Human − industrial robot collaboration

Close collaboration between human operators and industrial robots is one approach to meet the challenges of increased global competition and demographic change for manufacturing companies in the developed countries. These human-industrial robot collaborative (HIRC) assembly systems combine human flexibility, intelligence and tactile sense with robotic speed, endurance and repeatability. However, current personal safety legislation limits the possible collaborative applications that could be implemented in practice, but large research efforts are put in order to enable practical implementation of these future workstations. When the limitations of safety legislation are addressed and the collaborative systems can be implemented, a need to simulate these systems will rise. Virtual simulations are an important component in modern production system design and will be demanded in future assembly workstation design. No existing software has been found that can simulate and visualise HIRC tasks on an object simultaneously handled by both a human and an industrial robot. The aim of this thesis is to close this gap through development of a software solution that can simulate, visualise and evaluate HIRC assembly workstations. In addition, with the simulations as a base, mathematical optimisation techniques have been employed in order to find the optimal HIRC design. Industrial assembly cases at a heavy vehicle manufacturer were used as a foundation on which the development was conducted. The software was developed in an iterative search process and combined a number of different software and evaluation techniques. Robotic and human simulation tools were combined in order to achieve the simulation and visualisation elements of the software. Biomechanical load on the human and operation time, for both the human and the industrial robot, were evaluated as output from the simulations. Existing optimisation techniques were incorporated in the demonstrator software to design the most ideal assembly station. The resulting HIRC simulation demonstrator software makes it possible to simulate, visualise, evaluate and optimise collaborative workstations. This was validated through industrial cases in which improvements of the biomechanical load and operation time in HIRC workstations compared with manual stations were demonstrated. An example of how to optimise the geometric position of the handover between the human and the industrial robot was also presented through the cases. These results presents how the simulation software can contribute to design the most suitable future HIRC assembly systems and thus enable increased productivity and reduce biomechanical loads on the assembly operators.