The elements of an open architecture robot control system developed using Matlab/Simulink and a real time system are described. It offers the opportunity to control almost every robotic system (serial or parallel) with up to six axes while commercial robot controls are often designed for serial kinematic systems and can hardly be adapted to control robots with parallel structures.
The described open architecture robot control programmed in Matlab/Simulink and ANSI-C is a modular system. To adapt the control to a new robotic structure it is necessary to add the transformation algorithms, position control algorithms, inputs and outputs and machine specific error states to the pre-programmed modules of the system.
These modules are programmed by using Simulink elements extended by special functions of the real time system and so called S-Functions that are programmed in C-Code. In the control new functionalities can be implemented easily by adding new modules and connecting them with the present system. A pre-designed graphical user interface provides
most of the input buttons and display information needed for a robot control. Graphical buttons or displays can be added and connected with the required signal from Matlab/Simulink by drag and drop. An application example of a parallel robot shows the functionalities of the control.
At the Technical University Braunschweig a robot for the assembly of micro structures with an assembly positioning uncertainty below 1 μm is under development. In order to reach the demanded accuracy and robustness, an optical sensor is used. First a 2D-Sensor was tested. To reach the required cycle time a substantial reduction of the response time of this 2D-sensor was necessary. By the application of optimised 2D-algorithms the image processing takes place in video real time now. The extensive software update required an examination of the repeatability results of the 2D-sensor (standard deviation of 0.1 μm in both axes). An overview of the reproducibility and the dynamic cooperation with the parallel robot are presented. A prototype of a 3D-sensor for the robot was built. The reached reproducibility is presented. The 3D-sensor integrated into the robot allows the execution of assembly tasks with a positioning uncertainty better than 1 μm. For the assembly tasks the accurate position of the structures must be determined, which is marked by a defined pattern of circular marks. By photogrammetric measurement of the marks and a pattern recognition the spatial position of the structure is determined. The measurement volume is 7,5 x 11 x 6 mm3. To show the efficiency of the 3D-sensor a first test of its cooperation with the robot is described.