The study proposes an intelligent lower extremity rehabilitation training system controlled by adaptive fuzzy controllers (AFCs) and impedance controllers (ICs). The structure of the robotic leg exoskeleton can be divided into three parts including hip joint, knee joint, and ankle joint, which are driven by linear actuators and pulleys. Therefore, the movement of the robotic leg exoskeleton can be controlled by driving the linear actuators. The results of simulation reveal that the design of the proposed controllers presents good performances and , comparisons between the above controllers and PID controller are also made. | Vũ Đức Tân và Đtg Tạp chí KHOA HỌC & CÔNG NGHỆ 139(09): 213 - 217 COMPARISONS BETWEEN ADAPTIVE FUZZY CONTROLLER, IMPEDANCE CONTROLLER AND PID CONTROLLER FOR LOWER EXTREMITY REHABILITATION EXOSKELETON Vu Duc Tan*, Nguyen Thi Thanh Nga College of Technology - TNU SUMMARY The study proposes an intelligent lower extremity rehabilitation training system controlled by adaptive fuzzy controllers (AFCs) and impedance controllers (ICs). The structure of the robotic leg exoskeleton can be divided into three parts including hip joint, knee joint, and ankle joint, which are driven by linear actuators and pulleys. Therefore, the movement of the robotic leg exoskeleton can be controlled by driving the linear actuators. The results of simulation reveal that the design of the proposed controllers presents good performances and , comparisons between the above controllers and PID controller are also made. Keywords: adaptive fuzzy control,impedance control, PID, exoskeleton, rehabilitation, Simmechanics simulation INTRODUCTION* Scientific and technological work on exoskeletons began in the early 1960s, but only has recently been applied to rehabilitation and functional substitution in patients suffering from motor disorder [1]. After brief and unsuccessful attempts in these years, advances in sensing, actuation and computing technologies have renewed the confidence in the viability of developing an autonomous exoskeleton system for human performance augmentation. Not only do these advances permit the realization of more compact, lightweight and robust robotic hardware design, but they also permit the development of increasingly sophisticated control laws in terms of both real-time processing capability and design and analysis computer aided tools [2-5].The proposed robotic leg exoskeleton is configured with either a powered treadmills or a mobile platform to provide various rehabilitation purposes. The exoskeleton is comprised of two anthropomorphic legs and