Method for estimating a variation in preload applied to linear guideway

A method for estimating a variation in a preload applied to at least one linear guideway included in a machine tool, the method to be implemented by a plurality of vibration sensors and a computation module, the machine tool further including a table disposed on the at least one linear guideway, the plurality of vibration sensors being disposed on the table, the method comprising steps of:

• a) obtaining, via each of the plurality of vibration sensors, a first vibration signal that is generated according to detection of vibration of the table by the vibration sensor at a first time instant;
• b) determining, via the computation module, at least one first natural frequency that is associated with the table based on the first vibration signals obtained in step a) and at least one theoretical mode shape that is associated with the table;
• c) obtaining, via each of the plurality of vibration sensors, a second vibration signal that is generated according to detection of vibration of the table by the vibration sensor at a second time instant;
• d) determining, via the computation module, at least one second natural frequency that is associated with the table based on the second vibration signals obtained in step c) and the at least one theoretical mode shape;
• and
• e) determining, via the computation module, the variation in the preload applied to the at least one linear guideway based on the at least one first natural frequency and the at least one second natural frequency.