Abstract: Variety of mechanisms have been created currently to simulate the walking activilies of human body, and are mainly used in mobile robots. According to the specific requirements of reestablishing human walking functions and by studying the physiological structure of knee joint, we present in this article a planar linkage mechanism whose outline is similar to the lower limbs. This mechanism is able to imitate approximately the flexion and extension movements of hip, knee and ankle joints during a walking cycle. Walking aid mechanical device using this relatively simple mechanism would make the paralysis limbs to produce coordinate movements corresponding to the movements of normal joints. The aim of this design is creating a pratical device which enable the patient’s lower extremities to take some physical exercise during the process of locomotion

Key words: 步态, 步行机构, 康复器械