Robotic rehabilitation is the new therapy for patients that suffering from leg or limb injuries. Patient's second option is to use robotic rehabilitation instead of traditional rehabilitation because robotic rehabilitation consumes less money and shorter period of time. Robotics rehabilitation can be improved by constructing an exoskeleton. An exoskeleton is an external structure that contains links and joints attached to the patient's body. The challenging development in human-machine interface is to design product that serves the patient need to rehabilitate the injuries and to develop smart connection between the device and the human body. This exoskeleton design is required to perform one degree of freedom extension/flexion movement. The device consists of frame, motor, force sensor and casing. In this design the motor needs to develop the required amount of torque so the patient can perform the movement easily. © 2017 IEEE.