Comparison of peak power and energy requirements in different actuation concepts for active knee prosthesis

In this paper we investigated the peak power (PP) and energy (E) requirements for different active knee actuation concepts at three different gaits. A lower PP or ER requirement is an important issue because it could lead to a smaller motor and less battery chargings. In this paper we compare the PP and E requirements of direct drive (DD), series elastic actuator (SEA), series elastic damping actuator (SEDA) with passive and variable damping and parallel elastic damping actuator (PEDA) with passive and variable damping at level ground walking, stairs ascending and stairs descending. SEDA (variable damping) and PEDA (variable damping) were found to be the best concepts for the reduction of PP and E requirement with an E requirement reduction of 46.3 % and 48.5 % compared to the DD concept (at level ground walking). This advantage comes with the cost and control effort for variable damping. The SEA concept with an E requirement of 23.9 % compared to the DD concept in level ground walking is a suitable option for a simple design.