As part of the research efforts carried out at the Pontificia Universidad Católica del Perú, proposed models of lower limb exoskeletons were developed and simulated with the aim of getting valuable information for later mechanical design, and control system design, of the Lima lower limb exoskeleton for rehabilitation cases, which should replicate human gait and help people with gait impairments in the attempt to recover gait ability. This paper describes the process of modeling proposed for the Lima lower limb exoskeleton and shows simulation results that are important for future works.