ChapterSCO_85028453491

© Springer International Publishing AG 2017. In this paper a method to reduce the mechanical impedance of the joints of a lower limb exoskeleton is presented. When user is in charge of the motion the exoskeleton mimic its movements. Gravity, Friction and Interaction Force compensators are designed in order to reduce the force necessary to move the exoskeleton joints. Gravity compensation is used to mitigate the effect of the exoskeleton¿s weight. This weight adds a force component when the orientation of the limb is different to the gravity vector. The added Friction compensation effect reduces the frictional phenomena of the joints gearboxes. The Interaction Force is calculated from the measured strain of the segments of the exoskeleton. User intention is also detected using the Interaction Force. The gain block adjusts the weights of the friction and interaction compensators depending on the joint velocity. First in this work the context is shown. Followed by the experimental set-up, several compensators and its effects and the control algorithm.

Overview