Robust Velocity Constraint Control of Passive Load System for Human Wearable Interface

Abstract

These days, with the advancement of an aging society, the number of people who need rehabilitation is increasing and it is desired that robotics be applied to rehabilitation. However, considering interactions between humans and robots, problems involving safety of humans are concerned. Therefore, up to the present, passive systems that are constructed of controllable fluids have been developed. Passive systems are load systems, and then they generate reaction force only when external force acts on them. So, they are stable, safe and secure systems for people. But, they have not been controlled robustly. Modeling errors of actuators cause the deterioration of controllers. In this research, the passive system is constructed using magnetorheological (MR) fluids and the robust velocity constraint control based on the disturbance observer is proposed. The proposed method will be applied to rehabilitation trainings about an isokinetic contraction of specific types of muscle contraction. Compared to the conventional method, the validity of the proposed method is verified by experiments and safe and secure trainings using robots will be achieved.