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

Abstract

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).

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

“…Indeed, since in this case the system to be designed is a test rig, a specific approach for this kind of products/devices could be favorably used. It mirrors the structured approach that is normally applied (e.g., in the field of base and applied sciences) to design a test or experiment starting from a real situation/phenomenon to be investigated ( Figure 3), extended in this case with a further step to reach the concept of the test system [55]. The behavior conditions to be replicated are later identified and isolated due to their relevance to the present study.…”

“…The subsequent steps then aim to define a piece of test equipment able to simulate a controlled situation (here: a moving or motionless agricultural vehicle on a slope solicited by forces with different directions) and, thereby, to generate a response that is intelligible, reproducible and also representative of reality (here: the real working conditions of a farm tractor on hillsides). Preliminary steps useful in conceiving a test system, based on the approach followed to design a test/experiment starting from a real situation/phenomenon to be investigated (adapted from [55]).…”

“…Figure 3. Preliminary steps useful in conceiving a test system, based on the approach followed to design a test/experiment starting from a real situation/phenomenon to be investigated (adapted from [55]).…”

Safety Vision of Agricultural Tractors: An Engineering Perspective Based on Recent Studies (2009–2019)

“…Thirdly, the risk assessment of activities related to the use of tractors based on specific work tasks [123] and the development of risk scenarios based on the analysis of rollover fatalities were investigated [21]. Furthermore, in this research area we included studies which analyzed the problem of safety compliance of tractors at both the strategic [34,124] and market level [125], as well as the development of proper equipment for tractor testing [126].…”

Morphometry as a Key to Investigate the Stability to a Wind-Induced Rollover of Agricultural Equipment for Irrigation

“…This geometrical condition could happen when there is a modification of the direction of the above-cited resultant (e.g., in the case of irrigation systems, when there is a strong wind impacting on the frame) or when the support plane changes locally its inclination (e.g., in the case of self-propelled irrigation systems, due to the harshness of the ground experienced by the system wheels) [15]. In the agricultural engineering field, this phenomenon has been investigated especially with reference to farm tractors [16][17][18][19][20] but also to robots [21]. Indeed, the side-overturning of agricultural machines is a very important problem because it is the principal cause of deaths recorded every year [22][23][24][25][26][27].…”