Robotic Seating Assistance to Prevent Pressure Sores on Wheelchair Patients

To reduce the risk of pressure sores caused by sitting for long periods of time as, e.g., in a wheelchair an automatic sitting-posture coordination system that achieves depressurization motions is proposed for use by wheelchair patients. The system consists of a sitting-surface lifting device and a backrest-tension coordination device. Using the two devices, the system assists a patient in obtaining a suitable sitting posture. To realize depressurization, an. index of the risk of pressure sores is investigated by analyzing unconscious body movements of healthy people sitting for a long time; the results indicated that seated people want to depressurize when pressure or share stress increases on their buttocks because of having unsuitable postures. Therefore, the system estimates depressurization necessity according to the pressure concentration and share stress on the buttocks and then leads the patient to adopt a suitable sitting posture, which then better distributes the pressure concentration and/or share stress. Thus, patients can depressurize as needed using natural body motions similar to those of healthy people. The system's performance is verified by experiments using a prototype.