Stability tests of agricultural and operating machines by means of an installation composed by a rotating platform (“turntable”) with four weighting quadrants

The stability of agricultural machines, earth-moving machines, snow-compaction machines and, in general, of all vehicles that may operate on sloping terrains is a very important technical feature and should not be underestimated. In fact, it is correlated, above all, to the safety of the operators, but also to the preservation of the structural integrity of these vehicles, to the prosecution of the activities and to the preservation of the economic investment. Although these facts are well-known, the international legislation and technical standards do not yet have a sufficient level of detail to give an all-inclusive quantification of the stability of the vehicle under examination in all its working conditions, e.g., at different inclination angles of the support surface, at different climbing angles of the vehicle on the slope, with different tires and inflating pressures, and on different terrains. Actual standards limit the stability tests to the experimental measurement of the lateral rollover angle only. Furthermore, the realization of unconventional test equipment able to widen the usually-tested scenarios could not be simple, due to the necessary size that such equipment should have (to perform tests not in scale) and to the related difficulties of handling full-scale vehicles. This work illustrates the applications of a new rig for testing the stability of vehicles, able to address all the above-illustrated issues and of possible future adoption to certify the stability performance of machines and perform homologations. This installation, named “rotating platform” or “turntable”, has the peculiarity of being able to move the machine positioned on it according to two rotational degrees of freedom: (1) overall inclination of the support plane, (2) rotation of the support plane around an axis perpendicular to the plane. The same installation is also designed to record the weight supported by each wheel of the machine placed on it (by means of four sensorized quadrants), both when the platform is motionless and while the above-described movements of tilt and rotation are being carried out, thus locating precisely the spatial position of the vehicle center of gravity. The presented physical-mathematical models highlight the great potential of this facility, anticipate the outcomes of the recordings that the experimenters will have at disposal when the test rig will be effectively active, and help the future understanding of trends of data, thus maximizing the available information content

Definition of the Layout for a New Facility to Test the Static and Dynamic Stability of Agricultural Vehicles Operating on Sloping Grounds

In this study, a new rig for investigating the static and dynamic stability of agricultural machines was conceived: its architecture was studied and its layout was designed following a specific conceptual approach. The first part of the proposed design process specifically addresses the test equipment and follows a ‘top-down’ logic starting from the requisites of the tests to perform. This approach alternates analysis and synthesis phases and exploits two important principles of the creative design process: functional analysis and decomposition, and kinematic inversion. During this process, many solutions (kinematic mechanisms, actuators) were proposed and discussed based on their advantages and disadvantages towards the definition of an optimal configuration. Therefore, the layout of a new mechanical system has been developed, which is supposed to steer subsequent and more detailed design-phases appropriately. The proposed facility has many innovative features compared to traditional test systems, in which vehicles are tested for lateral overturning under static conditions with the steering components (wheels/central joint for conventional/articulated vehicles) usually in a configuration corresponding only to a straight-path trajectory. Indeed, the present test rig is a mechanical installation with three degrees of freedom. It presents a wide plane, which can be tilted, composed by two semi-platforms connected by a central articulation hinge, operated by hydraulic jacks which allow the different angulations of the semi-platforms. It is specifically thought for performing dynamic stability tests of vehicles, especially on circular trajectories. An additional subsystem embedded in one of the two semi-platforms, configured as a rotating platform (‘turntable’), can test the global (static) stability of motionless vehicles placed on it

Torque Prediction Model of a CI Engine for Agricultural Purposes Based on Exhaust Gas Temperatures and CFD-FVM Methodologies Validated with Experimental Tests

A truly universal system to optimize consumptions, monitor operation and predict maintenance interventions for internal combustion engines must be independent of onboard systems, if present. One of the least invasive methods of detecting engine performance involves the measurement of the exhaust gas temperature (EGT), which can be related to the instant torque through thermodynamic relations. The practical implementation of such a system requires great care since its torque-predictive capabilities are strongly influenced by the position chosen for the temperature-detection point(s) along the exhaust line, specific for each engine, the type of installation for the thermocouples, and the thermal characteristics of the interposed materials. After performing some preliminary tests at the dynamometric brake on a compression-ignition engine for agricultural purposes equipped with three thermocouples at different points in the exhaust duct, a novel procedure was developed to: (1) tune a CFD-FVM-model of the exhaust pipe and determine many unknown thermodynamic parameters concerning the engine (including the real EGT at the exhaust valve outlet in some engine operative conditions), (2) use the CFD-FVM results to considerably increase the predictive capability of an indirect torque-detection strategy based on the EGT. The joint use of the CFD-FVM software, Response Surface Method, and specific optimization algorithms was fundamental to these aims and granted the experimenters a full mastery of systems’ non-linearity and a maximum relative error on the torque estimations of 2.9%

Use of diesel-biodiesel-bioethanol blends in farm tractors: first results obtained with a mixed experimental-numerical approach

The fuelling of internal combustion engines with biofuels has certainly many environmental and energetic advantages. These advantages are particularly effective in the agricultural sector, where an integrated biofuel supply-chain would further benefit the overall carbon balance. Unfortunately, there are also some drawbacks, mainly concerning the engine performances (lowering of the torque curve), but also environmental (possible raising of the NOx emissions). However, by appropriately mixing two biofuels with known opposite effects on the combustion process, it is theoretically possible to compensate the aforementioned disadvantages. In this work, some experiments were carried out in this direction by fuelling a farm tractor with four different fuel mixes; the collected data were processed through the Response Surface Methodology to obtain multi-parameter regression equations useful to identify the optimal fuel mixtures composition. Thanks to this approach, it was found that biodiesel has a positive effect on the torque, while the addition of bioethanol has a much bigger detrimental effect; on the contrary, bioethanol should be added to a mixture with a minimum of 8-12 % of biodiesel to get advantages in terms of NOx concentration reduction

A parametric approach for evaluating the stability of agricultural tractors using implements during side-slope activities

A methodological approach for evaluating a priori the stability of agricultural vehicles equipped with different mounted implements and operating on sloping hillsides is shown here. It uses a Matlab simulator in its first phase and, subsequently, the Response Surface Modelling (RSM) to evaluate the coefficients of a set of regression equations able to account for the Type-I and Type-II stability of the whole vehicle (tractor + implement with known dimensions and mass). The regression equations can give reliable punctual numeric estimations of the minimum value of the Roll Stability Index (RSI) and can verify the existence of a Type-I equilibrium without the need of using the simulator or knowing any detail about the model implemented in it. The same equations can also be used to generate many intuitive graphs (\u201cequilibrium maps\u201d) useful to verify quickly the possible overturning of the vehicle. A case-study concerning a 4-wheel drive articulated tractor is then presented to show the potential of the approach and how using its tools. The tractor has been studied in three scenarios, differing on where the implement has to be connected to the tractor (1: frontally; 2: frontally-laterally; 3: in the back). After performing a series of simulations, a set of polynomial models (with 6 independent variables) has been created and verified. Then, these models were used, together with the related equilibrium maps, to predict the stability of 8 implements for scenario 1, 7 implements for scenario 2, and 3 implements for scenario 3, evidencing in particular the danger of using a lateral shredder with a mass greater than 245 kg. The proposed approach and its main outcomes (i.e., the regression equations and the equilibrium maps) can give an effective contribution to the preventive safety of the tractor driver, so it could be useful to integrate it in the homologation procedures for every agricultural vehicle and to include the resulting documentation within the tractor logbook

Proposal of a predictive mixed experimental-numerical approach for assessing the performance of farm tractor engines fuelled with diesel-biodiesel-bioethanol blends

The effect of biofuel blends on the engine performance and emissions of agricultural machines can be extremely complex to predict even if the properties and the effects of the pure substances in the blends can be sourced from the literature. Indeed, on the one hand, internal combustion engines (ICEs) have a high intrinsic operational complexity; on the other hand, biofuels show antithetic effects on engine performance and present positive or negative interactions that are difficult to determine a priori. This study applies the Response Surface Methodology (RSM), a numerical method typically applied in other disciplines (e.g., industrial engineering) and for other purposes (e.g., set-up of production machines), to analyse a large set of experimental data regarding the mechanical and environmental performances of an ICE used to power a farm tractor. The aim is twofold: i) to demonstrate the effectiveness of RSM in quantitatively assessing the effects of biofuels on a complex system like an ICE; ii) to supply easy-to-use correlations for the users to predict the effect of biofuel blends on performance and emissions of tractor engines. The methodology showed good prediction capabilities and yielded interesting outcomes. The effects of biofuel blends and physical fuel parameters were adopted to study the engine performance. Among all possible parameters depending on the fuel mixture, the viscosity of a fuel blend demonstrated a high statistical significance on some system responses directly related to the engine mechanical performances. This parameter can constitute an interesting indirect estimator of the mechanical performances of an engine fuelled with such blend, while it showed poor accuracy in predicting the emissions of the ICE (NOx, CO concentration and opacity of the exhaust gases) due to a higher influence of the chemical composition of the fuel blend on these parameters; rather, the blend composition showed a much higher accuracy in the assessment of the mechanical performance of the ICE

Mission Planning for the Estimation of the Field Coverage of Unmanned Aerial Systems in Monitoring Mission in Precision Farming

In the recent years, Unmanned Aerial Systems (UAS) have been largely employed in civil applications, such as aerial photography and topographic mapping, environmental monitoring, search and rescue, prevent of fires and disasters, environmental research and general photography and videos. Nevertheless, according to (AUVSI, 2013), agriculture is the main application where UAS will be employed in the near future. Small Unmanned Aerial Vehicles (UAVs) are flexible, easy to use and relative low-cost; thus, they can be employed in monitoring activities in precision farming, ensuring a prompt reaction to plant disease, lack of plants nutrients and environmental changes that are the main focus for farm efficiency and productivity. Recent development in high-resolution remote sensing and image processing technology has yield to small- size sensors compatible with small UAV payload weight. Each kind of sensor needs a certain flight pattern over the fields. However, a Remotely Piloted Aircraft Systems (RPAS) used for specialized operations or experimental activities has to be compliant with National Civil Aviation Authority regulations. On 2015, the Italian Aviation Authority (ENAC) published the second edition of the regulatory issue for this kind of aircrafts. The aim of this paper is the management analysis of RPAS for their use in survey missions for precision faming, taking into account the Italian regulatory prescription and two different kind of commercial sensors. UAVs are considered similarly to any other farm machine, describing the operative workflow and analysing the elementary time procedures associated to the different ways of planning a flight mission of the UAS on the field to be monitored. Actual rates of works, Effective Field Capacity (EFC) and Field Efficiency (FE), field coverage and survey cost are finally provided. The analysis includes also in-field pre-flight calibration procedures

feeding ecology of the scops owl otus scops aves strigiformes in the island of pianosa tuscan archipelago central italy outside the breeding period

ABSTRACTAll of the published studies but one about the diet of the Eurasian scops owl Otus scops, a nocturnal raptor of conservation concern, were carried out during the breeding period, just before or immediately after the chicks fledged. The species is a trans-Saharian migrant with few resident populations in Europe. Orthoptera make up the staple of its diet in summer. In this study, we investigated the diet of scops owls on the island of Pianosa after the breeding period through the analysis of pellets. A total of 327 fragments belonging to at least 14 taxa were identified from 56 pellets collected after the breeding period, between late August and March. By frequency, invertebrates constituted 80.00% of the diet, with Coleoptera being the most represented order (62.35% of the total diet) and Orthoptera poorly represented (8.24%). Vertebrates included two bird species, three small mammals and the Moorish gecko. Although the meal-to-pellet interval for scops owls is unknown, we suggest that the bank vol..