Retrofit and Interface of a SCARA Robot with a PLC for Real-Time Direct Joint Control

Robot proprietary controllers greatly limit the implementation of advanced control algorithms, as well as the interface and synchronization of robots with other devices. PLC-based robot control can overcome current limitations: being an open and flexible control architecture, it allows the development of arbitrary control schemes while ensuring real-time synchronization. In this paper, we replaced an obsolete SCARA robot controller with a PLC-based controller and developed software for the real-time implementation of high-performance control schemes. We then carried out experimental tests to evaluate the tracking capabilities of the SCARA manipulator with different commanded trajectories and velocities: during the tests, the robot achieved small tracking errors, proving the effectiveness of the proposed strategy.