Estimation of Energy Consumption when Wearing Power Assist Suits

Abstract

Abstract-Agricultural power assist suits (PAS) have been developed and researched in our laboratory. In this study, the performance of a PAS is evaluated without burdening subjects through kinetic simulation. According to the formula for deriving energy consumption, the ratio of the energy consumption to the joint torque is same. Therefore, the joint torque of the knee is derived to investigate the influence of kinetic simulation the on femur. According to kinetic simulation, a PAS can reduce energy consumption. Further, the performance of PAS can be extracted by adjusting size. The validity of simulation is evaluated by comparing with other results. The simulation results and dynamics calculations agree well, but the actual measurements of some subjects show differences. The factors considered are the measurement error of the joint angle, difference in the position for pasting the electrode to measure the myopotential, and the asymmetry of muscle tension. Differences with considerable errors were observed for some test subjects in comparison with actual values, but a good match was observed for the case in which the PAS was worn for those test subjects that also showed a good match for the case without the PAS.

Evaluation of Fatigue Reduction during Crop Harvesting Using a Power Assist Suit

“…The range of movements of the joints and the physical burden in retaining the posture when wearing the PAS have been evaluated [2]- [6]. The PAS was found to provide approximately 80% of the degree of freedom of the human body, and the muscle burden on the upper arms and thighs was reduced by 42.3 and 50.2%, respectively, on average during isometric exercises.…”