Torque required at the knee joint of a robotic assistive device for its thigh to follow the parabolic trajectory generated by its hip joint during sit-to-stand posture

Abstract

Exoskeletons are designed to assist and enhance the human beings ability to move with lesser efforts. The estimation of torque required at joints of an Exoskeleton is having a prior importance, to choose the right actuator. We have used motion analysis software to measure the parameters of motion during sit to stand phase (STS) and back to sit phase (BTS) and the torque is calculated using Lagrangian formulation. The variation in torque profile during this phase is studied in detail and a parabolic blend trajectory is defined.