Fundamentals for the design of lower-limb exoskeletons

The development of the lower-limb exoskeleton has been increased over the years, presenting a wide variety of devices that enhance or assist the user. These devices had a design process that followed two principal features that are centered on the user and the device itself. Firstly, the user-centered features are divided into targeted goals focused on the applications and anatomic concepts. Within these features, the user features are described depending on their needs and requirements to perform a specific task. According to these user features, the device-centered features are delimited in terms of two principal groups: mechanical design and actuation and control. The mechanical design of a lower-limb exoskeleton is composed of the device's structure, joints, and physical interfaces, which comprise key elements and highlight important design considerations. Finally, the actuation and control displayed the classification of actuators and control strategies commonly used in lower-limb exoskeletons. Taking into account the previous user-centered and device-centered features establishes an overall design process for lower-limb exoskeletons.