Operator Workplace Research Articles

Development of ergo-refined operator's workplace and biophysically actual cost-benefit analysis of riding type self-propelled machines with special reference for female operators.

Female agricultural workers contribute to 37% of the total agricultural workforce in India, however, most self-propelled machinery is designed for male agricultural workers. The primary objective was to determine the impact of the ergo-refined operator's workplace on various aspects of operator performance and comfort, including actuating force, posture, and physiological parameters. Experiments were carried out in real field conditions using a full factorial randomized design. Twelve female operators participated in the study, and measurements were taken for control lever actuating force, operator posture, heart rate, and other relevant parameters. The ergo-refined operator's workplace intervention resulted in significant reductions in actuating force for various control levers, angles of joints, working heart rate (WHR), oxygen consumption rate (OCR), muscle load, and whole-body vibration (WBV) acceleration. These reductions were observed under different operating conditions. The findings suggest that the ergo-refined operator's workplace is effective in enhancing operator comfort and reducing physical strain during the operation of riding type self-propelled machines. It contributes to improved safety, comfort, and operational efficiency for operators working in field conditions. ANOVA and MANOVA analyses confirmed the positive impact of operating conditions and engine speed on the measured parameters when using the ergo-refined operator's workplace.

METHODOLOGICAL FOUNDATIONS OF OPTIMAL SWARM MANAGEMENT OF UAVS IN ENERGY CROP SPRAYING WITH AGROCHEMICAL AGENTS

The work is devoted to research on the optimal management of a UAV swarm when spraying energy crops with toxic chemicals. The relevance of the work lies in the fact that, at present, the solution of chemical plant protection tasks using UAVs is based on the individual experience of a human operator, who manages a swarm of UAVs, as a rule, in a non-optimal way with significant time and cost costs. The purpose of the article is to develop methodological principles for optimal management of a UAV swarm when spraying energy crops with agrochemicals. In order to achieve the goal, the following tasks must be solved: the formulation of the task of optimizing the management of a UAV swarm is substantiated, taking into account the time and cost constraints for the performance of chemical plant protection tasks, a method of optimal management of a UAV swarm when spraying energy crops with toxic chemicals and foliar feeding is developed, which provides a solution tasks to maximize the number of sprayed plants in each field section under time and cost constraints, a structural diagram of the solution to the task of optimizing the UAV swarm management was developed for the high-quality practice of chemical plant protection tasks. The scientific novelty of the work consists in the application of the dynamic programming method in the distribution and management of a swarm of UAVs on each site when spraying energy crops with agrochemicals. The practical value of the work lies in the development of a structural scheme for solving the problem of optimizing the control of a UAV swarm, with the help of which the optimal number of UAVs in a given time sequence is calculated in special software. automated operator's workplace for high-quality performance of chemical protection and plant nutrition tasks.

SCADA project for milk evaporation in double-effect evaporators

Human-machine interface tools remain one of the components of production automation systems. Appearance and functional abilities cannot stand still in the same way as automation, in this regard, one of the important aspects of food production automation is highlighted in this paper – a human-machine interface aimed at improving the operator's workplace. At the dispatcher level of automation, it is necessary to provide for the solution of the entire range of tasks set during the implementation of this project. The objectives of the project are to reduce the time for decision-making by personnel, since the effectiveness of the enterprise partially depends on the speed of the task, notification of hazards and violations, as well as the prevention of emergency and abnormal situations during the evaporation of milk, storage and archiving of data on the course of the process necessary for the preparation of reports used to investigate the causes of any emergency when evaporating milk. The project of the human-machine interface of the milk evaporation process, developed in the TRACE MODE environment, is presented. A feature of TRACE MODE is the technology of a single programming line, that is, the ability to develop all the ACS modules using a single tool. In the developed project of the human-machine interface of the milk evaporation process, it is assumed to use two main operator stations and one backup. Two of them are for operator workstations and a backup one used in emergency situations. The developed project in the TRACE MODE environment makes it possible to improve the workplace of the operator of the vacuum evaporation plant, reduce the time required for response and decision-making by personnel. In addition, the automatic alarm system allows you to reduce the number of defective products, and, accordingly, increase output and reduce the cost of production per unit of raw materials. The developed project fully satisfies the technical task and has been put into production.

Study of a solid-state transmitting device with a phase correction system, which increases the summing efficiency

Modern radar is a complex system, built on the basis of almost all the achievements of such areas as radio electronics, computer engineering and, of course, microwave devices. One of the most important units of radar, which determines the potential characteristics of the system as a whole, is the transmitting device. Nowadays the task of signal transmission with minimal losses in transmission lines and obtaining required power levels at the output of the transmitting device is relevant. However, existing methods may be insufficient to accomplish this task. In this regard, it may be necessary to improve or develop new systems and methods using the latest advances in microwave and antenna technology, radio and microelectronics, the totality of which will provide devices with these parameters. One such way to increase the stacking efficiency and output power of the transmitting device is to correct the phase of the amplification channels of the transmitting device in the range of operating frequencies. In this article the advantages of using solid-state transmitting devices in radar stations over electric-vacuum amplifying devices are considered. The most common ways of summation the power of microwave devices are described. An algorithm of the phase correction system is presented. The results of an experimental study of the system of gain channel phase correction for a transmitting device with eight gain channels, operating in a relatively wide frequency range, are presented. The proposed amplification channel phase correction system compensates the existing difference in the electrical lengths of the elements of the divider-adder path and amplifying modules in accordance with the algorithm, by means of controlled phase shifters (integrated into each amplifying module). The change in the phases of the microwave signal in (n-1) amplification channels is performed based on the calculated phase corrections obtained on the basis of successive estimates of the total output power of the reference amplifying module with each of the (n - 1) modules, where n is the total number of amplifying modules (channels amplification) in the transmitter. The output power is estimated by the ADC according to the level of the microwave power envelope at the lower, middle and upper frequencies of the operating range, taken from the adder output by a directional coupler. The performance of the phase correction algorithm is ensured by the control device of the amplifying module, the control and monitoring device of the transmitting device, the automatic monitoring and control system from the processing and indication system, as well as the appropriate interface at the operator's workplace. The proposed algorithm corrects the phases of the amplification channels according to the values obtained by the calculation method based on the data measured in the process of phase correction, which made it possible to reduce the maximum required number of phase shifter adjustments to 3 for each of n and each frequency, thereby ensuring a threefold increase in device performance. It was experimentally confirmed that the application of the proposed technical solution increases the efficiency of power summation of the considered transmitter from 70% to 94% - 99% (excluding active losses in the divider-adder and RMSD of the output powers of the amplifying modules) and an increase in the output power of the transmitter by 30% was achieved. The obtained results can be used to improve the algorithmic-software support of developed or modernized transmitting devices of radar stations.

Экспериментальные исследования и идентификация модели динамической системы «виброзащитное кресло – оператор» мобильной машины

When creating new types of transport and technological mobile machines, it is important to ensure compliance with sanitary standards for vibrations at the driver’s seat. Anti-vibration seats are widely used to reduce vibrations transmitted from the engine and chassis of the machine to the operator's workplace. When designing a machine, mathematical modeling can be used to make a reasonable choice of seat parameters. Since the anti-vibration seat together with the operator’s body form a single dynamic system, the mathematical model must include both the anti-vibration seat and the operator’s body. The article presents an overview of mathematical models that describe vertical vibrations of the seated body. It describes an experimental setup for studying the dynamics of a human operator sitting in an anti-vibration seat. The experimental setup includes an electrodynamic vibration bench produced by LDS, control and recording equipment. The studies were carried out for the Sibeco anti-vibration seat. During testing, the base of the seat performed vertical harmonic vibrations with a gradually increasing frequency, while the amplitude of vibration accelerations was maintained constant. The accelerometers installed on the seat elements, on a special disk located on the seat cushion and on the operator’s body, recorded vibrations of these elements. As a result of processing experimental data, transfer functions were obtained. They connect the amplitudes of movement of various elements of the model with movements of the base in a given frequency range. The experiments were carried out with the participation of testers with different body weights. The article proposes a mathematical model that describes the vertical vibrations of the “vibrationprotective seat – operator’s body” system. The inertial and elastic-damping characteristics of the seat elements were determined earlier during special tests. Based on a comparison of calculated and experimental data, the parameters of the model elements describing the operator’s body were refined. The parameters of the mathematical model obtained during the study will be used in the future research for calculation estimates of the vibration load of the operator’s workplace.

Flight control and collision avoidance of three UAVs following each other

An unmanned aerial vehicle is a hardware and software complex with multi-purpose control. Unlike manned aviation, an unmanned aerial vehicle requires additional modules in its control system. These include the drone itself, the operator's workplace, software, data transmission lines and blocks necessary to fulfil the set flight objectives. The range of applications of unmanned aerial vehicles in the civil sector is not limited, but with the current state of the legal framework for the use of airspace, flight operations are somewhat difficult. The article formulates the main scientific position on the methodology of solving auxiliary tasks set in the work. The methodology specifies the main research stages, and it is a generalized methodological algorithm for the implementation of scientific research, which provides theoretical developments, field observations and simulation computer modelling. As a result of the study, it was found that the motion control systems of unmanned aerial vehicles are used for the process of their differentiation by the principle of complete external control, the advantages of which are considered in the work. For external control of divergence process of unmanned aerial vehicles, a method is considered for assessing the situation of convergence of unmanned aerial vehicles and choosing the manoeuvre of their difference using the area of dangerous courses, unmanned aerial vehicles approach, and it is possible to take into account the inertia of unmanned aerial vehicles when turning and the presence of navigational hazards that are in the manoeuvring area.

Development of hardware and software support of computer-integrated technology of complex of secondary condensation of ammonia production

The object of research is the technological complex of secondary condensation (TCSC) and the control system of a typical ammonia synthesis unit of the AM-1360 series. The analysis of the conditions of its functioning and hardware and technological design was carried out. The coordinates of the control vector are determined. The features of the proposed functional diagram and the necessary algorithmic software for the computer-integrated control technology of the TCSC with a correction subsystem for decision-making under uncertainty are established. The implementation of the proposed solutions is complicated by the use of the information and control complex TDC-300 (USA) with closed-type software installed on the existing ammonia synthesis units. The need for such a control complex to implement a decision-making subsystem under conditions of uncertainty is shown to supplement the existing control system with hardware and software of an «open» type. A computer-integrated TCSC technology based on a three-level hierarchical structure has been created. The implementation of the zero and first levels of such a structure form single software and hardware complex consisting of a programmable logic controller and an automated operator's workplace based on an industrial computer with installed software. A software implementation of decision-making on the correction of the coordinates of the control vector by additional hardware and software based on the VIPA logic controller and the Zenon SCADA system was made. A scheme of network information flows has been implemented, which illustrates the functioning of the decision-making correction subsystem in the general structure of the TCSC computer-integrated control technology. Implementation of the developed system allows, under the existing uncertainties, to reduce the secondary condensation temperature by an average of 3 °C, which ensures an annual reduction in natural gas consumption by 1 million nm3. The proposed approach to the possibility of combining «open» and «closed» type hardware and software can be applied in other industries.

Method for predicting the technical appearance of grain and forage harvesters of new generations with a substantiation of the structure of their vibration protection system

The work is devoted to the development of a method for predicting the technical progress of self-propelled grain and forage harvesters and the substantiation of systems for their implementation. The necessity of improving the existing and developing new methods for predicting the properties of machinery, taking into account the existing features of the agro-industrial enterprises operation, were substantiated. A new technique for the synthesis of the technical appearance of products is proposed with the possibility of identifying the nomenclature of defining parameters based on the actual change in their values, ranking indicators with highlighting the most important of them for each category of business entities, forecasting using fuzzy logic methods, as well as justification of required machine systems of new generations using object-oriented design methods. A description of each of the stages of the forecasting process is given. On the basis of mass-produced grain and forage harvesters in Russia, an analysis of their constructive evolution with the allocation of stable and inherited development criteria has been carried out. A comparative analysis of the actual change in the defining parameters for machinery of the current and previous generations is shown. The technique and the results of forecasting the selected defining parameters are presented. It is shown that the predicted level of properties forms multidirectional requirements, which, from the point of view of implementation on the basis of existing design approaches, are contradictory. Taking into account the existing problems of motion dynamics and vibration loading of the workplace of operators of machinery of the current generation, it is stated that those multidirectional requirements are unattainable. Using the methods of object-oriented analysis, an object-target diagram of classes of possible options for constructing a vibration protection system for machinery of a new generation has been compiled. The relations of inheritance, which established the hierarchical decomposition of goals, were determined. It is shown that it is more expedient to control the selected vibration processes of combines without significant changes in their design and layout by means of systems for dynamic stabilization of the body and vibration isolation of the operator's workplace.

SOLVING THE ISSUE OF MODERNIZATION OF PRODUCTION EQUIPMENT USING CYBER-PHYSICAL MANUFACTURING CONTROL SYSTEMS

Continuous improvement of the fleet of technological equipment, in the conditions of existing production, is a difficult task, the solution of which must take into account many parameters, such as mechanization, automation and application of new technologies within the concept of Industry 4.0. One of the effective methods of improving the technical and economic indicators and reliability of production is the modernization of existing technological equipment, which is based on the need to use modern methods of development and implementation of information technology, such as Industrial Internet of Things, cyber-physical production systems. The subject of this study is the testing of methods for developing additive cyber design for automation of complex industrial equipment. The goal of this article is to develop a cyber-physical production control system for the modernization of the DA2238B hydraulic press. To achieve this goal it is necessary to solve the following tasks: to analyze the technical characteristics and control system of the hydraulic press DA2238B; to carry out research of the scheme of hydraulic basic and, taking it into account, to choose sensors and executive mechanisms, and also operating modes; to develop the scheme of inclusion of the hydro equipment; to develop an automated control system based on a modern single-board computer and to develop an intuitive additive cyber-design of the operator interface; to conduct experimental research. Conclusions: as a result of research, a block diagram was developed and an automated control system based on LattePanda was implemented. Selected pressure and temperature sensors for control of pressing processes, which allowed to ensure accurate compliance with the requirements of the technological process. An automated operator's workplace has been developed, in which touch control based on additive cyber-design has been implemented. The developed control system provides: collection and analysis of production data on the basis of which it is possible to improve production technology and to provide forecasting of achievement "Lean Manufacturing".

Vibration levels on operator’s workplace and vibration protection characteristics of seat suspensions

This article analyzes the nature and parameters of the main operational disturbances, which energy is directly or indirectly transferred to the operator's workplace of tractor with a caterpillar or wheeled propeller when performing various technological operations, based on experimental research data. The main operating frequency range of these operational disturbances is considered. The contribution of each frequency component to the overall level of vibration at the operator's workplace is assessed. The example of implementation the results of field measurements of real operational disturbances and vibration characteristics on a K-744R1 (st.) wheeled tractor, which operated in a unit with a PG-3-5 plane cutter in the mode of plowing stubble at a constant speed of movement was used. The comparative study of vibration-protective properties of various designs of seat suspension was carried out. The technique of field measurements, including specialized equipment of the ZETLAB and Assistant companies, the mode, the sensor installation scheme and other conditions are described. Using the numerical Runge-Kutta method and mathematical modeling tools in the Simulink MatLab software environment, the operation of the serial suspension of the K-744R1 (st.) tractor seat, air suspension of the Sibeco seat with a scissor guiding mechanism and the innovative air suspension of the seat (based on Sibeco) with controlled extraction of vibration energy and its subsequent recuperation was simulated. There were obtained the calculated oscillograms and spectra of vertical accelerations on a seat cushion, sprung with each of the considered suspensions under the input action of measured real operational disturbances. The results of the analysis of the research results are summed up.

DERIVING THE DEPENDENCIES FOR THE VIBRATING CAPACITY INTRODUCED INTO WHEELSET ASSEMBLIES

Despite the very large difference in lifting capacity, bridge cranes have an almost identical vibration control system layout, which predetermines the general approach to the theoretical assessment of vibration and noise spectra both in the production premises and at the crane operator's workplace. The bridge crane is characterized by potential danger for not only operators but also production personnel located in the crane area within the production workshop during its operation. The safe operating conditions of cranes are determined by not only their technical condition but also the crane operator fatigue, which, in turn, is caused mainly by the impact of increased noise and vibration.

Comparative analysis of Russian and foreign regulatory requirements for vibration protection of a tractor operator

The paper discusses the main requirements of Russian and foreign regulatory documents on vibration protection of the operator's workplace of wheeled and tracked vehicles. Their comparative analysis was performed. The normalization of the parameters of general vibration at the workplaces of operators of tractors and self-propelled agricultural vehicles in our country occurs in accordance with the requirements of SN 2.2.4 / 2.1.8.566-96, GOST 12.1.012-2004 and GOST 12.2.019-2015. The root-mean-square values of vibration accelerations for a certain period of exposure in each octave (one-third octave) frequency band are allocated as the evaluation criteria. They are compared for compliance with the regulated values from a specific standard. At the international level, the object of compliance is the ISO 2631-1: 1997 standard, which establishes the requirements for vertical and horizontal vibration with a certain exposure time on a person from 1 minute to 24 hours in the frequency range from 1 to 80 Hz. The article shows that the most stringent requirements for the level of local vibration are established in the Russian Federation. They provide clear regulation of the type of work performed, duration, magnitude, direction of existing loads, etc. Relatively soft requirements are in most European countries, except Poland, where the MPL is regulated taking into account the age, gender and condition of a person. In addition, in the regulatory documents of most foreign countries there are two and sometimes three indicators: threshold (upper and lower) values and MPL. When the threshold is reached, primary measures are usually initiated to counter harmful factors.

Mathematical model of the cabin suspension system for grain and forage harvesters taking into account the dynamic properties of the supporting system

The paper is devoted to the study of the vibrational state of the operator's workplace of a transport-technological machine with a supporting system that undergoes torsional and bending elastic deformations during operation. Based on the previously carried experimental studies, the relevance of the work was substantiated and the goal was set to develop a computational model of spatial vibrations of the cabin on a non-existent system in the form of elastic cantilever beams. An original mathematical model of cabin vibrations on an elastic foundation is presented. It takes into account the nonlinear elastic and dissipative properties of the supporting system structure. A variant of the implementation of the developed mathematical model using the example of the mathematical modeling environment Mathcad is proposed. As an example of calculating the dynamic properties of a bearing system, a case of using the MSC Adams software package with an integrated finite element calculation module Flex is shown. It is presented that taking into account the dynamic properties of the carrier system in the model makes it possible to calculate the vibration load of the cabin with high accuracy and reproduce the resonance phenomena caused by the natural modes of vibration of the carrier system and disturbances from technological sources. The results of the verification of the computational model based on the analysis of the convergence of the values of the full corrected vibration acceleration in the center of mass of the grain harvester cabin, as well as the vibration spectra in linear directions obtained by experimental and computational methods, are presented. Directions for the development of measures and technical solutions for improving the vibration load of operators of transport and technological machines who have active sources of power disturbances on board, as well as a supporting system that experiences elastic deformations during operation are proposed.

Identyfication and Assessment of Occupational Hazards in the Working Environment of the Laser Cutter Operator

Abstract The purpose of this article was to identify occupational hazards at the laser cutter operator's workplace and to assess occupational risk. The article also indicates the basic requirements for the analyzed workplace. Research methods included: observation of the workplace (using a checklist), interviews with the employer, selected employees and a health and safety specialist, as well as analysis of the company's internal documents. The occupational risk assessment carried out at work using the Risk Score method showed that there are many different risk factors for accidents or diseases related to the work performed at the position of the laser cutter operator. However, thanks to the preventive measures applied, they are in the analyzed workplace at an acceptable (acceptable) level.

Design characteristics of an armored tractor for hot climate

The article discusses issues related to the field of tractor construction, specifically to tracked and wheeled tractors equipped with various attachments that perform earthmoving, loading, transport and other works in industrial and road construction in special conditions that require additional cooling of the power compartment and protection of the operator and the main components of the machinery from the bullets and shrapnel. Not every serial tractor and machinery based on it (including the engineering ones) is suitable for operation in the special conditions of countries with hot climates, especially in conditions of war or its consequences (undetected and not neutralized mines, unexploded bombs, etc.). The aim of the work is to link the known measures of strengthening the standard cooling system of the engine compartment of an armored tractor with its armor protection, excluding, at least, the negative consequences of such “heat engineering recipes” for the operational safety of the tractor driver mainly, and thereby improve the technical and operational characteristics of armored tractor. The proposed options make it possible to improve the technical and operational characteristics of the armored tractor through the use of such arrangement of the considered components of the tractor (the cabin with operator's workplace, the power compartment, limited by the hood, and the heat exchange hatch), that allow to meet the maximum requirements, which are a visibility from the cabin and protection of the cabine from weapons that fall into the cover. The results obtained seem to be a sufficient basis for an optimistic forecast of the implementation of this development in the existing technological structure of the domestic economy.

Lumbar-load analysis of a soldier while carrying the heavy loads

Background: The aim of the article was to create an appropriate computer model based on the real status of the mortar operator's workplace and to analyze the workplace. After that, for any possible exceedances from the aspect of the organism's load and safety, the aim is to redesign the workplace and bring it within the limits of the permissible load, and therefore the required safety. The aim is also to identify the characteristic work movements performed by the soldier and to carry out an ergonomic analysis of the soldier's efforts and to propose appropriate improvements. Methods: The analysis is performed on a total of 20 soldiers, from which is determined an average model of the following characteristics: 180 cm in height and 85 kg in weight. The task is to take a mine from the shell containing the mines, then transfer it to the mortar and fill the mortar barrel. The weight of the 120 mm mortar grenade is 14.8 kg. The average soldier is 26 years old and his military exercise lasts 4 hours. The CATIA software package (Dassault Systemes, Velizy-Villacoublay, France) is used for analysis. By knowing the anthropometric and work environment data, with ergonomic design and analysis, the following analyses were made: biomechanical analysis, rapid upper limb assessment (RULA) and carry analysis (option from CATIA software). Results: The proposed modification of the position resulted in a decrease in the L4/L5 torque from 316 Nm to 154 Nm along with decreasing of the compression force on the L4/ L5 from 5779 N to 3038 N (the compression force allowed is 3400 N), and while the RULA analysis is from the red color position 1 (score 7; maximum load requiring rapid repositioning of such position), revised final score 4 made in yellow (a solution acceptable for this work place). Conclusions: By ergonomic analysis, obtained proposal will lead to less chance of injury, prevention of burn out syndrome, fewer chances of illness, decreasing the fatigue, greater safety, less energy spent and better preparedness for all necessary tasks.

Impact of Human, workplace and indoor environmental risk factors on operator’s reliability in control rooms

Adequate design of control rooms is very important for increasing the reliability of operators working in them. Therefore, it is necessary to choose the best solution for improving the compliance between operators and elements of control room while dealing with problems of illumination, thermal climate and noise. For this purpose we will analyze the impact of execution time of operator's information processing tasks, motor and logical operator's tasks, operator's functional state, workplace risk factors and indoor environment parameters on operator's reliability in control room. Methodological approaches for these five groups are formed and used for experimental research and to determine the level of their quantitative values. Research results are showing the following levels of reliability for specific indicators: reaction time ‐ very good, coefficient of task complexity ‐ optimal, operator's error caused by stress ‐ very good, workplace risk factor ‐ critical and indoor environment ‐ good. Because the functional appropriateness and efficiency in the operator's workplace were inadequate, the following recommendations and solutions were proposed: signaling and control elements should be placed on the central part of the control desk, because due to poor control desk construction, they cause uneven burden on various operator's body parts.

Reduction of external noise of mobile energy facilities by using active noise control system in muffler

The paper describes a method for the reducing emission of low-frequency noise of modern automotive vehicles into the environment. The importance of reducing the external noise of modern mobile energy facilities made in Russia is substantiated. Standard methods for controlling external noise in technology are of low efficiency when low-frequency sound waves are reduced. In this case, it is in the low-frequency zone of the sound range that the main power of the noise emitted by the machinery lies. The most effective way to reduce such sound waves is to use active noise control systems. A design of a muffler using a similar system is presented. This muffler allowed one to reduce the emission of increased noise levels into the environment by 7-11 dB and to increase acoustic comfort at the operator's workplace by 3-5 dB.

The development and validation of an ergonomics index for assessing tractor operator work place

ABSTRACT: This study aimed to develop and validate an ergonomics index for the operator workplace assessment of agricultural tractors sold in the Brazilian market. To develop the ergonomics index, the operator work places were assessed for compliance with current, national and international, safety and ergonomics standards. The following standards were analyzed to develop ergonomics index: ISO 15077 (1996), which regulates the position of operator controls; ABNT NBR ISO 4254-1(2015) and ABNT NBR ISO 4252 (2011), which regulate the access to operator workplaces; and NR 12 (2010), which determines the mandatory items of operator workplaces.Thirty-four operator work places of 152 models of new agricultural tractors sold in the Brazilian market were analyzed in this study. Ergonomics index was developed and validated using these standards, and the findings enabled the ranking of agricultural tractors. Therefore, the proposed ergonomics index proved feasible and may be applied to other agricultural machines.

Decrease of the Vibration Load Level on the Tractor Operator Working Place by Means of Using of Vibrations Dynamic Dampers in the Cabin Suspension

This paper is devoted to description of the method for decreasing of the vibration load level on the tractor operator working place using vibrations dynamic dampers in the cabin suspension. Standard cabin vibration isolators of tractors of DT and VT series include the monolith rubber block and have limited capabilities to change its elastic parameters and adapt in the course of the impact of vertical and lateral vibration loads with various frequencies. Elastic-damping properties of these vibration isolators doesn’t allow one to provide comfortable conditions for the operator's work because their abilities of vibration damping aren’t sufficient especially at low-frequency vibrations. Dynamic vibration dampers installed in the cabin suspension were proposed by authors for decreasing of the vibration load level on the operator's workplace. 3D- model of the caterpillar chassis, suspension, engine, cabin and operator's seat of the tractor was created in the software “Universal mechanism” for performing of the computational research. This model was used to conduct research of sprung mass vibration for tractor motion with and without hook load at 3rd and 7th gears on the smooth surface and on testing areas with single, periodic and random bumps. Research results undoubtedly indicate the best vibroprotective properties of cabin suspensions with dynamic vibration isolators.