Investigating the dynamic behavior of a mid-sized forestry machine on sloped rough terrain

High-performing forestry machines, such as forwarders, must be able to handle large loads and to operate rough and sloped terrains. Present forwarders are almost exclusively six-or eight-wheeled machines with pairs of wheels mounted on bogies. Consequently, they have very limited chassis damping and levelling capabilities. Traditional forestry machine chassis design is unfavourable from an active machine levelling and operator full body vibration control standpoint. This paper analyses the dynamic behaviour of an existing mid-sized forwarder. The multi-objective concept performance is studied with multi-body simulations and response analysis. The main focus is to identify critical design issues of the machine, specifically while traveling in sloped terrain, and to compare its off-road performance with a new pendulum arm suspended forwarder, referred to as the XT28 machine. The main purpose of the presented investigation is to suggest criteria for assessing the performance of off-road forestry machines when operating on sloped and rough terrain. The target is to assist future research on the newly developed XT28 forwarder that is planned to be in the initial full scale test during the coming year.
QC 20150605