A rigid-flexible coupling pretravel error model for a touch-trigger probe in an on-machine inspection system

Touch-trigger probes are widely used in on-machine inspection (OMI) systems, which have become increasingly important in an interprocess inspection. The pretravel errors are often compensated by data-driven calibration. However, its accuracy is significantly affected by its internal mechanical structure and trigger mechanism. In this paper, we propose a rigid-flexible coupling pretravel error model, considering the bending of the stylus and the lifting of the stylus carrier in the triggering process. This paper presents a method to identify the acceleration of machine tool by fitting the measured results at different speeds into quadratic curves and establishes the response error model. The trigger force of 73 direction probes is identified by a three-directional force sensor. The trigger force identified by the experiment is analyzed in the rigid-flexible simulation model, and the trigger resistance threshold of the probe is obtained. The simulation model of trigger error is established. Through the response error model and trigger error simulation model proposed in this paper, the probe pretravel error compensation accuracy can be improved by 39.6%.