An application of user-friendly control for a Respiratory Rehabilitation and Assistance Robot

To treat patients suffering from dysfunction of the abdominal muscles, positive pressure devices that can inject air directly into a patient's mouth have been developed. But injection of air requires blocking of a patient's mouth with an air mask or air hose, which causes the patient additional inconvenience in talking and in breathing with their own mouth. The Respiratory Rehabilitation and Assistance Robot was developed to provide ventilation assistance without hindering patients from talking and breathing with their own mouth. The basic principle of the robot is a negative pressure assistance, using an abdomen pressuring part to push the abdomen of the user and help the user to exhale. The robot is mainly manipulated with an attached joystick. But without an additional control routine to govern the amount of force applied when the joystick is moved, usability and safety issues occur. In this research, linear, logarithmic, and exponential profiles that modify the joystick trajectory were tested to advance maneuverability of the robot conditioning the joystick signal. Through experiments, we found that logarithmic profiles with certain shape factors improve both usability and safety.