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The paper deals with a problem of position and orientation errors of mobile platform of large-sized parallel cabledriven robots. The advantages of parallel cable-driven robots are simplicity of structure and scalability. At the same time, parallel cable-driven robots are difficult to design due to the specific problems such as collision of cables, geometric and structural nonlinearity in the mathematical models of the main elements of the robot. In this paper, we consider the problem of eliminating the uncertainty associated with deformations of the elements of the robot structure. Such a configuration of the cable system is selected, in which the proximal anchor points of some cables can be considered without errors relatively to given positions. The cable system of a large-sized robot is mounted on the towers. The errors in the proximal anchor points relatively to given positions become significant due to the significant deformations of upper sections of the towers. The deformations of the towers in lower sections can be considered insignificant, and the proximal anchor points have to be located no higher than the middle of the tower to be considered corresponding to a given position. The aim is to compensate the position and orientation errors of the mobile platform of large-sized parallel cable-driven robot due to deformations of the cables and towers. The task suppose uncertainty about the coordinates of the proximal anchor points of the upper cables. Cable deformations are determined from Hooke’s law using tensile forces measurement in cables. The problem of compensations is solved in two stages. At the first stage, the approximate bias of the center of mass of the mobile platform along the vertical coordinate is found. It is defined as the height of the truncated pyramid, the edges of which are formed by stretched lower cables. At the second stage, rotation angles of the mobile platform are determined. Using the rotation matrix, biases in the heights of each distal anchor points are found in the tool coordinate system. In the studied cases PID regulation is used, however, more advanced techniques of automatic regulation, for example, optimal control, can provide better results. The tasks are applied to the model of large-sized symmetric parallel eight-cable-driven robot.

The paper deals with a problem of modeling of the dynamics of a parallel cable-driven robot with the inclusion of structural nonlinearity of cables in a mathematical model. Mathematical model is implemented in a computer model with the possibility of using of symbolic calculations. Parallel cable robots as a type of robotics have been developing in the last two or three decades. The research in the theoretical field was being carried out and the mathematical model of the cable system was being refined with the spread of the practical use of cable robots. This is a non-trivial task to draw up a dynamic model of a cable-driven robot. Cable-driven robots are highly nonlinear systems, because of the main reason for the nonlinearity is the properties of the cable system. As an element of a mechanical system, the cable or the wire rope is a unilateral constraint, since the cable works only for stretching, but not for compression. Thus, the cables are structurally nonlinear elements of the system. On the other hand, cables have the property of sagging under their own weight. Thus, the cables are geometrically nonlinear elements of the system. Under the condition of a payload mass that is utterly greater than the mass of each cable, the cables can be considered strained without sagging and geometric nonlinearity can be neglected. Since symbolic computations can be used in a computer model which implements a mathematical model of the dynamics of a robot, in such a way it must provide the possibility of symbolic computations with the condition of structural nonlinearity. The main aim of this work is to develop a method that ensures the inclusion of the structural nonlinearity of the cable system in the mathematical model. It is supposed to consider the possibility of implementation of the computer model with symbolic computations. The problem of including a mathematical model of cables as unilateral constraints in the model of highly loaded cable robots is considered. The justification for including the activation functions in a system of differential equations of dynamics of cable-driven robot is formulated. A model of wire ropes as unilateral constraints is represented via including the activation functions in a system of differential equations. With using of the proposed method, numerical solution of a problem of forward dynamics has been obtained for high-loaded parallel cable-driven robot.

The problem of controlling the shape of a sectional sprinkler of circular motion is considered and the conditions for the attainability of its optimal configuration and the stability of the programmed motion of the supporting traction trolleys providing the required movement are determined. The effect of self-orienting the support trolleys is confirmed and explained. Methods for controlling the movement of a group of sections of a sprinkler are proposed to ensure its optimal configuration, consisting in a sequence of adjusting the speeds of the support trolleys in accordance with the established laws. It is shown that with a rational construction of the configuration of the sprinkler and optimal control of the movement of the support trolleys, there is no need for drives for rotating the support trolleys relative to the sections of the sprinkler, which simplifies its design and control system.

An overview of new theoretical studies in the field of methods of heating hot sheet stamping of extra-strong metal alloys and the formulation of research tasks is presented

The prospects of using lidar as an element of technical vision of underwater walking vehicles are discussed. Walking machines appear to be the most suitable for seabed conditions. The proposed elements have a number of advantages over more traditional image sensors. Shown are already existing patents applicable for use in seabed conditions. It is proposed to use lidars for a system of automatic recognition and determination of geometric dimensions of anomalies and structural elements of technological pipelines in the oil and gas industry.

The results of theoretical studies in the field of temperature stresses arising during heating of the billet plate are presented. The theoretical equations of temperature stresses over the workpiece area are derived.

Mobile robots with walking propulsion devices operating in a "pulling" mode, which, as a rule, are unstable, are considered. It is explained to the jamming of propulsion device due to the orthogonality of the acting force to the virtual displacement of the point of application. The task is to develop such an algorithm for controlling the robot, which consists in purposefully changing the geometric orientation of the propulsion devices controlled by the swing drive, which will ensure stable motion. A method for controlling the orientation of the walking plane with its initial deviation from the programmed position is proposed, based on the implementation of a discrete control algorithm, which provides for the introduction of such a piecewise constant function at each step of the mover, which has received an initial perturbation, which will provide a stable motion mode in a finite number of steps. The change in the orientation of the walking planes of the propellers connected with the steering is controlled, and thereby the direction of movement of the robot body changes in the first step, as in the subsequent ones. The described algorithm assumes the fulfillment of two necessary conditions: the presence of an information-measuring system that controls the orientation of the walking planes and ensuring that the interaction forces of the feet controlled by the steering of the propulsion devices with the supporting surface are sufficient for the absence of slippage. An algorithm for controlling "dependent" propulsion devices (working out the programmed translational motion of the body) is presented, taking into account the fact that their orientation depends on the orientation of the controlled ones, which consists in changing the step length, which should also be determined to ensure movement stability. The main task of controlling "dependent" propulsion devices, which do not change the orientation of their walking plane at the initial moment of time, is to determine the points for setting the feet by changing the step length, in accordance with the established criteria and design constraints, in particular, energy efficiency, maximum efforts in drives, maximum and minimum stride length. The propulsion device will start to work in a stable "pushing" mode at the final stage of motion correction, by performing a sequence of actions. It has been established that the "pulling" mode of the walking propulsion device can be stable, with appropriate control.

At present, when every year there are more problems with the environment, humanity is in search of environmentally friendly products. Such is technical cannabis. This article is devoted to the development of the first tier of a trailed hemp harvester working with the Kirovets K-744 tractor. The advantages and disadvantages of the developed installation are given.

An energetically effective motion of a walking robot on a hard ground is considered. With the help of the methods of the classical calculus of variations, laws of the optimal acceleration and deceleration energy of the robot are calculated based on the minimum criterion. The resulting motion laws correspond to the extremals of the investigated quality functional.

This article is devoted to the development of a wheel-legged platform, the task of which is to move in natural conditions, off-road. A step-by-step scheme of overcoming an eight-point (eight-legged) wheel-legged platform and a mock-up built in SolidWorks are described. A layered hierarchic control system of the platform is presented.

The results of finite-element modeling of the mechanics of contact interaction of small-sized support elements (feet) of walking machines with weakly bearing soils are discussed. A flat contact task is formulated for rigid feet of a rectangular shape interacting with an elastoplastic supporting surface. Nonlinear models of soil behavior under loading were used. A two-stage iterative algorithm for solving the non-linear problem in the computer system of finite element analysis ANSYS is implemented. The task was solved under conditions of large deformations of the supporting surface. The simulation results showed that a sufficiently large amount of soil is loaded during the interaction of a small foot with a supporting surface. Under normal loading, the greatest stresses and strains occur directly under the foot. Here may be the destruction of the soil. At a standardized depth of 0,5 m, the stress decreases. The top layer of soil remains lightly loaded. In addition to vertical deformations, there is a «squeezing» of soil to the right and left from under the foot. With a tangential load, the stress and strain fields lose their symmetrical nature. The zones of greatest equivalent stresses and strains are shifted towards the action of the tangential load. The greatest ground stresses occur under the foot and on the lateral surface of the foot. In the direction of the tangential load, the entire mass of the soil, including its upper layers, is substantially loaded. Near the foot, in the zone of greatest stresses, a characteristic area appears, where the soil is squeezed up. Here the reverse process of compaction of the soil takes place. It is shown that the use of feet with a small supporting surface leads to an undesirable increase in soil stresses in the contact zone. On the other hand, in small feet, there is a decrease in the soil compaction zone and its upper layer is less loaded. Also, for small feet, the supporting surface is used more efficiently - the stresses along its length are distributed more evenly, and the side surface acts as a grouser.

The features of controlling the movement of a walking robot with orthogonal propulsion when overcoming obstacles are considered. The problem of the coordinated control of horizontal and vertical displacement drives is formulated to implement a motion mode that ensures optimality in the given criterion. The criterion of optimality is the minimum heat loss in the drive motors. A methodology for solving the problem and the simulation results are presented.

The article deals with the problems of mathematical modeling of chemical compounds by the example of adamantane derivatives. As the main me-thod, matrix forms of representation of the molecular structure are used, the use of which should be recognized as the most convenient for constructing mathematical models in the MATLAB package. The use of the theory of molecular assemblies when considering chemical compounds from the perspective of evolutionary modeling is substantiated. The possibility of formulating the problem of searching for the structure of chemical compounds of adamantane derivatives in the form of an optimization problem using genetic algorithms is shown. An attempt is made to generalize the results of modeling adamantane derivatives to a wider class of molecular compounds with a complex spatial structure.

The analysis of existing technical means for growing plants in controlled conditions of artificial climate is given. The concept of a multi-section climatic chamber is substantiated, design options are proposed, as well as a block diagram of automated control.

This article is devoted to an overview of docking mechanisms of the wheeled-walking platform for an agro-robot. It describes the advantages of dividing the wheeled-walking platform into two different platforms. An overview of the docking mechanism designs is presented. A table of advantages and disadvantages of each of the docking mechanisms is given.

Rubber-metal products represent one of the most important classes of products used in modern machine building. In most cases, reliability and durability of structures are determined by reliability and durability of component rubber products. Therefore, there are increased requirements for the calculation of rubber products. In the field of operational loads, the rubber is in a highly elastic state; i.e., it relates to elastomers. Since in a highly elastic state the rubber is a low-modulus material and allows for large operational deformations, a nonlinear theory of elasticity must be used to describe the stress–strain state. This paper discusses a specialized Maple-based calculation system that focuses on the calculation of the shear damper. This system helps solve any static problem with finite antiplane shear deformation with mixed boundary conditions and any generalized neo-Hookean potential of the strain energy for areas with a complex configuration. An example of comparing a numerical solution with a known exact solution for Treloar strain energy potential is given. For Fung’s deformation energy potential, a new exact solution obtained by a semi-partial method is given and is also compared to the numerical solution. The results of the compared solutions show the suitability of the proposed Maple-based calculation system.

We construct a programmed motion of the drive to adapt a walking mover to the supporting surface based on the optimality criterion that takes into account the energy costs of movement, the shockless interaction with the ground, and the traction–coupling properties in stepping.

A few indicators characterizing the efficiency of mobile robots in general and walking robots in particular, as well as operational (motion comfort and energy efficiency) and structural (pace) indicators are considered. A weighted quality functional of quality is constructed and its extreme value is sought. An analytical solution is obtained making it possible to perform a multicriteria optimization depending on the significance of a given indicator and on this basis to determine the optimal motion modes and the walking mover parameters.

The problem of choosing the program regime of a cycle mechanism motion on the basis of complex estimates of its energy and dynamic parameters is solved. An optimization criterion is formed as a functional consisting of the introduced parameters, which are determined by solving some differential equations describing the mechanism motion. For a specific mechanism, an example of complex estimate of its efficiency is given. An application procedure for the proposed method is discussed.

The expediency of introducing an additional damping device (analog of a shock absorber) into the cyclic walking mechanism of a mobile robot, which provides a dissipative connection of a ski-shaped foot with a support link, is discussed. The influence of the damper on the dynamics of the feet changing and the dynamics of the meeting of the foot with an obstacle is considered. It is shown that dissipation in the hinge of the foot leads to a decrease in the intensity of shock processes when changing feet and when meeting an obstacle, provides a decrease in power losses for vertical vibrations of the body, and also expands the propulsion unit’s capabilities for self-adaptation to an unorganized surface.

The underwater mobile transport robot, which is a platform assembled from the polygonal pontoon modules, is considered. The system are used anchor-rope movers, which ensures high stability and energy efficiency of the entire system due to interaction with the bottom surface. The aim of the study is to select the geometric shape of the module according to such criteria as specific heat losses in the movers, the length of the step and the tension of the ropes. The formulated criteria characterize the energy consumption and the level of dynamic loads in the considered dynamic system, and the achievement of their optimal values contributes to the increase of autonomy. It takes into account not only the exchange rate resistance to movement, but also the influence of the current, which, depending on the direction, can both promote the movement of the platform and counteract it.

This article focuses on the conditions for the safe operation of low-tonnage road trains (hereinafter LTRT) with trailers which are platforms with load capacities up to 3 tons that transport agricultural machines, mini-plants, and other equipment as well as tourist cabins. There are numerous risks in transporting such trailers that can occur due to a small turning radius or emergency braking. To assess the results of the research and experiments on the safe operation of LTRT with trailers, we used the works of the following scholars: Godjaev, Izmaylov, Komarov, Korolyash, Volchkov, Maloletov. As a result, we developed and tested a mechanical flexible coupling device under the leadership of the “Federal Scientific Agroengineering Center VIM” and the Volgograd State Technical University’s Department of Road Transport. Certificate No 2018137360, 22.10.2018. Further research can help define critical indicators for the safe operation of LTRT with load capacities up to 3.5 tons, so calculate the speed limit at critical turns, emergency braking, and reversing.

In the paper discussed results of investigation of increasing of shape passableness and adaptability to terrain for walking machines and robots with cyclic movers types. Usage of cyclic walking movers allows not to care about gait safety and stability and exclude the necessity in controlled adaptation system. By the other hand, strict trajectory of support points of cyclic type of walking mechanisms restricts abilities of adaptation to support surface and shape passableness of machine. In the paper considered the possibility of passive control of angular position of foot with hinge joint in transfer phase. Cyclic walking mechanism with one controlled degree of freedom was offered, it provides rising of the toe of foot with hinge joint both in straight and reverse movement (without entering an additional controlled actuator). Considered some features of synthesis of similar walking mechanisms. Presented the examples of their design in walking machines, intended for works at weak and waterlogged grounds, the results of real experiments are also shown. Presented, that passive foot control of cyclic mover significantly increases abilities of walking machines to adjust to rough ground and allows to overcome obstacles, which higher than height of support point of walking mechanism by more than two times. Some attention is devoted to the tasks of movement control of walking robotic systems with movers of cyclic type in condidtions of incomplete and ambiguous understanding about obstacle.

We consider cyclic mechanisms with one degree of freedom driven by engines of various types such as alternating and direct current motors, internal combustion engines, etc. We pose the problem of modifying the mechanism structure by joining additional links or by varying the parameters or operation mode of the original mechanism so as to minimize the thermal losses in the driving motor. The solution is based on the minimization of the functional determining the irreversible power losses. We show that, for the engines considered, all cyclic mechanisms with one degree of freedom should satisfy a fundamental condition ensuring the minimum of losses. We consider two examples, one of which corresponds to actually existing mechanisms.

Walking machines with cyclic drives are considered, the program motion of the machine and its drives that provide minimum of power expenditures is synthesized.

The issues around problem of increasing efficiency of walking machine motion have been discussed in this paper. Among them: ground or bearing cross-country ability, profile cross-country ability, maneuverability, the energy consumption.