In this paper, the new strategy of controlling complicated dynamical objects with variable or unknown parameters during their movement along smooth spatial trajectories is proposed. The proposed strategy is based on correcting program signals that define the movement of this object depending on accurate dynamical-object movement. Using this strategy considers the variance of dynamical object parameters and increased accuracy of their movement when typical linear controllers are used. The simulations and experimental researches confirmed the workability and efficacy of the proposed strategy.

Current states of mechatronic systems and the state of control objects in every cycle of functioning are usually evaluated with the aid of a set of values of controlled parameters, which are formed with measuring tracts of the system on the basis of signals of sensors. Presently, methods of the analysis of trends of changing the system parameters and control of their location within the limits of warning and emergency intervals are widely used in mechatronics. However, this provides identification of facts of development of already formed negative tendencies, when urgent managerial decisions and technical measures are required for avoidance of emergency situations. More effective control may be implemented during early assessment of the events, what is very important for mechatronic systems, in which systematic processes relatively quickly take place. In connection therewith the cyclic use has been considered of the three-stage process of continuous dynamic tracing of temporary rows of controlled parameters and the use of a fuzzy logic apparatus with the coded fuzzyfication for taking operative decisions about discovery of negative trends in each of five consecutive intervals of observation. Development of solutions in the mechatronic system about the steady increment or decrease of individual parametrical trends or availability of trend flats can be carried out with the aid of a finite set of production rules, which form a consecutive structure of logical conclusions. As for the logic of the simplest procedures of tracing the migration of parameters and production rules of generation of solutions are implemented in processors which support operations with a floating point and logical digit-to-digit operations.

We consider two problems in this work. The first is the justification for the possibility of obtaining the amplitude-frequency response (AFR) of the retina by processing rhythmic electroretinograms (RERG). The second problem is to approximate the obtained AFR of the retina in order to obtain additional formalized features of the current state of the retina in the form of the coefficients of the approximating polynomials. When we obtain the AFR of the eye retina, we take into consideration the spectrum of the input testing signal (stimulus). Light stimuli are periodically repeated short rectangular light pulses of five standard frequencies. Due to the fact that the retina is a nonlinear dynamic object, the changes in the AFR of the retina are evaluated and taken into consideration in the obtaining of the frequency characteristics for each frequency of light flashes. For the polynomial approximation of the obtained AFR's of the retina, it is proposed to distinguish two frequency ranges: the low-frequency range (from 0 to 50 Hz) and the high-frequency range (from 50 to 120 Hz). In the low-frequency range it is proposed to smooth the retinal AFR by the second degree polynomial smoothing, and in the high-frequency range - by the first degree polynomial smoothing. The proposed approximation of the frequency response allows to obtain 25 additional features from five experimentally determined AFR's for one person. In this case each AFR is characterized by five coefficients of smoothing polynomials. The results of the work allow us to compare different methods of classification (diagnosis) with using the received features.

In this paper, we formulated and solved the problem of fixed-lag smoothing estimation for continuous linear dynamical systems. The problems of other fixed-lag smoothing algorithm for continuous linear dynamical systems are indicated. Firstly, sometimes the fixed-lag smoothing algorithm is not stable. Secondly, the knowledge of state transition matrix is needed to implement algorithm. It is different to get it, especially for time-vary system. An algorithm is developed for generating the optimal smoothed estimate x(t - T|t) of the state x(t) of a continuous linear system, where t is the most recent measurement and T is a positive real constant. The recurrent algorithm is obtained using the properties of state transition matrix Ф(t₁, t₂) of a linear dynamical system. The developed method makes it possible to bypass the time-consuming procedure of finding state-transition matrix. The process of computing the fixed-lag smoothed estimate is discussed in terms of the algorithm's dependence on the solutions of the filtering and fixed-point smoothing problems. Therefore, the calculation of the estimation of fixed-lag smoothing depends on the value obtained during the filtering process. We give the simulation result of fixed-lag smoothing algorithms for a nonstationary linear system and compared it with the simulation result of filtering algorithms. It is showed that the estimation errors of fixed-lag smoothing are less than the estimation errors of filtering. We also used the fixed-lag smoothing algorithms to improve the localization accuracy of robots in the task of motion control of convoy robots. A node named fix_lag_smoothing is written using C++ in ROS

The solution of the inverse kinematics problem of the manipulator is considered. The inverse kinematics problem of multi-link manipulators is a multi-extremal optimization problem with functional and positional constraints. Global optimization algorithms are commonly used to solve that kind of tasks. In this paper the solution of the inverse kinematics problem using the hybrid search method is considered. This method is a combination of genetic algorithm and simplex search. The genetic algorithm is not able to move quickly towards the optimum, but is able to find a global optimum on a multi-extremal function. Simplex search quickly moves toward a local minimum, but is not able to find a global minimum. This combination uses the strengths of both search algorithms, while covering the weaknesses. At each step of the genetic algorithm, the best individuals are selected to become the centers of simplex searches. Simplex searches improve the population of the genetic algorithm. Thus, a global extremum can be found in several steps of the genetic algorithm. For testing several redundant and non-redundant manipulators was used and for each of them several desired positions was specified. In solving the inverse kinematics problems, the hybrid algorithm showed comparable accuracy with the genetic algorithm with larger number of calls of the objective function. In addition, this algorithm is very easy to implement and there are no issues associated with the gradients of the objective function and functional limitations. This method allows us to find solutions for non-redundant and redundant manipulators.

The paper considers the options of renewable power sources development for marine objects operated in absence of solar energy. Operation of many undersea vehicles is evidently limited by their battery charge. When operating at shallow depths, such vehicles experience pitch and roll in the wave-perturbed environment. Buoys floating on the water surface are also disturbed by sea waves. Moreover, when they are operated during polar night, solar energy cannot be used for charging their batteries. To solve this problem, it is proposed to use the energy of surface waves or the vehicle pitch and roll. It is quite possible to transform the energy of wave current and the orbital velocity of water particles motion into propeller rotation. Basic theory of using such devices for energy accumulation and their capabilities are studied. It is stated that several such devices installed in orthogonal directions relative to each other will transform the energy that is also generated by the undersea vehicle's propulsion when its depth is changing. Furthermore, the vehicle pitch/roll energy transformation into electric power is discussed. This idea is extremely attractive, so it is not new. However, generators of this type have never been used on undersea robotic vehicles. The paper presents an induction generator designed and patented by the author. It is shown that its operation is described by a differential equation of the 2^nd order. It is proposed to adjust the electromechanical system of such transformers to be resonant with the dominant pitch/roll oscillations. This can be done by varying the degree of the oscillating system damping. Potential engineering solutions and physical principles of their operation are discussed. The proposed small-size transformers are estimated in terms of power capacity and compared to the existing similar devices. It is demonstrated that the proposed generators are able to generate power of a few dozens Watt.

Lack of the haptic feedback in the minimally invasive surgery often results in the increase of the complexity and duration of the surgical operation. This study aims at creation of a system that provides transmission of tactile sensation and consists of a master manipulator, control unit, and actuator equipped with a force sensor. The user pushes the button on the manipulator. The motion of this button is synchronized with the motion of the slave actuator that indents into the soft tissue. The load upon the indenter is measured by the force sensor and transmitted to the control unit. The control unit determines the operating frequency of a piezoelectric actuator in such a way that the actuator generates a force corresponding to the measured load. This force is applied to the button of the manipulator, and the user feels it. Thus, the system ensures the tactile feedback. Mathematical model of the system is created. In order to describe the dynamics of the actuator subsystem, a simplified empirical model is used. Parameters of the model are identified based on experimental data. Numerical simulation of dynamics of the system is performed using the determined values of parameters for the case when the button moves harmonically. Soft tissue is modeled by linear elastic springs with different stiffness coefficients. Influence of the dry friction between slider and its guide is analyzed. It is shown that the system ensures tactile sensing and allows distinguishing objects with different stiffness characteristics based on maximum value of the force experienced by the user from the part of the button and the rate of growth of this force.

The technique of the direct current motor math model obtaining is considered in this article. Despite the fact that the classical math model is widely known and well studied it often becomes necessary to refine and determine its parameters by experiment. The technical documentation may not specify all motor parameter of interest. Sometimes there is no information about the motor at all. In addition the features that the classical model does not take into account can be presented in a real motor in practice. At the beginning of the paper the traditional model of the motor is under consideration as well as its static and dynamic characteristics. The model parameters to be determined are brought out. Further the analysis of the features that distinguish the behavior of the real motor from the behavior predicted by the model is carried out. These features are commutator operation, the geometry of the motor, and the reducer action on system. The influence of these features on the motor operation is researched by the different experiments and the conditions under which the parameters of motor model should be obtained are determined. Further the technique of math model obtaining based on the analysis done is carried out. The method is based on the experimental determination of current and torque ratio on the one hand and the applied voltage and rotation speed on the other hand. Wherein the technique takes into account the effect of motor shaft friction which is increasing when there is a load on it. The method for compensating this effect to exclude its influence on the math model determining result is proposed. An example of application of the described technique to determining model of Lego NXT servo motor is given further. The numerical values of the parameters and the graphical data are presented. Finally, the behavior of the real motor and the behavior calculated from the model obtained earlier are compared. As a demonstration system, the automatic control system of the motor shaft rotation angle based on the proportional controller is used.