Academic literature on the topic 'Tractor-implement hitches'

Geometric performance parameters of three-point hitch system of a most sold model of a 2-wheel drive Indian tractor were determined by generating the path of upper and lower hitch points by kinematic linkage analysis. At various locations of pivot point of upper link and adjustments in the length of lift rods, hitch linkage system of the tractor fulfilled all the requirements specified by the standards for category-I and II hitches. An insight into the kinematic linkage analysis revealed that the hitch linkage of the selected tractor is the most suitable for operations with soil working implements. Attachment of upper link to the topmost pivot point reduced the change in orientation of implement during lifting and ensured better weight transfer from implement to the rear axle of tractor. The kinematic linkage analysis has the potential to identify the best settings of the hitch linkage system for the effective utilization of tractor power during various farm operations.

Turning time occupies a significant part of the operations carried out by implement-and-tractor aggregates, especially in fields with short runs. Incorrectly executed turns increase the width of the turning strips, significantly increasing the idle path of the implement-and-tractor aggregate, with negative effect on its efficiency. The objective of this paper was to theoretically analyse the turning agility of an asymmetric implement-and-tractor aggregate, taking into account its forward speed and design parameters. Considering a trailed asymmetric swath reaper and tractor aggregate, the obtained equations allowed a numerical simulation in order to evaluate the headland turning agility of this implement-and-tractor aggregate. The minimal radii of the trailed asymmetric swath reaper and tractor aggregate are, respectively, 8.33 m for right-side turn and 4.90 m for left-side turn. Furthermore, the optimal angle between the longitudinal axis of the aggregating tractor and the hitch bar of the trailed asymmetric implement exists only in the case of left-side U-turns and its value is 1.12 rad (64°). It is not possible to cover right-side U-turns or both right- and left-side pear-shaped loop-turn in the optimal mode.

The dynamic model is significant for the analysis of the vibrational characteristics of the wheeled tractor system with implement and front axle hydropneumatic suspension. In this work, the nonlinear stiffness and damping equations are derived first. The dynamic coupling relationship among cabin, three-point hitch structure, and implement are figured out, and the dynamic model of the half agricultural wheeled tractor/implement system is presented considering the effects of three-point hitch structure, passive silent blocks of cabin, and front axle hydropneumatic suspension together. To validate the model, the power spectral densities (PSDs) of the driver seat, cabin, chassis, and implement acquired from numerical simulations are compared with those from experiments, respectively. Under different forward speeds, two groups of results match well. Based on the model, the influences of passive cabin suspension, implement, and front axle hydropneumatic suspension on the dynamical characteristics of the tractor system are investigated. Results indicate that the front axle hydropneumatic suspension will deteriorate the ride comfort of the driver but improve the handing stability. The passive cabin suspension reduces the operational stability while improving much more ride comfort than the front axle hydropneumatic suspension does. The driver’s comfortableness will be increased due to implement; meanwhile, handling stability will be compromised. Besides, the impacts of initial nitrogen volume, pressure of accumulators, and orifice diameter of throttle valves on the vibration characteristics of the tractor system are also inspected.

Abstract Currently manufactured tractors are equipped with a three-point hitch, which is used to connect semi-mounted implements to the tractor. The tractor three-point hitch is operated hydraulically, using various types of control. The most commonly used control is a force, positional and a mixed one. Each of these types of control has its specific characteristics and some advantages and disadvantages. Finally, each type of control is suitable for certain soil and terrain conditions. Particular attention was paid to a force control, which is improving the use of the tractor with a mounted implement, but on the other hand, adversely affects the uniformity of working depth of implements on soils with variable resistance. Based on theoretical analysis and experimental measurements, there has been determined the effect of soil resistance on the tillage depth, depending on initial conditions for implement deepening. Initial conditions for implement deepening are given by the tillage depth, soil resistance, and the cutting width of a plough. It was found that soil resistance strongly affects the tillage depth, and with increasing soil resistance the tillage depth decreases non-linearly. A gradual increasing of soil resistance is associated with a less-marked decreasing of the tillage depth. These facts will be further used in research, development and experimental verification of new control systems of the three-point hitch of tractors.

This paper describes the design, development and calibration of a three-point auto hitch dynamometer for measuring the horizontal and vertical forces that existed at the three-point hitch of an agricultural tractor. The design concept of the dynamometer was based on an instrumented inverted U frame assembly that was mounted between tractor links and implement. The design incorporates for both lower point hitch spread and mast height adjustments, and quick hitch capability in accordance with category 1 and II three-point hitch system. The force sensing elements were comprised of three steel extended octagonal ring transducers that were located between the inverted U frame and hook brackets. Electrical resistance strain gauges were mounted on the extended octagonal ring transducer at strain angle nodes to independently monitor strains that were proportional to the horizontal and vertical forces at the ring center. Each transducer was designed for maximum horizontal and vertical forces of 25 kN and 10 kN at measurement mean sensitivities of 25.19 µStrain/kN and 25.60 µStrain/kN, respectively. However, the complete dynamometer has been designed to measure the maximum resultant horizontal and vertical forces of 50 kN and 20 kN, respectively. Field demonstration tests on the dynamometer and data acquisition system showed that they were able to function effectively as intended. The data acquisition system was able to successfully scan and record the dynamometer signals as programmed. This dynamometer was part of the complete instrumentation system to be developed onboard a Massey Ferguson 3060 tractor for the generation of a comprehensive database on the power and energy requirements of the tractor and its working implement in the field.

This study presents a design of an adaptive neuro-fuzzy controller for tractors’ tillage operations. Since the classical controllers allows plowing depth errors due to the variations of lands structure, the use of the combined neural networks and fuzzy logic methods decreases these errors. The proposed controller is based on Adaptive Neuro-Fuzzy Inference System (ANFIS), which permits the generation of fuzzy rules to cancel the nonlinearity and disturbances on the implement. The design and simulations of the system, which consist of a hitch-implement mechanism, an electro-hydraulic actuator, and a neuro-fuzzy controller, are conducted in SolidWorks and MATLAB software. The performance of the proposed controller is analyzed and is contrasted with a Proportional Integral Derivative (PID) controller. The obtained results show that the neuro-fuzzy controller adapts perfectly to the dynamics of the system with rejection of disturbances.

An adjustable three-point hitch dynamometer with a draft capacity of 50 kN was developed to measure forces on the tractor and mounted implements. The design concept of the dynamometer was based on two linkage frames mounted between tractor links and the implement. The force sensing elements were comprised of a loadcell that was installed between the frames. The system provides variable width and height of the dynamometer links to satisfy a wide range of implement dimensions. All mounted tillage implements at categories II and III such as plows, cultivators and harrows were able to be tested by this dynamometer excluding mounted implements powered by power take-off (PTO). The dynamometer was calibrated and several field tests were conducted to measure the force required to pull a moldboard plow in a clay loam soil. The calibration showed a high degree of linearity between the draft requirements and the dynamometer outputs. Field tests showed that it was able to function effectively as intended without any mechanical problems.

The main criterion of the soil cultivation quality is tilling depth. The goal is to predict the trajectory of penetration and steady tool movement as well as the trajectory when hitting an obstacle and leaving it after the obstacle was hit. Factors that actively influence the trajectory can be the tractor motion speed, geometry and weightimplement and tiller tool. For this purpose on the basis of the number of hypotheses differential equation of front and rear mounted implements vibrations is composed relative to the tractor location in a vertical plane along the axis of its movement. In the hypothesis of the force interaction of toolswith soil main provisions proposed by Professor L.V. Gyachev are developed. Mechanical models of the mounted implement are built on the basis of simplifications. In particular, the position of tool at different movement moments is determined by some predetermined function of the generalized coordinate. For the generalized coordinate a rotational angle of the lower hitch links is selected. The pointed out dependence is named as the transmission function of the hitch. By setting in the differential equations of motion various external influences and by changing the power parameters of working bodies, it is possible to imitate changes of soil medium. Such mathematical models allow to simulate movement not only within real operation conditions but that is often more important, to simulate the tools operation in conditions that in practice cannot be created. This is achieved, for example, when we set very hard and long or set very light and short tools, very hard or very soft soil, etc. So you can more clearly see the new phenomena and trends that are difficult to suppose and impossible to see in the real conditions.As a result, new solutions to traditional problems appear.

Two wheel tractor (Power tiller) is the common means of soil tillage and other farm operations in Bangladesh due to easy access in fragmented land size with affordable price. A low cost and small robust 2WT driven (12 hp) No-till seeder has been developed with press wheel attachment and inclined plate seed meter assembly in Farm Machinery & Postharvest Process Engineering Division, BARI, Bangladesh for seeding different kinds of seeds. This is a pull type implement hitched at drawbar point of 2WT replacing the regular rotary part. The developed No-till seeder was used in the farmer’s field of Rajshahi areas for wheat, maize, pulses, and rice establishment during the year 2011-2014. The planter can pull 4 tynes in soft and medium hard soil but 3 tynes for hard soil. The planter was capable to apply seed and fertilizer in the furrows. The width and depth of the furrow opening were 30 mm and 60 mm, respectively. The planting depth, row spacing and seed rate can be adjusted according to standard practices. The No-till seeder works effectively through high density crop residue (1.5-2.4 t/ha) without any problem as there are sufficient residue clearances between toolbar and ground surface. Depending on the level of weed situation, round up herbicide was applied 2 days before of planting. There were significant yield difference in wheat, pulses but rice yield was lower than conventional transplanting method. No-till planted crops show less lodging tendency compare to conventional planted crops. There were significant cost differences between no-till and conventional method. The planting costs of wheat and maize in Notill system were 60% and 86% less than conventional planting method. It also reduces the average turn around time 7-9 days between the two crops. The effective area coverage by the seeder was 0.13ha/hr. The No-till seeder is a low cost (US$ 350-400; without power unit), light in weight and local manufacturer can fabricate complete unit within a short period of time. The No-till seeder can be used in other countries where 2WT is the common farming equipment.Bangladesh J. Agril. Res. 42(1): 27-34, March 2017

Les travaux de recherche exposés dans ce mémoire se positionnent dans le domaine de la conception sécuritaire. Cette thèse s’intéresse plus particulièrement à rendre opérationnelle la méthode IRAD (Innovative Risk Assessment Design), qui intègre la sécurité de manière systématique tout au long du processus de conception. Dans cet objectif, nous proposons dans un premier temps de formaliser un type de retour d’expérience (les rapports d’accident) qui détaille les faits liés aux éléments d’une situation de travail et à des événements qui ont mené à un accident. Ensuite, nous proposons deux démarches complémentaires de reconception sécuritaire: une démarche d’ingénierie inverse fonctionnelle pour la sécurité (FRES) et une démarche de réingénierie fonctionnelle pour la sécurité (FR2ES). FRES permet d’extraire les connaissances à la fois sur l’accident et sur la conception du système impliqué dans l’accident. Elle permet ensuite d’évaluer le niveau de sécurité du système par l’estimation d’un indicateur de sécurité dépendant notamment du type de risque identifié. Cet indicateur est utilisé comme paramètre d’aide à la décision lors de la phase de reconception du système. La deuxième démarche, FR2ES, permet de définir les objectifs de sécurité liés à chaque phase de la conception dans le but d’éliminer ou de réduire un risque donné. Les solutions les plus sécuritaires possibles sont ensuite obtenues d’une part en intégrant ces objectifs de sécurité dans le processus de reconception et d’autre part à l’aide de l’indicateur de sécurité appliqué aux solutions proposées. Enfin, l’applicabilité de ces démarches a été démontrée sur deux types de liaisons tracteurs-outils, l’arbre de transmission à cardans et la liaison trois points - systèmes permettant d’atteler les outils aux tracteurs et de les motoriser
The research presented in this thesis is positioned in the field of design for safety. This thesis is particularly interested in operationalizing the IRAD (Innovative Risk Assessment Design) method, which integrates safety systematically throughout the design process. For this purpose, in first step, we propose to formalize a type of experience feedback (accident reports) detailing the facts relating to the elements of a working situation and the events that led to an accident. In the next step, we propose two complementary approaches to redesign for safety: functional reverse engineering for safety (FRES) and functional re-engineering for safety (FR2ES). FRES is used to extract knowledge on both the accident and the design of the system involved in the accident. This approach allows assessing the safety level of the system by estimating a safety indicator depending on the type of identified risk. This indicator is used as a parameter for decision support during the redesign of the system. FR2ES defines the safety objectives related to each phase of the design in order to eliminate or reduce a given risk. The safest solutions are then obtained, on the one hand, by incorporating these safety objectives in the redesign process and, on the other hand, by using the safety indicator applied to the proposed solutions. Finally, the applicability of these approaches is demonstrated on two types of tractor-implement hitches: the power take off shaft and the three point hitch systems