In recent years, robust control has been used in a wide variety of situations. In particular, due to the shortage of manpower in the nursing care field, nursing care robots have been developed to assist mobility. However, a problem is that if the control performance deteriorates, the robot will not perform as desired, and in the case of nursing-care robots, there is a risk of injury to the person being assisted. Conventional observers also have the disadvantage that it can be difficult to maintain stability when the parameters of the system components change. Therefore, in this study, positioning control and velocity control are performed by simulation using an equivalent input disturbance observer that compensates for multiple disturbance elements by aggregating them into a single type.