This paper presents research on the development of a robotic exoskeleton system for human lower limb rehabilitation. In the first stage, an innovative structural solution for the exoskeleton leg is developed, based on a pantographic kinematic chain. A virtual prototype of the exoskeleton robotic system intended for rehabilitation is designed for use by a human subject with a height of 1.70 m. Based on the virtual model, a kinematic simulation is initially performed, followed by a dynamic simulation, in which the exoskeleton performs stepping movements on the ground using ADAMS software for multibody system analysis. Since the physical prototype is produced using rapid prototyping, a structural optimization of all kinematic elements in the robot’s structure has been carried out. For this purpose, finite element method (FEM)-based structural optimization was applied to achieve an optimal design, ensuring minimum mass and adequate stiffness of the kinematic elements. In future studies, the developed prototype will undergo experimental testing.