This paper describes a prototype 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 VICON system and inertial sensors to determine the human posture while sit to stand motion. EJAD uses two inertial sensors fused through an ANFIS algorithm. EJAD imitates the real motion of the caregiver. It consists of two main parts, a robot arm and an active walker. The robot arm is a 2-DOF planner manipulator. In addition, a back support with a passive joint will support the patient's back. Inertial sensors are used to compensate and adapt EJAD system depending on obtaining the patient posture through the measurements of the inertial sensors on the leg and trunk of the patient. ANFIS algorithm is applied to convert the inertial sensors signals to the right posture of the patient. A control scheme is proposed to control the system based on practical measurements taken from experiments. Computer simulation shows a good performance of EJAD in helping the patient.