root cause analysis for fixtures and locating schemes using variation data

摘要

This paper proposes a locating scheme method for diagnosis.The method utilises measurements/sensor readings to estimate the variatin in contact points between the fixture and the workpiece.Kinematic analysis is used to derive a linear sensitivity equation that relates position error in locators to sensor readings.By using a subspace estimation technique based on the sensitivity equation the sensor variation is separated into noise and locator variationl.The root cause of fixture failure is identified by ranking the estimated locator variation.The root cause of fixture failure is identified by ranking the estimated locator variation.The approach is attractive because it can deal with multiple coupled locator failures and is not limited to a 3-2-1 locating scheme,but works for an arbitrary determinstic locating scheme.