the following topographic coefficients have been chosen to develop the hazard indicator, i.e., the inclination angle of the terrain, the surface roughness and the height difference of the terrain. In addition, to obtain a safe trajectory in algorithm Lazy AT on the Mars surface, the terrain hazard indicator (risk indicator) for the modification of the Risk Lazy AT algorithm is also proposed in this paper. The comparing analysis modeling results of the Risk Lazy AT and Lazy Theta* has shown that our proposed algorithm Risk Lazy AT can guarantee the safety movement of a mobile object during the exploration on the surface of the planet. In light of the real-world surface features of the Mars terrain, the digital map of the planet’s surface has been developed and the spatial routing of the rover has been tested with our novel proposed algorithm, so-called Risk Lazy AT.

It is shown that the known limitations on the measurement of air parameters on board the helicopter due to significant aerodynamic disturbances introduced by inductive flows of vortex column of main rotor. This determines the need to create the means of measurement, taking into account the aerodynamics and dynamics of the helicopter flight. The known direction of overcoming these limitations is the use for measuring the information of aerodynamic field of vortex column of main rotor and its perception by means of the stationary multi-functional aerometric receiver. However, the need to protect a large number of full-pressure tubes installed in the flow channel of the multifunctional aerometric receiver, strict requirements for the identity and stability of the characteristics of the large number aerometric channels, complicate the design, reduce reliability, increase cost, inhibit the use of the air parameters measurement system on helicopters of various classes and purposes. Principles of construction, functional scheme, features of perception of primary information of measuring system of air parameters of the helicopter with the stationary receiver of a stream, ion-label and aerometric measuring channels are showed. Algorithms for processing primary information at various stages and flight modes, including: in the parking lot before the launch of the power plant and when rotating the rotor, when taxiing and maneuvering on the earth’s surface, on takeoff and landing modes and when flying at low speeds, at flight speeds, when the stationary receiver of primary information leaves the zone of the vortex column of the rotor using ion-label and aerometric measuring channels, are presented. It is shown that the proposed approaches to the construction, models and algorithms for processing the primary information of the measuring system air parameters of helicopter with ion-label and aerometric measurement channels allow to determine the speed and direction of the wind vector, altitude-velocity parameters of motion relative to the environment and atmospheric parameters in a wide range of helicopter operation, which determines its competitive advantages in solving problems of piloting and provide the flight safety of helicopters of different classes and purposes.