Robots Clip, Screw Or Rivet More And More Skillfully

They weld and rivet, glue and bend, stack and pack, cut and chop - robots are indispensable in industry. Most of the robots currently in use fulfill a typical range of tasks: every second robot is used for handling, 28 percent for welding processes - but only ten percent for assembly. Why?

Dynamic and diverse challenges

This is due to the comparatively dynamic and diverse challenges that assembly tasks are subject to. Boundary conditions such as small lot sizes, many product variants, short cycle times, the lowest possible prices as well as simple setup and changeover and last but not least the integration of people with their skills and knowledge must be taken into account in practice. There is a lot of potential, especially in the automotive industry, to automate assembly tasks, at least in part, and thus further increase the quality and efficiency of production.

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The market is on the move. The Fraunhofer IPA in Stuttgart showed last autumn which technologies are on the market, in particular for designers, but also system integrators and end users, which approaches are based on research and development, and which current solutions already exist in practice. The occasion was the 7th Robot-Assisted Assembly Forum, which offered the participants a well-founded overview of current technologies and market developments for assembly automation.

New ways in robot programming

The motto of the event was "Simply program robots and use them flexibly". Various technology providers presented solutions that make robots more intuitive to use, more versatile, and quicker to convert to new tasks. Automation experts also presented developments on the part of the research institute with which various joining processes can be (partially) automated in an innovative and economical way.

For example, the researchers are breaking new ground when programming robots. So far, the path of the robot has been determined before the task is executed at the programming time. For this purpose, the programmer specifies the desired movement of the robot in a programming language typical of robots. To do this, he positions the robot mainly manually using an operating device so that the system can save the coordinates of the workpiece that are important for the task. Based on this data and further program steps, the system carries out the task.

Assembly is often done manually

This method is complex and not very flexible because the robot follows an unchangeable list of points based on its specific kinematics. The point list only works with exactly the taught-in workpiece and the process, but not with inaccuracies or uncertainties in the process. If, for example, the workpiece is in a different position, if it has variants or another robot is to take over the task, the programmer has to re-teach the system. This cannot be implemented efficiently, which is why many assembly processes have so far often been carried out manually.

The procedure with the "Pitasc" software package for force-controlled assembly processes is completely different.: Here, the path is no longer specified to the robot system point by point in advance, but the algorithm itself calculates it at runtime based on target variables and boundary conditions. For this purpose, the process, workpiece and process parameters such as the ideal dimensions of the workpiece or those for the Assembly forces of the robot, i.e. the conditions to be fulfilled for the task, are first modeled in a general form. The assembly task is then available as a sequence of program modules, similar to a typical work schedule for manual assembly. By assigning variant-specific values ​​and using current sensor data, such as contact forces, distances or object detection,the system calculates how it has to move according to its kinematics and processes the process components as a sequence of tasks.

Content of the article:

• Page 1: Robots clip, screw or rivet more and more skillfully
• Page 2: Reusable program blocks
• Page 3: Determining the cheapest scenario

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