Design and Implementation of a control strategy for static balance of a lower limbs exoskeleton

Abstract

This  paper  considers  a  lower  limbs  exoskeleton  carrying  a  mannequin  which  has  hips  and  knees  actuated,  torso and a support feet; it presents the design and implementation of a control strategy for static balance of the exoskeleton and mannequin, this involves a low-level distributed control for joints angular position and a high level centralized control for balance. For angular positioning control in actuated joints, PID controllers are designed; this control allows to follow joints position trajectories, generated by the high level control strategy. Based on the horizontal deviation calculation of the total system mass center, a static balance control manipulates the joints to compensate small signal disturbances in the posture of the exoskeleton-mannequin. It is presented the protocol to obtain the parameters for the control law and the system initialization, the experimental results under different operating conditions and the performance analysis of the controlled system.