ANFIS-based Sensor Fusion System of Sit-to-stand for Elderly People Assistive Device Protocols

This paper describes the analysis and design of an assistive device for elderly people under development at the Egypt-Japan University of Science and Technology (E-JUST) named E-JUST assistive device (EJAD). Several experiments were carried out using a motion capture system (VICON) and inertial sensors to identify the human posture during the sit-to-stand motion. The EJAD uses only two inertial measurement units (IMUs) fused through an adaptive neuro-fuzzy inference systems (ANFIS) algorithm to imitate the real motion of the caregiver. The EJAD consists of two main parts, a robot arm and an active walker. The robot arm is a 2-degree-of-freedom (2-DOF) planar manipulator. In addition, a back support with a passive joint is used to support the patient's back. The IMUs on the leg and trunk of the patient are used to compensate for and adapt to the EJAD system motion depending on the obtained patient posture. The ANFIS algorithm is used to train the fuzzy system that converts the IMUs signals to the right posture of the patient. A control scheme is proposed to control the system motion based on practical measurements taken from the experiments. A computer simulation showed a relatively good performance of the EJAD in assisting the patient.