CN105458463A - Real-time welding seam tracking method of intelligent welding robot based on rotating arc sensing - Google Patents

Abstract

The invention relates to a real-time welding seam tracking method of an intelligent welding robot based on rotating arc sensing, and mainly solves the problems that a conventional welding robot is complex in space, welding seam tracks are difficult in demonstration and the conventional robot does not have the capacity of sensing outside information. The technical scheme of the real-time welding seam tracking method lies in that according to in the real-time welding seam tracking method disclosed by the invention, the characteristics of a rotating arc sensing type welding seam tracking system and the characteristics of a welding robot system are organically combined, a rotating arc welding seam tracking sensor is used for collecting the space pose information of a welding gun during welding in a real-time manner, a dimensionality classifier is used for separating the spatial attitudes of the sensor, a robot communication serial port is developed, obtained shift quantity and shift angle signals are converted into machine codes, the machine codes are transmitted to an amplified rotating arc real-time welding seam tracking sensor module in a real-time manner, a six-shaft executing mechanism is driven to perform real-time deviation correction, the deviation quantity of the real-time welding of the robot is effectively compensated, and the automated, flexible and intelligentized real-time welding seam tracking of the robot is realized.

Description

Based on the real-time welding seam tracking method of Intelligent welding robot of rotating arc sensor

Technical field

The invention belongs to welding autocontrol equipment technical field, be specifically related to a kind of real-time welding seam tracking method of Intelligent welding robot based on rotating arc sensor.

Background technology

Now, in the global overall background of industrial 4.0 High-tech strategy plans and Chinese 2025 machine-building under the new situation, the promotion and application of robot are absolutely necessary important step, and Automation of Welding, welding robot and intellectuality have become the trend of solder technology development.Increasing welding robot has been widely used in the every field of automated manufacturing.But, in present factory, most welding robot only maintains the level of traditional teaching playback, for the workpiece of spatial complex seam track and complicated size and dimension, a large amount of manual time need be spent to carry out teaching, not only bring huge manpower consumption, be also unfavorable for shortening the production cycle, reducing costs.

The stability requirement of teaching-playback robot welding conditions is very harsh.Actual welding produce in, due to the complexity of the seam track of different workpieces, different weld task, be difficult to even can not apparatus body curvilinear equation setting welding track, thus cause teaching difficulty, be difficult to thus obtain excellent welding quality and appearance of weld.Meanwhile, teaching type robot butt-welding fitting assembly precision requires high, large by the stress deformation interference in real time caused by welding.Topmost reason is, robot only possesses single actuating mechanism function, does not possess the ability of perception external information, and the spatial pose relation thus not by obtaining welding gun relative target seam track realizes autonomous correction and the weld joint tracking of robot.In order to address this problem, must give robot configuration extraneous detecting sensor, giving the ability that it obtains external information.

In conventional weld seam tracking sensor, arc sensor real-time is best, and tracking performance is stable and precision is high, and cost is low, is suitable for industrial production application.Simultaneously, rotary arc sensor is when carrying out spacescan collection signal, other existing sensors relatively, data sample Duplication can be reduced, improve signal characteristic dimension, thus extract the three-dimensional pose information of welding gun more accurately, comprise multiple free degree, and there is multivariant robot actuating mechanism be combined perfect complementary.At present, rotating arc sensor technology is applied in robot system, solves spatial complex seam track less from the research of motion tracking.Study for rotating arc sensor formula weld seam real-time tracking system and robot system, based on robot system, in conjunction with rotating arc sensor formula weld seam real-time tracking system, realize correction, for the application of THE WELD SEAM TRACKING TECHNOLOGY in robot provides theoretical reference, this is also welding robot towards the inevitable requirement of automation, flexibility and intelligent development.

Summary of the invention

For the problems referred to above, the present invention aims to provide a kind of good stability, fast response time, practical, the simple and real-time welding seam tracking method of Intelligent welding robot based on rotating arc sensor that is that easily realize.For different weld seams even spatial complex track, the seam tracking system of research based on rotary arc sensor and robot system organically combine, propose a kind of real-time welding seam tracking method of Intelligent welding robot based on rotating arc sensor, a kind of device for rotating the arc weld seam tracking transducer Signal Pretreatment and a kind of dimension grader being separated the spatial pose signal of welding gun are invented, overcome robot and only possess single actuating mechanism function, do not possess the limitation of the ability of perception external information.Invent a kind of rotating the arc real-time tracking extended serial port, development machines people communication serial ports on reservation welding robot original function module basis, side-play amount and deviation angle signal are converted to the machine language that welding robot system can identify after this serial port control circuit, by the real-time weld seam tracking sensor module of rotating the arc that the signal real-time Transmission obtained extremely increases, process this deviation signal in real time by robot system and perform corresponding actions.The spatial pose that the method obtains welding gun by rotary arc sensor realizes the flexible and changeable real-time tracking of robot, provides new method for rotating arc sensor technology realizes soldering joint automatic tracking in robot system.

The technical solution adopted for the present invention to solve the technical problems is: according to the features of rotating arc sensor formula seam tracking system and welding robot system, the present invention is organically combined.Welding robot retains original function module, the pretreatment such as filtering are carried out to the current signal that rotating the arc weld seam tracking transducer in welding process collects, add a kind of dimension grader device, dimension separation is carried out to this processing signals, obtain the spatial pose signal of welding gun, comprise the pairwise orthogonal direction side-play amount of arc center and Weld pipe mill, the side-play amount of welding gun height, three deviation angles of course angle, roll angle, the angle of pitch and desirable pose between welding gun weldment.Add a kind of rotating the arc real-time tracking extended serial port, development machines people communication serial ports, signal is converted to the machine language that welding robot system can identify after this serial port control circuit, by the real-time weld seam tracking sensor module of rotating the arc that the side-play amount obtained and deviation angle real-time Transmission extremely increase, perform correction action by six degree of freedom Intelligent welding robot.

Dimension grader of the present invention, based on the nearest principle of Euclidean distance.Rotating the arc tracking system is by the real-time welding current data-signal of sensing head collection in welding process, and this signal has multi-dimensional nature, the multiple spatial attitude of corresponding welding gun RF, RB, RU, RD, LF, LB, LU, LD, ZF, ZB, Z etc.In order to meet the correction n-back test of six degree of freedom intelligent robot system, first dimension grader extracts the spatial signature vectors of unknown posture of welding torch, then the Euclidean distance between various experience posture of welding torch spatial signature vectors is calculated, obtain a distance set, all distances are compared, value minimum in distance set, be then included into corresponding side-play amount and deviation angle type by the spatial signature vectors of current posture of welding torch.By that analogy, the empirical data that attitude before all welderings is corresponding can be obtained, and the characteristic vector of inevitable one or more the unknown posture of welding torch corresponding of experience welding gun pose feature space vector.If corresponding multiple, then get apart from minimum, all the other are all given up.The high-dimensional signal collected can be converted into the low dimension weld joint tracking side-play amount (angle) that can be performed by robot system thus.

Rotating the arc real-time tracking extended serial port of the present invention, mainly solves signal language conversion and the real-time communication problem of rotating the arc tracking system and six degree of freedom welding robot.This extended serial port is based on the open expansion interface of robot system, with the original module of robot system is separate again can real-time communication, be made up of transistor modular, gate module, FPGA permutation module, microcode performance element module, decoding unit module, I/O two-way modules etc.After the welding current signal filtering of sensing electric arc tracking system Real-time Collection, dimensionality reduction, side-play amount and deviation angle signal are still the signal of telecommunication, hold input successively through each unit module through extended serial port INPUT, are converted to the machine code of many group shifted signals.This machine code holds real-time Transmission to robot system control centre by OUTPUT, generates instruction set, become low and high level control signal through logic gates by a series of operational analysis.

The invention has the beneficial effects as follows: organically combine the rotating the arc tracking system and six axle Intelligent welding robot systems that gather multiple degrees of freedom spatial pose signal, dimension grader achieves the separation of gun welder space gesture, posture of welding torch identification can be met, tracking accuracy can be ensured again, rotating the arc real-time tracking extended serial port achieves the signal and communication between two Iarge-scale system, system is made to give full play to the comprehensive advantage of rotating arc sensor seam tracking system and robot system complementation, improve the adaptability of robot system, welding system stability after integrated is high, flexibility is strong, realize robot automation, flexibility and intelligentized real-time weld joint tracking, there is important actual application value, comply with the global overall background of current industrial 4.0 High-tech strategy plan and Chinese 2025 machine-building new trends.

Accompanying drawing explanation

Fig. 1 is the theory structure block diagram of the real-time weld joint tracking of robot based on rotating arc sensor.

Fig. 2 is dimension grader and rotating the arc real-time tracking extended serial port fundamental diagram.

Fig. 3 is the real-time seam tracking system schematic diagram of robot based on rotating arc sensor.

In figure: 1-wire-feed motor, 2-water-cooling system, 3-rotary arc sensor, 4-workpiece and chucking device, 5-gas cylinder, 6-rotating the arc tracking system control cabinet, 7-dimension grader, the signal conditioner of 8-tape code compiler, 9-mechanical arm, 10-Hall element, 11-robot control cabinet, 12-welding machine.

Fig. 4 is the real-time welding seam tracking method flow chart of Intelligent welding robot based on rotating arc sensor.

Fig. 5 is the real-time weld joint tracking instance graph of robot based on rotating arc sensor.

In figure: sensor and there is the initial position orientation relation of workpiece of complicated seam track when the real-time weld seam tracking sensor of 1.-robot, rotating the arc initializes, wherein: the 19-sensor be fixed in robot arrives the preset path of workpiece; 2.-welding starts front sensor and arrives welding starting point, wherein: 20-welds starting point; 3. actual welding operating point and Target Weld operating point in-welding process, wherein: 21-target seam track, the actual rotary arc sensor position of 22-, 23-rectifies a deviation direction vector, 24-target rotary arc sensor position; 4.-robot system compensate amount realizes real-time weld joint tracking, wherein: 25-sensor arrives ideal position; 5.-welding terminates sensor and gets back to initial pose according to certain track, each system reset, wherein: the motion path that 26-sensor resets.

Detailed description of the invention

Below in conjunction with drawings and Examples, the present invention is described in further detail, but do not limit the present invention.

Embodiment 1, the real-time seam tracking system of the described robot based on rotating arc sensor comprises rotary arc sensor 3, rotating the arc tracking system control cabinet 6, water-cooling system 2, Hall element 10; Robot system (rotating the arc real-time tracking extended serial port) 11, mechanical arm 9, dimension grader 7, signal conditioner 8; Welding machine 12, workpiece and clamping device 4, wire-feed motor 1, protective gas gas cylinder 5.Source of welding current the two poles of the earth in welding machine 12 connect wire-feed motor 1, Hall element 10 and robot system (rotating the arc real-time tracking extended serial port) 11 respectively; Hall element 10 is connected with rotating the arc tracking system control cabinet 6; Signal conditioner 8 is connected with rotating the arc tracking system control cabinet 6 and robot system (rotating the arc real-time tracking extended serial port) 11 respectively; Wire-feed motor 1 is connected with rotary arc sensor 3; Rotary arc sensor 3 coaxially connects firmly on the wrist axis of mechanical arm 10.Consult Fig. 1 and Fig. 3, all the other are with embodiment 1.

Embodiment 2, described dimension grader is based on Euclidean distance principle, calculate the Euclidean distance between the feature space of the welding current data of the unknown attitude that rotating the arc tracking system collects and empirical data sample characteristic of correspondence vector, namely correspondence is included into such recently.Suppose that the posture of welding torch of empirical data sample divides and has k class, is respectively u ₁, u ₂..., u _k, every class has a characteristic of correspondence space vector, then total k feature space vector, is denoted as Γ respectively ₁, Γ ₂..., Γ _k.And hypothesis is for the spatial signature vectors m class altogether of unknown posture of welding torch, be denoted as τ _m, then τ _n(1≤n≤m) and u _ieuclidean distance between the experience posture of welding torch characteristic vector of class is:

$d_i\left({\mathrm{\τ}}_n\right)=d({\mathrm{\τ}}_n,{\mathrm{\Γ}}_i)=\left|\right|{\mathrm{\τ}}_n-{\mathrm{\Γ}}_i\left|\right|=\sqrt{{({\mathrm{\τ}}_n-{\mathrm{\Γ}}_i)}^T({\mathrm{\τ}}_n-{\mathrm{\Γ}}_i)}$

The characteristic vector τ of unknown posture of welding torch _nafter the welding gun pose feature space vector of having trained with k class asks Euclidean distance respectively, obtain a distance set d ₁, d ₂..., d _k, to all i ≠ j, if d _i(τ _n) <d _j(τ _n), then d _i(τ _n) be value minimum in distance set, by the characteristic vector τ of current posture of welding torch _nbe included into u _iclass.By that analogy, all τ can be obtained _ncorresponding u _iclass empirical data, and the characteristic vector of inevitable one or more the unknown posture of welding torch corresponding of experience posture of welding torch.If corresponding multiple, then get apart from minimum, all the other all can be given up.

Be separated pairwise orthogonal direction side-play amount △ De, △ We that the spatial pose obtained comprises arc center and Weld pipe mill, the side-play amount △ He of welding gun height, three deviation angles of course angle β, roll angle θ, angle of pitch γ and desirable pose between welding gun weldment.Side-play amount and deviation angle signal are still the signal of telecommunication, hold input successively through transistor modular, gate module, FPGA permutation module, microcode performance element module, decoding unit module, I/O two-way modules through extended serial port INPUT, be converted to the machine code of many group shifted signals.This machine code holds real-time Transmission to robot system control centre by OUTPUT, generates instruction set, become the low and high level control signal of side-play amount and deviation angle through logic gates by a series of operational analysis.Its transformation matrices can be expressed as:

$\begin{array}{c}A=Trans(x,\mathrm{\&Delta;}De)Rot(x,\mathrm{\&gamma;})Trans(y,\mathrm{\&Delta;}He)Rot(y,\mathrm{\&beta;})Trans(z,\mathrm{\&Delta;}We)Rot(z,\mathrm{\&theta;})\\ =\left[\begin{array}{cccc}1& 0& 0& \mathrm{\&Delta;}De\\ 0& 1& 0& 0\\ 0& 0& 1& 0\\ 0& 0& 0& 1\end{array}\right]\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& \cos \mathrm{\&gamma;}& -\sin \mathrm{\&gamma;}& 0\\ 0& \sin \mathrm{\&gamma;}& \cos \mathrm{\&gamma;}& 0\\ 0& 0& 0& 1\end{array}\right]\left|\begin{array}{cccc}1& 0& 0& 0\\ 0& 1& 0& \mathrm{\&Delta;}De\\ 0& 0& 1& 0\\ 0& 0& 0& 1\end{array}\right|\\ \left[\begin{array}{cccc}\cos \mathrm{\&beta;}& 0& \sin \mathrm{\&beta;}& 0\\ 0& 1& 0& 0\\ -\sin \mathrm{\&beta;}& 0& \cos \mathrm{\&beta;}& 0\\ 0& 0& 0& 1\end{array}\right]\left[\begin{array}{cccc}1& 0& 0& 0\\ 0& 1& 0& 0\\ 0& 0& 1& \mathrm{\&Delta;}We\\ 0& 0& 0& 1\end{array}\right]\left[\begin{array}{cccc}\cos \mathrm{\&theta;}& -\sin \mathrm{\&theta;}& 0& 0\\ \sin \mathrm{\&theta;}& \cos \mathrm{\&theta;}& 0& 0\\ 0& 0& 1& 0\\ 0& 0& 0& 1\end{array}\right]\\ \left[\begin{array}{cccc}\cos \mathrm{\&beta;}\cos \mathrm{\&theta;}& -\cos \mathrm{\&beta;}\sin \mathrm{\&theta;}& \sin \mathrm{\&beta;}& \mathrm{\&Delta;}We\sin \mathrm{\&beta;}+\mathrm{\&Delta;}De\\ \sin \mathrm{\&gamma;}\sin \mathrm{\&beta;}\cos \mathrm{\&theta;}+\cos \mathrm{\&gamma;}\sin \mathrm{\&theta;}& -\sin \mathrm{\&gamma;}\sin \mathrm{\&beta;}\sin \mathrm{\&theta;}+\cos \mathrm{\&gamma;}\cos \mathrm{\&theta;}& -\sin \mathrm{\&gamma;}\cos \mathrm{\&beta;}& \mathrm{\&Delta;}We\sin \mathrm{\&gamma;}\cos \mathrm{\&theta;}+\mathrm{\&Delta;}He\cos \mathrm{\&gamma;}\\ -\cos \mathrm{\&gamma;}\sin \mathrm{\&beta;}\cos \mathrm{\&theta;}+\sin \mathrm{\&gamma;}\sin \mathrm{\&theta;}& \cos \mathrm{\&gamma;}\sin \mathrm{\&beta;}\sin \mathrm{\&theta;}+\sin \mathrm{\&gamma;}\cos \mathrm{\&theta;}& \cos \mathrm{\&gamma;}\cos \mathrm{\&beta;}& \mathrm{\&Delta;}We\cos \mathrm{\&gamma;}\cos \mathrm{\&theta;}+\mathrm{\&Delta;}He\sin \mathrm{\&gamma;}\\ 0& 0& 0& 0\end{array}\right]\end{array}$

Then the equation of motion of rotary arc sensor spatial attitude can be expressed as:

(x,y,z,1) ^T＝A(x _t,y _t,z _t,1) ^T

The sampled point in i-th cycle is defined, if (n-1)th joint is to the kinematic matrix A in the n-th joint _inrepresent.Total transformation matrix between robot base and rotating arc sensor gun welder end can be expressed as: ^iRt _iH=A _i1a _i2a _i3a _i4a _i5.By carrying out solving of kinematics model to multiple degrees of freedom welding robot, the pose just can tried to achieve when any sampled point between the relative rotary arc sensor end of basis coordinates system of robot according to above formula is expressed.Consult Fig. 2, all the other same above-described embodiments.

Embodiment 3, the real-time welding seam tracking method idiographic flow of the described Intelligent welding robot based on rotating arc sensor.Before welding starts, welding robot carries out initializing set, sets butt welded seam track analyze according to weld task and welding surroundings, for complex space seam track, analyzes the spatial movement scope of welding robot, selects suitable weldment assembling mode.Rotary arc sensor and mechanical arm 9 wrist axis coaxially assemble, in order to ensure the accuracy of welding striking, one section of suitable motion path 13 must be set, by teach box to sensor and mechanical arm carry out the setting of initial space pose and from initial position to the path setting of solder joint 14.Rotary arc sensor seam tracking system 6 initializing set, follow the tracks of relevant parameter by its control cabinet panel liquid crystal screen butt welded seam to set, comprise electric arc speed and the sweep radius setting of rotary arc sensor 3, Hall element 10 detects, and sensor water-cooling system 2 detects.Welding system initializing set, comprises wire feeder 1, and protective gas 5 detects, and the source of welding current 12 detects.Communication detection between rotating the arc tracking system, welding robot system 11.

Open welding button, the each axle servomotor of welding robot system driving device arm, rotary arc sensor is bond pad locations 14 from initial pose moves to workpiece, wrist axis makes rotary arc sensor 3 reach optimal spatial attitude by fine adjustment, simultaneously, robot system 11 sends to rotating the arc tracking system 6 and opens weldering order, and welding system and rotary arc sensor are started working, and striking starts welding.In welding process, rotary arc sensor 3 driver scanning groove, extracts the deviation signal relative to Weld pipe mill track, processes through signal conditioner 8 within each work period of system.This device comprises filtration module, the interference of removing noise signal.Dimension grader 7 is utilized to carry out the separation of sensor space attitude, comprise pairwise orthogonal direction side-play amount △ De, the △ We of arc center and Weld pipe mill, the side-play amount △ He of welding gun height, three deviation angles of course angle β, roll angle θ, angle of pitch γ and desirable pose between welding gun weldment.This shifted signal is converted into by rotating the arc real-time tracking extended serial port machine language that welding robot can identify thus realizes communication between rotary arc sensor and robot interface, transfer to the real-time weld joint tracking expansion module of rotating the arc of robot control system again, the correction motion compensation quantity of six axles is obtained after six degree of freedom Intelligent welding robot system analytic operation, drive each axle servomotor to make rotary arc sensor along correction direction 17 rapid adjustment to target seam track 15, perform correction action.Meanwhile, send the relevant parameter of instruction to rotating the arc tracking system adjustment rotary arc sensor, realize real-time dynamic optimum weld joint tracking.

After weld task completes, rifle is moved back in blow-out, and welding system and the real-time seam tracking system of rotating the arc quit work, and robot system drives each axle, and rotary arc sensor gets back to initial space attitude according to certain movement track 20.Consult Fig. 1 to Fig. 5, all the other same above-described embodiments.

Claims (3)

1. the real-time welding seam tracking method of Intelligent welding robot based on rotating arc sensor, it is characterized in that: rotating arc sensor weld seam real-time tracking system is combined with welding robot system, the spatial pose signal of welding gun when utilizing rotating the arc weld seam tracking transducer Real-time Collection to weld, after signal conditioner process, by the dimension grader of invention, the spatial pose of welding gun is separated into side-play amount and deviation angle, rotating the arc real-time tracking extended serial port through invention converts shifted signal to machine code, onlinely transfer to robot control system, drive six axle executing agency real-time deviation correctings.

2. a kind of real-time welding seam tracking method of Intelligent welding robot based on rotating arc sensor according to claim 1, invent a kind of dimension grader, it is characterized in that: the spatial pose information of welding gun during the welding of rotating the arc weld seam tracking transducer Real-time Collection, be translated into the machine language that robot can identify, dimension grader is utilized to carry out the separation of sensor space attitude, obtain side-play amount and deviation angle, the locus of rotating the arc weld seam tracking transducer phase butt welded seam performs correction action in the attitude angular deflection of the skew of the position of three dimensions system three axis and correspondence by six degree of freedom Intelligent welding robot.

3. a kind of real-time welding seam tracking method of Intelligent welding robot based on rotating arc sensor according to claim 1, invent a kind of rotating the arc real-time tracking extended serial port, it is characterized in that: development machines people communication serial ports, the shifted signal obtained is converted to machine language and real-time Transmission to amplification the real-time weld seam tracking sensor module of rotating the arc, process this deviation signal in real time by robot system and perform corresponding correction action.