With development of science and technology, robots are used in various regions, such as car manufacturing, radars and brain surgery. It can also do dangerous jobs for people, including cleaning skyscrapers, exploring outer spaces. Moreover, they can take place of housemaid to look after us and make our life more leisurable. Since it is so widely used, high dynamic performance controller of a robot arm is eagerly wanted. The aim of this project is to control a double link robot arm, to stabilize the two links at set point rejecting disturbances and to track functions with low frequency. If double link has been studied thoroughly, it is easy to expand the results to multi-link robot arms. Our future life will be easier if we let the robot do what we aim to do!