The necessity of stabilizing the movement of grain and forage harvesters as one of the main directions of increasing the productivity of the considered class of transport and technological machines is substantiated. It is shown that a modern combine can be represented in the form of two mass models, including a housing and an adapter, which allows you to organize controlled forced mobility between them, forming reactive torque components, controlling which can provide a given level of smoothness of the combine. The design scheme is given, an approximate component composition of the system is determined, and a description of the working process is given when stabilizing the longitudinal-angular vibrations of the self-propelled combine body. Based on the mathematical and simulation models of the combine previously developed by the author, modeling of its movement along a dirt road and asphalt concrete highway with different speeds in the initial state and with a working stabilization system was carried out. Based on a comparison of the spectral densities of the angles of longitudinal inclination of the housing of the forage harvester, the efficiency of the system in terms of stabilization of movement is shown. The efficiency of the system is confirmed by a decrease in the active vibration acceleration at the workplace in the entire normalized frequency range. The results of evaluating the health of the system are presented. The implementation of the adapter rotation angles is shown, the dimensional parameters and restrictions on the driving conditions that allow the adapter to move along the calculated rotation amplitudes are justified. The energy costs for the implementation of the proposed stabilization method are considered. It is shown that for a modern forage harvester, a motion stabilization system will require up to eight kW of power, which is an insignificant share in the energy structure of the combine. Conclusions are drawn and directions for further research are identified.
The paper presents the hydropneumatic suspension mathematical and simulation model development results for the grain combine harvester adapter. The urgency of the work in connection with the hydropneumatic suspensions spread and the need to increase the system efficiency for field relief copying has been substantiated. A computational model of a hydropneumatic suspension including hydraulic cylinders and hydropneumatic shock absorbers connected in parallel to them, including chokes and gas springs has been presented. A system of equations for the hydraulic cylinder piston motion, depending on the hydropneumatic suspension parameters and the number of the connected hydropneumatic shock absorbers has been presented. On the assumption basis, a simplified diagram of the adapter hydropneumatic suspension with back pressure and the corresponding equation system for determining the hydraulic cylinder piston movement have been drawn up. The model includes changing the parameters of external influence on the system, as well as the hydropneumatic accumulator presetting parameters. To assess the developed model’s performance, its simulation model, which was integrated into the well-known simulation model of the grain combine harvester movement, has been compiled. The modeling results of the combine movement on the field with real geometric evenness parameters have been presented. Based on the simulation results, an oscillogram of the hydraulic cylinder piston movement has been shown, depending on the hydropneumatic accumulators’ settings. Conclusions and directions for further research in this area have been presented.
This review-analytical article is devoted to the definition and justification of promising areas of modern combine-building. The paper presents an analysis of studies conducted in Russia and abroad, on the effect of the bias of soil preparation on one of the most important indicators of the efficiency of the operation of combine harvesters-total grain losses. To ensure a given efficiency of work on the slopes, the need to use special combines or to make changes to the existing ones is shown. The classification of combine harvesters is given depending on the suitability for work in fields with a slope. For each of the selected groups, a detailed analysis of their structures is carried out, distinctive features are identified, and mechanisms and systems are determined that ensure a reduction in grain losses of the combine harvester on soil preparation with complex terrain. The main reasons for the widespread use of such systems are identified. Based on the experimental data obtained during field testing of combine harvesters, the level of dynamic loads acting on their frameworks is shown. Spectral analysis of the acting accelerations on the adapter, arms of front and rear double-reduction axles are carried out. Based on the analysis the main frequencies at which the loads are formed are identified. The need for the introduction of suspension systems, which could also perform the function of leveling framework and facilitate the process of copying the topography of the soil preparation with a header is explained. A dynamic model of a combine harvester with a system of leveling and cushioning is presented, arguments are given for the creation and implementation of such systems. Conclusions are drawn and directions for further research on the development of multifunctional systems for individual implementations of combine harvesters working on soil preparation with complex terrain and having a competitive level of operational properties are determined.
The scientific-methodical substantiation and practical recommendations on stabilizing the movement of forage harvesters are proposed. Calculation of optimal mass and inertial parameters of the hull, as well as elastic properties of tires as the main element of the combine suspension system is theoretically grounded. The developed technique on the example of the combine prototype shows the possibility of calculating the optimal stiffness of tyres and weight of additional counterweights installed in the base of the machine to ensure the equality of natural frequencies of front and rear axle oscillations on elastic tyres. The modeling of the combine’s movement on the subsoil road and asphalt concrete highway with different speeds has been carried out on the basis of mathematical and imitation model of the combine developed by the authors earlier. In the order to evaluate the efficiency of the proposed method of improving the smoothness of running the comparison of peak and mean square values of the pitch angle of the hull, as well as the levels of vertical vibroaccelerations in the cabin on the floor under the seat of the operator of the combine in its basic design and improved version due to the use of counterweights of a given mass and optimized stiffness of tires. A simulation was used to perform an octave analysis of the workplace vibration load. It is shown that optimization of mass and inertial parameters of the body, as well as elastic properties of the combine harvester tires on the main driving modes provides improvement of comfort of the operator’s working place, especially in the most dangerous for human frequency range. The driving modes are defined, on which the best effect of rework is achieved. The stabilization process is described. The conclusions on the direction of further research are presented.
The paper is devoted to the development of systems and technical devices for reduction of dy-namic loads acting on operators and the supporting system of self-propelled vehicles. The goal of the paper is to develop an algorithm and a law of optimal control of the stabilization system. The set of tasks to be solved for this is determined, the requirements for the information field are highlight-ed, the element base of the stabilization system is substantiated. The problem of optimal control of the stabilization system is formulated. The development of a law of control of the stabilization sys-tem of the movement of self-propelled wheeled vehicles based on the principle of active inertial vi-bration damping is presented. The law of optimal control of the stabilization system with the possi-bility of correcting the requirements for attenuation and the type of transient process was developed. On the basis of quadratic integral criteria, the indicators for assessing the quality of system control are distinguished. It is substantiated that for the system of stabilization of the harvester body it is necessary to regulate the output variables, such as the angular velocity of the body and the angle of the longitudinal inclination of the harvester body. A linearized model of the longitudinal-angular motion of the combine is considered, the equations that connect the laws of the disturbed motion of the body and the law of optimal control are presented. With the help of simulation modeling, the effectiveness of the proposed stabilization method and the law of control of the stabilization system in terms of reducing the longitudinal angles of inclination of the body when driving on an asphalt-concrete highway and a dirt road are shown. The effectiveness of the proposed law of control for suppressing the pitch of the combine body during emergency braking is shown. The calculated values of the power spent on control of the stabilization system for the considered driving modes are given. On the basis of calculations, it is shown that in the total energy balance of the combine, the power consumption for control is insignificant, which confirms the efficiency of the proposed stabilization method and the law of control. Conclusions are drawn, stages and directions of further research are determined.
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