CN118168469A - Cylindrical coordinate profile scanning measuring device capable of compensating motion precision and application method thereof - Google Patents

Abstract

The invention discloses a cylindrical coordinate profile scanning measuring device capable of compensating motion precision and an application method thereof. The invention aims to realize high-precision rapid measurement of the free curved surface, has simple measurement process, reliable measurement result and high measurement precision, and can conveniently and high-precision and high-efficiency measure the free curved surface.

Description

Cylindrical coordinate profile scanning measuring device capable of compensating motion precision and application method thereof

Technical Field

The invention relates to a high-precision measurement technology in the manufacturing process of optical elements, in particular to a cylindrical coordinate profile scanning measurement device capable of compensating motion precision and an application method thereof.

Background

Optical freeform surfaces generally include irregularly shaped and non-rotationally symmetric surfaces, with surface shape accuracy typically requiring deep submicron or higher. In free-form surface processing, detection of processing precision is a key to influence the processing efficiency of the whole free-form surface, and in order to further improve the processing precision, the precision of the curved surface must be detected, so that ultra-precise measurement of the surface shape of the curved surface is particularly important. Because of the limitation of manufacturing precision of the measuring machine, structural design and assembly of the measuring machine and other reasons, the movement precision and Abbe error can be increased along with the expansion of the measuring range, and the measuring precision is seriously affected. Therefore, the motion accuracy and abbe error have become an important error that restricts the measurement accuracy of the high-accuracy measuring machine.

Disclosure of Invention

The invention aims to solve the technical problems: aiming at the problems in the prior art, the invention provides a cylindrical coordinate contour scanning measuring device capable of compensating motion precision and an application method thereof, and aims to realize high-precision rapid measurement of a free curved surface, and the invention has the advantages of simple measuring process, reliable measuring result, high measuring precision and convenience in measuring the free curved surface with high precision and high efficiency.

In order to solve the technical problems, the invention adopts the following technical scheme:

The cylindrical coordinate profile scanning measurement device capable of compensating for motion precision comprises a base, a measurement frame, a measuring head motion platform and a detection head, wherein a first turntable and a motion error sensor are arranged on the base, an objective table for placing a measured workpiece is arranged on the first turntable, and the motion error sensor is arranged adjacent to the objective table and used for detecting motion errors of the objective table; the measuring frame is provided with an X-direction flat crystal and a Z-direction flat crystal respectively, the measuring head moving platform is fixed on the measuring frame and comprises an X-axis moving module, a Z-axis moving module and a second turntable which are sequentially cascaded, the detecting head is arranged on the second turntable, the X-axis moving module is provided with an X-axis laser displacement sensor, the emitting laser direction of the X-axis laser displacement sensor is perpendicular to the X-direction flat crystal, the Z-axis moving module is provided with a Z-axis laser displacement sensor, and the emitting laser direction of the Z-axis laser displacement sensor is perpendicular to the Z-direction flat crystal.

Optionally, the motion error sensor includes a plurality of capacitance sensors, and the capacitance sensors form a capacitance structure with the stage made of metal, wherein at least one capacitance sensor is located on one side of the stage along a horizontal direction for detecting radial runout of the stage, and at least one capacitance sensor is located on one side of the stage along a vertical direction for detecting end surface runout of the stage.

Optionally, the detection head is a non-contact measurement head, and the five lines of the center line of the X-axis laser displacement sensor, the center line of the Z-axis laser displacement sensor, the axis line of the first turntable, the axis line of the second turntable and the center line of the detection head intersect at the same point when the second turntable is positioned in the middle of the X-axis motion module.

Optionally, a fixture is arranged on the base, and the capacitive sensor is mounted on the fixture.

Optionally, the base is a marble base.

In addition, the invention also provides an application method of the cylindrical coordinate profile scanning measurement device capable of compensating the motion precision, which comprises the following steps:

S101, placing a measured workpiece on an objective table, and adjusting the cylindrical coordinate profile scanning measuring device capable of compensating for motion precision, so that when a first turntable is positioned in the middle of an X-axis motion module, the laser center line of an X-axis laser displacement sensor, the laser center line of a Z-axis laser displacement sensor, the axial line of a first turntable, the axial line of a second turntable and the center line of a detection head intersect at the same point;

Step S102, controlling a detection head to carry out cylindrical coordinate contour scanning measurement on a measured workpiece placed on a stage through a first turntable and a detection head motion platform, and carrying out motion precision compensation on a cylindrical coordinate contour scanning measurement device capable of compensating motion precision: the device comprises an X-axis laser displacement sensor and a Z-axis laser displacement sensor for monitoring linear motion errors and compensating in real time, a hexahedral part measuring part perpendicularity error and compensating in real time, and a motion error sensor for monitoring radial runout and end surface runout generated when an objective table rotates and compensating.

Optionally, monitoring the linear motion error and performing real-time compensation by the X-axis laser displacement sensor and the Z-axis laser displacement sensor in step S102 includes:

Step S201, an X-axis laser displacement sensor and a Z-axis laser displacement sensor are arranged on a second turntable through a clamp in advance and calibrated;

Step S202, controlling an X-axis movement module and a Z-axis movement module to perform linear movement according to a preset track, monitoring an X-axis linear movement error by measuring the distance change between an X-direction flat crystal and an X-axis laser displacement sensor, and monitoring a Z-axis linear movement error by measuring the distance change between a Z-direction flat crystal and a Z-axis laser displacement sensor, wherein the distance is obtained by multiplying the time difference between the X-axis laser displacement sensor or the Z-axis laser displacement sensor transmitting a beam of laser and receiving a reflected laser signal by the speed of light;

And step S203, adjusting control parameters of the motion system by the control system according to the position data measured in real time, controlling the X-axis motion module to compensate the X-axis linear motion error in real time according to the measured X-axis linear motion error, and controlling the Z-axis motion module to compensate the Z-axis linear motion error in real time according to the measured Z-axis linear motion error.

Optionally, measuring the perpendicularity error of the piece through the hexahedral piece in step S102 and performing real-time compensation includes:

Step S301, installing and calibrating a contour scanning measuring device, and selecting measuring points uniformly distributed on each axis so as to comprehensively evaluate perpendicularity errors;

Step S302, measuring each axis of the contour scanning measuring device by using a hexahedral measuring piece, recording a measuring result, and determining a perpendicularity error;

Step S303, a real-time compensation scheme is formulated according to the determined perpendicularity error; and in the running process of the equipment, the perpendicularity error is compensated in real time according to the monitoring and adjusting compensation process of the real-time compensation scheme.

In step S303, after the real-time compensation of the perpendicularity error is performed according to the real-time compensation scheme monitoring and adjustment compensation process, the method further includes re-measuring the perpendicularity error between the axes, comparing the measured result with the measurement result when the measurement result is not compensated, and if the difference between the measured result and the measurement result does not meet the requirement, jumping to step S303 to re-adjust the real-time compensation scheme and optimize the real-time compensation.

Optionally, monitoring radial runout and end runout generated by the stage during rotation by the motion error sensor and compensating in step S102 includes:

Step S401, acquiring small changes of the position of the object table, which are caused by radial runout and end runout of the first turntable when the first turntable rotates under the object table, through a motion error sensor, converting the small changes into an electrical signal, and preprocessing the electrical signal through an amplifier and a filter;

Step S402, dynamically adjusting the rotating speed of the first turntable by adopting a specified closed-loop control algorithm through the preprocessed electric signals so as to offset the influence of radial runout and end surface runout of the first turntable on measurement.

Compared with the prior art, the invention has the following advantages:

1. According to the invention, the high-precision displacement sensor is combined with the optical flat crystal, and the measurement reference is built according to the Abbe principle, so that the measurement precision is not influenced by the motion precision during measurement; the non-contact measuring head is precisely positioned by adopting a high-precision laser displacement sensor, and linearity errors of the non-contact measuring head are compensated; the perpendicularity error of the hexahedral measuring piece is compensated by matching the hexahedral measuring piece with an autocollimator, so that the measuring result is not influenced by the perpendicularity error; the objective table is monitored through the plurality of capacitance sensors, so that the measurement accuracy is not affected by errors generated by rotation; thereby realizing high-precision and rapid free-form surface contour scanning measurement.

2. The invention adopts a laser interferometer with nanometer precision as a displacement sensor of a measuring system so as to provide high-precision positioning; and a high-resolution non-contact measuring head is adopted to realize high-precision workpiece surface profile measurement. And a plurality of capacitance sensors are adopted to realize high-precision rotation error measurement. And the separation and compensation of geometric errors are realized by adopting a high-precision optical standard component.

3. The invention is applicable to free-form surface optical elements, and can be used for high-precision measurement of various workpieces.

Drawings

Fig. 1 is a schematic structural diagram of a cylindrical coordinate profile scanning measurement device according to an embodiment of the present invention.

Legend description: 1. a base; 11. a first turntable; 12. a motion error sensor; 121. a clamp; 13. an objective table; 2. a measuring frame; 21. x-direction flat crystals; 22. z-direction flat crystals; 3. a measuring head moving platform; 31. an X-axis movement module; 311. an X-axis laser displacement sensor; 32. a Z-axis motion module; 321. a Z-axis laser displacement sensor; 33. a second turntable; 4. and a detection head.

Detailed Description

As shown in fig. 1, the present embodiment provides a cylindrical coordinate profile scanning measurement device capable of compensating for motion precision, which comprises a base 1, a measurement frame 2, a measuring head motion platform 3 and a detection head 4, wherein a first turntable 11 (turntable C) and a motion error sensor 12 are arranged on the base 1, a stage 13 for placing a measured workpiece is arranged on the first turntable 11, and the motion error sensor 12 is arranged adjacent to the stage 13 for detecting a motion error of the stage 13; the measuring frame 2 is respectively provided with an X-direction flat crystal 21 and a Z-direction flat crystal 22, the measuring head moving platform 3 is fixed on the measuring frame 2, the measuring head moving platform 3 comprises an X-axis moving module 31, a Z-axis moving module 32 and a second rotary table 33 which are sequentially cascaded, the detecting head 4 is arranged on the second rotary table 33 (rotary table A), the X-axis moving module 31 is provided with an X-axis laser displacement sensor 311, the emitting laser direction of the X-axis laser displacement sensor 311 is vertically arranged with the X-direction flat crystal 21, the Z-axis moving module 32 is provided with a Z-axis laser displacement sensor 321, and the emitting laser direction of the Z-axis laser displacement sensor 321 is vertically arranged with the Z-direction flat crystal 22. The X-direction flat crystal 21 and the Z-direction flat crystal 22 are crystal plane structures, and are used for realizing reflection of laser so that the X-axis laser displacement sensor 311 and the Z-axis laser displacement sensor 321 detect corresponding laser displacements. In this embodiment, the measuring frame 2 is located on the same plane as the rotation axis of the stage 13.

As shown in fig. 1, in the present embodiment, the first turntable 11 (turntable C) and the second turntable 33 (turntable a) can perform circumferential rotation, and the X-axis movement module 31 and the Z-axis movement module 32 can perform two-dimensional translational movement, so as to implement three-dimensional profile measurement of the workpiece to be measured placed on the stage 13, where the turntable and the displacement platform are both of a conventional structure. The first turntable 11 (turntable C), the second turntable 33 (turntable A), the X-axis movement module 31 and the Z-axis movement module 32 adopt precision work tables, and the four work tables form a complete movement system, so that the movement in a mode of combining rotation and translation can be realized.

In the embodiment, the detection head 4 is a non-contact type detection head, and a high-precision displacement sensor is adopted to combine with an optical flat crystal to build a measurement reference according to the Abbe principle; the high-precision displacement sensor and the optical flat are assembled according to the Abbe's principle, so that five lines of the central line of the X-axis laser displacement sensor 311, the central line of the Z-axis laser displacement sensor 321, the central line of the first turntable 11, the central line of the second turntable 33 and the central line of the detection head 4 are intersected at the same point when the second turntable 33 is positioned in the middle of the X-axis movement module 31. . Meanwhile, the main geometric errors affecting the motion precision of the system are geometric errors which are easy to identify and compensate, such as positioning errors, straightness errors, perpendicularity errors and the like. The positioning error is ensured by a high-precision displacement sensor, the linear motion error can be compensated in real time by a measuring reference, and the perpendicularity error is separated and compensated by a hexahedral measuring piece; radial runout and end runout generated during rotation of the objective table are monitored and compensated in real time through the capacitive sensor.

The motion error sensor 12 is used to monitor radial and axial errors that occur during rotation of the turntable. The motion error sensor 12 in this embodiment includes a plurality of capacitance sensors, and the capacitance sensors and the stage 13 made of metal form a capacitance structure, wherein at least one capacitance sensor is located on one side of the stage 13 along a horizontal direction for detecting radial runout of the stage 13, and at least one capacitance sensor is located on one side of the stage 13 along a vertical direction for detecting end runout of the stage 13, and a difference between a detected capacitance and a rated capacitance is a corresponding radial runout/end runout detection signal. As a preferred embodiment, in this embodiment, a pair of capacitive sensors arranged symmetrically with respect to the center of a circle is disposed on one side of the stage 13 along the horizontal direction for detecting radial runout of the stage 13, and a pair of capacitive sensors arranged symmetrically with respect to the center of a circle is disposed on one side of the stage 13 along the vertical direction for detecting end runout of the stage 13. The objective table is made of metal materials, the distance between the objective table and the capacitive sensor can be measured according to the displacement measuring principle of the capacitive sensor, and meanwhile, the sensor has very high sampling frequency, so that radial runout and end surface runout can be obtained.

As shown in fig. 1, the base 1 of the present embodiment is provided with a jig 121, and the motion error sensor 12 is mounted on the jig 121.

As a preferred embodiment, the base 1 in this example is a marble base.

In this embodiment, the measuring frame 2 includes a horizontal beam and a vertical beam, which are both rigid structures and are fixedly connected to each other, and are fixedly connected to the base through the vertical beams, the X-direction flat crystal 21 and the Z-direction flat crystal 22 are mounted on the measuring frame 2 which is vertically fixed to each other, the Z-direction flat crystal 22 is horizontally mounted, the X-direction flat crystal 21 is vertically mounted and is perpendicular to the light beam generated by the corresponding displacement sensor, and the capacitance sensor is located at the side and the lower side of the stage 13 and is fixedly connected to the base 1 through the fixture 121. The measuring frame 2 is required to have thermal and mechanical properties to prevent errors in the installation of the measuring standard.

In the present embodiment, the X-direction flat crystal 21 and the Z-direction flat crystal 22 as measurement references are high-precision flat crystals obtained by an advanced optical manufacturing method, and the material used is an optical material, and the surface facing the high-precision laser displacement sensor is a working surface.

The X-axis laser displacement sensor 311 and the Z-axis laser displacement sensor 321 in this embodiment are high-precision laser displacement sensors mounted on a motion system, and have the characteristics of large measurement stroke and high measurement precision, and are mounted above and beside a turntable a of the motion system, and the mounting principle is that the positions of the generated laser beam and the non-contact measuring head accord with abbe's principle, so that the non-contact measuring head is always perpendicular to the laser beam in the motion process and is kept on the same axis.

The components adopted by the device of the embodiment are all precise optical components, and can provide high-precision detection. The measuring plane (Z-direction flat crystal 22 and X-direction flat crystal 21) formed by the measuring frame 2 is independent of a moving system, so that the measuring precision is not influenced by the moving precision during measurement; the measuring system assembles a displacement sensor (a Z-axis laser displacement sensor 321 and an X-axis laser displacement sensor 311) and a measuring plane (a Z-direction flat crystal 22 and an X-direction flat crystal 21) according to an Abbe principle; the motion system can move along a measurement plane formed by the Z-direction flat crystal 22 and the X-direction flat crystal 21 so as to ensure that the displacement sensors (the Z-axis laser displacement sensor 321 and the X-axis laser displacement sensor 311) obtain the position coordinates of the detection head 4 through reflected laser reflected by the flat crystal, and the capacitance sensor (37) records the end face runout and the radial runout of the objective table 13; the perpendicularity error generated in the assembly process is separated and compensated through the auto-collimator and the hexahedral measuring piece. The high-precision flat crystals obtained by the advanced optical manufacturing method are adopted by the Z-direction flat crystal 22 and the X-direction flat crystal 21, the material is an optical material, and the surface opposite to the high-precision laser displacement sensor (the X-axis laser displacement sensor 311 and the Z-axis laser displacement sensor 321) is a working surface. The cylindrical coordinate profile scanning measurement device of this embodiment can be connected to an upper computer during operation, and the non-contact detection head 4, the X-axis laser displacement sensor 311, the Z-axis laser displacement sensor 321 and the output end of the capacitance sensor of the cylindrical coordinate profile scanning measurement device of this embodiment are respectively connected with the upper computer, and the turntable of the motion system is connected with the control end of the linear displacement platform. In addition, the motion system can be controlled in a centralized way through an upper computer, and can also be controlled to move independently through a controller of the motion system.

In summary, the cylindrical coordinate profile scanning measurement device of the embodiment adopts the high-precision displacement sensor and combines the optical flat crystal to build the measurement reference; assembling the high-precision displacement sensor and the optical flat according to the Abbe's principle, so that the five lines of the central line of the high-precision displacement sensor in the measuring system and the moving system, the axial line of the rotary table A, the axial line of the rotary table C and the central line of the measuring head are intersected at the same point when the rotary table A is positioned in the middle of the X-axis displacement platform; the motion system needs to move along the plane of the flat crystal, so that the high-precision laser displacement sensor obtains the position coordinates of the measuring head through flat crystal feedback and compensates straightness errors generated by the motion in real time, the perpendicularity of the assembly part is detected through the hexahedral part measuring piece, and the perpendicularity errors of the assembly part are separated; the capacitive sensor records axial errors and radial errors generated in the rotating process of the objective table; the three-dimensional contour of the workpiece to be measured is realized by combining the circumferential rotation of two rotary tables and the translational movement of two displacement platforms of the workpiece. The cylindrical coordinate profile scanning measurement device can realize high-precision detection of the free-form surface optical element, is quick and convenient in measurement process, reliable in measurement result and high in measurement precision, and is convenient for high-precision and high-efficiency measurement of the free-form surface optical element. The cylindrical coordinate profile scanning measurement device of the embodiment is built by combining a high-precision displacement sensor with an optical flat crystal according to an Abbe principle; geometric errors generated in the motion process are compensated by matching the laser displacement sensor and the autocollimator with a high-precision optical standard component, and errors generated during rotation of the objective table are monitored and compensated in real time by adopting a plurality of capacitance sensors, so that the motion precision of the system is improved, and high-precision and high-efficiency measurement is realized.

The workpiece contour coordinate measuring method of the cylindrical coordinate contour scanning measuring device of the embodiment is that an optical non-contact measuring head is perpendicular to the surface of a measured workpiece through a rotary table A so as to measure a steep slope, and the rotary table C and an objective table are combined to scan the workpiece at a high speed. The high-precision laser displacement sensor records position information through an open crystal and compensates straightness errors of the non-contact measuring head in the linear motion process; the capacitive sensor records the end face runout and the radial runout of the objective table and performs error compensation; meanwhile, the turntable C drives the workpiece to do circular motion, the non-contact measuring head records the contour information of the workpiece, and the contour of the workpiece is obtained through data processing, so that high-precision measurement is realized. The motion system drives the non-contact sensor to move, and is determined by the measurement system, the measurement system adopts a spiral scanning mode to measure, and the motion system moves along a set track. During measurement, the optical detection head 4 is perpendicular to the surface of the workpiece to be measured through the turntable A so as to measure a steep slope, and the turntable C is combined to scan the workpiece at a high speed. The high-precision laser displacement sensor records position information through a Z-direction flat crystal 22 and an X-direction flat crystal 21, compensates straightness errors of the non-contact measuring head in the linear motion process, records end face runout and radial runout of the objective table, and compensates rotation errors of the objective table in the circular motion process; meanwhile, the turntable C drives the workpiece to do circular motion, the non-contact measuring head records the contour information of the workpiece, and the contour of the workpiece is obtained through data processing, so that high-precision and high-efficiency measurement is realized. Mounting the workpiece on the stage 13; the workpiece can be driven to rotate through the objective table 13, meanwhile, the detection head 4 is driven to do spiral scanning motion through the motion system, surface profile information of the workpiece is obtained through the detection head 4, position information of the detection head 4 is obtained through movement of the Z-axis laser displacement sensor 321 and the X-axis laser displacement sensor 311, straightness errors of the detection head 4 in the moving process are compensated according to the obtained position information, namely: the position change quantity (the basic position is the initial position) of the detection head 4 is calculated through the moving distance of the displacement sensor, the position change quantity is subtracted from the surface profile information of the workpiece obtained by the detection head 4, the straightness error of the detection head 4 in the moving process can be compensated, the radial runout and the end surface runout error of the objective table 13 are monitored through the capacitance sensor (37), and the motion precision of the objective table is compensated in real time. When the detection head 4 is driven to do spiral scanning motion by the motion system, the motion reference (motion system) drives the detection head 4 to move and is determined by the measurement system. For example, when the motion system drives the detection head 4 to move along with spiral scanning, the rotation shaft of the objective table 13 is adopted to perform measurement, and the motion system carries the detection head 4 to perform spiral scanning, namely, the motion system moves along a plane (X-Z plane) formed by measurement references (Z-direction flat crystal 22 and X-direction flat crystal 21), and the workpiece performs circular motion along with the objective table 13. Therefore, the application method of the measuring device for motion precision compensation of the embodiment can realize high-precision measurement of the free curved surface with a large caliber, and has the advantages of simple measuring process, reliable measuring result and high measuring precision.

The embodiment also provides an application method of the motion precision compensated cylindrical coordinate profile scanning measurement device, which comprises the following steps:

Step S101, placing the measured workpiece on the objective table 13, adjusting the cylindrical coordinate profile scanning measuring device capable of compensating for motion precision, so that when the first rotary table 11 is positioned in the middle of the X-axis motion module 31, the laser center line of the X-axis laser displacement sensor 311, the laser center line of the Z-axis laser displacement sensor 321, the axis line of the first rotary table 11, the axis line of the second rotary table 33 and the center line of the detection head 4 are intersected at the same point;

Step S102, controlling the detection head 4 to perform cylindrical coordinate contour scanning measurement on the measured workpiece placed on the stage 13 through the first turntable 11 and the detection head moving platform 3, and performing motion precision compensation on the motion precision-compensated cylindrical coordinate contour scanning measurement device: the method comprises the steps of monitoring linear motion errors through an X-axis laser displacement sensor 311 and a Z-axis laser displacement sensor 321, compensating in real time, measuring perpendicularity errors of the parts through hexahedral parts, and monitoring radial runout and end surface runout generated when the object stage 13 rotates through a motion error sensor 12, and compensating.

In step S102 of this embodiment, monitoring the linear motion error and performing real-time compensation by the X-axis laser displacement sensor 311 and the Z-axis laser displacement sensor 321 includes:

Step S201, an X-axis laser displacement sensor 311 and a Z-axis laser displacement sensor 321 are arranged on the second turntable 33 through a clamp in advance and calibrated;

Step S202, the X-axis movement module 31 and the Z-axis movement module 32 are controlled to perform linear movement according to a preset track, after the movement is started, the X-axis linear movement error is monitored by measuring the distance change between the X-direction flat crystal 21 and the X-axis laser displacement sensor 311, the Z-axis linear movement error is monitored by measuring the distance change between the Z-direction flat crystal 22 and the Z-axis laser displacement sensor 321, and the distance is obtained by multiplying the time difference between the X-axis laser displacement sensor 311 or the Z-axis laser displacement sensor 321 transmitting a beam of laser and receiving the reflected laser signal by the speed of light;

In step S203, the control system adjusts the control parameters of the motion system according to the position data measured in real time, controls the X-axis motion module 31 to compensate the X-axis linear motion error in real time according to the measured X-axis linear motion error, and controls the Z-axis motion module 32 to compensate the Z-axis linear motion error in real time according to the measured Z-axis linear motion error.

The X-axis laser displacement sensor 311 or the Z-axis laser displacement sensor 321 is mounted on the second turntable 33 by a jig, and the X-axis laser displacement sensor 311 or the Z-axis laser displacement sensor 321 is calibrated to ensure accuracy and stability thereof. The X-axis movement module 31 and the Z-axis movement module 32 perform linear movement according to a predetermined trajectory. After starting the movement, the X-axis laser displacement sensor 311 or the Z-axis laser displacement sensor 321 monitors the linear movement error by measuring the change in distance between the flat crystals (X-direction flat crystal 21, Z-direction flat crystal 22) and the sensor. The sensor emits a beam of laser light and receives the reflected laser light signal, and the position of the object is determined by calculating the time difference of the reflected laser light. The sensor outputs a series of position data that can be used to analyze the linear motion error. According to the measured linear motion error, compensating the motion in real time through a control system; after the real-time compensation, the laser displacement sensor can measure the position of the object again for the feedback control system. The feedback control system can adjust the control parameters of the motion system according to the position data measured in real time to further reduce the linear motion error.

In step S102 of this embodiment, measuring the perpendicularity error of the piece through the hexahedral part and performing real-time compensation includes:

Step S301, installing and calibrating a contour scanning measuring device, and selecting measuring points uniformly distributed on each axis so as to comprehensively evaluate perpendicularity errors;

Step S302, measuring each axis of the contour scanning measuring device by using a hexahedral measuring piece, recording a measuring result, and determining a perpendicularity error;

Step S303, a real-time compensation scheme is formulated according to the determined perpendicularity error; and in the running process of the equipment, the perpendicularity error is compensated in real time according to the monitoring and adjusting compensation process of the real-time compensation scheme.

In step S303, after the real-time compensation of the perpendicularity error is performed according to the real-time compensation scheme monitoring and adjustment compensation process, the method further includes re-measuring the perpendicularity error between the axes, comparing the measured result with the measurement result when the measurement result is not compensated, and if the difference between the measured result and the measurement result does not meet the requirement, jumping to step S303 to re-adjust the real-time compensation scheme and optimize the real-time compensation.

The profile scanning measuring device is properly mounted and calibrated, and appropriate measuring points are selected, which are evenly distributed over the axes, so that the perpendicularity error can be evaluated comprehensively. Measuring each axis of the contour scanning measuring device by using a hexahedral measuring piece, recording a measuring result, and determining a perpendicularity error; according to the error, a proper real-time compensation scheme is formulated; in the running process of the equipment, special software or algorithm is adopted to monitor and adjust the compensation process according to a real-time compensation scheme to compensate errors in real time; after the real-time compensation is implemented, the perpendicularity error between the shafts is measured again, compared with the measurement result when the compensation is not implemented, and the real-time compensation scheme is adjusted according to the requirement and optimized.

In step S102 of this embodiment, monitoring radial runout and end runout generated when the stage 13 rotates by the motion error sensor 12 and compensating for the radial runout and the end runout includes:

Step S401, collecting that when the first turntable 11 under the objective table 13 rotates by the motion error sensor 12, the radial runout and the end runout of the first turntable 11 can cause the position of the objective table 13 to change slightly into a not-yet electric signal, and preprocessing by an amplifier and a filter;

In step S402, the pre-processed electric signal adopts a specified closed-loop control algorithm (a required closed-loop control algorithm may be selected according to needs, such as PID control algorithm, etc.) to dynamically adjust the rotation speed of the first turntable 11 so as to offset the influence of radial runout and end runout of the first turntable 11 on the measurement. When the first turntable 11 under the stage 13 rotates, the radial runout and the end runout of the first turntable 11 cause a minute change in the position of the stage, thereby changing the capacitance between the capacitance sensors. These small capacitance changes are converted into electrical signals, processed by amplifiers and filters, and finally transmitted to an upper computer for analysis. By analyzing the data returned by the capacitive sensor, the radial runout and the end runout of the objective table can be accurately measured, and a proper control algorithm is used for adjusting the system in real time so as to offset the influence of the motion error on the measurement; continuously monitoring the motion of the object stage in real time, and timely adjusting according to the data fed back by the sensor. And according to the real-time monitoring result and the actual motion condition, the compensation strategy is subjected to feedback adjustment, so that the system can effectively cope with various motion errors.

The above description is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above examples, and all technical solutions belonging to the concept of the present invention belong to the protection scope of the present invention. It should be noted that modifications and adaptations to the present invention may occur to one skilled in the art without departing from the principles of the present invention and are intended to be within the scope of the present invention.

Claims (10)

1. The cylindrical coordinate profile scanning measurement device capable of compensating motion precision is characterized by comprising a base (1), a measurement frame (2), a measuring head motion platform (3) and a detection head (4), wherein a first rotary table (11) and a motion error sensor (12) are arranged on the base (1), an objective table (13) for placing a measured workpiece is arranged on the first rotary table (11), and the motion error sensor (12) is arranged adjacent to the objective table (13) and used for detecting motion errors of the objective table (13); the measuring frame (2) is provided with an X-axis flat crystal (21) and a Z-axis flat crystal (22) respectively, the measuring head moving platform (3) is fixed on the measuring frame (2), the measuring head moving platform (3) comprises an X-axis moving module (31), a Z-axis moving module (32) and a second rotary table (33) which are sequentially cascaded, the detecting head (4) is installed on the second rotary table (33), the X-axis moving module (31) is provided with an X-axis laser displacement sensor (311), the emitting laser direction of the X-axis laser displacement sensor (311) is vertically arranged with the X-axis flat crystal (21), the Z-axis moving module (32) is provided with a Z-axis laser displacement sensor (321), and the emitting laser direction of the Z-axis laser displacement sensor (321) is vertically arranged with the Z-axis flat crystal (22).

2. The motion-precision-compensated cylindrical coordinate profile scanning measurement device according to claim 1, characterized in that the motion error sensor (12) comprises a plurality of capacitance sensors, and the capacitance sensors form a capacitance structure with the stage (13) made of metal, wherein at least one capacitance sensor is located on one side of the stage (13) in a horizontal direction for detecting radial runout of the stage (13), and at least one capacitance sensor is located on one side of the stage (13) in a vertical direction for detecting end-face runout of the stage (13).

3. The motion precision compensated cylindrical coordinate profile scanning measurement device according to claim 2, wherein the detection head (4) is a non-contact type measurement head, and five lines of a center line of the X-axis laser displacement sensor (311), a center line of the Z-axis laser displacement sensor (321), an axis line of the first turntable (11), an axis line of the second turntable (33) and a center line of the detection head (4) intersect at the same point when the second turntable (33) is located in the middle of the X-axis motion module (31).

4. The motion precision compensated cylindrical coordinate profile scanning measurement device according to claim 2, wherein a clamp (121) is provided on the base (1), and the capacitive sensor is mounted on the clamp (121).

5. The motion precision compensated cylindrical coordinate profile scanning measurement device of claim 1, wherein the base (1) is a marble base.

6. A method of using the motion accuracy compensated cylindrical coordinate profile scanning measurement apparatus of any one of claims 1-5, comprising:

S101, placing a measured workpiece on a stage (13), and adjusting the cylindrical coordinate profile scanning measuring device capable of compensating for motion precision, so that when a first turntable (11) is positioned in the middle of an X-axis motion module (31), the laser center line of an X-axis laser displacement sensor (311), the laser center line of a Z-axis laser displacement sensor (321), the axial line of the first turntable (11), the axial line of a second turntable (33) and the center line of a detection head (4) are intersected at the same point;

Step S102, a first rotating table (11) and a measuring head moving platform (3) control a detecting head (4) to carry out cylindrical coordinate contour scanning measurement on a measured workpiece placed on a carrying table (13), and a cylindrical coordinate contour scanning measuring device capable of compensating motion precision is used for compensating motion precision: the device comprises the steps of monitoring linear motion errors through an X-axis laser displacement sensor (311) and a Z-axis laser displacement sensor (321) and compensating in real time, measuring piece perpendicularity errors through hexahedral parts and compensating in real time, and monitoring radial runout and end surface runout generated when an objective table (13) rotates through a motion error sensor (12) and compensating.

7. The method of applying the motion-precision-compensated cylindrical coordinate profile scanning measurement apparatus as claimed in claim 6, wherein monitoring the linear motion error and performing the real-time compensation through the X-axis laser displacement sensor (311) and the Z-axis laser displacement sensor (321) in step S102 comprises:

Step S201, an X-axis laser displacement sensor (311) and a Z-axis laser displacement sensor (321) are arranged on a second turntable (33) through a clamp in advance and calibrated;

Step S202, controlling an X-axis movement module (31) and a Z-axis movement module (32) to perform linear movement according to a preset track, monitoring an X-axis linear movement error by measuring the distance change between an X-direction flat crystal (21) and an X-axis laser displacement sensor (311), and monitoring a Z-axis linear movement error by measuring the distance change between a Z-direction flat crystal (22) and a Z-axis laser displacement sensor (321), wherein the distance is obtained by multiplying the time difference between the X-axis laser displacement sensor (311) or the Z-axis laser displacement sensor (321) transmitting a beam of laser and receiving a reflected laser signal by the speed of light;

In step S203, the control system adjusts the control parameters of the motion system according to the position data measured in real time, and controls the X-axis motion module (31) to compensate the X-axis linear motion error in real time according to the measured X-axis linear motion error, and controls the Z-axis motion module (32) to compensate the Z-axis linear motion error in real time according to the measured Z-axis linear motion error.

8. The method of claim 6, wherein the measuring the perpendicularity error of the hexahedral workpiece in step S102 and performing real-time compensation comprises:

Step S301, installing and calibrating a contour scanning measuring device, and selecting measuring points uniformly distributed on each axis so as to comprehensively evaluate perpendicularity errors;

Step S302, measuring each axis of the contour scanning measuring device by using a hexahedral measuring piece, recording a measuring result, and determining a perpendicularity error;

Step S303, a real-time compensation scheme is formulated according to the determined perpendicularity error; and in the running process of the equipment, the perpendicularity error is compensated in real time according to the monitoring and adjusting compensation process of the real-time compensation scheme.

9. The method according to claim 8, wherein the step S303 is performed by measuring the perpendicularity error between the axes again after the real-time compensation of the perpendicularity error is performed by the real-time compensation scheme monitoring and adjusting compensation process, and comparing the measured result with the measurement result when the perpendicularity error is not compensated, and if the difference between the measured result and the measured result does not meet the requirement, the step S303 is skipped to readjust the real-time compensation scheme and optimize the real-time compensation.

10. The method of applying the motion-precision-compensated cylindrical coordinate profile scanning measuring apparatus as claimed in claim 6, wherein the step S102 of monitoring radial runout and end runout generated by the stage (13) during rotation by the motion error sensor (12) and compensating comprises:

Step S401, collecting small changes of the position of the object table (13) into an electrical signal through a motion error sensor (12) caused by radial runout and end surface runout of the first turntable (11) when the first turntable (11) under the object table (13) rotates, and preprocessing through an amplifier and a filter;

Step S402, dynamically adjusting the rotating speed of the first rotary table (11) through a preset closed-loop control algorithm to offset the influence of radial runout and end runout of the first rotary table (11) on measurement.