CN111123835A - Thermal displacement error measuring device and modeling method of numerical control machine tool - Google Patents
Thermal displacement error measuring device and modeling method of numerical control machine tool Download PDFInfo
- Publication number
- CN111123835A CN111123835A CN201911415645.0A CN201911415645A CN111123835A CN 111123835 A CN111123835 A CN 111123835A CN 201911415645 A CN201911415645 A CN 201911415645A CN 111123835 A CN111123835 A CN 111123835A
- Authority
- CN
- China
- Prior art keywords
- thermal
- measuring
- displacement
- measurement
- sensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
- G05B19/404—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/30—Nc systems
- G05B2219/34—Director, elements to supervisory
- G05B2219/34119—Function generator, filter after interpolator to control position error
Landscapes
- Engineering & Computer Science (AREA)
- Human Computer Interaction (AREA)
- Manufacturing & Machinery (AREA)
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Automation & Control Theory (AREA)
- Automatic Control Of Machine Tools (AREA)
- Numerical Control (AREA)
Abstract
The invention provides a thermal displacement error measuring device of a numerical control machine tool, which comprises a body to be measured, a plurality of displacement measuring sensors, a sensor fixing support, a plurality of temperature sensors and a data acquisition device, wherein the sensor fixing support is fixed on a tool rest component, the displacement measuring sensors are fixed on the sensor fixing support, one end of the body to be measured is fixed on a main shaft component, the displacement measuring sensors and the temperature sensors are connected with the data acquisition device through cables, and the data acquisition device is arranged in the numerical control machine tool and all the temperature sensors are installed in the numerical control machine tool. According to the thermal displacement error measuring device of the numerical control machine tool, the thermal displacement difference existing at the relative position between the tool rest component and the main shaft component at different temperatures is measured in real time through the displacement measuring sensor on the sensor fixing support and the body to be measured, and the obtained thermal displacement difference is more accurate.
Description
Technical Field
The invention relates to the field of numerical control machines, in particular to a thermal displacement error measuring device and a modeling method of a numerical control machine.
Background
The main shaft, the feed shaft and other parts of the numerical control machine are key parts for ensuring the performance and the precision requirements of the machine tool. The machine tool is influenced by an external heat source (ambient temperature) and an internal heat source (such as a motor, a hydraulic device, an electrical system, bearing operation and the like), so that the temperature of each part of the machine tool changes, and the deformation of each part of the machine tool is different due to different thermal expansion coefficients of different materials in the machine tool structure, so that the machine tool generates thermal deformation. The thermal deformation can not only destroy the original geometric accuracy of the machine tool and accelerate the abrasion of moving parts, but also cause the abnormity and the rejection of the processing dimensional accuracy of parts. Therefore, the influence of thermal deformation cannot be ignored particularly for precision machine tools and automated machine tools.
In precision processing machines such as high-end numerically controlled machines, the machining error caused by thermal deformation of the machine tool accounts for about 40% to 70% of the total error. Therefore, improving the thermal state characteristics of the machine tool and reducing the thermal error are important ways for improving the processing precision and stability of the numerical control machine tool. The thermal characteristics of machine tools and the reduction of thermal errors are currently improved by several approaches, for example:
1) improving the thermal environment and reducing the heating intensity of a heat source;
2) the structural design of the machine tool is improved or the high-precision grating ruler configuration is increased;
3) controlling the temperature rise of important parts of the machine tool, and taking measures to effectively cool and radiate the important parts;
the traditional method for improving the thermal error is to improve the structure and environment of the machine tool, the improvement effect is limited, and the thermal error cannot be completely avoided. Therefore, if the thermal error must be measured to obtain the thermal error, the error compensation is performed on the numerical control machine according to the thermal error, so that the thermal error problem of the numerical control machine can be completely solved. At present, the thermal error compensation of the numerical control machine tool is not accurate enough and the accurate thermal error value cannot be measured.
Disclosure of Invention
In order to overcome the defects of the prior art, an objective of the present invention is to provide a thermal displacement error measuring device for a numerical control machine, which can solve the problems that the thermal error compensation of the numerical control machine is not accurate enough and an accurate thermal error value cannot be measured.
The second objective of the present invention is to provide a thermal error modeling method for a numerical control machine, which can solve the problems that the thermal error compensation of the numerical control machine is not accurate enough and the accurate thermal error value cannot be measured.
One of the purposes of the invention is realized by adopting the following technical scheme:
the utility model provides a hot displacement error measuring device of digit control machine tool, digit control machine tool includes knife rest part, main shaft part, including the volume of awaiting measuring, a plurality of displacement measurement sensor, sensor fixed bolster, a plurality of temperature sensor and data acquisition device, the sensor fixed bolster is fixed on the knife rest part, displacement measurement sensor fixes on the sensor fixed bolster, the volume of awaiting measuring one end is fixed on the main shaft part, displacement measurement sensor with temperature sensor all with data acquisition device connects through the cable, data acquisition device is established and is all temperature sensor installs in the digit control machine tool, when carrying out hot displacement error measurement, knife rest part drives the sensor fixed bolster removes extremely on the main shaft part the volume of awaiting measuring department.
Further, the sensor fixed bolster is T type support, the sensor fixed bolster includes first measurement end, second measurement end and stiff end, first measurement end the second measurement end and the stiff end interconnect, first measurement end with the second measurement end is perpendicular, displacement measurement sensor fixes first measurement end with the second measurement end, the stiff end is fixed knife rest part bottom, the part of the body of awaiting measuring for containing a plurality of ladders.
Furthermore, the number of the displacement measuring sensors is two, one displacement measuring sensor is fixed at the first measuring end, and one displacement measuring sensor is fixed at the second measuring end.
Further, the first measuring end and the second measuring end are both provided with through holes, and the displacement measuring sensor is fixed in the through holes in a buckling mode.
Further, when thermal displacement error measurement is performed, the displacement measuring sensor on the first measuring end is moved to a step of the body to be measured.
The second purpose of the invention is realized by adopting the following technical scheme:
a thermal error modeling method of a numerical control machine tool comprises the following steps:
acquiring an initial value, namely acquiring an initial thermal displacement value measured when a displacement measuring sensor moves to a preset measuring position of an object to be measured at an initial moment, and acquiring initial temperature data which are measured by different temperature sensors and contain initial temperature values and temperature sensor position information;
measuring thermal errors, namely controlling a displacement measuring sensor to move to a preset measuring position on an object to be measured respectively according to preset interval time to measure the thermal errors to obtain displacement measuring data containing a measured thermal displacement value and measuring time, and acquiring temperature measuring data containing measured temperature values, measuring time and temperature sensor position information measured by different temperature sensors in real time according to the preset interval time;
calculating thermal errors, namely obtaining thermal error data containing measurement time and thermal displacement difference according to the displacement measurement data and the initial thermal displacement value, and obtaining temperature change data containing measurement time, temperature change value and temperature sensor position information according to the initial temperature data and the temperature measurement data;
and generating a thermal error model, and calculating to obtain the thermal error model at a preset measuring position according to the thermal error data and the temperature change data.
Further, if there are a plurality of preset measurement positions, there are a plurality of thermal error models, and the method further includes a compensation function calculation step of respectively obtaining measurement position information of different preset measurement positions, and respectively inputting different measurement times and corresponding measurement temperature values into the corresponding thermal error models to obtain a plurality of first thermal displacement difference sets corresponding to the measurement times, where each first thermal displacement difference set includes a plurality of first thermal displacement differences, each first thermal displacement difference set corresponds to a unique measurement time, and each first thermal displacement difference corresponds to a unique measurement position information; and obtaining a compensation function set containing different compensation functions according to the first thermal displacement difference set and the measurement position information, wherein each compensation function corresponds to the unique measurement time.
The method further comprises the steps of compensation processing, obtaining a position to be compensated and a time to be compensated, screening out a corresponding compensation function from the compensation function set according to the time to be compensated, solving a corresponding compensation value according to the compensation position and the compensation function, and performing compensation processing on the numerical control machine according to the compensation value.
Further, the initial thermal displacement value comprises an X-axis initial displacement value and a Z-axis initial displacement value, the X-axis initial displacement value is a displacement distance of the object to be measured relative to the first measuring end, and the Z-axis initial displacement value is a displacement distance of the object to be measured at the second measuring end; the thermal displacement difference comprises an X-axis thermal displacement difference and a Z-axis thermal displacement difference, the X-axis thermal displacement difference is the thermal displacement difference of the tool rest component and the spindle component in the horizontal direction with the first measuring end, and the Z-axis thermal displacement difference is the thermal displacement difference of the tool rest component and the spindle component in the horizontal direction with the second measuring end.
Further, the thermal error data includes X-axis thermal error data and Z-axis thermal error data, and the generated thermal error model specifically includes: and calculating to obtain an X-axis thermal error model at a preset measuring position according to the X-axis thermal error data and the temperature change data, and calculating to obtain a Z-axis thermal error model at the preset measuring position according to the Z-axis thermal error data and the temperature change data, wherein the X axis is the horizontal direction corresponding to the first measuring end, and the Z axis is the horizontal direction corresponding to the second measuring end.
Compared with the prior art, the invention has the beneficial effects that: the utility model provides a thermal displacement error measuring device of digit control machine tool, including the volume of awaiting measuring, a plurality of displacement measurement sensor, sensor fixed bolster, a plurality of temperature sensor and data acquisition device, the sensor fixed bolster is fixed on the knife rest part, displacement measurement sensor fixes on the sensor fixed bolster, the volume of awaiting measuring one end is fixed on the spindle unit, displacement measurement sensor with temperature sensor all with data acquisition device connects through the cable, data acquisition device establishes and all temperature sensor installs in the digit control machine tool, when carrying out thermal displacement error measurement, the knife rest part drives the sensor fixed bolster removes extremely on the spindle unit the volume of awaiting measuring department. The thermal displacement difference existing at the relative position between the tool rest component and the main shaft component at different temperatures is measured in real time through the displacement measuring sensor on the sensor fixing support and the to-be-measured body, the obtained thermal displacement difference is more accurate, and accurate error compensation can be carried out on the numerical control machine tool according to the thermal displacement difference obtained through measurement.
The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical solutions of the present invention more clearly understood and to implement them in accordance with the contents of the description, the following detailed description is given with reference to the preferred embodiments of the present invention and the accompanying drawings. The detailed description of the present invention is given in detail by the following examples and the accompanying drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:
FIG. 1 is a schematic cross-sectional view of a part of the structure of a thermal displacement error measuring device of a numerically controlled machine tool according to the present invention;
FIG. 2 is a schematic view of a partial structure of a thermal displacement error measuring device of a numerically controlled machine tool according to the present invention;
fig. 3 is a schematic structural diagram of a sensor fixing bracket of the thermal displacement error measuring device of the numerical control machine tool according to the present invention;
fig. 4 is a schematic flow chart of a method for modeling a thermal displacement error of a numerical control machine tool according to the present invention.
In the figure: 1. a body to be measured; 2. a displacement measuring sensor; 3. a sensor fixing bracket; 31. a first measuring end; 32. a second measuring end; 33. a fixed end; 4. a blade holder member; 5. a spindle unit; 6. a temperature sensor; 7. and a through hole.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and the detailed description, and it should be noted that any combination of the embodiments or technical features described below can be used to form a new embodiment without conflict.
As shown in fig. 1 to 3, in the device for measuring thermal displacement error of a numerical control machine tool according to the present invention, the numerical control machine tool in this embodiment includes a tool rest unit 4, a spindle unit 5, a spindle case, a feed shaft, a coolant tank, a bed, a motor, and the like, and the specific structure of the numerical control machine tool is the prior art and will not be described herein again. The thermal displacement error measuring device comprises a body to be measured 1, a plurality of displacement measuring sensors 2, a sensor fixing support 3, a plurality of temperature sensors 6 and a data acquisition device. In this embodiment, the sensor fixing bracket 3 is a T-shaped bracket, the sensor fixing bracket 3 includes a first measuring end 31, a second measuring end 32 and a fixing end 33, the first measuring end 31, the second measuring end 32 and the fixing end 33 are connected with each other, the first measuring end 31 is perpendicular to the second measuring end 32, the fixing end 33 is perpendicular to the second measuring end 32, the displacement measuring sensor 2 is fixed at the first measuring end 31 and the second measuring end 32, and the fixing end 33 is fixed at the bottom of the tool rest component 4; in the implementation, the number of the displacement measuring sensors 2 is 2, one first measuring end 31 is fixed on the sensor fixing frame, the other second measuring end 32 is fixed on the sensor fixing support 3, the displacement measuring sensors 2 are eddy current or laser type high-precision displacement measuring sensors 2, the resolution ratio is below 0.5 mu m, the measuring error is about +/-2 mu m, and the requirement of high-precision measurement in a numerical control machine tool can be met; and the parallel direction of the first measuring end 31 is the direction of movement of the tool head member 4 relative to the spindle member 5 in the X-axis, and the parallel direction of the second measuring end 32 is the direction of movement of the tool head member 4 relative to the spindle member 5 in the Z-axis. The measuring body 1 is a part containing a plurality of steps, one end of the measuring body 1 is fixed at one end of the spindle part 5, and inside the numerical control machine tool with the data acquisition device installed, a plurality of temperature sensors 6 are respectively placed at different positions close to a heat source of the numerical control machine tool, such as in a spindle box body, on a screw nut on a feeding shaft, at a cooling liquid water tank and the like, and the number and the installation position of the temperature sensors 6 are determined according to the position and the number of an actual heat source inside the numerical control machine tool. The displacement measuring sensor 2 and the temperature sensor 6 are both connected with a data acquisition device through cables, and the data acquisition device acquires displacement data and temperature data measured by the displacement measuring sensor 2 and the temperature sensor 6.
In this embodiment, the first measuring end 31 and the second measuring end 32 are both provided with a through hole 7, and the displacement measuring sensor 2 is snap-fixed in the through hole 7.
When measuring, control knife rest part 4 drives sensor fixed bolster 3 and moves to the body of awaiting measuring 1 department, make displacement measurement sensor 2 on the first measuring end 31 move to the different ladder departments of the body of awaiting measuring 1 respectively, displacement measurement sensor 2 on the first measuring end 31 and displacement measurement sensor 2 on the second measuring end 32 are all close to the body of awaiting measuring 1 this moment, carry out position measurement, and data transmission to data acquisition device that will measure the acquisition, different temperature sensor 6 sends the temperature data that obtains to data acquisition device with measuring simultaneously.
As shown in fig. 4, the present invention further provides a thermal error modeling method for a numerical control machine tool based on the thermal displacement error measuring apparatus, including the following steps:
and acquiring an initial value, namely acquiring a measured initial thermal displacement value when the displacement measuring sensor moves to a preset measuring position of the body to be measured at an initial moment, and acquiring initial temperature data which are measured by different temperature sensors and contain initial temperature values and temperature sensor position information. In this embodiment, the predetermined measurement position may be a plurality of points, each of which is a point at a different position on the object to be measured. In this embodiment, the initial thermal displacement value corresponding to each preset measurement position includes an X-axis initial displacement value and a Z-axis initial displacement value, where the X-axis initial displacement value is a displacement distance of the object to be measured relative to the first measurement end, and the Z-axis initial displacement value is a displacement distance of the object to be measured at the second measurement end.
And measuring thermal errors, namely controlling the displacement measuring sensor to move to a preset measuring position on the body to be measured respectively according to preset interval time to measure the thermal errors, so as to obtain displacement measuring data containing a measured thermal displacement value and measuring time, and acquiring temperature measuring data containing measured temperature values, measuring time and temperature sensor position information measured by different temperature sensors in real time according to the preset interval time. In this embodiment, the measurement thermal displacement values in the displacement measurement data corresponding to a single preset measurement position are divided into two types, including a plurality of X-axis measurement thermal displacement values and a plurality of Z-axis measurement thermal displacement values.
And calculating thermal error, namely obtaining thermal error data containing measurement time and thermal displacement difference according to the displacement measurement data and the initial thermal displacement value, and obtaining temperature change data containing measurement time, temperature change value and temperature sensor position information according to the initial temperature data and the temperature measurement data. In this embodiment, the thermal displacement difference corresponding to each preset measurement position includes an X-axis thermal displacement difference and a Z-axis thermal displacement difference, the X-axis thermal displacement difference is a thermal displacement difference between the tool rest component and the spindle component in the horizontal direction with the first measurement end, and the Z-axis thermal displacement difference is a thermal displacement difference between the tool rest component and the spindle component in the horizontal direction with the second measurement end; therefore, the thermal error data corresponding to a single preset measurement position comprises a plurality of X-axis thermal error data and a plurality of Z-axis thermal error data.
And generating a thermal error model, and calculating to obtain the thermal error model at the preset measuring position according to the thermal error data and the temperature change data. In this embodiment, each preset measurement position may obtain two thermal error types, specifically including an X-axis thermal error model and a Z-axis thermal error model, taking a single preset measurement position as an example, at this time, an X-axis thermal error model at the preset measurement position is obtained through calculation according to X-axis thermal error data and temperature change data corresponding to the preset measurement displacement, a Z-axis thermal error model at the preset measurement position is obtained through calculation according to Z-axis thermal error data and temperature change data corresponding to the preset measurement displacement, an X axis is a horizontal direction corresponding to a first measurement end, and a Z axis is a horizontal direction corresponding to a second measurement end, where the X axis and the Z axis in this embodiment are moving directions of the tool rest component relative to the main shaft component.
Calculating a compensation function, wherein when a plurality of preset measurement positions are provided in the embodiment, a plurality of thermal error models are provided, measurement position information of different preset measurement positions is obtained respectively, different measurement times and corresponding measurement temperature values are input into the corresponding thermal error models respectively, a plurality of first thermal displacement difference sets corresponding to the measurement times are obtained, each first thermal displacement difference set comprises a plurality of first thermal displacement differences, each first thermal displacement difference set corresponds to a unique measurement time, and each first thermal displacement difference corresponds to unique measurement position information; and obtaining a compensation function set containing different compensation functions according to the first thermal displacement difference set and the measurement position information, wherein each compensation function corresponds to the unique measurement time.
And compensation processing, namely acquiring the position to be compensated and the time to be compensated, screening out a corresponding compensation function from the compensation function set according to the time to be compensated, calculating a corresponding compensation value according to the compensation position and the compensation function, and performing compensation processing on the numerical control machine according to the compensation value.
The following description is made for the thermal error modeling method of the numerical control machine tool, by way of example:
firstly, explaining one point in preset measurement positions, assuming that the single preset measurement position is a point P1, measuring n heat source measurement points by using a temperature sensor, wherein the preset interval time is 5 minutes, and acquiring initial temperature values measured by different temperature sensors at the initial moment; meanwhile, the initial time is recorded as t0, when the measurement is started, the tool rest component is controlled to drive the displacement measurement sensor to move to a point P1 on the body to be measured, and the initial relative displacement, namely the initial thermal displacement value, of the body to be measured relative to the tool rest component is obtained, wherein the initial relative displacement comprises an initial thermal displacement value X1(t0), X2(t0), X3(t0) on an X axis and an initial thermal displacement value Z1(t0), Z2(t0) and Z3(t0) on a Z axis; then moving the displacement measuring sensor to a position P1 on the object to be measured at intervals of 5 minutes to obtain a measured thermal displacement value at each measuring moment, wherein the measured displacement values comprise a measured displacement value X1(ti), X2(ti), X3(ti) on an X axis and a measured displacement value Z1(ti), Z2(ti) and Z3(ti) on a Z axis, wherein i represents different measuring moments; according to the difference value between the measured displacement value and the initial displacement value, the thermal displacement difference corresponding to different moments at the position P1 on the object to be measured can be obtained, meanwhile, the measured temperature value measured by all the temperature sensors at each measuring moment is obtained, and the temperature change value measured by different temperature sensors at each measuring moment is obtained according to the measured temperature value and the initial temperature value. The set of thermal displacement differences on the X axis measured at different measurement times at the point P1 is recorded as Fx (P1), i represents different measurement times, the set of thermal displacement differences on the Z axis is recorded as FZ (P1), and i represents different measurement times; t represents the temperature change value corresponding to different sensors at different times. The thermal error model calculated according to the thermal error data and the temperature change data at the preset measurement position is specifically as follows:
therefore, Fx (P1) and T have a linear relation, and a thermal error model of the tool rest component at P1 on the body to be measured on the X axis can be obtained according to the following formula (1), formula (2) and formula (3); the specific formula is as follows:
Fxi(p1)＝β0+β1Ti1+β2Ti2+...+βnTin+εi(i＝1,2,...,m) (1)
wherein i represents different measuring time, i is 1,2,3, … … m; fxi(p1) thermal displacement difference of tool holder member in X-axis at measurement time i β0、β1、……、βnIs a parameter to be solved; t isi1、Ti2，…，TinIndicating temperature change values of different positions obtained at the ith moment when the preset measuring position is P1; 0. 1,2, … … and n are position information of the temperature sensor; t isinThe temperature change value corresponding to the temperature sensor with the temperature sensor position information of n at the time of i; epsiloniAre random error variables that are independent of each other and all follow a normal distribution.
Substituting the different measurement times in the above formula (1) results in the following formula (2):
wherein, Fx1(p1)、Fx2(p1)、……、Fxm(p1) is the difference in thermal displacement of the tool holder assembly in the X-axis at measurement times 1,2, … …, m β0、β1、……、βnTo be consultedCounting; t isinThe temperature change value corresponding to the temperature sensor with the temperature sensor position information of n at the time of i; epsilon1、ε2、……、εmIs a random error at measurement times 1,2, … …, m. Converting the above formula (2) into a matrix expression (3):
fx (p1) is a thermal displacement difference matrix at the preset measurement position p1, the dimension of the matrix is m × 1, T is a temperature matrix, the dimension is m × (n +1), β is a vector to be estimated and solved, epsilon is a random error, therefore, the values of all vectors β to be estimated and solved at the preset position p1 can be obtained according to the formula (3), and the parameter β to be solved can be obtained0、β1、……、βnβ in accordance with0、β1、……、βnAn X-axis thermal error model on the X-axis described above for the p1 position can be obtained. The values of the parameters to be found at the sheet position can be obtained according to the same method, so that a Z-axis thermal error model on the Z axis at the p1 position is obtained. In the present real-time example, a plurality of measurement positions are preset, so that by using the method, an X-axis thermal error model and a Z-axis thermal error model corresponding to different measurement positions to be measured can be obtained, and each measurement position corresponds to one X-axis thermal error model and one Z-axis thermal error model.
In this embodiment, a thermal error model corresponding to a preset number of preset measurement positions is taken first, and measurement position information corresponding to all the preset measurement positions is obtained; inputting different measuring time into the thermal error model to obtain thermal displacement difference at different preset positions at different measuring moments, screening out the thermal displacement difference and the measuring position information corresponding to all the preset measuring positions at the same measuring moment, and obtaining a compensation function according to a plurality of thermal displacement differences and a plurality of measuring position information, wherein the different measuring moments correspond to a unique compensation function (which is a fitting curve in essence); the thermal displacement difference fitting curve is divided into an X-axis compensation function and a Z-axis compensation function according to the category of the thermal displacement difference; the variable in the compensation function is the measurement position information. When the compensation processing is required to be carried out on the numerical control machine tool, the position to be compensated and the time to be compensated are obtained, the corresponding compensation function is screened out according to the time to be compensated, the position to be compensated is taken as the measured position information, and the measured position information is substituted into the compensation function, so that the compensation value on the X axis or the Y axis can be obtained. The thermal error modeling method for the numerical control machine tool in the embodiment can accurately compensate the thermal error of the numerical control machine tool.
The invention discloses a thermal displacement error measuring device of a numerical control machine tool, which comprises a body to be measured, a plurality of displacement measuring sensors, a sensor fixing support, a plurality of temperature sensors and a data acquisition device, wherein the sensor fixing support is fixed on a tool rest component, the displacement measuring sensors are fixed on the sensor fixing support, one end of the body to be measured is fixed on a main shaft component, the displacement measuring sensors and the temperature sensors are both connected with the data acquisition device through cables, the data acquisition device is arranged in the numerical control machine tool, and all the temperature sensors are arranged in the numerical control machine tool. The thermal displacement difference existing at the relative position between the tool rest component and the main shaft component at different temperatures is measured in real time through the displacement measuring sensor on the sensor fixing support and the to-be-measured body, the obtained thermal displacement difference is more accurate, and accurate error compensation can be carried out on the numerical control machine tool according to the thermal displacement difference obtained through measurement.
The foregoing is merely a preferred embodiment of the invention and is not intended to limit the invention in any manner; those skilled in the art can readily practice the invention as shown and described in the drawings and detailed description herein; however, those skilled in the art should appreciate that they can readily use the disclosed conception and specific embodiments as a basis for designing or modifying other structures for carrying out the same purposes of the present invention without departing from the scope of the invention as defined by the appended claims; meanwhile, any changes, modifications, and evolutions of the equivalent changes of the above embodiments according to the actual techniques of the present invention are still within the protection scope of the technical solution of the present invention.
Claims (10)
1. The utility model provides a hot displacement error measuring device of digit control machine tool, digit control machine tool includes knife rest part, spindle unit, its characterized in that: including the volume of awaiting measuring, a plurality of displacement measurement sensor, sensor fixed bolster, a plurality of temperature sensor and data acquisition device, the sensor fixed bolster is fixed on the knife rest part, the displacement measurement sensor is fixed on the sensor fixed bolster, the volume of awaiting measuring one end is fixed on the spindle unit, the displacement measurement sensor with temperature sensor all with data acquisition device connects through the cable, data acquisition device is established and is all temperature sensor installs in the digit control machine tool, when carrying out thermal displacement error measurement, the knife rest part drives the sensor fixed bolster removes extremely on the spindle unit volume of awaiting measuring department.
2. The apparatus according to claim 1, wherein the thermal displacement error measuring device comprises: the sensor fixed bolster is T type support, the sensor fixed bolster includes first measurement end, second measurement end and stiff end, first measurement end the second measurement end and the stiff end interconnect mutually, first measurement end with the second measurement end is perpendicular, displacement measurement sensor fixes first measurement end with the second measurement end, the stiff end is fixed knife rest part bottom, the part of the body of awaiting measuring for containing a plurality of ladders.
3. The apparatus according to claim 2, wherein the thermal displacement error measuring device comprises: the number of the displacement measuring sensors is two, one displacement measuring sensor is fixed at the first measuring end, and one displacement measuring sensor is fixed at the second measuring end.
4. The apparatus according to claim 2, wherein the thermal displacement error measuring device comprises: the first measuring end and the second measuring end are both provided with through holes, and the displacement measuring sensor is fixed in the through holes in a buckling mode.
5. The apparatus according to claim 2, wherein the thermal displacement error measuring device comprises: when thermal displacement error measurement is performed, the displacement measuring sensor on the first measuring end moves to a step of the body to be measured.
6. A thermal error modeling method of a numerically controlled machine tool based on the thermal displacement error measuring apparatus according to any one of claims 1 to 5, comprising the steps of:
acquiring an initial value, namely acquiring an initial thermal displacement value measured when a displacement measuring sensor moves to a preset measuring position of an object to be measured at an initial moment, and acquiring initial temperature data which are measured by different temperature sensors and contain initial temperature values and temperature sensor position information;
measuring thermal errors, namely controlling a displacement measuring sensor to move to a preset measuring position on an object to be measured respectively according to preset interval time to measure the thermal errors to obtain displacement measuring data containing a measured thermal displacement value and measuring time, and acquiring temperature measuring data containing measured temperature values, measuring time and temperature sensor position information measured by different temperature sensors in real time according to the preset interval time;
calculating thermal errors, namely obtaining thermal error data containing measurement time and thermal displacement difference according to the displacement measurement data and the initial thermal displacement value, and obtaining temperature change data containing measurement time, temperature change value and temperature sensor position information according to the initial temperature data and the temperature measurement data;
and generating a thermal error model, and calculating to obtain the thermal error model at a preset measuring position according to the thermal error data and the temperature change data.
7. A method of modeling thermal errors of a numerically controlled machine tool as recited in claim 6, wherein: the method comprises the steps of obtaining measurement position information of different preset measurement positions, inputting different measurement time and corresponding measurement temperature values into corresponding thermal error models respectively, and obtaining a plurality of first thermal displacement difference sets corresponding to the measurement time, wherein each first thermal displacement difference set comprises a plurality of first thermal displacement differences, each first thermal displacement difference set corresponds to a unique measurement time, and each first thermal displacement difference corresponds to the unique measurement position information; and obtaining a compensation function set containing different compensation functions according to the first thermal displacement difference set and the measurement position information, wherein each compensation function corresponds to the unique measurement time.
8. A method of modeling thermal errors of a numerically controlled machine tool as recited in claim 7, wherein: the compensation processing is also included, the position to be compensated and the time to be compensated are obtained, the corresponding compensation function is screened out from the compensation function set according to the time to be compensated, the corresponding compensation value is calculated according to the compensation position and the compensation function, and the compensation processing is carried out on the numerical control machine according to the compensation value.
9. A method of modeling thermal errors of a numerically controlled machine tool as recited in claim 6, wherein: the initial thermal displacement value comprises an X-axis initial displacement value and a Z-axis initial displacement value, the X-axis initial displacement value is the displacement distance of the object to be measured relative to the first measuring end, and the Z-axis initial displacement value is the displacement distance of the object to be measured at the second measuring end; the thermal displacement difference comprises an X-axis thermal displacement difference and a Z-axis thermal displacement difference, the X-axis thermal displacement difference is the thermal displacement difference of the tool rest component and the spindle component in the horizontal direction with the first measuring end, and the Z-axis thermal displacement difference is the thermal displacement difference of the tool rest component and the spindle component in the horizontal direction with the second measuring end.
10. A method of modeling thermal errors of a numerically controlled machine tool as recited in claim 9, wherein: the thermal error data comprises X-axis thermal error data and Z-axis thermal error data, and the generated thermal error model specifically comprises: and calculating to obtain an X-axis thermal error model at a preset measuring position according to the X-axis thermal error data and the temperature change data, and calculating to obtain a Z-axis thermal error model at the preset measuring position according to the Z-axis thermal error data and the temperature change data, wherein the X axis is the horizontal direction corresponding to the first measuring end, and the Z axis is the horizontal direction corresponding to the second measuring end.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911415645.0A CN111123835A (en) | 2019-12-31 | 2019-12-31 | Thermal displacement error measuring device and modeling method of numerical control machine tool |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201911415645.0A CN111123835A (en) | 2019-12-31 | 2019-12-31 | Thermal displacement error measuring device and modeling method of numerical control machine tool |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111123835A true CN111123835A (en) | 2020-05-08 |
Family
ID=70506689
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201911415645.0A Pending CN111123835A (en) | 2019-12-31 | 2019-12-31 | Thermal displacement error measuring device and modeling method of numerical control machine tool |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111123835A (en) |
-
2019
- 2019-12-31 CN CN201911415645.0A patent/CN111123835A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Mayr et al. | Thermal issues in machine tools | |
| Ramesh et al. | Error compensation in machine tools—a review: Part II: thermal errors | |
| Wang et al. | Compensation for the thermal error of a multi-axis machining center | |
| US6269284B1 (en) | Real time machine tool error correction using global differential wet modeling | |
| Wu et al. | Thermal error compensation method for machine center | |
| WO2019084948A1 (en) | Radial thermal drift error modeling and compensation method for main spindle of horizontal cnc lathe | |
| CN102854841B (en) | Shape and position error in-situ compensating and processing method for curved surface parts | |
| Larue et al. | Deviation of a machined surface in flank milling | |
| US20100152881A1 (en) | Thermal error compensation method for machine tools | |
| Zhu | Robust thermal error modeling and compensation for CNC machine tools | |
| JP2002515995A (en) | Real-time error correction of machine tools using full differential wet modeling | |
| Guiassa et al. | Closed door machining error compensation of complex surfaces using the cutting compliance coefficient and on-machine measurement for a milling process | |
| Mares et al. | Robustness and portability of machine tool thermal error compensation model based on control of participating thermal sources | |
| Mareš et al. | Thermal error minimization of a turning-milling center with respect to its multi-functionality | |
| Horejš et al. | Compensation of thermally induced errors in five-axis computer numerical control machining centers equipped with different spindles | |
| Bushuev et al. | Precision and efficiency of metal-cutting machines | |
| Soons | Accuracy analysis of multi-axis machines | |
| CN111123835A (en) | Thermal displacement error measuring device and modeling method of numerical control machine tool | |
| Naumann et al. | Hybrid correction of thermal errors using temperature and deformation sensors | |
| Blaser | Adaptive learning control for thermal error compensation | |
| Mares et al. | AN UPDATE OF THERMAL ERROR COMPENSATION MODEL VIA ON-MACHINE MEASUREMENT. | |
| CN211403217U (en) | Thermal displacement error measuring device of numerical control machine tool | |
| Spaan | Software error compensation of machine tools | |
| Xiao et al. | Analysis and compensation of surface flatness of thin-walled valve body parts | |
| Liu et al. | Comparison of accuracy stability using a thermal compensator and grating ruler |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |