We propose a fast motion controller for a robot which has a flexible arm using the IDCS control scheme. The IDCS control scheme, which corresponds to a numerical computation of the inverse dynamics of the systems, allows stable high performance control even when the system model is known with inaccuracies. We applied in simulation the IDCS controller to the robot arm and compared the performances of the IDCS to the most commonly controller used industrial robots: PID controller to consider the performances of the IDCS. We can get good simulation model of the robot for the IDCS by means of identifying the inertial parameters using generalized coordinates of the baselink, the joint angles and the external forces information.