Page - 147 - in Proceedings - OAGM & ARW Joint Workshop 2016 on "Computer Vision and Robotics“

3. Assistive Robotic System Robot-based production nowadays is essential for industrial manufacturing. Due to safety reasons industrial robots are placed in a cell behind spatially separating safety equipment such as fences. As precise playback machines for movements, industrial robots remain insensitive towards their environment and repeat predefined sequences of actions. Industrial robots cannot react to changes in their environment and require reprogramming. [6] differentiate automatic and manual robot programming systems. In industrial scenarios robot specialists do reprogramming and reconfiguration partly with text based, controller integrated, teach pendant based (online) tools as well as with CAD-based graphical robot simulation tools. Results are, apart from some sensor signal inputs, more or less inflexible robot programs. Recently, a new class of industrial robots hit the market namely, [7] [8] [9] to mention a few, which can be potentially used in the same environment as human co-workers if relevant norms (A,B level norms that define Safety Integrity levels, performance levels, application specific C level standards) are fulfilled. [10] [11] define four modes of human-robot coexistence and collaboration as relevant for robotic applications. [12] specifies safety requirements for collaborative industrial robot systems and the work environment, and supplements the requirements and guidance on collaborative industrial robot operation. Programming of collaborative robot systems is equivalent to standard industrial robots since trained robot programmers are target on the one hand. On the other hand programming is simplified using macros to support unexperienced users. [9] provides the possibility of hand guidance during system teach in. This input modality is evaluated in the project, but gear friction renders exact hand guided teach-in difficult. Industrial installations of collaborative robots remain (until the integration of the project results) inflexible and unintelligent playback machines for movements and process technology such as intelligent cameras etc. It remains complicated and almost impossible with commercially available systems to integrate that renders in adaptive behavior. The AssistMe projects wants to enable naïve operators to manually teach a robotic arm for their purposes with little pre-knowledge requested. Afterwards a safe and user-friendly cooperation with the robot in the production process should be possible. 4. Use Cases 4.1 Assembly of automotive combustion engines (use case A) The assembly of a combustion engine includes the installation of a cylinder head cover. The installation is carried out manually by stacking the cover with pre-inserted screws onto the motor block and tightening the screws with a manual power tool. The electronic screwdriver of the manual workplace is fitted with a push start mechanism, electronic control unit and a shut-off clutch and therefore starts rotating when pushed onto the screw and stops motion when retracted respectively when a predefined torque is reached. The working instruction of the workstation includes several additional process steps. An automatic screw tightening system is expected to provide assistance and to reduce the workload at the workstation for the human worker. A state-of-the-art collaborative robot system [10] [11] is equipped with the power tool (Figure 1) and programmed to perform screw tightening operations in the required order and accuracy to meet a defined process quality (screw-in depth, torque,…). In the first expansion stage, the project evaluated the effectivity and simplicity of the user interface as implemented by the robot manufacturer and proposed modifications, which will inform the implementation of expansion Stage 2 and 3. 147