A theoretical and experimental study of the traction properties of agricultural gantry systems

Saabunud / Received 12.04.2020 ; Aktsepteeritud / Accepted 18.05.2020 ; Avaldatud veebis / Published online 18.05.2020 ; Vastutav autor / Corresponding author: Jüri Olt e-mail: [email protected] movement conditions experienced by an agricultural gantry system along the solid and level ground surface of permanent artificial tracks must make it possible to generate most of its maximum tractive force. Concurrently, the adhesive ability of the agricultural gantry system on the ground surface of such permanent artificial tracks must be sufficient to generate nominal drawbar pull when working at a certain level of slip. This means that there exists the need to seek out the following compromise: the maximum slippage experienced by the wheeled chassis of an agricultural gantry system must be such that, in a situation in which the level of adhesion with the surface of permanent artificial tracks is suitable, it will be able to generate the maximum possible tractive force. The effect of the parameters that involve an agricultural gantry system's wheels – and the physical and mechanical properties of the ground surface along which they move – on potential slippage has not yet been sufficiently studied. This effect cannot be taken into consideration without taking into account the dynamics of any rolling resistance being offered by the agricultural gantry system's chassis. The purpose of this particular study is to research the traction properties of an agricultural gantry system's wheeled chassis in terms of its movement along compacted and level ground upon which have been mounted permanent artificial tracks. The research determines that the wheels of such an agricultural gantry system that are rolling along permanent artificial tracks suffer less slippage and therefore generate a higher level of tractive force. As a result, the agricultural gantry system loses less of its speed of movement and, therefore, uses less energy in that movement. When an agricultural gantry system moves across an agricultural field that has been prepared for sowing, the research also determines the maximum tractive force that its wheels can develop when the adhesion coefficient is set at a figure that is between 0.22–0.24. Once such movement begins along permanent artificial tracks, this coefficient decreases to between 0.15–0.17. An agricultural gantry system's wheels are able to generate a higher level of tractive force when moving along on permanent artificial tracks. This figure is at least 30% higher when its movement has to be considered across an agricultural field that has been prepared for sowing

A theoretical and experimental study of combined agricultural gantry unit with a mineral fertiliser spreader

Saabunud / Received 06.07.2020 ; Aktsepteeritud / Accepted 03.08.2020 ; Avaldatud veebis / Published online 03.08.2020 ; Vastutav autor / Corresponding author: Jüri Olt e-mail: [email protected] to apply mineral fertilisers to the soil are an important part of practically every form of agricultural technology. The current global trend of transitioning to bridge and gantry-type agricultural systems leaves the unanswered relevant question of the effectiveness of the technological process of applying mineral fertilisers to the soil. This is relevant because, in gantry agriculture, a section of the arable soil is separated as an engineering area. This is why the main difference in gantry agriculture from traditional methods of the bulk spreading of fertiliser onto a field is that, with gantry systems, the amount of fertiliser that lands within the engineering zone are limited. This significantly affects the manufacturing costs involved in the entire area of agricultural technology and, as a result, the production costs of the end product. This study aimed to research the patterns that are apparent in affecting the parameters involved in the use of gantry-type equipment when applying fertiliser with the parameters and operational modes of a specially-developed electric spreader of mineral fertilisers. The physical object of the study was the agricultural gantry equipment that had been developed by the authors. This equipment, which is used for spreading fertiliser, was in the form of a tractor-mounted, suspended, single-disc spreader which was known as JarMet, and which had especially been modified to run from an electrical supply. The study indicated that the biggest influence on the speed of rotation of the centrifugal disc in the mineral fertiliser spreader stems from its height above the ground, the distance of track of the agricultural gantry itself, and the aerodynamic coefficient of the fertiliser. It was determined that, for the agricultural gantry with a distance of tracks of 3.5 m, a sufficient angular speed of the single-disc centrifugal tool is 15.5 rad·s−1, with a power demand for driving this at 0.35 kW·h. When using agricultural gantries of this type with an extended track width of up to 6 m, the necessary angular speed of the centrifugal tool for spreading fertiliser increases exponentially, to 318.2 rad·s−1, with the power demand for driving it increasing to the third power

Исследования специализированного ширококолейного агросредства для колейной системы земледелия

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 the smoothness 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

Кінематика повороту ширококолійних засобів механізації сільськогосподарського виробництва для колійної системи землеробства

З позиції мінімалізації непродуктивних витрат на повороти ширококолійних засобів механізації сільськогосподарського виробництва для колійної системи землеробства найбільш оптимальним є таким спосіб, за яким керовані мотор-колеса його шасі з одного боку повертають платформу відносно вертикальній осі, яка співпадає з місцем кріплення колісного візка до неї з іншого боку, яке розміщено на поперечній осі симетрії агрозасобу, безпосередньо посередині між колесами. При цьому колеса з іншого боку залишаються у своєму прямолінійному нерухомому стані. Для отримання щонайменшого радіусу траєкторії повороту, значення якого наближається до величини колії агрозасобу бажано, щоб його колісна база була як можна меншою і не перевищувала за своїм абсолютним значенням 25% від величини колії. За вказаною умовою щонайменшим є і кут повороту керованих коліс ширококолійного агрозасобу, що є бажаним з позиції технічного виконання механізму приводу та щонайменших енерговитрат на цей процес

Дослідження поперечних зміщень робочих органів ширококолійних агрозасобів для колійної системи землеробства

Метою досліджень є розробка математичних залежностей, що дозволять визначити допустимі межі поперечних зміщень робочих органів ширококолійного агрозасобу і обґрунтувати величину захисної зони, виходячи за умов відсутності пошкоджуваності рослин

До питання компонування спеціалізованих ширококолійних енерготехнологічних транспортних засобів для колійної системи землеробства

Метою досліджень є підвищення ефективності функціонування та використання ширококолійних засобів механізації сільськогосподарського виробництва для колійної системи землеробства шляхом вибору найоптимальнішої компонувальної схеми з позиції задовільної стійкості та плавності їх руху