CN105750694A - Route self-searching complex curved surface bead welding method based on magnetic control rotating arc sensing - Google Patents

Abstract

The invention discloses a route self-searching complex curved surface bead welding method based on magnetic control rotating arc sensing. According to the main principle of the method, a curved surface is scanned through a magnetic control rotating arc sensor, a sampling point current signal is collected through a Hall sensor, an interval and direction dividing sensor conducts interval and direction dividing on a sampling point in each rotating period, an operation processor calculates the average current of each interval, conducts filtering processing, and then determines the direction of the minimum average current of a sampling period, a position compensation controller compares the average current value of the sampling period with the average current value of a reference period, the height of a welding gun is automatically adjusted, and arc breaking and gun colliding are stably avoided. A multi-axis driver controls a four-axis linkage welding machine, it is guaranteed that the welding direction faces the direction corresponding to a sampling set with the current minimum average current, welding is always conducted at the low horizontal height position of the curved surface, when the change fluctuation of average currents of all intervals of the sampling period is small, it is judged that the current curved surface tends to be smooth, and bead welding of the curved surface is completed.

Description

Based on magnetic control rotating arc sensor from the complex-curved overlaying method in pathfinding footpath

Technical field

The present invention relates to automatic field, be a kind of based on magnetic control rotating arc sensor from the complex-curved overlaying method in pathfinding footpath.

Background technology

Welding is a kind of conventional manufacturing process and technology, and built-up welding as a kind of economic of material surface modifying quick process, be applied to the manufacture of each industrial department parts, reparation and process for modifying surface more and more widely.In actual weld deposit process, substantially it is desirable that workpiece portion faces to be welded is smooth, when surface of the work is complex-shaped, during as there is curved surface, tradition bead-welding technology cannot directly be suitable for, and the automaticity of weld deposit process is relatively low, it is necessary to artificial the carrying out adjusting guarantee built-up welding work in real time.For solving the technological difficulties of built-up welding under complex-curved condition, it is proposed to a kind of based on magnetic control rotating arc sensor from the complex-curved overlaying method in pathfinding footpath, have positive role to promoting the automatization of bead-welding technology further.

Summary of the invention

In order to solve the deficiency that prior art exists, better promote the automation development of bead-welding technology, for on current built-up welding production line, there is the built-up welding of complex curved surface part only by manually-operated mode, thus the built-up welding effect produced is poor, surfacing layer quality thickness does not reach the problems such as requirement, propose a kind of based on magnetic control rotating arc sensor from the complex-curved overlaying method in pathfinding footpath, its system control block figure is as shown in Figure 1: the system authority of the method sampling includes: magnetic control rotary arc sensor, divide to interval sensor, arithmetic and control unit, position compensation controller, four-axle linked welding machine；The method divides sampling interval and locality by dividing to interval sensor, according to magnetic control arc sensor acquisition welding current, arithmetic and control unit calculates the direction that the minimum set of samples of average current is corresponding, four-axle linked welding machine controls welding gun all the time along the minimum namely direction welding that curved surface level height is relatively low of average current, the process of following cycle sampling and location, when the average current of sampling interval changes fluctuation less than or equal to reference interval, when the built-up welding of front curve completes.Out-of-flatness place of curved surface is filled up until the complete built-up welding of whole curved surface is smooth by constantly welding；Position compensation controller ensures not exist together arc stability thus realizing the automatic surfacing having complex curved surface part at curved surface height simultaneously, specifically includes following steps:

The first step: divide sampling interval and determine direction signal, and gathering the welding current signal of reference position

Magnetic control rotary arc sensor is arranged on welding gun, the motor shaft place driving magnetic pole rotation is provided with the optical code disk of the index point of 64, the characteristics of motion of electric arc is controlled according to magnetic field, divide, to interval sensor, one sampling period is divided into 8 intervals, concurrently set often adjacent two intervals as a set of samples, in each set of samples, two interval centre positions are a direction signal, arrange 8 optocouplers in order to position this 8 direction signals.When repair starts, first in the welding current signal in the station acquisition that curved surface is smooth one or more sampling period as reference data, reference cycle average current and sampling interval average current standard deviation is determined, as the standard reference data processed with follow-up welding current signal after data process.

Second step: determine the high and low position of welding gun according to the average current signal in reference cycle

The position compensation controller average current value according to the average current value analogy reference sample cycle in sampling period in each sampling period accepted, when dry extension of electrode is constant, according to rotating the arc arc length and electric current classical formulas computing, it is converted into equivalence arc length difference in order to control welding gun high and low position, to prevent when curved surface elevational change is bigger, such as occur during curve recess to hit rifle when current interruption and curved protrusion, it is ensured that the stability of welding arc in automatic surfacing process.

3rd step: determine welding direction according to the welding arc signal of current sample period difference set of samples

Hall element gathers the average welding current value of different sampling intervals in current sample period, adopt interval method of analysis of variance, when calculating current sample period average current variance more than reference cycle average current variance, determine the set of samples that average welding current value is minimum, position the direction signal that this set of samples interval is corresponding, corresponding formula according to welding current and arc length, assert that this direction is towards the relatively low position of curved surface level height, drive four-axle linked welding machine to control welding gun and carry out the welding sampling in next cycle along this direction, ensure that welding direction is all the time towards curved surface level height lower；Only when the sampling period, each interval average current value variance was less than or equal to reference cycle interval average current variance, assert the now approximate burnishing surface of curved surface.Along with welding sampling carries out to curve recess direction all the time, the irregular position of curved surface is compensated always, and a range of curved surface tends to smooth, and this technical process of following cycle is until complex-curved smooth by whole built-up welding.

The invention has the beneficial effects as follows: propose a kind of based on magnetic control rotating arc sensor from the complex-curved overlaying method in pathfinding footpath, the method signal detection curved surface out-of-flatness position by welding itself, by constantly filling up complex-curved out-of-flatness place, it is finally reached the complete built-up welding of whole curved surface；Adopt the signal of welding arc itself, real-time is good, multiple sensor co-ordinations, system stability is high, the intelligence degree of technique is high, the problem such as the automaticity solving complex-curved built-up welding is not high, production efficiency is low, surfacing quality is general and cost of labor is bigger, the development for automatization's technique for overlaying is laid a good foundation.

Accompanying drawing explanation

Fig. 1 is automatic surfacing system block diagram

Fig. 2 is automatic surfacing process chart

Fig. 3 is point to interval sensor operation principle schematic diagram

Fig. 4 is system motion illustraton of model

Case study on implementation

In order to better express technical scheme and the beneficial effect of whole invention, below in conjunction with drawings and Examples, the present invention is described in further details.But, embodiments of the present invention are not limited to this.

Embodiment 1 present invention based on magnetic control rotating arc sensor from the complex-curved overlaying method in pathfinding footpath as it is shown in figure 1, include magnetic control rotary arc sensor, point to interval sensor, arithmetic and control unit, position compensation controller, four-axle linked welding machine；Wherein divide to interval sensor operation principle as shown in Figure 3, one is rotated sampling period 8 sampling intervals of division and locality, concurrently set often adjacent two intervals as a set of samples, in each set of samples, two interval centre positions are a direction signal, optical code disk are installed 8 optocouplers in order to position each direction signal；As shown in Figure 2 in workflow, when starting working, magnetic control arc sensor first gathers the welding current signal in reference cycle, arithmetic and control unit calculates all directions correspondence interval average current, four-axle linked welding machine controls welding gun all the time along the less direction of set of samples average current and the welding of curved surface level height lower position direction, until each interval average current change fluctuation is only small, now current region curved surface is similar to smooth, if there is also other region curved surface, continues welding sampling process；The surface topography of certain limit change curved surface it is in as shown in Figure 4 by constantly filling up the out-of-flatness of curved surface, finally make the whole built-up welding of whole curved surface smooth, and position compensation controller can ensure that and do not exist together arc stability thus the automatic surfacing that realizes under complex-curved condition at curved surface height.

The present invention based on magnetic control rotating arc sensor to be embodied as step from the complex-curved overlaying method in pathfinding footpath as follows:

The first step: divide sampling interval and determine direction signal, and gathering the welding current signal of reference position

As shown in Figure 3: magnetic control rotary arc sensor is arranged on welding gun, the motor shaft place driving magnetic pole rotation is provided with the optical code disk of the index point of 64, the characteristics of motion of electric arc is controlled according to magnetic field, point to interval position sensor, is divided into a, b, c, d, e, 8 intervals such as f, g and h one sampling period, in the single cycle, for zone leveling electric currentX value a～h, then be represented by:

$I_{a_n}=\frac{I_{cm+1}+I_{cm+2}+...I_{cm+3}}{s}$

$I_{b_n}=\frac{I_{cm+s+1}+I_{cm+s+2}+...I_{cm+2s}}{s}$

$I_{c_n}=\frac{I_{cm+2s+1}+I_{cm+2s+2}+...I_{cm+3s}}{s}$

$I_{d_n}=\frac{I_{cm+3s+1}+I_{cm+3s+2}+...I_{cm+4s}}{s}$

$I_{e_n}=\frac{I_{cm+4s+1}+I_{cm+4s+2}+...I_{cm+5s}}{s}$

$I_{f_n}=\frac{I_{cm+5s+1}+I_{cm+5s+2}+...I_{cm+6s}}{s}$

$I_{g_n}=\frac{I_{cm+6s+1}+I_{cm+6s+2}+...I_{cm+7s}}{s}$

$I_{h_n}=\frac{I_{cm+7s+1}+I_{cm+7s+2}+...I_{cm+8s}}{s}$

In formula: c is the data number in a sampling period；N is the revolution number of magnetic pole；S=c/8.

Concurrently setting often adjacent two intervals is a set of samples, and two the interval centre positions often organized are a direction signal, arrange 8 optocouplers in order to position the direction signal of 1-8.The average welding current of each set of samples is usedRepresent, it is known that:

$\begin{array}{cccc}{I}_{1_n}=\frac{1}{2}(I_{a_n}+I_{b_n})& I_{2_n}=\frac{1}{2}(I_{b_n}+I_{c_n})& I_{3_n}=\frac{1}{2}(I_{c_n}+I_{d_n})& I_{4_n}=\frac{1}{2}(I_{d_n}+I_{e_n})\end{array}$

$\begin{array}{cccc}{I}_{5_n}=\frac{1}{2}(I_{e_n}+I_{f_n})& I_{6_n}=\frac{1}{2}(I_{f_n}+I_{g_n})& I_{7_n}=\frac{1}{2}(I_{g_n}+I_{h_n})& I_{8_n}=\frac{1}{2}(I_{h_n}+I_{a_n})\end{array}$

8 sampled datas when the sampled data in reference cycle is exactly n=0, the average welding current meansigma methods I in reference cycle₀Represent,

$I_0=\frac{I_{a_0}+I_{b_0}+...I_{h_0}}{8}$

Second step: determine the high and low position of welding gun according to the average current signal in reference cycle

As shown in Figure 4, first take the sampling period in the position that curved surface is smooth, the average current value in each sampling period is contrasted the average current value in reference sample cycle by position compensation controller, when dry extension of electrode is constant, according to rotating the arc GMAW welding system arc length and electric current classical formulas computing

$L_n=\frac{U_0-(R+R_0)I_n-U}{v_n}$

In formula: v_nRepresent current change rate in the sampling period

It is converted into equivalence arc length difference e=L_n-L₀, in order to control welding gun high and low position, to prevent when curved surface elevational change is bigger, such as occur during curve recess to hit rifle when current interruption and curved protrusion, it is ensured that the stability of welding arc in automatic surfacing process.

3rd step: determine welding direction according to the welding arc signal of current sample period difference set of samples

Hall element gathers the average welding current value of different sampling intervals in current sample period, and arithmetic and control unit adopts interval method of analysis of variance, by average current I in the single sampling period_nRepresent, average current variance D (I_n) it is represented by:

$D\left(I_n\right)=E\left\{{\[I_{x_n}-E\left(I_{x_n}\right)\]}^2\right\}=\frac{1}{8}\[{(I_{a_n}-I_n)}^2+{(I_{b_n}-I_n)}^2+...+{(I_{h_n}-I_n)}^2\]$

When sampling interval average current value variance more than reference cycle average current variance and D (I_n) > D (I₀) time, it is determined that 8 set of samplesMinimum value, obtain the direction signal that the minimum set of samples of average current is corresponding, corresponding formula according to welding current and arc length, assert that this direction is towards curved surface level height lower position, drive four-axle linked welding machine to control welding gun and carry out the welding sampling in next cycle along this direction, it is ensured that welding is all the time in curved surface level height lower；Only when each interval average current value variance calculated is less than or equal to reference cycle interval average current variance and D (I_n)≤D(I₀) time, assert the now approximate burnishing surface of curved surface, whole process side weld edge fit is sampled, along with welding carries out to curved surface level height is relatively low all the time, the irregular position of curved surface is compensated always, and a range of curved surface tends to smooth, circulates this technical process until complex-curved smooth by whole built-up welding.

Case study on implementation 2 present disclosure applies equally to the automatic processing of the surface of the work heap welding coat of complicated shape.

The above is only the preferred embodiment of the present invention, it is noted that some improvement done under the premise without departing from the principles of the invention, is all considered as protection scope of the present invention.

Claims (4)

1. based on magnetic control rotating arc sensor from the complex-curved overlaying method in pathfinding footpath, for the automatic surfacing of complex curved surface part, it is characterized in that: the system of the method includes: magnetic control rotary arc sensor, point to interval sensor, arithmetic and control unit, position compensation controller, four-axle linked welding machine；The method divides sampling interval and locality by dividing to interval sensor, magnetic control rotary arc sensor gathers welding current, arithmetic and control unit calculates all directions correspondence interval average current, four-axle linked welding machine controls welding gun all the time along the less namely direction welding that curved surface level height is relatively low of average current, position compensation controller ensures not exist together arc stability at curved surface height, until when each interval average current change fluctuation is only small, the built-up welding of curved surface completes.

2. according to claim 1 based on magnetic control rotating arc sensor from the complex-curved overlaying method in pathfinding footpath, it is characterized in that: point the direction locating module from 8 optocouplers to interval sensor, data sampling and the signal processing module that include being made up of optical code disk and are constituted, 8 sampling intervals will be divided into the sampling period by direction locating module and 8 intervals divide to, often adjacent two intervals are as a set of samples, the corresponding direction signal of each set of samples, this direction is the direction of motion of welding gun.

3. according to claim 1 based on magnetic control rotating arc sensor from the complex-curved overlaying method in pathfinding footpath, it is characterized in that: position compensation controller includes data reception module, data computation module and AD conversion module composition, the average current value in each sampling period is contrasted the average current value in previous sampling period, according to rotating the arc arc length and electric current classical formulas computing, it is converted into equivalence arc length difference in order to control welding gun high and low position, prevent from hitting rifle in the current interruption of curve recess place and curved protrusion place, to ensure the stability of welding arc in automatic surfacing process.

4. according to claim 1 based on magnetic control rotating arc sensor from the complex-curved overlaying method in pathfinding footpath, it is characterized in that: when sampling starts, first position sampling one periodic weld current signal smooth at curved surface is as the reference cycle, the welding current signal of sampling interval is received by Hall element, arithmetical unit calculates the average current value in each interval after the filtered process of controller, adopt interval method of analysis of variance, when the sampling period, each interval average current variance was more than reference cycle interval average current variance, the direction that the minimum set of samples of average current is corresponding is selected in contrast, according to electric current arc length corresponding relation, assert that the curved surface level height in this direction is relatively low, four-axle linked welding machine is according to the direction feedback control welding gun advance divided to range restraint device；Constantly fill up curved surface out-of-flatness place, until when sampling period average current variance is less than or equal to reference cycle interval average current variance, assert now curved surface convergence burnishing surface, completing the automatic surfacing under complex-curved condition.