Control method for a machine tool with numerical control
A control method for a tool machine is provided. The machine tool includes adjustment devices which are used to produce relative displacement between a machining head and a work piece. The adjustment movements are detected by sensors associated with the adjustment devices. A value for the relative displacement from the machining head to the work piece is determined from the signals of the sensors associated with the adjustment devices. The adjustment devices are controlled according to the value of relative displacement in order to produce predetermined adjustment movements. State variables which describe relative displacement between the machining head and work pieces are detected in at least one additional sensor. The state variables are taken into account when the value for the relative displacement is determined.
1. A machine tool, comprising:
a machining head;
a workpiece holder comprising a workpiece;
an adjustment device to create a relative displacement between the machining head and the workpiece;
a numerical control to control the adjustment device based upon a value of the relative displacement of the machining head to the workpiece;
a sensor assigned to the adjustment device to detect adjustment movements of the adjustment device;
additional sensors to create a state variable based upon a relative displacement between the machining head and the workpiece,
wherein the machining head includes a first additional sensor and the workpiece holder includes a second additional sensor, and
wherein the additional sensors are configured to detect measurement inaccuracies due to a dynamic behavior between the adjustment device and the machining head during a machining of the workpiece; and
a value for the relative displacement between the machining head and the workpiece based upon signals of the sensor assigned to the adjustment device and based upon the state variable,
wherein the state variable detected by the additional sensors is selected from the group consisting of: temperature, inclination, angular speed, angular acceleration, axial acceleration in at least one direction, and a combination thereof.
2. The machine tool as claimed in claim 1 , wherein the sensor has a measurement resolution ranging down to at least a few μm.
3. The machine tool as claimed in claim 1 , wherein the adjustment devices create adjustment movements of the machining head.
4. The machine tool as claimed in claim 1 , wherein the additional sensor is integrated into the workpiece holder.
5. The machine tool as claimed in claim 1 , wherein the adjustment device creates adjustment movements of the workpiece.
6. The machine tool as claimed in claim 1 , wherein the additional sensor is integrated in the machining head.
7. The machine tool as claimed in claim 1 , wherein the machine tool comprises:
a machine bed, and
a comparison sensor in the machine bed to detect state variables of the machine.
8. The machine tool as claimed in claim 7 , wherein the comparison sensor and the additional sensor are detecting the same state variable.
9. The machine tool as claimed in claim 1 , wherein the machine tool comprises an integrated additional sensor for detecting state variables.