Self-propelled Chassis Research Articles

Вплив причіпних ланок на керованість тракторних самохідних шасі

An analysis of methods for calculating the distribution of normal reactions of the road between the axles of the tractor unit was carried out. It is shown that they are based on the misconception that traction forces and rolling resistance forces are applied in the spots of contact of the wheels with the road. The research shows that installing a towing link on a tractor self-propelled chassis through the rear suspension system at a level below the axis of the rear wheels (the diameter of which is larger in relation to the diameter of the front wheels) allows reducing the additional unloading of the front wheels. A more correct scheme of the tractor unit with the application of the traction force and the rolling resistance force on the wheel axles is calculated, which determines the increase in the total normal reaction on the front wheels of the tractor self-propelled chassis when working with the towing link. It is shown that an increase in the difference in the dynamic radii of the front and rear wheels, a decrease in the vertical coordinate of the center of mass of the tractor unit leads to an increase in the normal reaction of the road on the front wheels. Since the controllability of wheeled machines increases with the growth of the normal reaction on the front wheels, the presence of towing links with the attachment point located below the axis of the rear driving wheel increases the controllability of the tractor unit based on the self-propelled chassis. The problem of determining the total normal reaction of the road on the front wheels of a tractor self-propelled chassis with a trailing link in the case of application of the traction force and the force of movement resistance on the wheel axles has been solved. To increase the accuracy of finding the total normal reaction of the road on the front wheels of the tractor self-propelled chassis, which will allow to clarify the assessment of the controllability of the latter when moving with a towed link. Increasing the difference in the dynamic radii of the wheels and reducing the base of the tractor self-propelled chassis allows you to increase the value of the total normal reaction of the road on the wheels in relation to the horizontal reaction in the hinge of the axle of the trailer link. It was determined that the operation of the tractor self-propelled chassis with trailing links is characterized by a higher efficiency factor of its chassis compared to a universal tractor of class 0.6 and higher efforts under the condition that its front platform is loaded.

PECULIARITIES OF TRACTION CALCULATION OF A TRACTOR SELFPROPELLED CHASSIS WHEN COMBINED WITH ATTACHMENTS AND IMPLEMENTS

A mathematical model describing the features of traction calculation of self-propelled chassis in a hinged unit isconsidered. The peculiarities of applying a typical traction calculation to self-propelled chassis are analysed, in particular,taking into account the distribution of forces and moments in the longitudinal-vertical plane, which affect the couplingand traction capacities of the chassis. The paper considers aggregation, in which the self-propelled chassis is loaded withthe weight of the machine, which in turn affects the vertical component of the soil reaction on the working bodies. Thecalculation of traction resistance takes into account the part of the rolling resistance force caused by the normal loading ofthe self-propelled chassis from the forceful impact of the mounted machinesThus, the traction resistance of a mounted machine in a machine generally consists of the horizontal component ofthe soil reaction on the working members and the rolling resistance force caused by the tractor or self-propelled chassisloading during operation. The ratio of these components in the balance of traction resistance is determined by the adoptedmethod of aggregation and the design parameters of the machine. The ratio of these components is also influenced by theoperating conditions of the machine: with an increase in soil density, the resistance to the working bodies increases andthe rolling resistance decreases; a decrease in density, an increase in humidity and other factors increase the rollingresistance while simultaneously reducing the magnitude of the soil reaction on the working bodies.

ANALYSIS OF DYNAMICS OF VOLUME HYDRAULIC POWER STEERING SELF-PROPELLED TRACTOR CHASSIS

Goal. Analysis of the dynamics of the hydraulic fluid power steering drive of the wheeled tractor self-propelled chassis СШ2540 by simulating the operation of a hydraulic cylinder with a one-sided rod for moving the steering trapezoid when turning the wheels and studying the change in the pressure of the working fluid and the movement of the hydraulic cylinder rod under different load modes. Research methodology. The method of simulation modeling is used, when the variables describing the behavior of the steering hydraulic cylinder are determined by certain load algorithms and operating fluid flows, and are described by differential equations. The differential equations that determine the pressure of the working fluid in the cavities of the hydraulic cylinder and the movement of its rod when the working fluid is fed into the piston or rod cavity are based on the laws of mechanics, the principle of the continuity of the flow of the working fluid and its compressibility. The VisSim package of application programs was used for modeling according to the proposed methodology. The changes of the parameters in the hydraulic cylinder of turning the wheels when they are shifted from the task of the control action in the form of an increase in the external load and the flow of the working fluid in the output channels of the metering pump overcome by the hydraulic cylinder were studied. The influence of the modulus of elasticity of the working fluid, which decreases when it is saturated with undissolved air, was also investigated. The results. When starting the hydraulic steering drive, i.e. when turning the steering wheel from its neutral position, depending on the external load and the intensity of the driver's work at the wheel, oscillatory processes take place in the hydraulic cylinder cavities, which can significantly exceed the working pressure. The results of the research give a reason to conclude that it is necessary to study the nature of the increase in the flow rate and pressure of the working fluid on a full-scale sample of the tractor chassis metering pump, i.e. by replacing the flow rate simulation with its actual value. Setting the loading time and flow rate of the working fluid using the map-VisSim unit is more convenient than setting it with analytical expressions, as it makes it possible to simulate different acceleration rates of the hydraulic cylinder and, if necessary, to control the stationary mode of the steering wheel in the neutral position.

APPROACHES TO THE DEVELOPMENT OF A LIGHT FIRE MODULE ROCKET LAUNCHERS SYSTEM ON WHEELED (TRACKED) CHASSIS

Today, in the conditions of russia's open armed aggression against Ukraine and the intense multi-faceted struggle against it - armed, informational, economic, the Armed Forces of Ukraine have to create combat-ready groups of troops (forces) that must be able to ensure the fulfillment of the tasks assigned to them at a given level. Based on the experience of conducting hostilities starting from February 24, 2022, it becomes clear that one of the important components of the effective conduct of hostilities by troops (forces) is the timely and reasonable use of missile forces and artillery.
 One of the common effective and promising fire means of the field artillery of the ground forces is the reactive system of volley fire. Shelling from such systems not only destroys manpower and equipment, but also creates a powerful psychological impact on the enemy's personnel. So, despite the appearance of new modern means of destruction, rocket launcher systems will continue to play the role of a strong argument on the battlefield for a long time, and designers will continue to work on their further improvement.
 Today, systems of volley fire represent combat platforms that are widely used by the Ground Forces in conducting all forms and types of combat operations. Development of new, improvement of existing systems of volley fire, improvement of their combat effectiveness is an important scientific and technical task.
 The most important advantages of reactive systems of volley fire are the surprise of the attack and the high density of fire, which is carried out in a very short time on site targets with a high degree of damage, both offensively and defensively, in any weather, both day and night.
 In a number of modern local conflicts, aviation units for unguided air missiles of the S-5 and S-8 types installed on various self-propelled chassis were used as improvised systems of volley fire.
 But the lack of developed special sights and sufficient stabilization of unguided aircraft missiles during launch gives low accuracy. Therefore, the issue of increasing the accuracy and efficiency of the use of unguided air missiles from a wheeled (tracked) chassis requires further development.
 The article substantiates the need to create a light fire module for the use of unguided aircraft missiles from wheeled (tracked) chassis instead of using standard aviation units of unguided missile weapons, proposed solutions to improve the accuracy and efficiency of application.

Studying the strength of a small-sized loader working equipment

Problem. The growth in the volume of construction work carried out in the improvement of adjacent territories, playgrounds, and pedestrian paths requires the use of a wide range of small-sized machines for earthwork and road construction, including loaders. The main requirements for small-sized loaders are small dimensions, which makes it possible to perform work in cramped conditions, good maneuverability, light weight, which allows for low pressure on the surfaces on which the equipment moves, ensuring the safety of loading operations, efficiency and economy. These conditions are fully met by a variety of construction equipment that is combined with self-propelled chassis, which have been manufactured for many years at Ukrainian enterprises and used by organizations for the improvement and beautification of urban space. The indisputable advantage of self-propelled chassis over a large number of short wheelbase loaders, which are also widely used in the public utilities sector, is greater stability due to the large wheelbase and the possibility of using additional outriggers installed on the machine, as well as the availability of a self-unloading platform for transporting goods. The operation of small-sized forklifts based on self-propelled chassis in cramped conditions, along with builders performing installation work, requires increased attention to ensuring the strength of the machine's metal structure, so the issue of studying the load of working equipment is an urgent task. Goal. The aim of the study is to develop scientifically based recommendations for reducing the load of small-sized forklift equipment based on the created design scheme, determining the acting forces and stresses, and rational modes of operation of the forklift. Methodology. The design position in which the handle of the working equipment is located horizontally and the maximum load acts on it is considered. The design load is the maximum weight of the cargo, taking into account the dynamic coefficient. The calculated position for the boom is the position of the greatest bending moment, i.e. the position at maximum reach. The center of gravity of the boom and handle, as well as the weight of the metal structure, were determined using a computer model. The loads acting in the boom joints are determined using a simplified, calculated, boom scheme, for which We will discard the handle, replacing its action with the corresponding reaction and consider the handle separately to determine this load. Given that the force of action from the boom on the handle will be equal in modulo to the force of action from the handle on the boom, and the reactions in the hydraulic cylinder joints will also be equal, we will depict the diagram of the forces acting on the boom. Results. Based on the developed design schemes of the boom and arm, we studied the loading of working equipment, which was carried out using the created program at variable values of the load weight from 4000N to 4500N, the coefficient of dynamism equal to 1, 1.1...1.5, and the height of the arm section from 0.14 to 0.16 m. The analysis of the research results showed that an increase in the coefficient of dynamism to a value of 1.5 at a load weight of 4500N leads to an increase in the acting force to 6840N, but the stresses are within the permissible limits. Increasing the load with which the forklift operates to 5000N requires an increase in the height of the handle section to 0.15m to ensure that the stresses are within the permissible limits. The analysis of the dependence of the acting stresses on the weight of the load and the coefficient of dynamism made it possible to propose recommendations for rational modes of operation of the forklift, which consist of limiting the load to 4500N and the coefficient of dynamism within 1.3-1.4 with a handle cross-sectional height of 0.14m and a wall thickness of 0.05m. It is also proposed to work without jerks, smoothly at low lifting speeds, within the range of the coefficient of dynamism up to 1.3-1.4. Practical meaning. The developed research methodology is proposed for use in the operation of a small-sized forklift in various modes, as well as in the design of working equipment for forklifts of a similar class and design.

ASSESSMENT OF THE STABILITY OF THE FRONT PIVOT AXLE DURING STEADY-STATE MOTION OF A TRACTOR SELF-PROPELLED CHASSIS

In known scientific and technical literature, insufficient attention is paid to the study of dynamic processes of wheeled vehicles with a steering front axle. The use of front swivel axle on a self-propelled chassis makes it possible to minimize the moment of resistance to turning and reduce the wear of front wheel tires in comparison with rotary guide wheels. This modernization can provide a wider range of attachments for mechanized work equipment. The aim of this work is to increase the stability of the rectilinear steady-state motion of a self-propelled tractor chassis by creating stabilizing moments on the front pivot axle by shifting the axis of rotation of the front axle in the direction of the longitudinal axis of the machine. The stability of the rectilinear steady-state motion of a self-propelled tractor chassis is investigated when creating stabilizing moments on the front steering axle by shifting the vertical axis of rotation of the front axle in the direction of the longitudinal axis of the machine. This scientific article shows that when the steering axle moves, it is possible to reduce the lateral force on the front axle to zero, which makes it possible to reduce the moment of resistance to turning. A straight-line steady-state movement of a tractor is considered, where a violation of the stability of the front steering axle may occur during a short-term impact on an obstacle on the road. In some cases, the angular acceleration and angular velocity of the bridge in the road plane may be the exciting factor. The loading scheme of a front swing bridge under the action of an exciting angular acceleration is determined. The calculation of the effect of the exciting factors on the power steering cylinder is presented. The stabilizing moment that occurs when the axis of the vertical shaft of the front steering axle drive is displaced is determined. The differential equation of the front axle's circular motion was analyzed, which revealed its stability under the action of short-term excitatory forces in the rectilinear steady-state motion of the self-propelled chassis. An estimation of the motion of the front steering axle of a self-propelled chassis is presented, with the determined proportionality coefficients and coefficients of the differential equation, which describes the stable motion of the front steering axle in the steady-state rectilinear motion of the machine under the action of short-term disturbing forces. Keywords: self-propelled chassis, front swivel axle, stability, stabilizing moment, steady-state motion

ОСОБЕННОСТИ КОНСТРУКЦИИ ТРАКТОРОВ ДЛЯ РАБОТЫ НА СКЛОНАХ

The problems of creating tractors, self-propelled chassis, forestry and agricultural machines of special designs for the mechanization of crop production, land reclamation and construction in hard-to-reach conditions of forest, agricultural and mountain lands are considered in the work. A comparative analysis of design solutions that have found application in domestic and foreign tractors used in the performance of technological and transport operations on sloping lands and badlands in agriculture and forestry is given. It is noted that a number of models of universal row-crop tractors provide for the possibility of increasing stability by turning the housings of the remote final drives relative to the rear axle housing. For tractors, at the same time, the wheelbase increases and the ground clearance (ground clearance) decreases. It is indicated that the analysis of the features of the operation of wheeled tractors on the slopes made it possible to substantiate the methods and means that improve their main indicators: differential lock; lowering the center of gravity; the use of tires with high lugs, additional steel wheels, lugs, expanders; the use of half-tracks and wheeled tractors with a 4K4 wheel arrangement. The advantages and disadvantages of using tracked and wheeled tractors as the base machine have been established. Slope preference for tractors with front drive axle. Such tractors, equipped with the previously listed devices, have better traction properties, maneuverability and controllability, approaching caterpillar tractors in these indicators. Recommendations for the implementation on slopes, forest and agricultural lands of all-wheel drive low-clearance wheeled tractors are given in the work. In conclusion, it is indicated that, despite the considered features, when creating tractors for working on small-contour plots located on slopes up to 25 °, preference is given to wheeled low-clearance tractors, which is caused by a cheap design due to minor design changes compared to the basic models.

Рeculiarities of control commands generation for oculographic interfaces under the conditions of vestibular impacts

The article presents the results of a study of the parameters of human eye movement when using an oculographic interface to control a self-propelled chassis. In the course of the experiment, it was shown that from race to race, the time spent by the subjects on one race was reduced, the number of errors and the number of subjects who did not successfully complete their races decreased. On the basis of cluster analysis, individual typological features of the reaction of eye movement to the movement of the user’s head during the execution of the main commands for controlling the self-propelled chassis were revealed. It is shown that when the self-propelled chassis is moving, the generation of the “forward” and “backward” commands by the optical-oculographic interface is generally carried out according to the scenario common for users, and does not require correction when controlling the self-propelled chassis. At the same time, the generation of turn commands is a more individual process, which is associated both with the calibration of the device and with the individual position of the user’s head and eyes and, therefore, requires more careful control when using oculographic interfaces.

Обоснование выбора параметров электромеханической трансмиссии для трактора тягового класса 0,6-0,9 и согласование тяговых характеристик

The parameters of electromechanical transmission for the tractor of 0.6-0.9 traction class are selected based on the analysis of traction and hitching characteristics of the complete machine. The authors have made theoretical calculations of the operating characteristics of the prototype tractor with an internal combustion engine and the tractor layout with an electric drive, traction calculation of the prototype tractor and the tractor layout, and calculation of the characteristics of the electric drive and electric motors. For the calculations, a six-speed manual variable gearbox was selected. The initial data for performing the calculations were obtained from the results of tractor traction tests in the North Caucasian machine test station. Two profi le backgrounds of the support base were selected: a fi eld prepared for sowing (fallow) and stubble. As a result of research, it was established that a tractor-model designed on the basis of the self-propelled chassis of a pulling class 0.6 to. 0.9 with capacity up to 50 kW on the “Fiel d prepared for sowing” background reaches the greatest towing effi ciency (0.53) with the 15 kW electric motor and the greatest drawbar pull (5.78 kN) with the 18 kW electric motor. On the “Stubble” background, for 15, 18 and 22kW electric motors, the pulling effi ciency is 68%, but the tractor layout with the 22kW electric motor can develop the maximum drawbar pull of 11.35kN. The maximum pulling power of 16.7 kN is observed in the prototype tractor with an internal combustion engine. Therefore, the 15-kW electric motor can be the only most suitable substitute for a combustion engine by traction effi ciency.

PRINCIPLES OF RATIONAL AGGREGATION OF TRACTOR SELF-PROPELLED CHASSIS

The article considers the optimal location of the mounted machine on the frame of the self-propelled chassis for the rational use of traction and coupling properties of the machine-tractor unit. The criteria of their optimal aggregation are determined taking into account the conditions of fulfillment of the corresponding agrotechnical requirements. Recommendations for checking the possibility of aggregating it with a specific attachment are provided. Theoretically and experimentally it is proved that the tractor of classical layout is inferior to self-propelled tractor chassis of similar weight and power in traction, fuel economy, passability, controllability, maneuverability, stability and a number of other parameters and has no possibility of axle suspension. Different layout schemes, redistribution of normal reactions along the axes and the specifics of the force action distinguish the traction dynamics of TSSH from the traction dynamics of the tractor

TRACTION LOADS OF A SEEDING UNIT BASED ON A SELF-PROPELLED CHASSIS

The calculation of the traction forces arising from the interaction of the working bodies of the sowing unit based on a self-propelled chassis with the soil, taking into account the agrotechnical requirements for performing the technological operation of selective sowing, will allow to justify the parameters of the working bodies and the choice of optimal working speeds of the unit. (Research purpose) The research purpose is evaluating the traction resistance arising from the interaction of the working bodies of the sowing unit based on the self-propelled chassis of the VTZ-30SSH with soil. (Materials and methods) Carried out the calculation of the traction resistance of the sowing unit based on a self-propelled chassis, using technical characteristics, reference data and mathematical dependencies. (Results and discussion) In order to complete the machine-tractor unit with working bodies, an analytical calculation of the traction resistance of the sowing unit based on the VTZ-30SSH self-propelled chassis for sowing cereals, legumes and oilseeds, in the range of operating speeds of the chassis, taking into account the agrotechnical requirements for the technological operation of selective sowing. It was shown that the soil background is a field prepared for selective sowing. In order to determine the mechanical energy costs of a selective seeder based on a self-propelled chassis, the traction resistance arising from the interaction of working bodies with the soil and mechanical losses in the unit were calculated. (Conclusions) It was found that the evaluation of the traction resistance of the working bodies for the first, second and third gears is up to 20 percent of the nominal traction force of the self-propelled chassis or the degree of loading of the self-propelled chassis. It was stated that the calculations of the traction loads of the sowing unit will be used to justify the parameters of the working bodies of the breeding seeder for sowing grain crops in order to reduce material costs.

DEVELOPMENT OF THE LAYOUT OF AUTOMATED CONTROL AND MONITORING SYSTEM OF BREEDING SEEDER

The development of the layout of the automated control of the breeding seeder are aimed at improving the technical level of the sowing machine to ensure the required quality of sowing on breeding and seed plots, and improving the working environment of the operator of the sowing unit. The use of automated control of the technological process involves automation of the operation of sowing machines, control of the flight of seeds in seed ducts, operational parameters of the unit. (Research purpose) The research purpose is developing a layout scheme for the automated control of a breeding seeder for the second and the third stages of work that improve the quality of sowing of cereals, legumes and oilseeds. (Materials and methods) The article presents a comparative analysis of advanced technologies, technical means, various design solutions to select the most appropriate elements of automated control of the breeding seeder. (Results and discussion) The article proposes a layout of automation tools for a breeding seeder based on a VTZ-30SSH chassis for sowing grain, legumes and oilseeds at the second and the third stages of work. The automation tools of the seeder are designed to monitor and control the operation of the batch seeding machine and the cassette loading device, control the flight of seeds, as well as display the speed and operating time of the unit, the sown area. (Conclusions) The article presents automation tools for a breeding seeder based on a VTZ-30SSH chassis type in order to control seed sowing, rotation of the sowing shaft, measurement and indication of operational parameters: movement speed, sown area, operating time of the unit. The article also presents a scheme for their installation on a breeding seeder based on a self-propelled chassis.

Increasing the Reliability of the Power unit of the Self-Propelled Tractor Chassis T-16M

Increasing the Reliability of the Power unit of the Self-Propelled Tractor Chassis T-16M

Варианты компоновки основного технологического оборудования на базовых шасси мобильных транспортно-перегрузочных канатных комплексов и их сравнительный анализ

Mobile ropeways formed by mobile transport and reloading rope complexes (terminal stations) on the basis of self-propelled wheeled chassis of high load capacity and cross-country ability are a promising type of transporting equipment for use in many branches of industrial production and maintenance – construction and mining industry, forestry and agriculture, elimination of the consequences of natural and man-made disasters, etc. The article develops a classification of self-propelled terminal stations based on such features as the location of the key element of the main technological equipment — the end tower of the rope system — on a wheeled chassis and the type of its fixation in the working position during the operation of the mobile ropeway. As promising variants of the structural design of mobile transport and technological rope complexes, options with an end, central and remote arrangement of the end tower; with hydraulic, rope, rope-hydraulic and rod types of fixing the end tower in the working position; with the installation of the end tower in the working position directly by a lifting hydraulic cylinder, using a folding rod and two-stage lifting are proposed. A brief description of the designs and the principle of operation of a large number of modifications of self-propelled terminal stations of various listed variants of the structural design of mobile rope complexes is given when preparing them for operation and during operation itself. A comparative analysis of the considered variants of mobile rope complexes is carried out on the basis of taking into account their main design and technical and economic characteristics, which made it possible to formulate both advantages and disadvantages of different design options.

Обеспечение вертикального габарита самоходной машины со штанговым механизмом установки и фиксации концевой опоры для мобильной канатной дороги

Mobile ropeways for carrying out loading and unloading and transport and transfer operations in previously unsettled or inaccessible areas, formed with the help of terminal base stations connected by a single rope system on the basis of self-propelled wheeled or tracked chassis of increased carrying capacity and cross-country ability, are a promising type of lifting and transport equipment ensuring the prompt deployment of the necessary technological tools. The article deals with the layout of the mechanism for installing and fixing the end tower using a folding bar, consisting of two articulated links. A mathematical model has been developed that provides the required normative vertical dimension of a self-propelled base station of a mobile ropeway with the aim of its safe independent movement to the place of deployment of the ropeway along general roads. The analysis of the influence of standard dimensional requirements, design dimensions of the chassis carrying frame and the height of the end tower on the main design dimensions of the articulated folding rod in the transport position is carried out. Calculations have shown that the considered design makes it possible to provide the standard vertical dimension of a base station on a 6-axle self-propelled chassis with an end tower length of up to 18 m.

Justification of parameters of the executive drive of a robotic manipulator of a loading and transport unit

To solve the problem of mechanization and automation of loading operations when harvesting vegetables Packed in bags, a loading and transport unit is proposed. A parallel-sequential structure manipulator has been developed for the loading and transport robot. The service area of the pincer grip is obtained from the condition of the specified chassis width. The geometrical parameters of the manipulator boom actuating drive from the condition of providing the required service area are justified. The choice of actuators is based on the condition of minimizing the influence of the maximum value of the force acting on the output link. The analytical dependence of the force on the rod of the Executive actuator on the angle of inclination of the arm of the manipulator is obtained. Graphical dependences of the force on the actuator rod on the angle of rotation of the boom in the form of a three-dimensional surface are constructed. Analytically favorable conditions for the transfer of motion and forces in mechanics are formulated. The quality of motion transmission in the lever mechanisms of the manipulator was evaluated according to the criteria for reducing the pressure angles in the hinges. The description of the loading and transport robot manipulator device is presented. An experimental sample of a parallel-serial manipulator was developed and manufactured. Taking into account the formulated dependencies and limitations allowed us to create a universal prototype of the manipulator, which can be installed on various self-propelled chassis. A system for controlling actuators according to various laws of program movements has been developed. Determining the coordinates of bags of vegetables is determined by the technical vision system.

ESTIMATION OF THE EASE IN CONTROL OF A PERSPECTIVE TRACTOR’S SELFPROPELLED CHASSIS

In the existing science-and-technical literature, insufficient attention is paid to the research in dynamics of wheeled machines with rotary front axle. The use of rotary axle compared to that of rotary guide wheels enables minimizing the momentum of turning resistance, decreasing tires’ wear-off, and improving maneuverability of the mentioned machines. The use of the front rotary axle can be most efficient in tractors’ self-propelled chassis due to sufficient space available under its technological frame. The momentum of resistance to the turning of the guiding axle is proportional to the amount of the side force influencing the front axle. It is shown in the article that at certain law of the rotary axle movement, it is possible to decrease the impact of side force on the front axle to zero, which means bringing to zero the momentum of resistance to turning. An algorithm of automatic control of the process of front axle turning is offered.

Design and experiment of a high-clearance self-propelled sprayer chassis

A large high-clearance self-propelled sprayer chassis was designed according to the requirements of the sprayer’s driving operation and the overall goal. The structural characteristics and working principle of the chassis drive system, suspension system, track adjustment system, and frame were analyzed. A finite element analysis of the frame was carried out under four extreme conditions: full load bending, full load torsion, full load emergency braking and full load emergency turning. Under these four conditions, the maximum stress values of the frame were 149.45 MPa, 219 MPa, 151.44 MPa, and 123.27 MPa respectively, and the maximum strain values were 1.12 mm, 2.22 mm, 0.95 mm, and 1.16 mm respectively. A theoretical analysis of the stability, steering ability, and obstacle navigation of the sprayer chassis was conducted. The results showed that the upper angle θlim, lower angle θ׳lim and lateral limit tumbling angle φlim of the sprayer chassis were 50.1°, 30.0° and 35.3° respectively. The minimum turning radius of the chassis was 5816 mm, and the minimum turning width was 4113 mm. The maximum obstacle crossing heights of the front and rear wheels were 466 mm and 457 mm. The theoretical analysis showed that the designed chassis met the field management operations of large plots. A field experiment of the high-clearance self-propelled sprayer chassis at full load was conducted. The experimental results were consistent with the theoretical analysis results. The sprayer chassis not only good handling stability but also good ride comfort. The results of this study provide references for the design of high-clearance self-propelled sprayer chassis. Keywords: high-clearance self-propelled sprayer, chassis performance, frame, suspension, design, experiment DOI: 10.25165/j.ijabe.20201302.5262 Citation: Chen Y, Mao E R, Li W, Zhang S, Song Z H, Yang S J, et al. Design and experiment of a high-clearance self-propelled sprayer chassis. Int J Agric & Biol Eng, 2020; 13(2): 71–80.

DEVELOPMENT OF THE COMBUSTION CHAMBER OF GAS ENGINE, CONVERTED ON THE BASIS OF DIESELS D-120 OR D-144 ENGINES TO WORK FOR ON LIQUEFIED PETROLEUM GAS

The expediency of using vehicles of liquefied petroleum gas as a motor fuel, as com-pared with traditional liquid motor fuels, in particular with diesel fuel, is shown. The advantages of converting diesel engines into gas ICEs with forced ignition with respect to conversion into gas diesel engines are substantiated. The analysis of methods for reducing the compression ratio in diesel engines when converting them into gas ICEs with forced ignition has been carried out. It is shown that for converting diesel engines into gas ICEs with forced ignition, it is advisable to use the Otto thermo-dynamic cycle with a decrease in the geometric degree of compression. The choice is grounded and an open combustion chamber in the form of an inverted axisymmetric “truncated cone” is developed. The proposed shape of the combustion chamber of a gas internal combustion engine for operation in the LPG reduces the geometric compression ratio of D-120 and D-144 diesel engines with an unseparated spherical combustion chamber, which reduces the geometric compression ratio from ε = 16,5 to ε = 9,4. The developed form of the combustion chamber allows the new diesel pistons or diesel pistons which are in operation to be in operation to be refined, instead of making special new gas pistons and to reduce the geometric compression ratio of diesel engines only by increasing the combustion chamber volume in the piston. This method of reducing the geometric degree of compression using conventional lathes is the most technologically advanced and cheap, as well as the least time consuming. Keywords: self-propelled chassis SSh-2540, wheeled tractors, diesel engines D-120 and D-144, gas engine with forced ignition, liquefied petroleum gas (LPG), compression ratio of the internal com-bustion engine, vehicles operating in the LPG.

Comparative Analysis and Synthesis of Schemes of Balanced Suspension of Planetary Rovers with Autonomous Control

The passive suspension of a six-wheeled self-propelled chassis is analyzed in terms of the influence of its kinematic and geometric parameters on the configuration, cross-country ability, and static stability of low-speed autonomous planetary rovers. The results of the synthesis of a new suspension scheme for a four-wheeled chassis are presented.