The purpose of this paper is to present a novel mechatronic system for gait re-education which consists of a body weight support system (BWS system) and a treadmill. This publication covers mainly issues related to the design and optimization process of a control algorithm dedicated for the unloading system. The proposed control system is based on a fuzzy logic controller coupled with a PID regulator. The optimization of parameters for regulators has been conducted based on numerical simulations in which a hybrid optimization method combining a genetic algorithm with a gradient algorithm has been used. The developed control system has been tested experimentally.