Modeling and simulation of CMMs probe trigger pre-travel error

Touch-trigger probe is the most widely precision probe used in CMMs, probe trigger pre-travel error is one major factor affecting the dynamic measurement accuracy of CMMs. This paper analyzes the mechanism of the switch displacement, elastic bending of measuring rod, contact deformation and probe frictional sliding in the process of trigger and builds trigger pre-travel error model of probe. Through modeling and simulation, this paper proposes to control the direction of touch-trigger inside the critical angle so as to decrease the touch-trigger pre-travel error.