CN101559513B - Welding track detection and control method of container corrugated plate based on laser ranging - Google Patents

Abstract

The invention relates to a welding track detection and control method of a container corrugated plate based on laser ranging, including the following steps: A. track detection is carried out; B. trackidentification is carried out; C. track control is carried out; D. the relative position relation between a welding gun and a welding seam is adjusted at last by performing mechanism actions. In the invention, the information of welding seam is obtained by a laser displacement sensor, and track fitting is carried out after effective wave filtering treatment to realize track detection; simultaneously, the problem of track detection and control in automatic welding of the container corrugated plate is fundamentally solved by combining track interpolation algorithm of a minimum deviation method.The invention further explains the smooth conversion of welding parameters of inflection points in detail, and proposes an adjustable inflection point parameter conversion method in smooth degree. In the filed test welding by using the method in the invention, the track tracking effect reaches intended goal, thereby improving the welding quality and welding efficiency of the container corrugated plate, and improving the labor environment.

Description

Container corrugated plate welding track Detection ﹠ Controling method based on laser ranging

Technical field

The present invention relates to a kind of Detection ﹠ Controling method, especially a kind of container corrugated plate welding track Detection ﹠ Controling method based on laser ranging.

Background technology

At present, the research of welding track control technology is to weld one of the emphasis of industrial technology research and difficult point, studies the forward position both at home and abroad and mainly concentrates on following aspect: one, welding track information sensing technology; Two, Trajectory Tracking Control theory and algorithm.In automatic welding process, accurately detecting the variation of obtaining weld seam is the key that guarantees welding quality, and the sensor technology that wherein is used for weld joint tracking is more and more important.In the research and development of welding track detection technique, various multi-form sensors have appearred successively, and wherein touch sensor, arc sensor and optical pickocff are used comparatively general.Touch sensor is the change in location of guide rod or guide wheel with the weld seam change transitions, and being converted into the signal of telecommunication, this sensor once was used widely aborning owing to stable performance, with low cost, but because the restriction of tracking accuracy and speed, high accuracy, high-speed welding field have been not suitable for; Arc sensor is a tracking target with the parameter of electric arc itself, can change by the real time reaction weld seam, but the influence that accuracy of detection is subject to mode of metal transfer in the welding process, splashes, especially in the welding to the butt joint of thin plate weldment and lap joint, application process is difficult to be grasped.Optical pickocff causes people's attention gradually with characteristics such as acquired information are abundant, accuracy is high, detection range is wide by contrast, and has obtained day by day using widely at the welding production field, and this realization for Automation of Welding provides advantage.What application was more in the optical pickocff is laser sensor, infrared sensor, vision sensor etc., adopt modernized image sensing apparatus and intelligentized image processing methods such as ccd video camera, infrared thermoviewer, provide assurance for accurately obtaining weld seam information, further guaranteed the stability and the reliability of welding process.While, the intelligent weld seam detection tracking system of Chan Shenging made the research of welding track automatic control technology enter into a brand-new stage on this basis along with the continuous replacement upgrading of microprocessor technology, numerous high-performance microprocessors emerges in large numbers.

Summary of the invention

The objective of the invention is for overcoming above-mentioned the deficiencies in the prior art, a kind of container corrugated plate welding track Detection ﹠ Controling method based on laser ranging is provided.

For achieving the above object, the present invention adopts following technical proposals:

A kind of container corrugated plate welding track Detection ﹠ Controling method based on laser ranging may further comprise the steps:

A. carry out track detection; Behind the system initialization, horizontal feed starts as the active feed shaft, detects the ripple track of corrugated plating in real time by the laser accurate displacement transducer, and detected weld seam initial information data are sent to microprocessor, and image data is carried out filtering, storage;

B. carry out track identification; By microprocessor data signal is handled, extracted the information of weld seam, whether the flex point judge module is flex point constantly discerning current location simultaneously, and promptly horizontal segment is differentiated with the tie point of go up a slope section, lower slope section; Flex point then guarantees welding quality by change weldingvoltage, welding current, speed of welding, startup swing control in this way;

C. carry out TRAJECTORY CONTROL; Differentiate the result by microprocessor according to corrugated plating change in location that detects and flex point,, track is carried out interpolation operation, each reference axis is controlled in real time based on track data;

D. move at last and regulate relative position relation between welding gun and the weld seam, promptly do up-down adjustment, thereby reach the purpose of weld joint tracking with driven by motor lifting shaft leading screw by executing agency; In the whole system running, the welding voltage and current is shown in real time.

Passing through in the described steps A adopted the non-contact detecting mode when laser accurate displacement transducer detects the ripple rail of corrugated plating in real time.

Horizontal segment, the section of going up a slope and lower slope section welding condition are independent the setting among the described step B.

Horizontal segment, go up a slope section and the level and smooth conversion and control of lower slope section welding condition among the described step B.

The differentiation of flex point specifically by judging the size of image data point departure degree, distinguish the data point that belongs to different slopes section, is carried out linear fit in the section then among the described step B under separately.

The present invention obtains the information of weld seam by laser sensor, after handling, carry out track fitting through effective filtering, realize the detection of track, simultaneously in conjunction with the track interpolation algorithm of minimum deviation method, the track detection that fundamentally solves in the automatic welding of corrugated plating is controlled this problem.The present invention has also carried out in detail explanation to the level and smooth conversion of the welding parameter of flex point, and has proposed the adjustable flex point parameter transformation method of level and smooth degree.Through adopting the on-the-spot test weld of method of the present invention, the track following effect has reached the set goal, has improved container corrugated plate welding quality and welding efficiency, has improved work situation; The TRAJECTORY CONTROL precision is less than 0.2mm; Speed of welding is more than 3 times of manual welding; Weld seam smoothness height, uniform in shaping, high conformity; The man-machine interaction close friend, line operating personnel only need simple operations can realize automatic welding.

Description of drawings

Fig. 1 is an overview flow chart of the present invention;

Fig. 2 is that functional parameter is selected the setting program flow process;

Fig. 3 is corrugated plating acquired original data point distribution figure;

Fig. 4 is data point distribution figure behind the medium filtering;

Fig. 5 is data point distribution figure behind the glide filter;

Fig. 6 is data point distribution figure behind the adaptive-filtering;

Fig. 7 is a slip variance distribution map;

Fig. 8 is the fitting a straight line figure of upward slope section;

Fig. 9 is sectional linear fitting figure;

Figure 10 is that weldingvoltage seamlessly transits procedure chart;

Figure 11 is that welding current seamlessly transits procedure chart;

Figure 12 is that speed of welding seamlessly transits procedure chart;

Figure 13 is the interpolation direction of feed figure that is scheduled to;

Figure 14 is the interpolation trajectory diagram that adopts minimum deviation method.

The specific embodiment

The present invention is further described below in conjunction with drawings and Examples.

A kind of container corrugated plate welding track Detection ﹠ Controling method based on laser ranging may further comprise the steps:

A. carry out track detection; Behind the system initialization, horizontal feed starts as the active feed shaft, detects the ripple track of corrugated plating in real time by the laser accurate displacement transducer, and detected weld seam initial information data are sent to microprocessor, and image data is carried out filtering, storage;

B. carry out track identification; By microprocessor data signal is handled, extracted the information of weld seam, whether the flex point judge module is flex point constantly discerning current location simultaneously, and promptly horizontal segment is differentiated with the tie point of go up a slope section, lower slope section; Flex point then guarantees welding quality by change weldingvoltage, welding current, speed of welding, startup swing control in this way;

C. carry out TRAJECTORY CONTROL; Differentiate the result by microprocessor according to corrugated plating change in location that detects and flex point,, track is carried out interpolation operation, each reference axis is controlled in real time based on track data;

D. move at last and regulate relative position relation between welding gun and the weld seam, promptly do up-down adjustment, thereby reach the purpose of weld joint tracking with driven by motor lifting shaft leading screw by executing agency; In the whole system running, the welding voltage and current is shown in real time.

Passing through in the described steps A adopted the non-contact detecting mode when laser accurate displacement transducer detects the ripple rail of corrugated plating in real time.

Horizontal segment, the section of going up a slope and lower slope section welding condition are independent the setting among the described step B.

Horizontal segment, go up a slope section and the level and smooth conversion and control of lower slope section welding condition among the described step B.

The differentiation of flex point specifically by judging the size of image data point departure degree, distinguish the data point that belongs to different slopes section, is carried out linear fit in the section then among the described step B under separately.

1. program overall procedure

At first behind the system initialization, horizontal feed starts as the active feed shaft, the data acquisition module BOB(beginning of block) is gathered the ripple track, to image data carry out filtering, the storage after, based on this track data, track is carried out interpolation operation, and drive motors is done corresponding adjustment, whether the flex point judge module is flex point constantly discerning current location simultaneously, and flex point then waits and guarantees welding quality by change weldingvoltage, welding current, speed of welding, startup swing control in this way.In the whole system running, weldingvoltage, electric current have been carried out real-time demonstration.As shown in Figure 1.

Program organization realizes

1). the parameter setting

Utilize the microswitch of encoder to select parameter, when being function 1 by next time the time, pressing at twice o'clock is function 2 ... parameter declaration information and parameter value show on charactron simultaneously, when left-handed/during dextrorotation encoder handle, can realize the size adjustment of data, after the parameter adjustment, if do not do any operation at parameter adjusting interface in 5 seconds, parameter is regulated pattern and is withdrawed from automatically, simultaneously the parameter that changes is deposited in the EEPROM of single-chip microcomputer.As shown in Figure 2.

2). communication module

System is in the whole service process, need constantly communicate by letter with welding machine: the welding machine initialize communications, start/stop welding machine, the conversion of welding conditions etc., with the welding machine initialize communications be after system powers on, to gage of wire, weld information such as solid welding wire, welding machine control mode is provided with; Want butt welding machine to send startup/halt instruction in welding beginning and end; In welding process, need the conversion welding conditions as the section of going up a slope, then need to control the conversion that welding machine is accurately realized weldingvoltage, electric current.This shows in the whole system running, to the accuracy of communication, ageing having relatively high expectations, this will realisticly show the handshake communication of system and welding machine so that transmission information is confirmed in program implement, as accepting data when welding machine, and verification is correct, then postbacks confirmation of system, if welding machine is to accepting the data check mistake, then postback information that requires repeating transmission of system, this kind postbacks affirmation mechanism and improved the final accuracy of accepting of information.

In concrete traffic operation process, there is multiple implementation, promptly adopt inquiry mode from USART transmission/reception data as minor function, inquiry mode not only efficient is low, and the meeting obliterated data, can not realize the parallel processing of multitask, reduce the efficient of system.

For the vacant time in the transmission and the acceptance of data, the computing and the processing that system can be walked abreast carry out other, simultaneously in order to improve the reliability of communication, adopted two interruptions+double buffering mode to realize the mode of high-speed asynchronous serial communication in the program, make full use of high speed and the big advantage of ram space of AVR, embodied the programming thought of advantages.

Adopt the reception of two 16 bytes and the operational efficiency that transmission buffer improves MCU, when main program calls transmission data subprogram, if it is not idle that USART sends mouth, when promptly sending data, then data to be sent are put into transmission buffer, MCU needn't wait for that current transmission finishes, and can transfer to continue to carry out other task.After the hardware of USART sends data, can produce one and be sent completely interruption, in interrupt service routine, data in the transmission buffer are sent successively again; When main program calls when accepting data, if receiving data port, USART accepting data, and MCU can't obtain complete desired data, and this moment, MCU also needn't wait for the end of current reception process, can continue to carry out other task.After the hardware of USART is put into reception buffer with data to be received, and the reception data are finished, can produce an acceptance and finish interruption, in interrupt service routine, data in the buffer are offered main program and use.This communication modes provides guarantee for the reliable and stable transmission data of system.

3). display module

Adopt the hardware display circuit that charactron drives and control chip CH451 builds,, need the abundant support of program code, except carrying out also needing calling of correlation function the initialization to it although circuit is comparatively simple on connecting.After the CH451 electrification reset, single-chip microcomputer must be before DCLK exports serial clock, and an output low level pulse (become low level by high level and revert to high level again) on DIN notifies CH451 to enable its serial line interface earlier.

DCLK is used to provide transfer of data required serial clock, and CH451 receives data at the rising edge of DCLK pulse train from DIN, exports data at its trailing edge from DOUT, and this paper only needs a slice CH451 to satisfy the demands, so the DOUT pin is not used.CH451 is inner, and what adopt is that 12 shift register receives data, and at the rising edge of DCLK pulse train, the one digit number on the DIN pin is according to being moved into the highest of shift register.CH451 allows serial clock frequency by the input of DCLK pin more than 10MHz, to guarantee to realize serial input-output operation at a high speed.

4). the data filtering module

Owing to have the various interference that can not expect in the running environment of system, welding process is very complicated, disturb as arc light, electromagnetic interference, mechanical oscillation etc. all can exert an influence to the operation result of system, especially obvious especially at collection corrugated plating Wave data noise, as it not being added certain processing, sometimes or even can not discern the ripple track, generation for fear of this phenomenon, need externally adopt hardware circuit to carry out filtering, usually also need by capture program data to be carried out supple-settlement, method commonly used has: the limit filtration method, median filtering method, the arithmetic average filter method, moving average filter method etc.; The limit filtration method is rule of thumb to judge the maximum deflection difference value e that is allowed between definite double sampling value, whether the absolute value delta of difference of judging this sub-value and last sub-value when detecting next new value is smaller or equal to e, as satisfying Δ≤e, then detected new sampled value is effective.As Δ 〉=e, then detected new sampled value is invalid, abandons this value, uses sub-value and replaces this sampled value, and this filtering mode can effectively overcome the spike that causes because of accidentalia to be disturbed, but to the inhibition ability of PERIODIC INTERFERENCE.Median filtering method at first puts in order continuous sampling N time (N generally is taken as odd number) sampled value by size, gets median and is this virtual value.This filtering mode can effectively overcome the fluctuation that causes because of accidentalia to be disturbed, to the variation of temperature, liquid level slowly measured parameter good filtering effect is arranged.But it is unsuitable to fast-changing parameters such as flow, speed.The arithmetic average filter method is that a N continuous sampled value is carried out the arithmetic average computing.Choosing signal smoothing degree, sensitivity of N is all influential, the actual use needs according to actual conditions choosing of N to be chosen N, this filtering mode is applicable to that the signal to generally having random disturbances carries out filtering, the characteristics of signal are that a mean value is arranged like this, signal is fluctuation up and down near a certain number range, inapplicable for requiring the data computation processing speed to control in real time faster, when relatively wasting machine.The moving average filter method is to regard a formation as getting N sampled value continuously, the length of formation is fixed as N (chosen in advance), the value that is obtained of at every turn sampling is pressed into formation, be about to new data and put into tail of the queue, and lose data of original head of the queue, then the data of the N in the formation are carried out the arithmetic average computing, obtain new filter value, this filtering mode has good inhibition effect to PERIODIC INTERFERENCE, and the smoothness height is applicable to the system of the higher-order of oscillation.But sensitivity is low, and is relatively poor to the inhibitory action that the accidental pulse feature that occurs disturbs, and is difficult for eliminating because the caused sampled value deviation of impulse disturbances.

The filtering mode that the present invention adopts has taken into full account the existing pluses and minuses of above-mentioned filtering mode, and main source that disturbs in the coupling system running and variation, carried out following adaptive-filtering processing to gathering the data of coming: the new data that at every turn samples is carried out amplitude limiting processing earlier; A filtering interval [d is set ₁, d ₂, d ₃... d _k], its length is k, d _iRepresent current sampled value.The sample variance value in calculation of filtered interval is with each calculated value and predefined filtering algorithm identification threshold values K _Sliding, K _In, K _CalculateCompare: in current filtering interval,, select automatically to adopt different filtering modes, promptly selected moving average filter processing, medium filtering, arithmetic average filter method respectively for use according to the difference of the interval sample variance value of filtering.Because comparatively obvious in the variation of ascents and descents segment data, in order to obtain higher sensitivity, when the interval variance yields of filtering was big, the value of N was suitably got littler.

As seen from Figure 3, raw data points contains obvious noise, can not directly apply to the judgement and the motion control of flex point, is track detection and the control that guarantees accurately to realize, must carry out filtering and handle.

Below be adaptive filter algorithm of the present invention with simple adopt median filtering algorithm, merely adopt behind the moving average filter algorithm filtering data point distribution map.

From Fig. 4 we as can be seen, the smooth effect of data is not fine behind the medium filtering, the phenomenon that exists data point to lose on the section of slope simultaneously, but medium filtering can meet the demands at the horizontal segment filter effect.

As shown in Figure 5, data distribute more steadily on slope section behind the moving average filter, and filter effect is better, but near section junction, slope (flex point), the corner angle loss in detail is serious, brings difficulty for the identification of flex point.

As shown in Figure 6, the corner angle part general performance that adaptive filter algorithm reaches in flex point on the section of slope goes out filtering feature preferably, for the basis has been carried out in further flex point identification.

2. the match of welding gun track

In experiment and exploration, usually can produce a large amount of measurement data.In order to make analysis, prediction according to these data and to judge, important execution foundation is provided for policymaker and executing agency, need carry out match to the gained measurement data, promptly seek the function of a reflection data variation rule.As given one group of orderly data point P _i, i=0,1,2 ..., n, these points can measure in shape from certain, also can be that the designer provides.Require curve of structure in proper order by these data points, be called these data points are carried out interpolation (interpolation), the curve of being constructed is called interpolation curve.Construct a curve and make it under certain meaning the most curve near structure and be called and approach (approximation), the curve of being constructed is called approximating curve.Data fitting is different with data interpolating to be, the handled data volume of data fitting is big and can not guarantee that each data does not have error, is irrational so require a function strictness by each data point.Data fitting method is asked fitting function, and interpolation method is asked interpolating function.

Mathematical Modeling need be based upon on the basis of rational model hypothesis, and to be that hypothesis is rational at first embody the trend of selecting certain type fitting function to make it to meet data variation.The selection of fitting function is more flexible, can select linear function, polynomial function, exponential function, trigonometric function or other function, and this should make a choice according to data distribution trend and actual needs.What herein each slope section is adopted is linear fit (piecewise linear model) method of branch slope section, obtains weld seam information

Suppose that each slope section fitting function is a linear function, promptly the figure of fitting function is a straight line on the plane.Because errors of experimental data, the data point of measurement fails accurately to drop on the straight line.Before the match computing, what primarily determine is the point set that participates in current match, the data point that promptly satisfies what condition can less straight line model of root-mean-square error of match, needs promptly also to judge that the corrugated plating corner position is to make linear fit respectively at horizontal segment, the section of going up a slope, lower slope section respectively.This paper takes is big submethod by the departure degree of judgement sample data point, distinguishes the data point that belongs to different sections, is carrying out linear fit in the section then under separately.

The departure degree at sample number strong point is described with the variance of sample, and this value size is described the variable dispersion degree, is the amount of weighing a sample fluctuation size, and sample variance is big more, and the fluctuation of sample data is just big more.According to this characteristic, in flex point is differentiated, data discrete degree for observation sample point, filtered data are carried out the window slip asks variance to handle, at first obtain n data point (system begins to start from horizontal segment), and calculate variance yields as initial value, and be that the window of n is mobile on the observation data interval with length then, recomputate corresponding variance d between this window region when mobile at every turn _Newly, and and a last window region between data variance d _FormerContrast, the contrast principle is: if d _Newly＞d _FormerAnd

Assert that then this enters the new data point of window (put the first place that is the window formation) position is corner position; If d _Newly＜d _FormerAnd

Assert that then last position (these data of next time sliding are about to grand window) the data point institute correspondence position that is positioned at the window formation is corner position, wherein n _TurnSize and working environment disturb, the gradient of corrugated plating is relevant.

Adopting this method that the flex point identification of corrugated plating is realized, is initial point with the starting point, and the sensor movement direction is an X-axis, and the corrugated plating short transverse is set up coordinate system for the Y direction, gets n=6, n in the identifying _Turn=12, at first observe whole data set with sliding window, the variance that obtains sliding distributes, as shown in Figure 7

Carry out the identification of flex point below and judge, the identifying of first flex point as follows:

Table 2-3 window slip variance table (unit: 0.1mm)

In the variance of comparison window 5 and window 6 as can be known, d ₅＜d ₆And

By judgment principle as can be known this new data point (promptly put the first place of the 6th window formation) position m31 that enters window be corner position, and can judge that by Change in Mean trend this point is the upward slope starting point.

Determine after the flex point that next step is that fitting function y=ax+b is determined in segmentation, be exactly with a and b as undetermined coefficient, determine a plane and straight line, make that the pairing point set of data is positioned as close to this straight line in the table.Can be by least square method about the system of linear equations (n is a number of data points for the treatment of match) of unknown number a and b

$\left\{\begin{array}{c}\mathrm{nb}+\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_{i}a=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i\\ \underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_{i}b+\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i^{2}a=\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{x}_i{y}_i\end{array}\right.$

Find the solution this linear equation in two unknowns group get final product undetermined coefficient a and b, thereby the linear fit function.Fig. 8 cathetus is the result of the linear fit at upward slope hop count strong point.

Linear model is y=0.3463x+147.5, and the root-mean-square error RMSE of match is 4.269.From actual effect, filtered The data line fitting method is obtained the corrugated sections curve meet the corrugated plating TP.Fig. 9 is whole fitting result:

Concrete piecewise fitting model is:

Table 2-4 piecewise fitting model table

Section	Model of fit	Root-mean-square error
			AB	y＝0.003333x+1321	1.215
BC	y＝0.3636x+1128	5.119
			CD	y＝0.005055x+1587	1.584
DE	y＝-0.3696x+2297	4.697
			EF	y＝-0.006441x+1342	3.486
FG	y＝0.3463x+147.5	4.269
			GH	y＝-0.0003497x+1596	1.421
HI	y＝-0.3709x+3369	7.011
			IJ	y＝-0.001273x+1330	1.177

3. the level and smooth conversion of weldingvoltage, electric current, speed

Because the requirement of welding procedure, need take different speeds of welding, weldingvoltage, welding current in each slope section, especially in the section of going up a slope, welding fabrication sterogram when adopting same speed of welding, weldingvoltage, welding current as shown below, the welding quality of going up a slope does not as we can see from the figure reach requirement fully, this shows the importance of welding parameter conversion.Welding parameter is carried out conversion near flex point, and the kick of welding parameter brings unfavorable factor to be: one, influence flex point place welding quality, two, the impact of butt welding machine performance; In order to eliminate above-mentioned unfavorable factor, make near the variation of the welding parameter of slope section flex point not present step evolution, by using a sliding window that the welding parameter of flex point the right and left is carried out smooth transformation, the length of sliding window has determined level and smooth degree, and concrete principle is as follows:

Table 2-5 voltage location distribution table (unit: V)

The X position	X 1	X 2	X 3	X 4	X 5	X 6	X 7	X 8	X 9
										Voltage	231.0	231.0	231.0	231.0	153.0	153.0	153.0	153.0	153.0

As above shown in the table, flex point is present between X4 and the X5, and for principle of specification, having selected length for use is 5 sliding window, promptly

At X ₃The virtual voltage of position is $\frac{{\mathrm{<figure-callout\; id="1"\; label="X"\; filenames="H2009100156112E00071.png"\; state="\{\{state\}\}">X</figure-callout>}}_1+X_2+{\mathrm{<figure-callout\; id="3"\; label="X"\; filenames="H2009100156112E00072.png"\; state="\{\{state\}\}">X</figure-callout>}}_3+X_4+X_5}{5}=215.4V$

X ₄The virtual voltage of position is $\frac{X_2+{\mathrm{<figure-callout\; id="3"\; label="X"\; filenames="H2009100156112E00072.png"\; state="\{\{state\}\}">X</figure-callout>}}_3+X_4+X_5+X_6}{5}=199.8V$

X ₅The virtual voltage of position is $\frac{{\mathrm{<figure-callout\; id="3"\; label="X"\; filenames="H2009100156112E00072.png"\; state="\{\{state\}\}">X</figure-callout>}}_3+X_4+X_5+X_6+X_7}{5}=184.2V$

X ₆The virtual voltage of position is $\frac{X_4+X_5+X_6+X_7+X_8}{5}=168.6V$

X ₇The virtual voltage of position is $\frac{X_5+X_6+X_7+X_8+X_9}{5}=153.0V$

From the value of each position voltage, this mode has played the effect to the buffering of welding voltage change, because the length of window of choosing 5, the amplitude of variation of voltage is still bigger, should further enlarge the length of window in the practical application.Following Figure 10, Figure 11, the change procedure figure of voltage, electric current, speed of welding when Figure 12 is the length of window of choosing 15; the sudden change of as can be seen from the figure original parameter is a buffering of process all; guarantee the welding quality at flex point place, improved the protection level of butt welding machine.

Following table is that the welding parameter near 34 data points in the position flex point changes

Table 2-6 welding parameter change list

4. track INTERPOLATION CONTROL OF PULSE

Interpolation algorithm is one of core technology of digital control system, and interpolation operation is one of calculation task important in the computer numerical control.It must be real-time that interpolation is calculated, and promptly must finish calculation task in the limited time.The running time of patching plug program and computational accuracy affect the performance indications such as control accuracy, speed and working ability of whole system.It is exactly the master data of digital control system according to input that interpolation is calculated, as straight line terminal point coordinate value, circular arc starting point, the center of circle, terminal point coordinate value, feed speed etc., by calculating, the shape description of workpiece profile is come out, send feeding according to result of calculation to each coordinate while calculating and instruct.In fact interpolation is exactly the process of closeization of data.Interpolation available hardware and software are realized.In Computerized digital control system (CNC), interpolation work is generally finished by software.Also useful software carries out rough interpolation, carries out the CNC system of thin interpolation with hardware.The software interpolating method is divided into two classes, i.e. pulse increment interpolation and data sampling interpolation.

The interpolation algorithm that the motion control of Butt welding gun is adopted is based on minimum deviation method, as shown below, want the error of three kinds of situations of tentative calculation in every one step of interpolation of the section of going up a slope, promptly need under X-axis feeding relatively separately or independent Y-axis feeding or X-axis and three kinds of situations of Y-axis feeding simultaneously, if this interpolation finishes, the welding gun end is from the deviation of giving boning out, and selects the direction of feed of a less direction of deviation as welding gun.As shown below, three directions 1., 2., 3. respectively as predetermined direction of feed to be selected, concrete selected deviation decision by each direction of feed; The predetermined direction of feed of lower slope section be among Figure 13 3., 4., 5..

Under the prerequisite of the gradient θ of corrugated plating near 45 degree, adopt the method can obtain higher interpolation precision and arithmetic speed, on the basis that guarantees interpolation precision, further improved the efficient of interpolation.

Adopt the interpolation track feeding mode of minimum deviation method can not resemble and sharply change in x direction or y direction the point-to-point comparison method, particularly (as the GH section among Figure 14) can realize constant speed feed in one section, and this is favourable to the welding fabrication quality.

Claims (1)

1. the container corrugated plate welding track Detection ﹠ Controling method based on laser ranging is characterized in that, may further comprise the steps:

A. carry out track detection; Behind the system initialization, horizontal feed starts as the active feed shaft, detects the ripple track of corrugated plating in real time by the laser accurate displacement transducer, and detected weld seam initial information data are sent to microprocessor, and image data is carried out filtering, storage; The described non-contact detecting mode that adopts when detecting the ripple rail of corrugated plating in real time by the laser accurate displacement transducer;

B. carry out track identification; By microprocessor data signal is handled, extracted the information of weld seam, whether the flex point judge module is flex point constantly discerning current location simultaneously, and promptly horizontal segment is differentiated with the tie point of go up a slope section, lower slope section; Flex point then guarantees welding quality by change weldingvoltage, welding current, speed of welding, startup swing control in this way;

The differentiation of described flex point specifically by judging the size of image data point departure degree, distinguish the data point that belongs to different slopes section, is carried out linear fit in the section then under separately; The departure degree at sample number strong point is described with the variance of sample, this value size is described the variable dispersion degree, it is the amount of weighing a sample fluctuation size, sample variance is big more, the fluctuation of sample data is just big more, according to this characteristic, in flex point is differentiated, be the data discrete degree of observation sample point, filtered data carried out the window slip ask variance to handle; Concrete sectional linear fitting model is:

Section Model of fit Root-mean-square error AB y＝0.003333x+1321 1.215 BC y＝0.3636x+1128 5.119 CD y＝0.005055x+1587 1.584 DE y＝-0.3696x+2297 4.697 EF y＝-0.006441x+1342 3.486 FG y＝0.3463x+147.5 4.269 GH y＝-0.0003497x+1596 1.421 HI y＝-0.3709x+3369 7.011 IJ y＝-0.001273x+1330 1.177

Described horizontal segment, the section of going up a slope and lower slope section welding condition are independent the setting;

Described horizontal segment, go up a slope section and the level and smooth conversion and control of lower slope section welding condition are carried out smooth transformation by using a sliding window to the welding parameter of flex point the right and left, and the length of sliding window has determined level and smooth degree;

C. carry out TRAJECTORY CONTROL; Differentiate the result by microprocessor according to corrugated plating change in location that detects and flex point,, track is carried out interpolation operation, each reference axis is controlled in real time based on track data; The interpolation operation that the motion control of Butt welding gun is adopted is based on minimum deviation method, want the error of three kinds of situations of tentative calculation in every one step of interpolation of the section of going up a slope, promptly need under X-axis feeding relatively separately or independent Y-axis feeding or X-axis and three kinds of situations of Y-axis feeding simultaneously, if this interpolation finishes, the welding gun end is from the deviation of giving boning out, and selects the direction of feed of a less direction of deviation as welding gun; Under the prerequisite of the gradient θ of corrugated plating near 45 degree, adopt the method can obtain higher interpolation precision and arithmetic speed, on the basis that guarantees interpolation precision, further improved the efficient of interpolation;

D. move at last and regulate relative position relation between welding gun and the weld seam, promptly do up-down adjustment, thereby reach the purpose of weld joint tracking with driven by motor lifting shaft leading screw by executing agency; In the whole system running, the welding voltage and current is shown in real time.

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