The complexity of objects and control systems increases the requirements for mathematical models. The structural identifiability (SI) assessment of nonlinear systems is one of the identification problems. Until now, this problem solves by parametric methods using various approximation methods. This approach is not always effective under uncertainty. We apply an approach to SI estimation based on the analysis of virtual framework. There is an objects class whose properties describe by nonsymmetric nonlinearities. The paper generalizes and develops the virtual framework (VF) method for systems with asymmetric non-linearities. Requirements for the system input are formed based on the excitation constancy property and S-synchronizability. Considering S-synchronizability gives VF that most fully reflect nonlinear properties of the system. A method for designing virtual structures based on the measurement information analysis describes. Structural identifiability fundamentals described for systems with symmetric nonlinearities. Splitting of the initial nonlinear system obtains for the VF application. Two methods consider for evaluating SI systems with nonsymmetric nonlinearities (NN) and propose their development on systems with nonsymmetric nonlinearities. Virtual framework almost homotheticity conditions obtain for SI estimation. A NN class with parametric features considers and conditions for estimating their almost homotheticity obtain. Conditions of almost homothety and h-identifiability obtain for systems with NN. The detectability and recoverability proofed for virtual frameworks guaranteed the SI estimation under uncertainty. The conditions under which the nonsymmetric nonlinearity is hypothetical symmetric nonlinearity obtained. The described approach to the SI assessment is general. If the SI of specific nonlinear systems analyzes, then features these systems consider. These features require modification of proposed algorithms and procedures. SI evaluation examples of closed nonlinear systems given under uncertainty and of the excitation constancy fulfillment.

The paper proposes a new method for synthesizing a full-order state vector observer for a certain class of linear stationary systems with unknown input signal. Two approaches that ensure the convergence of the estimation error (i.e., the error between the state vector estimate and the true state vector) to zero in a finite time are considered. The convergence time is set by the designer in the process of observer construction. The system parameters are assumed to be known and stationary, but the relative degree (from the measured output and the unknown input) is equal to one. The synthesis process using the first approach consists of two stages. In the first stage two auxiliary observers are used to estimate the initial conditions of the object in finite time. In the second stage, a third observer is introduced into the loop to perform online estimation of the system state vector. All the above three observers have the same structure that provides their insensitivity to the input signal, but different parameters. The second approach uses aggregation of auxiliary observers and introduce a delay operator to estimate the state vector. This method provides convergence of the observation error to zero after a delay time. The paper contains a rigorous mathematical proofs of the performance of the obtained solutions. To demonstrate the effectiveness and operability of the proposed approach computer simulation was carried out in the MATLAB Simulink software environment. A two-channel fourth-order mechanical system is considered as an plant. The simulation results illustrate the convergence of the state vector estimation error to zero in a finite time specified by the developer.

The key features and the principle of operation of a multidimensional fuzzy interval-logic controller with interconnected adjustable parameters developed by the authors are considered. The scheme of interpretation of continuous physical quantities by an equivalent set of terms and the basic version of the block diagram of the regulator are presented. The main elements of the logical output block are described, including the block of production rules, which includes a predefined database of values of control actions on control objects in the form of ordinal numbers of terms of output continuous quantities. The advantages and features of setting up the mutual connections between the input and output continuous values of the regulator are considered, which is expressed in determining the functional dependencies between them. The set of parameters possessed by the terms of input continuous quantities in relation to specific output continuous quantities of the regulator is described. The methods of defuzzification of the values of output continuous quantities within the boundaries of their terms are shown. The possibility of combining input and output continuous quantities into groups when setting up mutual connections between them is described. The mechanism of determining groups of interrelated continuous quantities is illustrated, the total number of which is determined by forming a matrix of relationships, according to the author’s scheme. The algorithm of sequential processing of the contents of the cells of the matrix of relationships, consisting of three steps, is considered. Expressions are given for calculating the basic parameters of a multidimensional fuzzy interval-logic controller with interrelated adjustable parameters. The results of a computational experiment to reduce the system of production rules of the regulator in determining the relationships between input and output continuous quantities are presented.

The main problems associated with the creation of autonomous intelligent robots capable of performing various complex tasks in a priori undescribed unstable problematic environments, based on the processing of knowledge presented in an abstract way, are outlined. To store typical elements of an abstract knowledge representation model, the article recommends using long-term and short-term memory. Long-term memory with associative search and data retrieval is designed to permanently store information necessary for planning a variety of purposeful activities that provide the robot with the ability to solve various complex behavioral tasks. In short-term memory, submodels of knowledge representation are entered from long-term memory, which are necessary for solving the current task of a certain type in the short term, related to the fulfillment of the task formulated for the autonomous intelligent robot. At the same time, with each change in the type of the current task of behavior being solved by an autonomous intelligent robot, a corresponding update of knowledge stored in short-term memory is simultaneously carried out. Original constructions of typical elements of the model for representing abstract knowledge in the form of various behavioral skills, set regardless of a particular subject area, have been developed. This approach to building a knowledge representation model allows autonomous intelligent robots to adapt to the current operating conditions and, on this basis, organize purposeful activities in complex unstable problematic environments. Various tools and rules for processing abstract knowledge are proposed, which endow autonomous intelligent robots with the ability to eliminate the differences between the current and target situation of the problem environment both in terms of the values of structurally equivalent relations of the same name in them, and in the current states of objects in the environment. This, in turn, makes it possible to create intelligent problem solvers for autonomous intelligent robots for various purposes, capable of performing complex tasks in unstable a priori uncertain conditions of a problematic environment.

The work proposes an algorithm for controlling a wheeled robot in an environment with static and dynamic obstacles. A wheeled robot (WR) consists of a platform, two wheels with a differential drive and one roller, which is used solely for the stability of the structure and does not affect the dynamics of the system. The robot’s motion algorithm assumes its movement from the starting point to the final point in an environment with obstacles. The robot’s motion program is specified through servo-constraints, and the algorithm that implements the motion program is based on the potential field method. In the case of a dynamic obstacle, a repulsive field of a shape elongated in the direction of movement of the obstacle is constructed, allowing the robot to safely go around it. It is possible to change the geometric dimensions of the field using the entered numerical parameters. An algorithm for overcoming a potential hole by a robot is presented, according to which the robot is taken out of the potential hole and directed to a global goal by an introduced fictitious point located outside the critical region (local minimum region) and having its own attractive field. The paper presents the results of numerical simulation of the robot’s movement both in an environment with static and dynamic obstacles, as well as the results of a numerical experiment with overcoming the region of a potential well. Graphs of the required mechanical parameters are presented. The results of numerical simulation confirm the effectiveness of the proposed algorithms.

The article presents the results of the development of a prototype of a functional layout of a soft exoskeleton of the hand, which is part of a robotic complex for restoring the function of the upper limb of patients after a stroke. The use of the layout will allow for therapy based on a mixed approach, which implements both assistance in carrying out independent movements of the patient’s hand, and their full implementation using data on its movement recorded during rehabilitation procedures. The authors of the manuscript present a comparative and quantitative analysis of two options for laying a cable system that drives the patient’s hand and fingers. To determine the best option for laying cables, a parametric study of the amount of work performed and the bending time of one finger was carried out, depending on the options for laying with and without taking into account the load. In the first variant, the cables were laid with small stitches of the order of one centimeter along the lower surface of the finger. In the second variant, the cable passed through the glove in places of natural attachment of tendons to bones. Testing was carried out on the index finger of a relaxed healthy person. At the initial moment of time, the hand occupied a position along the body, the fingers were completely unclenched, while a load was fixed on the distal phalanx. The flexion time of the finger was determined by a touch sensor attached to the palm of the hand. The results of experimental studies showed that cables with a minimum number of attachment points to the base of the exoskeleton in places of natural attachment of tendons to the bone give maximum effort and ensure the achievement of the largest range of possible positions of the phalanges of the fingers. The results of studies of the developed efforts on the part of the device on the fingers of a healthy person are also presented, which allow us to conclude that it can be used for rehabilitation purposes.