A reconfigurable robotic system is used at PROFACTOR to demonstrate some advantages of the 4DIAC initiative. A modular 6-DOF robot that is composed out of mechatronic components is used, as depicted in the figure below. 1. The robot consists out of six separate joints, which are PowerCube modules provided from Schunk company. They are connected with each other via special connector elements. The hardware (embedded control) setup of the reconfigurable robotic system is also shown in the figure.
Respectively two robot axes are controlled by PC/104 embedded PCs equipped with a Debian Linux and an OSADL real-time kernel patch. Furthermore, the FORTE runtime environment is installed on each of the PC/104 controllers. The data exchange between the PC/104 and the PowerCubes is done via CAN.The engineering and visualization PC is connected via standard Ethernet to the PC/104 controllers.
The engineering of the IEC 61499 robot control program is carried out via the 4DIAC-IDE. The visualization and HMI are also modeled with IEC 61499 FBs. Therefore the Java-based FBRT is used as runtime environment for the execution of the visualization application since the FORTE does not support the execution of HMI SIFBs. The hardware structure of the modular 6-DOF robot described above has lead to the implementation of a Robot Control Application (RCA) and a Robot HMI Application (RHA). The RCA contains the implemented control concept as an IEC 61499 application. Each component of the control concept has its own IEC 61499 FB representative. For visualization and parameterization issues, a specific RHA was developed. The RHA is also built out of special IEC 61499 HMI Service In-terface Function Blocks (SIFBs). The two applications communicate with each other via Publish/Subscribe Function Blocks.
The IEC 61499 system model for the robot controller consists of four different remote devices. One remote device is ex-ecuted on the Visualization PC (equipped with the FBRT since the FORTE provides no HMI functionality as it is provides by the FBRT), the other three devices are executed on the PC/104 embedded hardware (equipped with the FORTE). The communication among all devices is done via Ethernet. The whole RHA is mapped to the visualization device while the trajectory calculation and the feed-forward control function blocks are mapped to the PowerCube 1&2 Device. A High-Gain Observer FB is mapped to the PowerCube 5&6 Device. The other control modules (CAN SIFB and controller FBs) are represented as sub-applications in the RCA and are distributed to the three PowerCube devices. For the interaction of the PC/104 embedded controllers and the PowerCube modules the special CAN SIFBs have been developed.