The Economic Value of Augmentative Exoskeletons and their Assistance

Understanding the success of augmentative exoskeletons is critical to their impact on society. Many exoskeletons are developed to address impairments stemming from neuromotor pathology, which  provides guidance for understanding their abilities; however, for augmentative exoskeletons that  assist able-bodied users, a clear metric of success remains an open question. In this study, we leverage  an approach from economics--the Vickrey second-price auction--to quantify the economic value  added by lower-limb exoskeletons during uphill walking. In our protocol, participants describe the  monetary compensation needed to continue walking uphill for consecutive bouts of two minutes. To incentivize truthful descriptions of participant's “price to walk,” their compensation amounts were  provided as bids in Vickrey auctions before each bout. We compared these data across different  conditions to determine the marginal value of the exoskeleton weight, assistance, and weight +  assistance. Our approach found that the total value of the exoskeleton and its assistance was modest  ($3.40/hr, SD: $3.35/hr); while most participants found the assistance itself valuable ($19.76/hr, SD:  $19.43/hr), this value was nearly offset by the cost of wearing the exoskeleton weight (-$18.59/hr, SD:  $18.28/hr). Our approach and results demonstrate that economic value can be a powerful tool to  develop exoskeletons that maximize user benefit.