Mobile robotic cart development to support home oxygen therapy patients: Study on handling interface for mobile robotic cart similar to wheeled walker

Abstract

We propose a motion control interface system for a mobile robotic cart to support Home Oxygen Therapy (HOT) patients when they go out. Our goal is to realize a mobile robotic cart similar to a wheeled walker that carries oxygen devices in front of patients, because HOT patients whose physical strength has especially waned would like to use such a cart according to the results of our questionnaire given to patients. The proposed handling interface of the mobile robotic cart adopts simple mechanisms and commonly used force sensors to sense only pushing and pulling forces from the user. We also apply a two-degrees-of-freedom (2 D.O.F.) control system to control the velocity and response time of the robotic cart. The feedforward controller of the 2 D.O.F. control system, which is an impedanceadjustable element, is expected to be used not only to adjust the response time but also to compensate for interference between the forces applied by the user and the robotic cart during operation. In this study we evaluated the effectiveness of our proposed handling interface mechanisms and control system by performing several experiments on a prototype robotic cart, and then we carried out user tests on some HOT patients and received a positive evaluation of the robotic cart's performance.