Body weight support (BWS) systems are widely used in gait rehabilitation. These systems allow patients to gradually increase training intensity and promote independent walking. Currently, there is no standardized method to assess the performance of BWS systems. This work proposes methods and metrics that can be used to assess and compare any overground, force controlled BWS systems. The RYSEN, a novel, cable-driven, three-dimensional overground BWS system, developed by Motek Medical B.V., Delft University of Technology, GTX Medical and École Polytechnique Fédérale de Lausanne, is used as a case study throughout this work.

Analytical methods are proposed that allow to (1) define the non-linearity bounds of static spring systems and (2) select the most important configurations for performance evaluation using sensitivity analyses on weighted stiffness matrices. These analytical methods resulted in testing the system in one direction at a time for a limited number of configurations. Furthermore, experiments are proposed based on three modes of operation: static force tracking, sinusoidal force tracking and disturbance rejection. The input signals for these experiments are based on human walking and support strategies. A test setup, equipped with an external sensor and reciprocal mechanism, was used to objectively obtain the frequency response, tracking and estimation error of the RYSEN. The experiments were successful in characterizing the RYSEN in the chosen configurations.