Static Stability Analysis on Mini Excavator Chassis with Articulated Boom for Oil Palm Harvesting

Abstract

Harvesting machine is a promising technology for palms above 5 m in height. The stability of oil palm harvesting machines equipped with articulated booms is crucial for ensuring safety, operational efficiency, and reduced mechanical wear during harvesting activities. A machine with a 2.5-t mini excavator chassis and a 300 kg lightweight articulated boom with 3-degrees-of-freedom scissor-type cutter has been developed to evaluate its performance. The machine could reach up to 12 m in height. This study investigated the static stability of such machines under varying operational conditions, particularly in response to terrain slope changes. The influence on the machine's centre of gravity (CoG) and tipping moment was evaluated, along with moment distribution and tipping-over stability. Results showed that extending the load weight significantly shifted the CoG, reducing the stability factor (SF). Machine stability factors were calculated at boom angles of 30° (SF = 2.68), 45° (SF = 1.90), and 60° (SF = 1.54), all of which exceeded the critical value of 1, confirming the system's stability under these conditions.  The combined system's CoG was determined as CGx = 1.52 m and CGy = 1.12 m, incorporating the base and boom contributions at a static condition. The critical tipping angle of the machine was 35.7°, or approximately a 60% slope grade. These findings confirmed that the modified chassis of existing work machinery can be utilised as a safe machine, reducing development time and allowing for quick deployment in oil palm harvesting.