Replication of skilled polishing technique with serial–parallel mechanism polishing machine

• Tool trajectory, posture and polishing force were acquired from a skilled worker.
• The acquired technique was replicated by using the polishing machine with FIFO.
• The replication system was evaluated by polishing test of viscoelastic polymer.
• The obtained surface quality was equivalent to that performed by the skilled worker.

Currently, viscoelastic polymers are used to coat automotive body to prevent scratches. On the other hand, the application of a polymer with high viscoelasticity makes the repair polishing process of the coated body more difficult. Hence, performing the polishing process requires the operator to be technically skilled. However, the number of workers with necessary technical skill has been decreasing because of an aging population. In addition, the surface quality and process time are dependent on the proficiency level of the worker. To automate the repair polishing process, in our past research, a serial–parallel mechanism polishing machine was developed to simultaneously control the tool trajectory, tool posture, and polishing force. The present study aims to construct a replication system of a skilled polishing technique on the basis of the above three physical parameters by applying the developed polishing machine. First, the tool trajectory, tool posture, and polishing force of a skilled worker, which reflect the polishing technique, were acquired using a high-speed camera and a dynamometer. By inputting the acquired data to the developed machine, the machine can copy the polishing technique because the tool trajectory, tool posture, and polishing force can be independently controlled. From the results of the polishing test, the surface quality after polishing was comparable to that of the skilled worker output, which satisfies the criteria of surface quality.