The task of controlling robotic manipulators is frequently assigned to PLCs in state-of-the-art manufacturing systems. By integrating a suitable human-machine interface, the control system can provide the human operator the possibility to move the manipulator to the desired position, monitor its operation or even save its current position. Based on these saved points, recipes defining complex motion sequences can be assembled to assist a given manufacturing task.
The aim of this thesis was to implement a simple, easy-to-use control system for a manipulator model using Rockwell Automation devices (PLC and HMI panel).
The control software supports movements specified both by joint- and Cartesian coordinates. For this purpose, software modules processing the signals of motor encoders, realizing low-level joint control and computing the solution of direct and inverse geometric problems were implemented. Computations and sub-tasks are carried out by Add-On instructions according to the state machine realized by the main routine. Safe operation of the control software is supervised by a safety module.
Operation of the manipulator is assisted by a graphical user interface realized by a touch panel. The user can move the manipulator both joint-by-joint or by Cartesian coordinates. The current position of the tool can be saved, and motion sequences can be specified based upon them. The control system supports both single and cyclic execution of such sequences.