Model and control of the ELLTIO with two degrees of freedom

Exoskeletons are robots attached for the extremities of the human body focused on increasing their strength, speed and performance primarily. The main applications are in the military, industry and medicine. The exoskeleton used in the rehabilitation of limbs because of accident or illness that cause little muscle activity or null. The ELLTIO (Exoskeleton for Lower Limb Training with Instrumented Orthoses) is an exoskeleton of two degrees of freedom for rehabilitation in ankle and knee. The design and manufacture of the exoskeleton is based on the instrumentation of a right lower limb orthoses. The exoskeleton contains sensors to estimate the force produced by a human and are incorporated in the SEA actuators (Serial Elastics Actuators) to amplify the human force. Moreover contains sensors to estimate the angular position and velocity in joints to control the movement of the leg. The goal of this paper is the design of a PD control with gravity compensation based to dynamic model of experimental prototype. The prototype can be increased or decreased the human force as needed in different exercises, this will allow the user an evolutionary improvement to achieve a full rehabilitation as possible.