Effect of thresher drive linkage design on human physiological workload of a pedal operated thresher

Abstract: Pedal operated paddy threshers are widely used in the rice growing countries such as India, Bangladesh, Bhutan, Korea and some African countries. Thresher-drive linkage plays a vital role in human-machine interaction and workload on the human operator. The four-bar linkage design used in pedal operated paddy thresher was replaced with four alternative designs of thresher drive-linkages to assess the load application pattern and physiological work load while operating the pedal operated paddy thresher. The machine was tested with five operators for physiological workload estimation. The linkage combinations were found to have significant effect s at 1 % level on the work pulse rate and workload to operators. Considering the force-displacement relationships and physiological workload on the operators, linkage three was found to be the most promising design with lowest work pulse rate of  45.90 beats min -1 and change in energy expenditure rate of 214.5 W (12.87 kJ min -1 ). Keywords: p edal operated thresher, t hresher, t hresher drive linkage, p hysiological workload