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

Abstract

A parametric approach for evaluating the stability of agricultural tractors using implements during side-slope activities / Bietresato, M.; Carabin, G.; Vidoni, R.; Mazzetto, F.; Gasparetto, A.. -In: CONTEMPORARY ENGINEERING SCIENCES. -ISSN 1313-ISSN -6569. -8:28(2015, pp. 1289-1309. OriginalA parametric approach for evaluating the stability of agricultural tractors using implements during side-slope activities 1290Marco Bietresato et al. AbstractA 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 ("equilibrium maps") 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.

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

“…The key point to ensure the operators' safety as well as the operability of a machine is the full knowledge of the stability performance of agricultural machines. The critical parameter is the CoG position as a function of other constructive parameters, also in vehicle operating configurations that foresee the presence of payloads or mounted/trailed implements [23][24][25][26], or of a battery pack as a consequence of the electric hybridization of a conventional vehicle [27]. As acknowledged in literature, the CoG position affects the operation of any active-safety device acting on several on-board technical systems [16,[28][29][30][31].…”

Proposal of a Predictive Mixed Experimental- Numerical Approach for Assessing the Performance of Farm Tractor Engines Fuelled with Diesel- Biodiesel-Bioethanol Blends

“…After an Analysis of Variance (ANOVA) test, aimed at highlighting the parameters of influence on the above-indicated variable (response), the subsequent application of the Response Surface Methodology (RSM) allowed the calculation of the regression function coefficients that describe the effects of the statistically-significant independent variables on the response [62] (Figure 2). The RSM is a very effective numerical tool that allows the calculation of an explicit polynomial regression-function from a set of input data that is the best approximation, in a limited validity domain, of the real function governing the phenomenon under study [63][64][65][66][67]. As opposed to other mathematical tools such as artificial neural networks [68], the RSM gives as a result an explicit polynomial function that is the first part of the Taylor series of an unknown real function f(x i ).…”

Increasing the safety of agricultural machinery operating on sloping grounds by performing static and dynamic tests of stability on a new-concept facility

“…The platform is angled until the first wheel loses the contact with the supporting plane, as performed in the usual tests with a vehicle in the straight-ahead travelling configuration. Indeed, turning manoeuvres for articulated vehicles are particularly critical for the safety and deserve to be further investigated: the two halves of the frame are angled and the supporting polygon could be considerably modified [15][16][17][18]. These two tests have evident limits: vehicles are tested under static conditions at the side-overturning only, with their steering members (wheels, central joint) in a configuration corresponding to a straight-path travelling or in a specific turning angle, i.e.…”