https://synergypublishers.com/pms/index.php/jrr <h3>Journal of Rehabilitation Robotics (JRR) has ceased publication and is no longer accepting submissions.</h3> <h3>All previously published articles are available in the archive of the journal.</h3> Synergy Publishers en-US Journal of Rehabilitation Robotics 2308-8354 https://synergypublishers.com/pms/index.php/jrr/article/view/1415 Stable trajectory tracking is one of the most important challenges in wearable rehabilitation robots design. Feedback controllers play a critical role to achieve this goal. There are different options to implement such a controller, e.g. PID, Fuzzy and hybrid systems. Traditionally, the performance of controllers is examined by try and error on hardware setups. It can be easily translated to more wasted time and cost. In this paper, we tried to make the design process more dynamic and efficient in. first, we proposed a simulation tool (based on NEXUSES® and MATLAB®) for a wearable rehabilitation robot with two links and 3 degrees-of-freedom, which duplicates elbow, wrist, and shoulder movement in 2-D space. Then, by the help of the tool we studied the benefits and functionality of one type of controller: classical PID. Our simulation result is verified that the Classical PID is improved the stability of trajectory tracking. Keywords: Classical PID, Wearable rehabilitation robot system, two links robots. Niloofar Sayyad Khodashenas Copyright (c) 2020-04-20 2020-04-20 8 1 1 7 10.12970/2308-8354.2020.08.01