In this paper, a model of an orthotic robot's lower limb rotation system is presented. The system is intended for use in typical contemporary orthotic robots such as the 'Veni-Prometheus' System for Verticalization and Aiding Motion designed at the Faculty of Mechatronics, Warsaw University of Technology. In the paper, the state of the art is briefly stated, with the relatively low number of orthotic robots allowing realization of pivoting turns highlighted. The intended two-stage pivoting

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... ng movement is analyzed in detail and the operating conditions as well as limitations of the turning module are indicated. The conception of a turning module introduces additional degree of freedom to the existing orthotic robot designs by realizing the rotation about the lengthwise axis in the thigh link. A three-dimensional model and its analysis are shown. The proposed design ensures the necessary movement of the lower limb and the torso of an impaired person during the execution of pivoting turn while remaining compact in order to ease the introduction of the turning system to different orthotic robot designs.