Feasibility analysis of cobots forautomation of tightening stationsin motor vehicle engine assemblylines

Abstract: The trend of increasingly automated tightening stations in the motor vehiclepowertrain production industry, is driving the tooling industry to adapt its offering.This thesis aims to answer the question if collaborative robots (cobots)are suitable for tightening applications in motor vehicle engine assembly lines.A collaborative robot is in principle similar to a conventional industrial roboticarm. The part that dierentiates it from an industrial robot is its ability todetect and in some cases prevent a collision with a human of close proximity.In order to answer this question three case studies are conducted where thedeployment of collaborative robots is assessed. To specically answer the caseof a motor vehicle engine line, two lines are mapped station by station. Thenthese stations are recreated with a collaborative robot and a tightening tooland a few applications are tested on an actual motor. The rest is simulatedwith equations, dictating how much time is needed to complete a sequence oftightenings.As a result, most stations on a motor vehicle assembly line could in theorybe done by using tightening tools together with one or multiple collaborativerobots. However, these kinds of lines are often highly automated. For this reasonlarge industrial robots and multi-tool xtures are preferred today. The largevolumes of these lines, mostly mitigate the expected nancial gains of replacinga human operator with a cobot. In many cases, the cobot would not have thetime to complete all bolts of an application on an engine within the give takttime. Multi-cylinder engines (which is the absolute norm for passenger cars)have too many bolts for one cobot and tool to complete. If multiple cobots areto be used, the cost of the station further increases. Furthermore, re-balancinga line simply to accommodate a cobot would also not be benecial.Probably a much better application for collaborative robots and tightening toolsare smaller, more operator dependent lines. Here the value of a cobot can beutilized to a greater extent. These manufacturers have greater product varianceand re-balance their lines more often. As a suggestion for further research, thissegment could be invesigated further.