Above knee prosthesis for ascending/descending stairs with no external energy source

The study deals with an above-knee prosthesis that allows amputees stairs ascending/descending with no external energy sources. Our previous study certified that the employed hydraulic system propelled by the antagonistic actions of knee and ankle joints enables stairs ascending/descending as well as level walking. The paper deals with the subsequent developments to get amputee's walking gait close to normal ones. We combined flow control valve (FCV) into the hydraulic system that is automatically driven during walking. The walking experiments certified that the FCV provides the double knee action that normally appears in healthier persons' walking gait, and it also provides a smooth transition from level ground walking to stairs ascending. However, it was found some instability in the stairs descending.