SCIENCE & EDUCATION

One of the promising ways to solve the problems of improving smoothness of motion of multi-wheeled vehicles (MWV) is development of suspension control systems to ensure stabilization of the MWV’s housing under different influences. On the basis of application of methods of fuzzy logic an adaptive proportional differential law of continuous MWV suspension control was developed. Methods of simulation modeling were used to analyze efficiency of the developed control law for active and semi-active suspension systems. It was shown that the proposed adaptive proportional differential law for semi-active suspension system could be considered more preferable for practical application in MWV suspensions in comparison with the similar law for active suspension systems due to their similar efficiency and lower energy costs.

Possibility of application of a flywheel with a drive in ground mobile robots as an auxiliary energy source is considered in this article. Motion modes of the mobile robot with a flywheel accumulating energy during braking are also considered. The material of the rotor’s flywheel was chosen, and its rational form was determined. Energy parameters of the flywheel were calculated. The basic block diagram of the hybrid mobile robot with two energy sources – an electrochemical accumulator and a flywheel –is presented in this article. In order to provide a rational configuration it was proposed to produce a flywheel with an electric motor in the common block.

Results of an experimental investigation of dynamic loading of a transport machine hydro-mechanical transmission are described in the article. On the basis of comparing resonance oscillations frequencies of dynamic torque with frequencies of diesel perturbations, the authors proposed and hypothesis substantiated a hypothesis of implementing sub-harmonic resonances in a mechanical system which has essentially nonlinear elastic response. Theoretical study of dynamic processes in the system using linearization of the nonlinear characteristic by means of the harmonic balance method was carried out. The obtained analytical dependences allowed to tune out a nonlinear system from resonance by varying the characteristics of an elastic vibration damper. The authors also provide a variant of constructive implementation of a matching gear of hydro-mechanical transmission using a new type of vibration damper, as well as results of an experimental evaluation of effectiveness of the developed design solutions.

The authors developed rational finite element models of truck cabs for studies of passive safety under impact loading executed in accordance with the current standard of passive safety. The obtained results were estimated with consideration of errors and efforts; the problem was solved by means of FEM software (ANSYS and LS-DYNA). The influence of structural factors on the solution (doors, panels, trims, etc.) was also investigated. Calculations based on the finite element method provide one with complete information on the process of emergency loading required for estimating passive safety of truck cabs.

In this article the author analyzes influence of step length on energy efficiency of movement of walking machines and heavy robots. Marching modes of walking machines with periodic leg movement are considered. The analysis is based on theoretical research results and field tests of prototypes of walking machine with cyclic propulsion plants. The nature of changes in the structure of energy consumption by increasing step length is determined. The most significant components of energy consumption at different speeds are identified. It is shown that an increase in step length, at a constant speed, significantly reduces inertial load of walking machines and reduces the power required for movement. It was also shown that walking machines with simple and reliable cyclic walking propellers can be claimed for introduction of new soil conservation and resource-saving technologies in agriculture.

This article considers the question of stability rating of a tracklaying vehicle’s curvilinear motion, considering the lateral drift. Methods of the theory of ordinary differential equations were used to determine stability boundaries of a dynamic model. The solution obtained by the numerical method with the specified step of integration is presented with a discrete sequence of points in a metric space. It was shown that the phase trajectory tends to an isolated limit set which, in the model, is a local integral manifold. Stability conditions of the limit set are emphasized. The developed algorithm of numerical stability assessment of solution of a system of equations is based on the Poincare-Bendixson theorem for differentiable manifolds. Also, the author considers an approach to solving the problem of motion stability on the basis of mapping the dynamic regimes on the parameter plane and defining the boundary of the domain of possible motion parameters of a tracklaying vehicle.

 The authors describe reasons for creating environmentally friendly vehicles, such as electric vehicles with a hybrid power plant. Specifications of the best known world analogues of electric LC vehicles are presented in this work. The authors consider features of the experimental model of the "NNSTU-Electro" electric vehicle created on the basis of "Gazelle" chassis developed and produced in the NNSTU. The results of theoretical and experimental studies of traction-speed characteristics and energy consumption when driving an NNSTU-Electro electric car in the urban cycle and steady motion are also provided in this article.

The authors developed finite-element models of different levels for thin wireframe elements of bodies and cabs of cars with consideration of their structural peculiarities; their impact behavior was investigated according to existent standards of passive safety; the obtained results of calculations were evaluated with account for errors and effort put into development and solving this problem by using software systems that implement the FEM (ANSYS and LS-DYNA); basing on those evaluations, rational finite element models were proposed.

The paper presents differential equations of vehicle’s motion at the moment of gear shifting during ascent or descent of a vehicle. The influence of time of gear shifting on the value of vehicle's speed variation and generalized parameter – the actual interval of revolution of transmission’s drive portion in cases of gear shifting to the speed-increasing or speed-reducing gear. Analytical dependences between the size of the actual interval of revolution, parameters of the gear box, car and external resistance factors were obtained. Conclusions regarding the influence of the actual interval of revolution on the output parameters of transmission and vehicle were drawn.

The article describes a method of determining power requirement for drives of prospective test and measurement exercise bench in order to develop and evaluate performance of special equipment in fast cars. The method is based on mathematical modeling of machine dynamics when driving on uneven terrain and simulation of body movements obtained in the model of vibrational stand platform. With the proposed method it was possible to determine the capacity of drives to simulate the dynamics of the housing for a high-speed track-type vehicle.

The paper presents the structure and mathematical model of a prospective test and measurement exercise bench for development and evaluation of performance of special equipment of fast cars. The mathematical model of the stand includes a car dynamic model when driving on uneven terrain, and a model of the vibrational platform of the stand. The use of the model allows to adequately identify the driving power of a real stand.

One of the most important stages during formation of technical characteristics of a new vehicle is carrying out engineering analysis of the product, formation of circuit design which meets obtained values of influential parameters, realization of the draft design. Under these conditions, decision-making means choosing an alternative which simultaneously meets both fuzzy objectives and fuzzy constraints. The authors of the article developed a method of choosing an optimal circuit design which is characterized by selection in fuzzy conditions on the basis of a multi-criteria analysis of alternatives in equilibrium and non-equilibrium criteria according to the Bellman-Zadeh scheme. The analysis of design maps of possible realization of extra-light high Doppler wheeled vehicles for mountain operational conditions on the basis of domestic production units was carried out by the methods of fuzzy multi-criteria analysis and allowed to choose an optimal circuit design.

In the paper, the author presents a step-by-step analysis of formation of technical shape of super-light high-mobility wheeled vehicles (OLVKTS) for mountain conditions. The basic features and problems arising at each stage were revealed. The author carried out an analysis of the features of operating conditions in the mountains, on the basis of which requirements for equipment and implementation of various structural OLVKTS systems were set. A range of key parameters that determine technical configuration OLVKTS was proposed.

The article systematizes information about characteristics of snow cover significantly influencing cross-country ability, movability, mobility, energy efficiency and other properties of the vehicles. The authors provide equations of the most important communication parameters of snow cover condition, such as density, hardness, rigidity, cohesion, coefficient of internal friction, moisture, temperature, relative deformation, shear which are obtained from experimental data. Basing on the analysis of these dependencies the authors specify existing models of snow which are used to describe interaction of an engine with its support base.

The article presents information about the most common car parking systems based on the use of mechanized equipment. The author highlights key design features of these types of systems.

The article covers a comparative performance analysis of ordinary parking lifts and rotary parking lifts, taking into consideration calculation of expenditures: purchasing and installation per one parking place. Two types of parking lifts were considered: a rotary parking lift and a parking lift with two cabins. Main stages of their operation were emphasized. Based on the results of this work, conclusions re efficient use of rotary parking lift were made.

This paper presents an algorithm that allows to estimate the stress-strain state of the rubber-metallic pin of caterpillar tracks caused by mounting rubber-metallic pin in the holes of eyelets and subsequent loading torque. Algorithm was numerically implemented with the use of the finite element method. The distribution analysis of components of the stress tensor due to the assembly and torsion is included in the article.

The authors present an analysis of several fan installations and consider their aerodynamic characteristics under condition of air stream during car motion and fan operation. The advantages and disadvantages of these installations were considered. Fan installation with hot-performance capabilities in all car operation modes was developed.

The article presents information about creating systems of all-wheel steering (AWS) for different types of vehicles. The authors give a detailed description of the known laws of all-wheel steering, and also present the original law obtained on the basis of theoretical and experimental studies. The authors present a mathematical model of a wheeled machine that predicted characteristics of curvilinear motion with different variants of steering system. The solution to the problem of evaluating the effectiveness of AWS laws was considered by the example of a vehicle with the  8 × 8 wheel forumla and 1-2-3-4 steering. The technique of computational experiments, corresponding to the CMP field testing of vehicles, as well as the results of numerical simulations, is presented in the article. Basing on the analysis of data, they proved feasibility of the developed AWS law for vehicles of various types and purposes.

The authors present the results of theoretical studies of motion of a wheel transport system with individual power distribution to the wheels with the developed control laws for electromechanical transmission, basing on the principle of redistribution of moments proportional to the relative normal load to be carried by each propeller. The authors studied two versions of the law controlling traction electric motors: "torque" and "the degree of the total power." Advantages of the "degree of use of the total power" approach are proved by the results of mathematical simulation of transport complex movement with the  8 × 8 wheel forumla on the rigid support base for the following cases: ascent, curvilinear motion with a fixed radius, rectilinear acceleration with different intensity effects on the controls (accelerator pedal).