Powered attendant-propelled wheelchair with assist-as-needed control based on individual physical capabilities

Abstract

This paper discussed if a powered attendant propelled wheelchairs (PAPW) with assist-as-needed control reduces energy consumption and maximise attendant's physical activity in powered system use. This study introduced a PAPW with force velocity assist control (FVAC) based on individual capability of pushing force velocity relationship. This PAPW assists attendant pushing when more pushing force is needed over usual range of individual physical capabilities of pushing. With the PAPW, we investigated the performance of the FVAC and compared it with proportional assist control (PAC) on a flat level surface and a longitudinal slope (6.5%) with three participants. The experimental results showed that the PAPW with the FVAC reduced 50% of pushing force on the slope and this was similar performance of the PAC in terms of assisting. The FVAC also reduced 79% of mean mechanical assisting power on the flat against the PAC. These results support that the PAPW with the FVAC has flexibilities to adapt to individual physical capabilities and provides certain level of physical activities with sufficient assisting when needed, and low energy consumption for long time and distance operations for attendants. the assisting boundary and assisted attendant pushing when more pushing force over the endurable individual physical capability was needed. The validation in this study shows that the FVAC achieves similar performance to the PAC in terms of reduction of pushing force, in addition, better performance to keep certain level of attendant's physical activities and to reduce mechanical power compared with the PAC, especially 79% reduction on the flat. The flat condition would account for the main part of environments in travelling, so the driving distance and