• ## DETERMINATION OF THE FRICTION COEFFICIENT OF THE HEAVYDUTY DISC BRAKES OF AGRICULTURAL VEHICLES

pg(s) 193-198

This article discusses the braking system of a heavy-duty engine for the determination of the friction coefficient. The agricultural vehicle progresses at 40 km / h speed; its weight is 30,000 kg. While braking such a heavy vehicle, a significant amount of heat is released as a result of the disc brake’s friction. A significant part of the resulting heat is removed from the system using oil cooling. The cooling oil lubricates the various components and affects the frictional conditions significantly. This article describes the construction of the braking system. It contains a description of the measurements on the test bench and the evaluation of the results. This study determines the frictional performance and describes the method for determining the friction coefficient of a given construction. The author shows the changes in the friction coefficient depending on the pressure and the temperature, and draws conclusions from the results.

• ## STUDY PLANE-PARALLEL MOTION MOVEMENT COMBINED SEEDING UNIT

pg(s) 199-202

Conducted analytical studies, resulted in the construction of a new mathematical model of plane-parallel motion combined simultaneous sowing unit and bandpass mineral fertilizers. If you use the original equation in the form of Lagrange II-the kind, the system was composed of six differential equations of motion, that describes the behavior of the combined unit with its plane-parallel motion. Defined analytical expressions for the forces, that act on the machine unit, can be solved on the PC.

• ## EXPLOITATIONAL CHARACTERISTICS OF ELECTRIC VEHICLES

pg(s) 203-207

Various electric vehicles are exploited in Latvia. The paper analyses experimental data for three different electric vehicles: a Fiat Fiorino Electrico, a conversed automobile Renault Clio and a Think City. The paper focuses on the following parameters of the electric vehicles: charging parameters, range per charge and cost per charge. Lower cost per 100 km distance covered – EUR 2.91for conversed Renault Clio.

• ## ON THE ISSUE OF REDUCING THE HARMFUL INFLUENCE OF THE MOBILE AGRICULTURAL SYSTEMS UNITS ON THE SOIL

pg(s) 208-210

The article is devoted to the problem of increasing the efficiency of using mobile agricultural aggregates by reducing the impact of their running systems on the soil. The work on the efficiency of the use of mobile agricultural units based on the automobile chassis in agroindustrial production is analyzed, which shows the results of studies on the changes in their designs with the purpose of reducing the harmful influence of chassis running systems on soil. One of the ways to reduce the harmful influence of running systems of mobile agricultural units on Execution of technological operations, both in field conditions and in transport operations while driving along the road Mobile roads. The main ways that will ensure the effective use of the automobile chassis in field conditions and on highways are analyzed. It has been found that the most effective is the equipment of automobile chassis with wide – profile tires with adjustable internal air pressure and a tire – pumping control system, which makes it possible to effectively use the chassis both in the main technological operations (in the field) and in transport operations (on the roads). The influence of the air pressure in the tire of the wheel of the running system of the KrAZ – 6322 automobile chassis and the normal load on the contact area of the tire with the supporting surface and pressure on it is established. To use the automobile chassis for performing agricultural operations in field conditions, it is necessary to equip it with wide – profile tires with adjustable internal air pressure and a tire – pumping monitoring system that will reduce the negative impact on the soil of the mobile agricultural unit and expand the list of technological operations on which it can be used.

• ## THE EFFECT OF N-BUTANOL ADDITIONS TO DIESEL FUEL ON ENGINE PERFORMANCE AND EXHAUST EMISSIONS

pg(s) 211-214

The article deals with the effects of butanol-diesel fuel blends on performance and exhaust emissions of a turbocharged, CRDI 1154HP (85 kW) diesel engine. Load characteristics were taken when running with normal diesel fuel and n-butanol-diesel fuel blends DB1, DB2, DB3, and DB4 possessing 1wt%, 2wt%, 3wt%, and 4wt% of fuel-oxygen at speeds of 1800 and 2500 rpm. The auto-ignition delay increased by 15.5%, burn angle MBF 50 and the combustion ended 7.6% and 6.5% earlier in the cycle, bsfc and engine efficiency were 2.8% and 1.9% higher when using fuel blend DB4 than the respective values of 17.40, 20.90 and 61.20 CADs, 234.4 g/kWh and 0.361 a fully loaded (100%) straight diesel develops at speed of 2500 rpm. The NOx, CO, THC emissions, and smoke decreased by 5.1%, 29.5%, 3.7 times, and 48.1% against the respective values of 1020 ppm, 563 ppm, 260 ppm, and 12.9% a straight diesel develops under these test conditions.

• ## TESTING THE SYSTEMS OF THE AUTONOMOUS AGRICULTURAL ROBOT

pg(s) 215-218

The aim of the paper was to test of the concept of the navigation system for the autonomous robot for sowing and wide row planting. Autonomous work of the robot in the field of traction and agronomic processes is implemented based on data from many sensors (cameras, position sensors, distance sensors, and others). The robot is intended for ecologic cultivation requiring mechanical removal of weeds or in crops with application of selective liquid agrochemicals limited to the minimum. The use of a vision system, based on the map coordinates of the position of the sown seeds, allows for their care on an early stage of plant development. Main sensor system is based on a specialized GPS receiver and inertial navigation providing position information with an accuracy of around 10 mm. To determine the angular acceleration the IMU (Inertial Measurement Unit) is used. Additionally, information from the acceleration sensors and wheel encoders is used for navigation purposes. This system is used to: control the speed of the robot, keep the robot on the designated path, and detect the precise position of the seeds. The exact information of the seeds position is used to build maps of seeds, which will be used as supporting information for precision weeding, and to control the position of and operation of key components. The front camera view is used to increase positioning accuracy of the robot. It will allow corrections of the robot path regarding the rows of plants. The vision system is also used for detection of non-moving objects. A structure of requirements for the SQL database has been developed, which is used to store plant and weed geo-data, as well as store data about plants and weeds, based on images recorded by the vision system.

• ## APPLYING SWOT ANALYSIS IN ASSESSING THE CAPACITY OF AGRICULTURAL PRODUCTION IN CONDITIONS OF DROUGHT AND CHANGING CLIMATE

pg(s) 219-222

Soil and water resources, used for the needs of farming production are strategically important on a regional, national and global scale. One of these resources – soils, has an extremely long recovery period, hence it is assumed practically unrecoverable. The second resource – water, has the property of not being wasted in nature; in fact, it only changes its physical state, and is purified if in movement. At the same time, due to considerably short-sighted human activity, a process of aeration sets over already fertile arable land, precipitation changes location, as well as intensity.
Analysing strengths and weaknesses of applying technological processes in farming, especially in the conditions of prolonged droughts and changing climate, will be crucial to making the right decisions, concerning the development of farming production technologies. But mere analyses, no matter how detailed and accurate they are, will be useless without the next step-planning.
Therefore, applying SWOT analysis as a tool can help the awareness of guidelines and failures during the strategic planning for the usage of
these irreplaceable natural resources.

• ## THE BENEFITS AND EFFICIENCY OF PRECISION IRRIGATION

pg(s) 223-231

The contribution was to develop methods for irrigation management using knowledge in the field of precision agriculture. In the monitoring points were established basic hydrolimits: Field capacity (FC) and wilting point (WP). Irrigation rate ranged from 0 to 40 mm for a specific term assessment of soil moisture. Throughout the growing season used to be applied precisely five irrigation benefits. A high savings were observed between conventional and precise irrigation (water, energy and economic savings). The results show that it is a fully effective system of precision agriculture, although the procurement and introduction of new technology and the software requires first expending a considerable financial cost. Higher demands are placed on the skill and education services.

• ## THE STUDY WIDE SPAN TRACTOR (VEHICLES) FOR CONTROLLED TRAFFIC FARMING

pg(s) 232-234

Promising energy technology means for controlled traffic farming are wide span tractor (vehicles). The effectiveness of the practical use of wide span tractor (vehicles) depends on a sound scientific base or theoretical frameworks, concerning the study of their technological properties. The article presents the theoretical basis of the dynamics of plane-parallel movement wide span tractor (vehicles) in the horizontal and vertical plane as well as its cornering. Developed the theory of plane-parallel movement wide span tractor (vehicle) allows for the justification of new schemes, design parameters and operating modes with acceptable controllability and stability of motion in the horizontal plane. Ride wide span tractor (vehicles), as a dynamical system, moving through the traces of permanent tramlines significantly depends on the characteristics of the irregularities of the longitudinal profile. The desired character of the internal structure of the longitudinal profile laid tramlines is almost possible to obtain the appropriate technology for its formation. Quality testing of dynamic system input perturbations, which are irregularities of the longitudinal profile permanent tramlines and the unevenness of the traction resistance of the soil, depends on the scheme and the constructive and other settings wide span tractor (vehicles). A significant impact on thesmoothness of the latter renders the rigidity of the tire support wheels, the magnitude of which can be influenced, within certain limits, by changing the air pressure in them. Improve driving dynamics the technological part of the wide span tractor (vehicles) is observed by increasing the rigidity of the tire its supporting wheels and operating mass. The offered new scheme of the turn of a wide span tractor (vehicle) for controlled traffic farming on the turning strip by turning the undercarriage, using the steerable wheels from its one board around the turning centre arranged in the centre of the space between the wheels from the other board, allows shifting of the tractor, simultaneously with the turn, to the next operating position with better kinematic parameters. In addition to it, the improvement of the turnability characteristics is achieved at such a design embodiment of the wide span tractor (vehicle) when the relation of its wheelbase to the width of the wheeltrack is as small as possible.

• ## TECHNOLOGY AND MEANS FOR MECHANIZATION FOR THE RATIONAL AND SAFE APPLICATION OF PESTICIDES

pg(s) 235-237

The paper analyzes the results of research in the sector of mechanization for the evaluation of efficiency of deposition of dispersed drops of fluid on the treated surface when using conventional hydraulic nozzles and rotating disk atomizers, mesh or perforated drums with the forced deposition of small drops. The necessity of using forced deposition of small droplets when creating new working bodies to the spraying technique on the basis of the rotating disc atomizers, mesh, or perforated.

• ## SOIL CHARACTERIZATION BY THE CAPILLARY EFFECT

pg(s) 238-241

Granular materials are a collection of distinct macroscopic particles. Consequently soils, which are used for agricultural purposes are a part of them. In comparison with other simulation models, creating a numerical simulation with the discrete element method (DEM) for different soils prove to be difficult. The reason for this is that there are an enormous number of particles. Therefore it is not possible to reproduce every one of them. On this account, parcels are used in the numerical simulation. These are larger and also have different physical properties. However, also for the modelling of parcels characteristic variables are necessary. This variable should be determined by using the capillary effect.