Abstarct: Assistive robots are used to help users with muscle weakness and joint problems by reducing the force on muscles and joints. Elderly people and people with osteoarthritis are among these users. By reducing the force on the muscles, these robots can also help increase the power of healthy users. The knee joint is more prone to injury than any other joint in the body, so in this study we design, analyze, and control a single-knee exoskeleton robot to help walk. We first modeled the exoskeleton robot of the knee and obtained the system's dynamic equations using Lagrange equations. Then, the mathematical model is validated using Adams software. Given that the robot interacts with humans, we must have the most compatibility between humans and robots. baxsed on this, a controller should be designed that, in addition to helping, has the best interaction with humans. For this purpose, we used the fuzzy output feedback assist control method. The results show that the proposed method, in addition to behaving appropriately at all operating frequencies of the system; reduces the torque required by the human-exo system compared to the unassisted system. Finally, the proposed control method is implemented on the built exoskeleton robot.