A direct pose feedback (DPF) control method applied to a DPF controlled machine is provided. The DPF control method includes a pose compensation control in addition to the position feedback control. The pose compensation control includes an initiation step, a reference system step, an actual pose calculation step and a position compensation step. The sum of the primary driving value and the compensation driving value is output to the driver of each of the motors. The advantage of the DPF control method is that the existing real-time position control loop in the controller can remain unchanged, while the pose compensation control is added to eliminate tool pose error resulted from geometric errors in the machine. The DPF controlled machine uses a pose measuring mechanism to measure the actual pose of the tool and to compensate the tool pose error. Hence, the DPF controlled machine is free of geometric errors.

An application method of the thermal error-temperature loop in the spindle of a CNC machine tool. This uses a bar and two displacement sensors to determine radial thermal errors of the spindle. Meanwhile two temperature sensors are used to determine the temperature of the upper and lower surfaces of the spindle box. Then, the thermal error-temperature loop is drawn with the temperature difference between two temperature sensors as the abscissa and the radial thermal error of the spindle as the ordinate. Finally, the loop is employed to analyze the mechanism of the radial thermal deformation of the spindle and the thermal error level is evaluated. Since the method is based on measured data, the results of the analysis are closer to the reality, compared to those from the numerical simulations.

An online geometric/thermal error measurement and compensation system for computer numerically controlled (CNC) machine tools belonging to the technical field of error testing and compensation of CNC machine tools. The online CNC machine tool geometric/thermal error measurement and compensation system includes two parts: the hardware platform and the measurement and compensation software. The hardware platform includes a unidirectional acceleration sensor, a precision integrated circuit (IC) temperature sensor, a multi-channel temperature data collector, and a geometric/thermal error measurement and compensation host. The error measurement and compensation software runs in the geometric/thermal error measurement and compensation host and realizes testing and compensation of geometric and thermal errors in machine tools, which are communicated to the FANUC CNC system.

A thermal displacement compensation apparatus for compensating a dimensional measurement error due to a thermal displacement of a workpiece, including a machine learning device for learning shape measurement data at the time of inspection of the workpiece, wherein the machine learning device observes image data showing the temperature distribution of the workpiece and shape data after machining as state variables representing the current state of the environment, acquires judgment data indicating the shape measurement data at the time of inspection, and learns the image data showing the temperature distribution of the workpiece and shape data after machining and the shape measurement data at the time of inspection in association with each other using the observed state variables and the acquired judgment data.

The present invention relates to an apparatus and a method of automatically converting thermal displacement compensation parameters of a machine tool, which automatically convert a compensation parameter of a thermal displacement compensation equation of a machine tool so that the compensation parameter is optimized to a current thermal displacement state of the machine tool in real time based on Z-directional or Y-directional displacement data of a tool tip end of a reference tool measured by a tool measuring unit according to an operation state of the machine tool or various kinds of machine tools or thermal displacement data of the machine tool calculated by measuring a processed portion of a processed material, and temperature data measured by a temperature measuring unit, to minimize a processing error according to thermal displacement and improve processing accuracy of the machine tool.

An application method of the thermal error-temperature loop in the spindle of a CNC machine tool. This uses a bar and two displacement sensors to determine radial thermal errors of the spindle. Meanwhile two temperature sensors are used to determine the temperature of the upper and lower surfaces of the spindle box. Then, the thermal error-temperature loop is drawn with the temperature difference between two temperature sensors as the abscissa and the radial thermal error of the spindle as the ordinate. Finally, the loop is employed to analyze the mechanism of the radial thermal deformation of the spindle and the thermal error level is evaluated. Since the method is based on measured data, the results of the analysis are closer to the reality, compared to those from the numerical simulations.

A method includes four steps, (1) setting an initial tool temperature, (2) estimating a temperature of a tool or a position measurement sensor based on the initial tool temperature and a temperature of a spindle, (3) estimating an amount of thermal displacement of the tool or the position measurement sensor with a preliminarily set tool thermal displacement estimation formula based on the estimated temperature, and (4) moving a feed shaft of the machine tool based on the estimated amount of thermal displacement to perform a correction. In the second step, the temperature of the spindle is measured, then a tool-mounted portion temperature of the spindle from the measured temperature is estimated. Further, the temperature of the tool or the position measurement sensor is estimated with the tool-mounted portion temperature, the initial tool temperature of the tool or the position measurement sensor, and the preliminarily set tool temperature estimation formula.

Provided is a thermal displacement correction device capable of continuing a thermal displacement correction with high accuracy even when some of a plurality of sensors fail. The thermal displacement correction device includes a sensor information acquisition unit that acquires machine tool temperatures detected by the sensor and a state of the sensors, a thermal displacement estimating method storage unit that stores a plurality of thermal displacement estimating methods, a thermal displacement estimating method selection unit that selects a thermal displacement estimating method to be used for estimating the thermal displacement amount of the machine tool based on the state of the sensors, and a thermal displacement estimating unit that estimates the thermal displacement amount of the machine tool based on the machine tool temperature according to the thermal displacement estimating method selected by the thermal displacement estimating method selection unit.

A measurement, calibration and compensation system for machine tool includes a first positioning base; two first speckle image sensors for sensing speckle positions of an object holding unit at a first XY plane and a first XZ plane of the first positioning base before and after the machine tool is started for machining; a second positioning base; two second speckle image sensors for sensing speckle positions of a cutter holding unit at a second XY plane and a second YZ plane of the second positioning base before and after the machine tool is started for machining. Thus, the thermal expansion at all axes of the machine tool can be measured in a simplified and low-cost way, and the absolute positioning coordinates of all axes of the machine tool can be calibrated in real time to avoid reduced positioning accuracy due to the thermal expansion of the multi-axis machine tool.

A method for operating a gear cutting machine comprising the following steps: machining a first workpiece (1) in the machine, wherein the first workpiece (1) heats up due to the machining, determining at least one characteristic workpiece variable in the first workpiece (1) in the heated state, wherein a measuring device of the machine is used for the determination, determining a compensation on the basis of the at least one characteristic workpiece variable of the first workpiece (1) and at least one characteristic workpiece variable of a reference workpiece, wherein the characteristic workpiece variable of the reference workpiece is determined in the machine after a steady-state temperature has been reached, at least one compensation value is determined in the course of determining the compensation, adjusting of the machine setting by taking into account the at least one compensation value, and machining a further workpiece (2) in the machine.