This paper presents a brief review of the state-of-the-art in the field of earthquake study and forecasting. We analyze the principles of the methods for determination of the coordinates of earthquake focuses by means of ground seismic stations. We demonstrate that those methods cannot be used in the system for monitoring of the beginning of the earthquake preparation process (in the network of RNM ASP stations). As we know, the beginning of the earthquake process is accompanied by spreading of noisy seismic-acoustic signals. Theoretically, the system for monitoring of the beginning of the earthquake process is based on the technologies for seismic-acoustic signal processing - Robust Noise Monitoring (RNM). The noise characteristics determined by RNM technologies indicate the beginning of the anomalous seismic processes (ASP) and, consequently, a possibility of ASP monitoring. Considering that the seismic-acoustic signal can be represented as the sum of the useful signal and noise (g = X + e), we present the technologies for determining noise characteristics. It is demonstrated in the paper that a change in the estimate of the cross-correlation function R_Xe(m = 0) between the useful signal Х(iDt) and the noise e(iDt), noise variance D_e and the value of noise correlation R_Xee(m = 0) determine the beginning of ASP. One RNM ASP station determines the beginning of ASP within a radius of about 500 km. Determination of the location of an expected earthquake requires a network of RNM ASP stations. We analyze the results of the noise technology-based monitoring of the anomalous seismic processes performed from July 2010 to June 2014 by nine seismic-acoustic stations built at the head of 10 m, 200 m, 300 m and 1400-5000 m deep wells. Based on the results of the experimental data obtained in the period covering over three years, an intelligent system has been built, which allows us to identify the location of the zone of an earthquake, using the combinations of time of change in the estimate of the correlation function between the useful signal and the noise of the seismic-acoustic information received from different stations 10-20 hours before the earthquake. In the long term, the system can be used by seismologists as a tool for determination of the location of the zone of an expected earthquake.

The authors discuss a possibility of application of the feedback principle for the task of control of a free-flying space handling robot (SHR) in the mode of handling operation. They propose a robot consisting of the main body (case), which has the control system by rotation and translational movement, and the three-links manipulator with rotation degree of freedom for each link. The SHR is expected to have a system of technical vision for obtaining information about the location of the target and the distance to it. The mathematical model of the space handling robot is introduced. For simplicity reasons the plane motion of the SHR is considered. The model has the coordinates of a grip deflection from a target in the inertial space in an explicit form. An algorithm is proposed for estimation of the coordinates with account of the information about the direction of the target and the distance to it. This information is obtained with the use of the range finder built in the video camera which is placed on the SHR case. The task of the control algorithm formation by the target capture in the inertial space is solved. The control task is determined as the solution of the three subtasks: 1) continuous target tracking, 2) accessibility of the target and 3) guarantee of soft-docking. The first subtask is an auxiliary one. But its solution is necessary for realization of measurements of the distance between the grip and the target. As a way to solve the second subtask the authors suggest a modification of the well-known random search with a return algorithm. Its efficiency is guaranteed by taking into account only the successful random steps of control which decrease the distance to the target. For soft docking (subtask 3) the area of the suggested algorithm must be restricted by the time moment when the SHR enters the small area which includes point A (target). An example of the free-flying space robot dynamics computer simulation is presented, which proves the efficiency of the proposed algorithm.

Mobile robot's motion control on different uneven surfaces under the influence of the external forces in unidentified environment has been analyzed. The mobile robotic platform consists of two parts - the external one and internal one. The relative movement of these parts causes movement of the robotic platform. The robot has pneumatic power source and a set of suction caps for different walls. The environment may include various moving and static obstacles which robot should avoid while moving. The robotic platform has its safe zone defined by robot's and obstacles' speed limits to prevent a crash. Any moving obstacle has its own trajectory and overall dimensions, which could be calculated by processing the data from the vision system. The vision system of the robot consists of a set of sensors: a laser scanner, an ultrasonic sensor and a camera. The robot's control system receives complex data from the sensors and calculates the linear and angular velocities of the robotic platform and the nearest obstacles, and, using its database, decides what behavior model should be applied. Different situations of the robot's and obstacles' relative positions with various values of the relative speed were analyzed. The strategy of the roundabout ways uses the data from the robot's sensors. The motion control algorithms for detouring of the moving and static obstacles were proposed. They envision different situations, which can happen on a wall while the robot moves to the point of destination.

The article is dedicated to the mathematical modeling of a movement trajectory of an automobile wheel. The authors discuss a problem of the description of a wheel braking process and calculation of its parameters in real time. They analyze the efficiency of the most widespread numerical methods which are applied for this purpose and considered the conditions, necessary for carrying out of the numerical modeling process of braking of an automobile wheel in real time. They propose and analyze a new method of the numerical solution of the equations of movement of a wheel in a braking mode. It is based on adaptation of the system to the integration process. Adaptation is carried out by means of application of a variable step of integration. Integration with small and greater steps is applied for elimination of the instability of calculation. At the initial stage the integration is done by small steps in order to ensure stability of the solution. The further integration is done by greater steps in order to decrease the time for calculation and maintain the stability of the solution. It was demonstrated, that application of the proposed method allows us to reduce the total time necessary for calculation due to an increase of the integration step without a bigger error risk in the counted parameters. This method is most effective for calculation of the movement parameters of an automobile wheel, loaded by maximal brake moment, in the braking mode on the road surface of any kind and state.

The article describes the technique of synthesis of the algorithm for control of the stabilization drive. The actuating element of the control system is a brushless direct current motor. So, the rotor of the executive motor rotates due to an external torque, and the position of the stator should be controlled. The objectives imposed on the transient process: no position overshoot and the maximum allowed range of the controlled object rotation velocity. A feature of the considered drive is the fact that the rotor of the executive motor rotates with a variable frequency and the rotation angle of the stator should be stabilized in its value. The velocity of the rotation of the drive rotor under an external torque significantly exceeds (almost two orders of the magnitude) the maximum allowed rotation velocity of the controlled object associated with the motor stator. The above requirements to the time-varying rotation velocity are satisfied by the developed control algorithm. The article describes the system of mathematical models of the executive motor, which takes into account its features, the algorithm of the synthesis of quasi-optimal control law and its modification with the maximum speed limit. The article presents the results of the computer simulation of the systems with such control algorithm, which prove the efficiency of the proposed system. The technique is used in the development of the stabilization drive of correction module for the small-size roll rotating aircraft. Experimental tests have shown the efficiency of the developed control algorithm.

The topic of the article is the problem of the correct selection of time for an optimal spacecraft turn from any initial position to the prescribed final angular position. The case, when a spacecraft is rotated with a minimal magnitude of the angular momentum, is considered. The optimal control is within the class of the regular motions. It is assumed that the dynamics of the spacecraft rotation during a turn corresponds to the well-known control method [1], which includes a maximal possible acceleration of rotation of a spacecraft, rotation with constant module of angular momentum and the maximal possible slowing down of the angular momentum. At the acceleration and braking phases the control moment is the greatest possible and is parallel to the spacecraft angular momentum; between the acceleration and braking phases the controlling moment is formed from the condition that spacecraft motion occurred strictly along the appointed trajectory of rotation defined by computational turn vector and a preset value of the modulus of the angular momentum. Formalized equations are presented, and computational expressions for definition of the optimal duration of reorientation maneuver are derived for the known mass-inertial characteristics of a spacecraft, if the attitude control is implemented with the use of the inertial actuators (system of powered gyroscopes, gyrodynes). The condition for determination of the moment of the beginning of the braking, which uses the current parameters of motion (information on the angular position of a spacecraft and measurements of the angular velocity) is presented, which increases considerably the accuracy of spacecraft movement to the required position. This paper is continuation of [1, 2].

The authors discuss the design of modern on-board equipment for visualization of the air navigation parameters and geo-details (digital district map) with certain requirements to the quality of the visualized information to be displayed. This kind of quality may be characterized in terms of brightness contrast for each color displayed on the screen. In order to ensure stable readability of the image for a pilot, a special procedure should choose chromaticity the coordinates of the image elements. The problem is considered of the research of the avionics on-board indication equipment in order to determine the set of chromaticity coordinate values for the displayed image with the use of automated design tools, which would allow an enhanced visual perception of the image details in the presence of intense external illumination. Various color coding systems used in the on-board indication equipment based on liquid crystal panels (systems of RGB and XY formats) are examined. The calculation of the chromaticity coordinates was based on Maxwell's color mixing triangle by mutual transformations between the elements of XY-plane and decimal codes of RGB-palette, used in the software of the on-board indication equipment. The scheme workstation for the research is proposed, the main components of the developed automated design tools, installed as part of the workstation, are described. The experimental results containing the measures of the brightness levels and estimated brightness contrast values, which were obtained for the given set of colors, are presented. An algorithm for an automated search for a global maximum on the function of two variables, which represents brightness contrast distribution in the chromaticity coordinates plane, is proposed. The decision-making rule approving the use of RGB-codes is the case when the brightness contrast of the test image displayed in any predefined color exceeds two. The results of the research are the methodology and the algorithm of searching the chromaticity coordinate values, which ensure the maximal brightness contrast level and the corresponding values of chromaticity coordinates at the points of maximal contrast.

This work describes the synthesis method for the system of automatic correction of linear displacements of the underwater vehicles. Often in the process of movement of an underwater vehicle the angles of roll and trim appear under the influence of torque impacts by grasped cargo, underwater cable, vehicle asymmetry and other perturbing factors. In some cases it is impossible to compensate for the unwanted angular underwater vehicle displacements with the help of thrust created by its propulsors. Uncontrollable changes in the spatial orientation of an underwater vehicle misroute it from the given direction. As a result, there is a problem of an accurate vehicle movement in a given direction even, notwithstanding the uncontrollable angles of roll and trim. In presence of the external forces and torques of the arbitrary non-zero values of the angles of roll and trim the proposed system automatically changes the corresponding propulsors' thrusts depending on the current values of the said angles. It ensures a high-accuracy underwater vehicle movement in a direction. Besides, the developed system allows us to eliminate the underwater vehicle's displacement from a given spatial trajectory, caused by the asymmetry of the vehicle and different values of the added mass of fluid and viscous friction coefficient when the underwater vehicle moves with different degrees of freedom. As result of using the proposed correction, an operator can control the desired torque vector of an underwater vehicle without considering the appearance of the arbitrary roll and trim angles. The results of the performed numerical simulations proved high efficiency of the synthesized complex control system, which has simple practical implementation and does not require installation of additional equipment and navigation systems for the underwater vehicles.

The article is devoted to the study of a numerical modeling of the impact of a rogue wave on a full-sized contour (middle-vessel cross section) in order to obtain the quantitative estimates of its motion parameters. The numerical simulation of rogue wave with the height of 30 meters and wavelength of 120-190 meters was fulfilled in a numerical wave tank with the length of 1000 meters and water depth of 250 meters, which was characterized by the following key features: a) Computational Fluid Dynamics theory; b) Reynolds-Averaged Navier-Stokes Equations using the Volume of Fluid method of the free surface and Three Degrees of Freedom method for describing the movement of the contour. Two maxima in the process of nonlinear transformation of a rogue wave were discovered. Free-floating contour was used to simulate a capsizing due to a rogue wave. Contour was mounted on the surface of the water in such a way that its position in the future would coincide with the x-coordinate of the second maximum of the rogue wave. The maximum of the water velocity in the area, located in the midst of the front, exceeded the velocity of the rogue wave. This caused the beginning of formation of a water jet from the specified zone named as plunging breaker. Simultaneous lifting, horizontal movement at high speed and capsizing of the contour were caused due to a huge steepness of the rogue wave front. The paper treats in detail the aspects associated with the numerical modeling of the contour capsize and estimation of the parameters of its motion. The time histories of the computed velocity of displacement, heeling angle, angle velocity and acceleration, forces, moment of impulse, power of heeling moment, heeling moment of the contour were calculated. The study indicates that the contours of the vessels of up to 9260 t cannot resist the heeling action of the rogue wave. Average capsizing time is half of the period of the rogue wave, which eliminates a chance for vessel's maneuver. Therefore, we can recommend the skippers to avoid swimming sideways to a wave even in calm sea conditions.