Development of an automatically deployable roll over protective structure for agricultural tractors based on hydraulic power

Abstract

An inadequate use of the deployable Roll Over Protective Structure (ROPS) in agricultural tractors contributes to fatalities in rollover events. To help to resolve this problem, an automatically deployable ROPS was designed, constructed and tested. The prototype, called HydraROPS, established two assistance levels for the elevation of the foldable ROPS. In the first level, the driver decides to change the ROPS’ position and this change is made using the manual activation on the board. In the second level, an automatic change to the operative position occurs in situations of impending rollover, without the intervention of the driver. In this level, it automatically sends a phone message with the GPS location to contact emergency response personnel. The tractor’s hydraulic power was used to move the protective structure. In order to increase the deployment speed of ROPS, a pressure accumulator was included in the hydraulic circuit. The deployment time of the ROPS without the pressure accumulator was 2.599 s and with the pressure accumulator 0.743 s. The results of the research show that the pressure accumulator assembled in the hydraulic circuit reduced the deployment time of ROPS by 71%; and that the electronic control system can correctly predict overturn. HydraROPS has the advantage compared to other automatic deployment devices of protective structures that can be installed on tractors equipped with a certified rollover protective structure. The installation in marketable tractor models does not modify the protection structure; therefore a new certification of the protection structure is not necessary.