MULTI-FACTOR OPTIMIZATION OF PARAMETERS OF THE RESEARCHED ENERGY SAVING SYSTEMS APPLIED IN TIMBER ROAD TRANSPORT

A promising direction has been substantiated that increases the efficiency of timber road transport during timber hauling, based on the development and use of various recuperative mechanisms in its design. The analysis of foreign literature has been carried out and the authors' developments and the obtained research results in this area are described. Parametric optimization of eight types of investigated recuperative energy-saving systems has been carried out on the basis of mathematical modeling. A diagram of options for optimizing the design parameters of energy-saving systems is presented, including one-factor, two-factor and multi-factor optimization. Algorithms for multifactorial optimization of design parameters and uniform distribution of a given number of points of a computer experiment in a multifactor space are presented. A mathematical apparatus for the uniform distribution of points in a multifactor space has been developed. The choice of neural network approximation for solving the problem of multifactor optimization is substantiated. An artificial neural network topology diagram is presented. An algorithm for studying the factor space using an approximating radial neural network has been developed. A method of multifactor optimization is proposed, which makes it possible to ensure a minimum of computer experiments that uniformly cover the multifactor space with highly detailed representation of response surfaces and ensuring the search for optimal regions of the factor space. Optimization of parameters of eight investigated recuperative energy-saving systems for timber road transport has been made.</jats:p

ASSESSMENT OF THE RELEVANCE OF A PROMISING DESIGN OF A REMOTELY CONTROLLED LOGGING VEHICLE WITH A SLIDING FRAME AND CONTROLLED WHEEL MODULES

The tendency of development of timber trucks in the world is considered. Possible ways of increasing their efficiency at the present time are described. The results of the analysis of scientific works of foreign scientists in the field of increasing the productivity of timber trucks are presented. It was revealed that the duration of the process of loading and unloading timber has a significant effect on the productivity of timber trucks and on the final cost of the timber they export. The importance of reducing the labor intensity of unloading timber by improving the means for self-unloading of timber trucks has been substantiated. The goal of the research is formulated, which consists in the development of a promising design of a remotely controlled logging vehicle with a sliding frame and controlled wheel modules. Two groups of loading and unloading mechanisms used for loading and unloading timber on timber trucks are considered. The classification of devices for loading and unloading timber trucks by individual cranes, rope installations and self-propelled unloaders is presented. The dependences of the change in the residence time of timber trucks at the points of loading and unloading and their movement in an empty state on the number of timber trucks used in the link without self-loading and self-unloading means are described. The analysis of existing devices used for self-loading and self-unloading of timber trucks is presented. On the basis of the identified shortcomings, in order to eliminate them, a schematic diagram of a remotely controlled logging vehicle with a sliding frame and controlled wheel modules is proposed. A technological map of unloading a remotely controlled timber truck with a sliding frame and controlled wheel modules and an updated classification of means for self-unloading timber trucks are presented</jats:p

RESULTS OF THE STUDY OF THE MOVEMENT OF A TIMBER ROAD TRAIN EQUIPPED WITH A FITCH WITH A SPRING SHOCK ABSORBER

Based on the analysis of scientific works of foreign authors, the main factors influencing the efficiency of the operation of timber tractors with semi-trailers have been identified. A promising design of a fifth wheel coupling with a spring shock absorber for timber tractors with semi-trailers that haul timber in difficult road conditions is proposed. A mathematical model of the movement along a logging road of a logging tractor with a semi-trailer equipped with a fifth wheel coupling with a spring shock absorber has been developed. Based on the developed computer program, a preliminary assessment of the performance indicators of the proposed design of the coupling device was carried out. It has been established that the spring shock absorber of the fifth wheel coupling provides, during braking and acceleration, a decrease in the amplitude of acceleration oscillations between a timber tractor and a semi-trailer with timber in the range from 0.95 to 0.6 m/s2. It was found that in order to reduce unfavorable vibrations of a semi-trailer with timber relative to a timber tractor, it is advisable to use dry friction in a spring shock absorber.</jats:p

COMPUTER SIMULATION RESULTS OF FUNCTIONING OF THE PNEUMATIC SUBSYSTEM OF RECOVERABLE HYDRAULIC DRIVE OF A FOREST TRUCK WITH A SEMI-TRAILER

The relevance of developing new devices for accumulation and conversion of compressed air energy in a regenerative hydraulic drive of a timber truck with a semitrailer has been substantiated. The layout of recuperative mechanisms on a timber tractor with a semitrailer and the diagram of a recuperative hydraulic drive with subsystems for accumulating and converting compressed air energy are presented. A simplified diagram of a pneumatic energy-saving system for studying the functioning of the subsystems of accumulation and energy conversion of compressed air is presented. A mathematical model has been developed to evaluate the efficiency of using a pneumatic energy-saving system, which includes the equations of change in the gas state in its elements, solved by the Euler numerical method. A modeling algorithm is described, consisting of seven repeating steps performed in the process of computer simulation. The developed computer program is presented, which allows studying pneumatic energy-saving system. Computer experiments with the most typical set of its design and technological parameters are presented. The time dependences of the volume of the pneumatic cavities under consideration, the amount of substance in them, pressure and air temperature in the pneumatic cavities under consideration are obtained. The influence of the diameter of the pneumatic cylinder on the filling time of the receiver, the number of strokes of the piston and thermal efficiency has been defined</jats:p

RESULTS OF PROCESS SIMULATION OF FEEDING AND DISTRIBUTING LUBRICANT IN THE FIFTH-WHEEL COUPLING OF HAULING TRACTOR WITH SADDLE TRAILER

The necessity of increasing the efficiency of the fifth wheel coupling of hauling tractor with saddle trailer has been substantiated. The analysis of the works of foreign scientists investigating the influence of fifth wheel couplings on the efficiency of functioning of road trains has been carried out. The importance of periodically applying the lubricant recommended by the manufacturer to the rubbing surfaces of the base plate and the saddle of the fifth wheel coupling of hauling tractor has been described. The goal of the work is formulated to determine the optimal number of outlets in the seat for supplying the minimum amount of lubricant that ensures full coverage of the seat surface, as well as long-term retention on it. To achieve this goal, a mathematical model and a computer program based on it have been developed. The schemes of representation in the model of the mounting plate of the hauling tractor and the base plate of the saddle trailer, the interface form with the results of modeling the supply and distribution of lubricant over the rubbing surfaces of the fifth wheel coupling, as well as a diagram of the main input and output parameters of the simulation model are given. The time dependences of the coefficient of lubricant coverage of the mounting plate of the fifth wheel coupling seat with different periodicity of lubricant supply through a variable number of outlet openings are obtained. It was found that the increase in the coefficient of coverage of the mounting plate of the fifth wheel coupling with a lubricant over time occurs according to an exponential law. The optimum number of openings for the lubricant supply is 5-7</jats:p

IMPROVEMENT OF THE ENERGY RECOVERY SYSTEM OF A TIMBER TRACTOR WITH A LUMBER TRUCK

The place of road transport in logging production has been considered. The main advantages of using timber tractors with timber drags in comparison with other layout schemes of timber road trains have been described. Conse-quences of dynamic loads acting on the pivot of the turning bunk of a timber-carrying area from frequent braking of a timber tractor with a timber drag have been given. Based on the analysis of scientific works of foreign scientists, the promising direction of research in the field of recuperation of various types of energy in road transport is substantiated, which makes it possible to reduce dynamic loads during braking in the pivot pin and at the same time accumulate, with subsequent useful use, energy unproductively dissipated into the surrounding space from the energy forces of the trailer with a pack of whips. The design of the main manufacturers of platforms for timber haulers with timber drags has been described. The requirements for timber haulers with timber drags operated on public roads have been considered. The main forces acting on the links of a timber tractor with a timber drag during braking have been analyzed. Diagrams of the mutual positions of a timber tractor with a timber drag when moving along a timber road on the rise, downhill and turn have been given. The analysis of the dependences of the forces arising in the pivot of the swivel bunk of a timber platform during the movement of a timber tractor with a timber drag on the turning radius and speed of movement has been carried out. A promising design of a recuperative bolster device for a timber haulage site has been proposed. It enables to accumulate hydraulic energy during frequent braking of a timber tractor with a timber drag, followed by its use in the process of loading and unloading timber by a hydraulic manipulator</jats:p

SIMULATION MODELING OF RECUPERATIVE SPRING-HYDRAULIC FIFTH-WHEEL COUPLING OF FOREST TRACTOR WITH SADDLE TRAILER

The importance of using timber road transport in the technological process of harvesting and hauling timber has been substantiated. The influence of the design flaws of fifth-wheel couplings on the safety indicators of the road train, its stability, productivity, and fuel consumption, which are manifested during the operation of timber tractors with semitrailers, has been revealed. The work of foreign authors aimed at improving the efficiency of using fifth-wheel couplings used in the designs of tractors with saddle trailer has been considered. The advantages of using the proposed recuperative spring-hydraulic fifth-wheel coupling device in a timber lorry train have been described. They consist in ensuring a simultaneous increase in the reliability of road train, recuperating energy of the working fluid, reducing the magnitude of dynamic loads, as well as ensuring favorable working conditions for the driver. On the basis of the developed mathematical and simulation functioning models of a timber tractor with a saddle trailer equipped with the proposed design of a recuperative spring-hydraulic fifth wheel coupling, computer experiments have been carried out, which made it possible to obtain the dependence of the influence of the inner diameter of the hydraulic cylinder, the stiffness of the springs used in the recuperative spring-hydraulic fifth wheel coupling on the longitudinal acceleration of the semitrailer and the average value of the recovered power. It was revealed that the optimal spring stiffness of the recuperative spring-hydraulic fifth wheel coupling, which is in the range from 150 to 200 kN/m, makes it possible to achieve the value of the average recovered power in the range from 7 to 8.4 kW</jats:p

TWO-FACTOR PARAMETER OPTIMIZATION OF PROMISING MODULAR HYDROPNEUMATIC SUSPENSION FOR LOGGING ROAD TRANSPORT

The necessity to reduce the cost of timber haulage by logging road transport to increase the efficiency of logging in the Russian Federation has been substantiated. The drawbacks of the timber road transport equipped with traditional suspension systems, which are manifested when they transport timber along low quality logging roads, have been revealed. A promising direction for improving the operational properties of timber road transport used for hauling timber is described. It consists in the development of effective design schemes for suspensions for timber road transport with optimal suspension parameters. The scientific works of foreign scientists in this direction has been considered. Taking into account the identified shortcomings, a promising scheme of modular hydropneumatic suspension for timber road transport has been developed, which makes it possible to recuperate the energy of the working fluid when moving on the roads of low quality, compensate for leaks of working fluid, and also control the ground clearance from the driver's cab remotely. Two-factor optimization has been carried out, which allows identifying favorable combinations of the two factors under study. The graphs of the influence of the pneumatic cylinder diameter heat transfer coefficient on the maximum vertical acceleration of the sprung mass, as well as on the maximum gas pressure in the pneumatic cylinder and the amplitude of the temperature change have been obtained. The cartograms of optimization of the design parameters for perspective hydropneumatic suspension have been presented.</jats:p

MODELING THE OPERATION OF A RECUPERATIVE SPRING-HYDRAULIC FIFTH-WHEEL COUPLING LOCATED IN THE SEMITRAILER OF LUMBER TRUCK

The substantiation of the necessity of using timber trucks, consisting of timber tractors with semi-trailers, when transporting timber, is given. Attention is focused on improving the efficiency of the functioning of log trucks by con-structive improvement of the fifth-wheel couplings used in them. The analysis of scientific works of foreign scientists engaged in the study of the influence of fifth- wheel coupling on the efficiency of log trucks is carried out. A promising scheme of a recuperative spring-hydraulic fifth-wheel coupling, located in the front part of the semi-trailer frame of a timber tractor, is proposed, which has significant advantages in comparison with other similar devices. At the first stage, a mathematical model of the proposed fifth-wheel coupling was developed; at the second stage, a computer program for a preliminary assessment of the efficiency of the functioning of a timber tractor with a semitrailer equipped with a recuperative spring-hydraulic fifth-wheel coupling is made. The dependences of the change in the average values of the recuperative power and longitudinal acceleration of the trailer relative to the timber tractor on the inner diameter of the hydraulic cylinders of the recuperative device, the mass of the semi-trailer and the frequency of braking and accelera-tion of the timber road train are obtained. It was revealed that the optimal diameter of the hydraulic cylinders of the recuperative device for the given conditions, providing the maximum recuperative power, should be in the range of 50-60 mm. It was found that with an increase in the mass of a semitrailer of a logging tractor, as well as with an increase in the frequency of braking and acceleration, an increase in the recovered power is observed</jats:p