Evaluation and stability comparison of different vehicle configurations for robotic agricultural operations on side-slopes

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

“…For these reasons, notwithstanding the complexity of these topics and the potential difficulty of finding viable technical solutions, a continuous work of improvement on agricultural machines to minimize the risk factors can have important repercussions also for the society [1][2][3][4]. In particular, vehicles working in agricultural side-slope activities can easily reach critical conditions from the point of view of their stability [5][6][7][8][9][10]. Therefore, the mechanization of side-slope activities [11] and, in general, the dynamic behaviour of off-road vehicles has been studying since the eighties and it is still an open field of investigation.…”

“…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.…”

“…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].…”

“…wheeled agricultural tractors having a central joint used for steering [20][21][22]. Due to the particular architecture of these tractors, beside a higher agility and a lower turning radius than conventional tractors with the same dimensions, they have a supporting polygon that varies with the steering angle [9]: their behaviour is very different from conventional tractors and, maybe, not completely predictable in all situations by inexperienced drivers. Then, the rollover angle of an articulated tractor is calculated in a quasi-static condition and in several slope and angular conditions.…”

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.…”