Development of a hybrid exoskeleton to reduce muscle strain in oil palm harvesting

Abstract

Oil palm harvesting is one of the biggest and highly developing agricultural sector throughout the world. Malaysia, the second top producer of palm oil in the world, with 17.32 million tonnes produced in 2016. Within 1960-2005, areas under oil palm plantation were increased from 54,000 hectares to 4.05 million hectares, which reflects a compound annual growth of 10.06%. In the same time period, palm oil production was increased from 94,000 tonnes to 15 million tonnes. In this area, oil palm harvesting is an essential part where a lot of workers are facing frequent body pain. Most common injuries experienced by workers are health, safety and ergonomic injuries. Long hours of manual works in awkward posture and handling load without any support are the reasons behind this pain. The aim of this study was to develop a hybrid exoskeleton exclusive for oil palm harvesting to reduce muscle strain. Isoelasticity approach was used for gravitational compensation while DC linear motor was used for torque compensation and position control. EMG signal was used to check muscle strain due to harvesting work. As the signals were contaminated with some noises, it was not feasible for discussion. So, low pass filter has been developed using MATLAB DSP tools. Then the filtered data of each cases (i.e. without exoskeleton, with passive exoskeleton and with hybrid exoskeleton) was compared with each other. From the comparison, it can be seen that the overall muscle strain was reduced by 16% using passive exoskeleton and by 23% using hybrid exoskeleton. According to the results, it is evident that, the developed exoskeleton can be implemented in palm oil harvesting which will reduce the pain level of the workers at a significant rate.