The development of the Digital Twin of an exoskeleton for upper limb rehabilitation task for hemiplegic patients, and its Virtual Commissioning prior to its manufacture is presented in this work. In these context biomechanical and clinical design criteria are integrated into Digital Twin concept. The power actuators, the development of 4 freedoms degree's mechanisms for shoulder and elbow flexion/extension, external and internal rotation and abduction of the upper limb, and prone/supination of wrist, the control system and user