A revised kineto-static model for Phase I tractor rollover

Guzzomi, Andrew

doi:10.1016/j.biosystemseng.2012.06.007

Cited by 36 publications

(21 citation statements)

References 7 publications

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“…the distance corresponding to the scenario in which the CoG projection is on the baseline border (Type II instability; Figure 3). In this case, the instability of each part (Type I instability) is also evaluated by checking if the projection of the front and rear centres of mass fall inside or outside the proper stability triangle [13,14,9]. …”

Section: The Stability Simulatormentioning

confidence: 99%

“…For example, the use of the energetic approach in [12] allowed to analyse the different initial rollover conditions of tractors and to evaluate the energy available at rollover start. However, the most recent works analysing the stability of agricultural machines [13,5,9,14] use an analytical-Newtonian approach combined with a kineto-static approach based on rigid bodies: the rollover initiation angle of conventional farm tractors fitted with front-axle pivot is studied in [13] while the articulated tractors are treated in [14,5]. The approach followed in the kinematic description of these two types of tractors is basically the same: a first (anterior) body groups the front axle and wheels and a second (posterior) body the remaining part of the machine and the rear wheels.…”

Section: Introductionmentioning

confidence: 99%

“…The present work uses an approach similar to [13,5,9,14] for the calculation of the stability of a vehicle and deals with articulated farm tractors, i.e. wheeled agricultural tractors having a central joint used for steering [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

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

Bietresato¹,

Carabin²,

Vidoni³

et al. 2015

ces

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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.

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Section: The Stability Simulatormentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

Bietresato¹,

Carabin²,

Vidoni³

et al. 2015

ces

View full text Add to dashboard Cite

show abstract

“…The direction of projection is parallel to the direction of the resultant force (applied to the vehicle's COG). A sideways overturning or a lateral rollover of an agricultural machine is not a so-rare event as it can be triggered by the existence of one (or more) of these three, quite common, conditions [8][9][10][11]…”

Section: Stability Issues and Causes Of Rollover Formentioning

confidence: 99%

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

Bietresato¹,

Mazzetto²

2018

Int. J. SAFE

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Using agricultural machines on slopes is very risky for operators: drivers difficultly have a correct perception of the stability condition of their vehicles when travelling, especially because it is impossible to instantly check the ground elevation and harshness in correspondence of each wheel. Moreover, the tests that are usually performed to characterize these machines' stability are scarcely helpful in real conditions: these tests check the lateral overturning (maximum angle) in two static configurations only. Evidently, these do not cover most of real situations, do not locate its centre-of-mass and do not consider the centrifugal force (causing load-transfers and dynamically-variable readjustments of the machine's trim in turnings), thus making impossible the setup of eventual active/passive safety-systems to be installed on vehicles.Therefore, with the aim of overcoming the limitations of actual tests, giving a higher level of information to the tractors' manufacturers and users, we have conceived a completely-new test-apparatus to be installed within our laboratory: the Tiltable Platform. It integrates two subsystems, illustrated hereinafter.(1) The tiltable/angleable plane is a wide flat structure (15×15 m), able to simulate different groundgradients, allowing a vehicle to manoeuvre/travel on it along circular paths in a controlled and safe environment. It can also generate an angle at half of its width, transversal to the maximum-slope direction (simulating the exits of an agricultural machine from the inter-rows). (2) The tilting turntable: has a circular shape and is divided into quadrants, each capable of measuring the weight sustained due to a motionless vehicle positioned on them; it is installed on a tilting structure and can rotate around a vertical axis, thus allowing to vary the angular position of the vehicle's longitudinal axis with reference to the maximum-slope direction.Finally, this test-rig will be useful to develop new test-methodologies to certify the agricultural machines' stability in real operating-conditions (e.g. operating with ballast/mounted-implements).

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“…In (Popescu & Sutru, 2009) the longitudinal stability of the tractor-front-end loader system and of tractorforklift system was studied in the most difficult work situations: braking and moving the load on the forks while descending on a slope. The same analytical approach is used also in (Guzzomi, 2012) where a geometrical model for predicting the rollover initiation angle of traditional farm tractors fitted with front-axle pivot under quasi-static conditions is presented. The model uses a kineto-static approach based on two rigid bodies: the front axle and wheels (anterior body), and the remaining machine and the rear wheels (posterior body).…”

Section: Journal Of Agricultural Engineering 2013; Volume Xliv(s2):e133mentioning

confidence: 99%

Simulated stability tests of a small articulated tractor designed for extreme-sloped vineyards

Mazzetto¹,

Bietresato²,

Gasparetto³

et al. 2013

J Agricult Engineer

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A new reversible wheeled articulated tractor, designed to work in terraced vineyards trained with "pergola" system, common in mountain areas, is here described in its latest version and analysed through numerical simulations.This tractor has small dimensions, necessary to operate in that environment, and its central articulation has two rotational degrees-offreedom. The described features are surely strong design points but could be critical for vehicle's stability, as affecting the supporting base's dimensions and shape. Therefore, the tractor was equipped with a new automatic safety system: a self-locking articulation activated by contact sensors on the wheels. This device makes the vehicle partially-rigid in case of lateral unbalancing, so that rollover can happen only by overcoming the whole vehicle mass.A mathematical description of vehicle-ground interactions was implemented to deeply inquiry the tractor behaviour in different configurations (straight, angled) at increasing values of ground slope; roll and pitch stability indexes were then computed and used for comparisons with conventional tractors.Thanks to the low centre-of-gravity, the resulting rollover angle with the vehicle in straight configuration is promising (43.8°→96%): it is greater than the maximum lateral (20°→36%) and frontal (38°→78%) slope angle ever recorded on terraced vineyards. The same rollover angle is lower when the tractor turns.

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A revised kineto-static model for Phase I tractor rollover

Cited by 36 publications

References 7 publications

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

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

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

Simulated stability tests of a small articulated tractor designed for extreme-sloped vineyards

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