In the optimization process of the

In the optimization process of the treadmill speed control system, the target function was formulated in such a way as to minimize the adverse effects of the horizontal component of the weight-reducing force on the patient [4]. Unfortunately, considering only the swing angle of the rope in the target function was insufficient. It resulted in a situation, where the rope was oscillating around the vertical position, which involves a change in the direction of the horizontal force applied to the patient. Although the values of the swing angle were low, such frequent changes in the treadmill speed and in the direction of the weightreducing force made it more difficult for patients to maintain balance. Due to that, two criteria were taken into account during optimization: the swing angle of the rope and angular acceleration resulting from the swing of the rope [7, 23, 34]. The weighted sum method was used to formulate the front of the megacriterion Y show in the Equation 13.