Assembly process monitoring algorithm using force data and deformation data

In robotic assembly with smaller repeatability than the assembly tolerance, failure should not occur. However, in the industrial field, assemblies may fail because of positional errors in the assembled parts and other factors. Owing to the characteristics of position control, the robot tries to move to the desired position irrespective of the failure of assembly. This situation causes excessive contact force, which can lead to the damage of parts and robots. To prevent this, an assembly process monitoring algorithm is proposed in this study. The role of this algorithm is to monitor, from the sensor information measured in the assembly process, whether the assembly state is formed; thus, the robot may recognize whether the assembly is normally performed or not. In this study, the monitoring performance was verified by applying the algorithm to the process of assembling the parts of a tablet PC.