Each machine tool includes one or more drive chains. The measurement of the drive chain error is to measure the deviation between the actual motion of the two ends of the drive chain and the theoretical requirements. There are many ways to measure the error of the drive train. From the overall analysis, the previous measurement methods have the following shortcomings: 1 The instrument has strong specificity and poor flexibility. An instrument can often only measure a limited and limited variety of drive chains. When the transmission mode changes or the transmission ratio is irrational, special measurement components are required. When it is necessary to add functions or modify existing functions, it is often limited by the circuit hardware. 2 The instrument has limited error handling function. The instrument is limited by the hardware circuit. It is impossible to store the sampled data in large quantities and perform post-processing on the measured data in time. In order to analyze and describe the measurement process in real time through graphical means, manual processing is required.
1 Main research direction With the development of computer technology, a general-purpose high-precision machine tool transmission chain error comprehensive measurement system is developed. With the microcomputer as the core, a high-performance software package is developed, which cooperates with other peripheral devices to meet various types of transmissions in principle. The measurement of the chain's comprehensive error.
Week) High-precision data acquisition and counting card (64-bit word length), which realizes data acquisition, conversion, and buffer functions, and serves as an interface between the microcomputer and the drive chain. ) Measurement data storage, query, printing and other functions.
2 system structure and principle 2.1 system structure error measurement system consists of DC motor speed control driver, grating frequency multiplier, computer + counting card, printer. See the connection block diagram.
Each part of the function introduction: DC motor speed control drive: drive the speed reducer according to the desired direction of rotation and speed.
The circular grating measuring device is respectively connected with the driving shaft and the driven shaft of the speed reducer, and outputs a sinusoidal waveform corresponding to the rotating angle according to the rotating angle of the driving shaft and the driven shaft of the speed reducer. The circular grating A is 10800 lines/rotation, and the circular grating B is 10800 lines/rotation.
: Converts the sine wave output from the circular grating into a square wave and multiplies it to output to the computer. The A-end frequency multiplier is 5 times the frequency, and the B-end frequency multiplier is 5 times.
Computer counting card: Filters the input circular grating pulse signal, 4 times the frequency, and counts. (4-bit word length) error processing software package: Collect A and B measurement data and calculate the error.
2.2 System principle (1) Resolution: 渺 / pulse) One pulse equivalent) () Transmission chain error analysis principle: Transmission chain error refers to the difference between the theoretical rotation angle of the driven shaft and the actual rotation angle. Theoretical rotation angle: According to the system structure, set the reduction ratio of the reducer to 6, the rotation angle of the drive shaft A, and the rotation angle B of the driven shaft according to the transmission chain. Formula 1: Shake) Actual rotation angle: Since the reducer and the circular grating are rigidly connected directly Mode, different rotation angles, the circular grating will output the corresponding number of pulses, set the drive shaft rotation angle to A, then the circular grating output pulse number A1, the slave axis rotation angle is B, the grating output pulse number B1, then the computer receives the A The number of pulses of B and B is calculated according to the following formula: the number of pulses = the number of pulses output by the circular grating xEXE multiplier) the number of times of counting cards.
Let the number of pulses of the A channel be N-, and the number of pulses of the B channel be N. Actually, according to the formula 2: When the driving shaft and the driven shaft rotate one revolution: the error pulse calculation: Nb theory - Nb actual error angle calculation: 6) Computer measurement process: In order to ensure measurement accuracy, the computer uses interrupt technology. When the computer counter reaches the sampling interval, the computer automatically enters the interrupt service routine. The interrupt service program checks the actual position and theoretical position of the slave axis, and collects, calculates and stores the data. The drive chain error of the point is returned to the main program after waiting for the next interval. When the driven axle rotates for one cycle, the test process ends.
6) Free-range measurement and calculation: refers to the measurement of the gap generated when the gears mesh with each other. When measuring the lost motion, the reducer first rotates forward for several revolutions, eliminates the forward gear gap, and then slowly rotates from the stop state to the reverse direction. Due to the existence of the reverse gear gap, the driven shaft circular grating starts to have no pulse output. After the backlash of the gear is eliminated, the driven shaft grating starts to have a continuous pulse output. At this time, the angle at which the driving shaft rotates is converted to the slave axis, which is the lost motion angle.
During the measurement process, the computer first observes the master axis. When the master axis has a continuous pulse output in the reverse direction, it indicates that it begins to enter the measurement idle phase. When the slave axis has continuous pulse output, it enters the idle calculation program and the test process ends.
3 system error analysis system error refers to the error caused by the displacement signal sensor to the error calculation output process. According to it, the transmission chain error 'is output through the sensor, EXE, buffer counter, computer time-sharing reading and computer calculation. Therefore, the source of systematic error should be analyzed from the following aspects: 3.1 Sensor error In this project, the error of the sensor is not only the error of the circular grating angle measuring device, but it has been proved by a large number of tests and test analysis that the error is 6". Detailed, specific detection methods and measurement data have been given in the submitted grating measuring device detection method and measurement accuracy report.
Because the electronic logic digital operation circuit used by EXE itself converts the signal waveform into a square wave to a square wave and multiplier 6 times, there is no error in the conversion and frequency multiplication process. For detailed technical specifications, see the CAAS-Grating Frequency Multiplier Instruction Manual.
3.3 Counter error The grating signal acquisition card used in this project is a fifth-generation grating signal acquisition card designed for years of experience in the acquisition of grating signal acquisition of CMM. It uses COMSâ–¡ array circuit and grating pulse signal four. Multiplier, count. There is no error in principle. The counter uses the 8253 programmable counter/timer to count the three raster pulses simultaneously. An 8259 programmable interrupt controller uses interrupt processing for the absolute zero signal, alarm signal, and clear signal of the three inputs. The card is equipped with a long-line receiver MC3%8=, which is used to enhance the long-line driving capability and anti-interference ability of the grating signal.
3.4 Computer reading error reading error refers to the computer reading the counter value in a time-sharing manner, first read the road and then read the 'road, although the computer speed is very high 6/0;), it may still bring a pulse error 6〃) .
3.5 Computer calculation error formulas 2 and 8 are the basis of the transmission chain comprehensive error measurement system. In order to calculate the transmission chain error, we use a double-byte floating-point storage area of ​​62-bit word length), and store the floating formulas calculated by Equations 2 and 8. Points. Even so. Since the transmission ratio 5 is an irrational number, there is a possibility of rounding error. The error is within 6" of a pulse equivalent. Because the system error = brick sensor error 2> computer time-sharing reading error > computer operation error 2) 12, the systematic theoretical analysis error is basically consistent with the measured result, and the systematic error is less than 12 second.
4 Conclusion High-precision machine tool drive chain error comprehensive measurement down page 34) Edit the data. 6 Provides a general method of detecting errors.
However, AD0 is very flexible and can only use a part of the model as needed.
When accessing data in the AD0 recordset, since all elements in the AD0 record set are of type variant, they must be converted. You can use the AD0 macro to create a data binding interface for the recordset. Since the IAD0RecordBinding interface does not have a method for deleting records, you need to delete the records by using the Delete (AffectRecord) method of the recordset smart pointer.
3.3 Client User Interface Design According to the requirements of system planning, the client application interface should display many reports, and each report view is connected to one or more SQL tables, and has corresponding operation commands for management. According to ergonomics theory, the client user interface should be friendly and easy to operate. To do this, we use VC++'s multiview programming capabilities to create a view for each report.
The corresponding work view can be popped up at any time as needed. The specific design is as follows: divide the screen into two areas, create a first view area on the left side of the screen, as a work area, to control the display content of the second view; create a second view area on the right side as a management operation area, which is VC++ Split window technology and derive two CFormYiew view classes to compose.
The management operation area view is used to display data reports. There are many ways to implement them. However, in order to get friendly interaction and user-friendly interface, a customized report control is designed, which has a user-definable header. Table footer and table body.
4 Conclusions This paper introduces the planning and development process of supply management software based on the planning and development process of supply management software based on AD0. The developed supply management software system is based on a two-tier client/server structured database model with a friendly user interface and good database access performance. Through the practical application in a factory, the software has the advantages of stable and reliable, fast running speed and easy operation, which is welcomed by users.
(Finish)
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