CN101655356A - Graduation device for detecting surface shape of aspheric optical element - Google Patents

Abstract

An indexing device for detecting the surface shape of an aspheric optical element relates to an indexing device for precisely controlling the rotation angle displacement. An indexing device for detecting the surface shape of an aspheric optical element that can provide real-time feedback, compensate for the amount of movement, and realize precise control of angular displacement is provided. Including control system and indexing device, the control system is equipped with industrial computer, interface circuit board, servo amplifier, servo motor, angle encoder and encoder digital display table. The indexing device is provided with a base, an upper bearing seat, a main shaft, a motor seat, a deep groove ball bearing, a main shaft synchronous belt pulley, a motor synchronous belt pulley, a synchronous belt, a rotating disk and a fixture.

Description

Indexing device for surface shape detection of aspheric optical elements

technical field

The invention relates to an indexing device for precisely controlling the rotation angle displacement, in particular to an indexing device for detecting the surface shape of an aspheric optical element.

Background technique

The development of precision and ultra-precision machining has directly affected the development of cutting-edge technology and the defense industry. Countries around the world have invested a lot of manpower and material resources in the development and research of precision and ultra-precision technology (see literature: Yuan Guojun. The latest progress in precision machining technology at home and abroad; Tool Technology, 2008, 42(10): 5-13). In recent years, many precision and ultra-precision turning, grinding, polishing and other machine tool equipment have been developed at home and abroad, and new precision machining technology and precision measurement technology have been developed. Multi-axis and multi-degree-of-freedom precision machining and testing equipment have also emerged as the times require, and in precision and ultra-precision machining and testing equipment, the accuracy of the rotary axis is also continuously improving with the requirements of manufacturing accuracy. The traditional CNC rotary mechanism generally uses a worm gear mechanism or an arc-shaped cam mechanism with wire meshing as the driving device, lacking feedback compensation, and the positioning accuracy is increasingly unable to meet the requirements of precision and ultra-precision machining.

With the development of precision and ultra-precision machining and testing technology, grating scales, as a tool for precision measurement, have been widely used in the fields of precision instruments, coordinate measurement, precision positioning and high-precision precision machining. The grating ruler refers to a grating sensor composed of a light source, two gratings (indicating grating and scale grating) and photoelectric detection devices. The grating ruler can be divided into straight grating and circular grating. The grating ruler has the advantages of high sensitivity, high resolution, corrosion resistance, anti-electromagnetic interference, good stability and high reliability. Its wide application greatly improves the control and positioning accuracy.

Shaanxi University of Science and Technology has provided a horizontal thin-type point-engagement cam mechanism CNC rotary table with the publication number CN 1907645A, including a base and an indexing shaft with bearings. The indexing shaft is set on the base through the bearings. On the base, an index plate connected to the index shaft is also provided, and a spherical tapered roller is arranged on the outside of the index plate, and the spherical tapered roller is engaged with the arc cam arranged in the base. The invention adopts controllable point meshing contact, and when the profile surface of the spherical cone roller and the cam profile surface of the arc surface are driven without backlash, the adaptability of the mechanism to position error and shape error can be improved. The point-meshing spherical tapered roller cam mechanism is easy to achieve high-speed and high-precision requirements, has a long service life, high positioning accuracy, simple manufacturing process, and relatively low requirements for processing and assembly accuracy, accurate indexing, and is not affected by the number of rollers. It can be pre-tightened, convenient to eliminate gaps, high load-bearing capacity, and low temperature rise.

Contents of the invention

The purpose of the present invention is to provide an aspheric surface that can provide real-time feedback, compensation of motion, and precise control of angular displacement in view of the problems of the existing CNC rotary table, such as low control accuracy, low positioning accuracy, lack of information feedback, and no error compensation. Indexing device for surface shape detection of optical components.

The technical solution of the present invention is to combine the servo motor and the angle encoder into the indexing device, drive the angle encoder through the servo motor, and collect, feed back and compensate the angular displacement in real time by the angle encoder.

The invention includes two parts, a control system and an indexing device.

The control system is equipped with industrial computer, interface circuit board, servo amplifier, servo motor, angle encoder and encoder digital display table. The motion controller of the industrial computer is installed in the PCI slot of the IPC and connected to the servo amplifier through the interface circuit board. The input end is connected, the output end of the servo amplifier is connected to the servo motor, and the angle encoder used to generate the angle shift signal is driven by the servo motor. The data output end of the angle encoder is connected to the input end of the encoder digital display meter, and the encoder digital display meter The output end is connected to the RS-232-C interface of the industrial computer, and the entire control system forms a closed-loop feedback system.

The indexing device is equipped with a base, an upper bearing seat, a main shaft, a motor base, a deep groove ball bearing, a main shaft synchronous pulley, a motor synchronous pulley, a synchronous belt, a rotating disc and a fixture, and the angle encoder of the control system is installed on the base. After the main shaft is fixed on the hollow shaft of the angle encoder, the main shaft is inserted into the inner hole of the deep groove ball bearing; the deep groove ball bearing is connected to the upper bearing seat, and then the upper bearing seat is integrated with the base, and the servo motor is installed on the motor seat , The motor synchronous pulley is installed on the shaft of the servo motor, the motor synchronous pulley is connected with the main shaft synchronous pulley on the main shaft through the synchronous belt, and drives the main shaft to move, so as to realize the relative rotation of the circular grating in the angle encoder. The rotating disk is installed on the main shaft and is driven to rotate by the main shaft. The rotating disk is equipped with a fixture for fixing the workpiece to be processed and tested.

The measurement reference of the angle encoder is a circular grating ruler, which adopts the principle of photoelectric scanning. The photoelectric scanning of the grating scale is non-contact and frictionless. Set the angle output range of the angle encoder to 0°～360°, and the positioning accuracy can reach arc-second level. The angle encoder has built-in bearings, and the accuracy of the system is ±1". When measuring, the main shaft can be directly connected to the shaft of the angle encoder. The angular displacement value is directly input into the encoder digital display table, and directly displayed on the encoder digital display table , and input the industrial computer. The resolution of the encoder digital display can reach 0.0001°.

The main shaft is fixed on the hollow shaft of the angle encoder, preferably the main shaft is fixed on the hollow shaft of the angle encoder by screws.

When controlling, the user inputs information such as control parameters and target positions to the industrial computer through the interface, writes the command program, sends control pulses to the servo motor to drive the servo motor to move, drives the main shaft and the hollow shaft of the angle encoder to move together, and the angle encoder generates an angle. The displacement signal is output to the digital display meter of the encoder, and the angular displacement signal is sent to the industrial computer while being displayed on the digital display meter of the encoder. The actual angular displacement is constantly compared and compensated with the target angular displacement until the set accuracy is reached.

The drive mode of the angle encoder is a servo motor driven pulley structure, and the pulley is a synchronous pulley structure.

The rotating disc is made of granite, which has the advantages of small deformation, good stability, high strength and high hardness, and can maintain high precision under heavy load and normal temperature.

There are two fixtures, which are used to fix the workpiece to be processed and tested. The clamping part of the single fixture has an included angle of 120°, and the distance between the two fixtures is adjustable. Fixtures can hold workpieces of various shapes and sizes.

The invention measures the angular displacement through the circular grating, has high precision and small structure, and is suitable for the processing and detection of small workpieces; the whole structure and control system are simple, convenient, relatively independent, and can be used in conjunction with other equipment. It is widely used and has the advantages of High feasibility.

Description of drawings

FIG. 1 is a block diagram of the structure and composition of the control system of the embodiment of the present invention.

Fig. 2 is a schematic diagram of the structure and composition of the indexing device according to the embodiment of the present invention.

Fig. 3 is a top view of the structure of the embodiment of the present invention.

Detailed ways

The present invention will be further described below by means of embodiments in conjunction with the accompanying drawings.

The embodiments of the present invention basically include two parts: a control system and an indexing device.

Referring to Fig. 1, the control system is provided with an industrial computer A1, an interface circuit board A2, a servo amplifier A3, a servo motor A4, an angle encoder A5 and an encoder digital display meter A6. The motion controller of the industrial computer A1 is installed in the PCI slot of the IPC, connected to the input terminal of the servo amplifier A3 through the interface circuit board A2, the output terminal of the servo amplifier A3 is connected to the servo motor A4, and the angle encoder A5 is driven by the servo motor A4 , the data output end of the angle encoder A5 is connected to the input end of the encoder digital display meter A6, and the output end of the encoder digital display meter A6 is connected to the RS-232-C interface of the industrial computer A1. The whole control system forms a closed-loop feedback system.

Referring to Figures 2 and 3, the indexing device is provided with a base 1, an upper bearing seat 2, a main shaft 3, a deep groove ball bearing 4, a main shaft timing pulley 5, a motor base 6, a motor timing pulley 7, a timing belt 8, and a rotating disk 9 and clamp 10. The angle encoder A5 is mounted on the base 1, the main shaft 3 is fixed on the hollow shaft of the angle encoder A5 by screws, and then the main shaft is inserted into the inner hole of the deep groove ball bearing 4, and the deep groove ball bearing 4 is fitted on the upper bearing seat 2 , and then the upper bearing seat 2 is integrated with the base 1, and the angle encoder A5 is contained inside to form a protection to prevent it from being damaged. The transmission relationship between the servo motor A4 and the main shaft 3 is as follows: the servo motor A4 is installed on the motor base 6, the motor synchronous pulley 7 is installed on the rotating shaft of the servo motor A4, and the motor synchronous pulley 7 is synchronized with the main shaft on the main shaft 3 through the synchronous belt 8 The belt pulley 5 is connected and drives the main shaft 3 to move to realize the relative rotation of the circular grating in the angle encoder A5. The rotating disk 9 is installed on the main shaft 3 and is driven to rotate by the main shaft 3. Two clamps 0 are installed on the rotating disk 9 to fix the workpiece.

During control, the user inputs information such as control parameters and target angular displacement to the industrial computer A1 through the interface, writes an instruction program, sends control pulses to the servo motor A4 to drive the servo motor A4 to move, and drives the spindle 3 and the hollow shaft of the angle encoder A5 to move together , the angle encoder A5 generates an angular displacement signal, which is output to the encoder digital display meter A6, and the angular displacement is sent to the industrial computer A1 while being displayed on the encoder digital display meter A6. The actual angular displacement is continuously compared with the target angular displacement until the set accuracy is achieved.

In this embodiment, a circular grating scale is used in the angle encoder, the number of engraved lines is 36000, and the accuracy of the system is ±1". The angle encoder has a built-in bearing, a built-in stator coupling and a hollow shaft. Set the angle code The angle output range of the encoder is 0°～360°, and the positioning accuracy can reach the second arc level. When measuring, the main shaft can be directly connected with the axis of the angle encoder. The angular displacement value is directly input into the encoder digital display table, and the encoder digital display It can be directly displayed on the meter and input into the industrial computer. The resolution of the encoder digital display meter can reach 0.0001°. The angle encoder can be a HEIDENHAIN encoder.

The drive mode of the angle encoder is a servo motor driven pulley structure, and the pulley is a T-shaped synchronous pulley structure.

In the embodiment of the present invention, the servo motor adopts the servo motor produced by Fuji Electric Co., Ltd.

Claims (5)

1. be used for the dividing apparatus that aspheric optical element surface shape detects, it is characterized in that comprising control system and dividing apparatus two parts;

Control system is provided with industrial computer, interface card, servoamplifier, servomotor, angular encoder and scrambler digital display meter, the motion controller of industrial computer is installed in the PCI slot of IPC and through interface card and links to each other with the input end of servoamplifier, the output servo motor termination of servoamplifier, the angular encoder that is used to produce the angular misalignment signal by driven by servomotor, the data output end of angular encoder links to each other with scrambler digital display meter input end, and scrambler digital display meter output terminal inserts the RS-232-C interface of industrial computer;

Dividing apparatus is provided with base, top chock, main shaft, motor cabinet, deep groove ball bearing, main shaft synchronous pulley, motor synchronous belt wheel, synchronous band, rotating disc and anchor clamps, the angular encoder of control system is contained on the base, after main shaft was fixed on the tubular shaft of angular encoder, main shaft inserted the deep groove ball bearing endoporus; Deep groove ball bearing connects at top chock, again top chock and base are dressed up one, servomotor is contained on the motor cabinet, the motor synchronous belt wheel is contained in the rotating shaft of servomotor, the motor synchronous belt wheel passes through to be with synchronously the main shaft synchronous pulley with on the main shaft to link to each other, and drives motion of main shaft, and rotating disc is installed on the main shaft, by the main shaft driven rotary, anchor clamps are contained on the rotating disc.

2. the dividing apparatus that is used for the aspheric optical element surface shape detection as claimed in claim 1, the angle output area that it is characterized in that described angular encoder is 0 °～360 °.

3. the dividing apparatus that is used for the aspheric optical element surface shape detection as claimed in claim 1 or 2 is characterized in that described angular encoder has built-in bearing.

4. as claimed in claim 1ly be used for the dividing apparatus that aspheric optical element surface shape detects, it is characterized in that described main shaft by screw retention on the tubular shaft of angular encoder.

5. the dividing apparatus that is used for the aspheric optical element surface shape detection as claimed in claim 1 is characterized in that the retained part of described anchor clamps has 120 ° of angles.

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