CN105081524A - Cooperative control method for track online dynamic programming and weld pass tracking in welding process - Google Patents

Abstract

The invention provides a cooperative control method for track online dynamic programming and weld pass tracking in a welding process and belongs to the technical field of movable welding robots. According to the method, the advantages that the joint welding groove detection in front of a welding area is achieved by a structured light visual sensor detecting area ahead of an electric arc, and welding torch poses are obtained by an electric arc sensor in real time are combined sufficiently; based on the weld pass isometric approximation theory, the cooperative decoupling control over the track online dynamic programming and weld pass tracking of a robot body is achieved. By means of the method, the welding speed stability and weld pass tracking accuracy of a movable welding robot in the large structure complex tracking welding joint welding process can be improved, and the local large curvature of the joint track and the welding joint forming quality in a bevel area are improved; the method can be applied to the movable robot welding process in equipment manufacturing of ships, energy sources, rail transit and the like and is especially applicable to the welding occasions of curved welding joints of large bevel or large curvature.

Description

In welding process, the online Dynamic Programming of track and welding bead follow the tracks of collaborative control method

Technical field

The invention belongs to mobile (formula) Technology of Welding Robot field.Relate to the online Dynamic Programming of track and welding bead in a kind of welding process and follow the tracks of collaborative control method, the aspects such as mobile robot's automatic welding can be widely used in.

Background technology

Large-scale component welding occasion in the fields such as resource equipment, heavy-duty machinery, shipbuilding, mobile welding robot becomes the effective ways solving large scale, complicated space curve welding seam automatic welding because of advantages such as its grand movement abilities.Limited by the impulse stroke of airborne actuator devices (such as mechanical arm, rectangular coordinate system formula X-Y balladeur train etc.) on the robot body being installed on mobile welding robot, need to adjust its position and attitude in real time to ensure welding torch centering Weld pipe mill in conjunction with robot body, namely under the Collaborative Control of robot body and airborne executing agency, carry out weld job.

Existing mobile welding robot mainly adopts the weld seam tracking sensor of single type, comprise arc sensor, vision sensor two class: adopt the mobile welding robot of arc sensor only to detect molten bath zone and therefrom obtain welding deviation information, the actual correction behavior adjustment pose of the real-time welding deviation information that robot body obtains according to arc sensor or airborne executing agency, requires that airborne executing agency has larger effective impulse stroke; And, the electromechanical inertial impact that the accompany movement of robot body on welding bead is subject to mobile welding robot system causes control hysteresis, particularly mobile welding robot is needed to perform wide-angle turning motion to follow the tracks of the region of seam track in curved welding seam track local deep camber region and knuckle region etc., because being difficult to adjust pose in time, very easily produce and partially weld defect, or cause appearance of weld bad because speed of welding changes; Adopt the mobile welding robot of vision sensor to disturb in order to avoid strong arc light, vision sensor surveyed area usually and electric arc melting bath region there is certain distance, be difficult to real-Time Compensation because of welding base metal temperature distortion and cause the change of position while welding and size.

In sum, prior art is all difficult to take into account mobile welding robot to the dynamic response in the complicated track weld seam welding process of large scale and static accuracy, and is difficult to solve the technical problem that robot body motion is coupled with airborne executing agency motion control.

Summary of the invention

The object of the invention is to overcome the deficiencies in the prior art, propose the online Dynamic Programming of track and welding bead in a kind of welding process and follow the tracks of collaborative control method, to ensure quality of weld seam molding while realizing the welding bead accurate tracking in the welding of large scale complicated track weld seam.

To achieve these goals, the present invention takes following technical scheme:

In welding process, the online Dynamic Programming of track and welding bead follow the tracks of a collaborative control method, comprise the following steps:

1) set up mobile welding robot system coordinate system, comprising: basic cartesian coordinate system O _xyz, robot body coordinate system M _xyz, airborne executing agency coordinate system U _xyzwith structured light sensor coordinate system L _xyz, wherein, airborne executing agency coordinate system U _xyzwith structured light sensor coordinate system L _xyzx-axis forward consistent with the direction of robot body straight forward, z-axis forward is consistent with the direction of ground normal, and y-axis forward is determined by lefft-hand rule, airborne executing agency coordinate system U _xyzinitial point be positioned at the fixed connection place of airborne executing agency and robot body;

2) when welding arc scans groove with swing, rotation or swing-rotary composite movement form, adopt structured light sensor to extract the positional information of front, weld zone seam welds groove characteristic point i, comprise bevel for welding characteristic point i and welding torch at structured light sensor coordinate system L _xyzoffset distance E on middle y-axis direction _iwith bevel for welding characteristic point at structured light sensor coordinate system L _xyzin coordinate, adopt arc sensor to gather arc energy signal in real time simultaneously, integration differential method, characteristic harmonics method or extremum method is adopted to extract through signal filtering and the real-time welding torch posture information of amplifying in the arc energy signal after processing, welding torch pose is adjusted according to obtained real-time welding torch posture information by airborne executing agency, while airborne executing agency adjustment welding torch pose, arc sensor starts the arc energy signals collecting in next cycle, circulation like this, namely realizes welding bead and follows the tracks of;

3) according to bevel for welding characteristic point at structured light sensor coordinate system L _xyzin coordinate, carry out coordinate transform to basic cartesian coordinate system O _xyz, obtain the coordinate G of bevel for welding characteristic point i _i=(x _i, y _i);

4) according to step 2) and 3) solve the coordinate of a series of bevel for welding characteristic point successively, obtain a bevel for welding characteristic point coordinate sequence { G ₁, G ₂..., G _nand an offset distance array { E ₁, E ₂..., E _n, wherein

$N=\frac{\mathrm{\λ}}{{\mathrm{vT}}_{op}}+1$

In formula: λ is the distance that structured light sensor is prepended to welding torch, v is speed of welding, T _opfor the bevel for welding characteristic point position information extraction cycle;

5) SPL is adopted to carry out the Fitting Calculation to bevel for welding characteristic point coordinate sequence, obtain lopcus function S (x) to be welded and carry out differentiate, solving the tangent slope k of each bevel for welding characteristic point on lopcus function S (x) to be welded in bevel for welding characteristic point coordinate sequence _i, i=1,2 ..., N, obtains comprising N number of bevel for welding characteristic point position auto―control P _i=[x _iy _iarctan (k _i)], i=1,2 ..., the set of N;

6) set threshold value σ with compare, and set threshold value ζ and Δ E compares, when or during Δ E> ζ, robot body performs continuous path Motion trajectory; When or during Δ E<-ζ, robot body performs around car body center pivot turn trajectory planning; When and during-ζ≤Δ E≤ζ, robot body performs point-to-point craspedodrome trajectory planning, wherein:

$\left\{\begin{array}{c}\mathrm{\&Delta;}E=E_N-E_1\\ \mathrm{\&sigma;}=L_m-L_s+\frac{1}{2}{L}_a,\frac{1}{2}{L}_a<L_m<L_a\\ \mathrm{\&zeta;}=\frac{1}{4}{L}_a\end{array}\right.$

In formula: E ₁and E _nbe respectively the 1st and N number of bevel for welding characteristic point and welding torch at structured light sensor coordinate system L _xyzon middle y-axis direction offset distance, L _sfor welding torch is at airborne executing agency coordinate system U _xyzin y coordinate, L _afor airborne executing agency is at airborne executing agency coordinate system U _xyzmaximum functional stroke on middle y-axis direction, L _mfor airborne executing agency is at airborne executing agency coordinate system U _xyzdefault impulse stroke on middle y-axis direction;

7) robot body is according to continuous path Motion trajectory, around car body center pivot turn trajectory planning or the adjustment of point-to-point craspedodrome trajectory planning execution pose, repeat step 2 simultaneously) ~ 6), carry out trajectory planning next time, namely realize the online Dynamic Programming of track in welding process and welding bead and follow the tracks of collaborative control.

In technique scheme, step 6) described in continuous path Motion trajectory, the method for employing is:

According to step 5) described in the set of bevel for welding characteristic point position auto―control, adopt following formula:

$\left[\begin{array}{c}{x}_{pi}\\ y_{pi}\\ {\mathrm{\&theta;}}_{pi}\end{array}\right]=\left[\begin{array}{c}{x}_i+\frac{1}{2}{L}_{a}sin\left(arctan\left(\frac{dS\left(x_i\right)}{dx}\right)\right)\\ y_i-\frac{1}{2}{L}_a\cos \left(arctan\left(\frac{dS\left(x_i\right)}{dx}\right)\right)\\ \arctan \left(\frac{dS\left(x_i\right)}{dx}\right)\end{array}\right],i=1,2,...,N$

Computing machine human body position auto―control of i-th on robot body movement locus: U _pi: [x _pi, y _pi, θ _pi], (i=1,2 ..., N), wherein: S (x _i) be functional value upper i-th of lopcus function S (x) to be welded, x _pi, y _pito be respectively on robot body movement locus at i-th at basic cartesian coordinate system O _xyzin coordinate, θ _pifor robot body azimuth of i-th on robot body movement locus, adopt SPL to the coordinate (x of whole point on robot body movement locus _pi, y _pi), i=1,2 ..., N carries out interpolation calculation, generates continuous and level and smooth robot body movement locus;

In technique scheme, step 6) described in around car body center pivot turn trajectory planning, the method for employing is:

Control machine human body left and right sides driving wheel, makes driving wheel velocity magnitude equal, and direction is contrary, realizes robot body around the pivot turn of car body center, robot body angle of turn θ _remploying following formula calculates:

${\mathrm{\&theta;}}_R=arctan\left(\frac{dS\left(x_N\right)}{dx}\right)-arctan\left(\frac{dS\left(x_1\right)}{dx}\right).$

In technique scheme, step 6) described in point-to-point craspedodrome trajectory planning, the method for employing is:

Keep robot body left and right sides driving wheel velocity-stabilization, make robot body be λ along current direction displacement length, translational speed size remains unchanged.

Welding torch of the present invention adopts the one of the rotary welding torch of magnetic control, machinery rotating type welding torch, automatically controlled swing type welding torch or mechanical swinging type welding torch.

The present invention has the following advantages and the technique effect of high-lighting: fully integrated structure light vision sensor surveyed area be ahead of electric arc realize front, weld zone seam welds groove detect and the advantage of arc sensor Real-time Obtaining welding torch pose by the collaborative uneoupled control to robot body and airborne executing agency, can effectively solve mobile welding robot in the parametric curve weld seam welding process of large scale because of electromechanical inertial cause tracing control delayed, be difficult to take into account the technical problem such as dynamic response and static accuracy; Improve speed of welding stability and the welding track smoothness of mobile welding robot, particularly can improve the quality of weld seam molding in curved welding seam track deep camber region, local and weld seams shaped zigzag line knuckle region.The method in large-scale component complicated track welding line automatic welding comparatively conventional method there is clear superiority, there is important actual application value, can be widely used in mobile robot's welding process of the equipment manufacturing such as boats and ships, heavy-duty machinery, the energy and track traffic, be particularly useful for large-size cylinder body girth joint, gantry crossbeam side weld seam, bucket-wheel stacker reclaimer bucket wheel weld seam, locomotive central sill and the large turns such as side structure string beam weld seam or deep camber curved welding seam weld occasion.

Accompanying drawing explanation

Fig. 1 is that in welding process, the online Dynamic Programming of track and welding bead follow the tracks of collaborative control method FB(flow block).

Fig. 2 is robot body kinematics model schematic diagram of the present invention.

Fig. 3 is continuous path Motion trajectory schematic diagram of the present invention.

In Fig. 3-Fig. 5: a, b are respectively the two ends of seam track; S is the point on seam track.

Fig. 4 is that the present invention is around car body center pivot turn trajectory planning schematic diagram.

Fig. 5 is point-to-point craspedodrome trajectory planning schematic diagram of the present invention.

Fig. 6 is the mobile welding robot system architecture principle schematic realizing the method for the invention.

In figure: 1-mobile robot; 2-structured light sensor; 3-image pick-up card; 4-welding torch; 5-Hall element or signal transmitting device; 6-signal acquisition process module; 7-industrial computer; 8-motion control card; 9-airborne executing agency; 10-Movement Controller of Mobile Robot; 11-source of welding current; 12-workpiece.

Detailed description of the invention

Below in conjunction with drawings and Examples, the principle of the invention and the course of work are described in further details.

Figure 1 shows that in welding process of the present invention, the online Dynamic Programming of track and welding bead follow the tracks of collaborative control method FB(flow block), comprise following step:

1) set up mobile welding robot system coordinate system, comprising: basic cartesian coordinate system O _xyz, robot body coordinate system M _xyz, airborne executing agency coordinate system U _xyzwith structured light sensor coordinate system L _xyz, wherein, airborne executing agency coordinate system U _xyzwith structured light sensor coordinate system L _xyzx-axis forward consistent with the direction of robot body straight forward, z-axis forward is consistent with the direction of ground normal, and y-axis forward is determined by lefft-hand rule, airborne executing agency coordinate system U _xyzinitial point be positioned at the fixed connection place of airborne executing agency and robot body, robot body of the present invention has in the displacement of XOY plane and angle two frees degree of rotating around Z axis in basic cartesian coordinate system;

Set up the kinematics model of robot body of the present invention, the method adopted is: because robot body of the present invention adopts with side wheel parallel drive, be two-wheeled model when carrying out that two dimensional surface motion pose calculates by robot body model simplification, and ignore squeegee action and car body longitudinal sliding motion.As shown in Figure 2, robot body moves to p ' from p point, R is radius of turn, b is left and right wheels spacing, θ, θ ', the Δ θ angle that is respectively robot body initial orientation angle, back track parallactic angle and turns over, inscribe robot body center time (k+1) at basic cartesian coordinate system O _xyzin pose (x ^k+1, y ^k+1, θ ^k+1) calculated by following formula (1) or following formula (2),

$\left\{\begin{array}{c}{x}^{k+1}=x^k+\frac{r}{2}{\&Integral;}_{T_k}^{T_{k+1}}\left({{\mathrm{\&omega;}}_r}^k+{{\mathrm{\&omega;}}_l}^k\right){\mathrm{cos\&theta;}}^{k}dt\\ y^{k+1}=y^k+\frac{r}{2}{\&Integral;}_{T_k}^{T_{k+1}}\left({{\mathrm{\&omega;}}_r}^k+{{\mathrm{\&omega;}}_l}^k\right){\mathrm{sin\&theta;}}^{k}dt\\ {\mathrm{\&theta;}}^{k+1}={\mathrm{\&theta;}}^k+\frac{r}{b}{\&Integral;}_{T_k}^{T_{k+1}}\left|{{\mathrm{\&omega;}}_r}^k-{{\mathrm{\&omega;}}_l}^k\right|dt\end{array}\right.---\left(1\right)$

$\left\{\begin{array}{c}{x}^{k+1}=x^k+{\mathrm{\&pi;rcos\&theta;}}^k{\&Integral;}_{T_k}^{T_{k+1}}\left({n_l}^k+{n_r}^k\right)dt\\ y^{k+1}=y^k+{\mathrm{\&pi;rsin\&theta;}}^k{\&Integral;}_{T_k}^{T_{k+1}}\left({n_l}^k+{n_r}^k\right)dt\\ {\mathrm{\&theta;}}^{k+1}={\mathrm{\&theta;}}^k+\frac{2\mathrm{\&pi;}r}{b}{\&Integral;}_{T_k}^{T_{k+1}}\left({n_r}^k-{n_l}^k\right)dt\end{array}\right.---\left(2\right)$

In formula: T is the period of motion, r is radius of wheel, ω _land ω _rbe respectively left and right wheel angles speed, n _land n _rbe respectively left and right wheels rotating speed;

2) in the present embodiment, structured light sensor is adopted to tilt to be incident upon on seam welds groove by structured light, when welding arc scans groove with rotary motion form under additional transverse rotating magnetic field controls, gather the structural light stripes image comprising groove geometry feature, adopt adaptive threshold fuzziness, medium filtering successively, the step of refinement and slope calculations processes and feature extraction image, obtain the positional information of bevel for welding characteristic point i, comprise bevel for welding characteristic point i and welding torch at structured light sensor coordinate system L _xyzoffset distance E on middle y-axis direction _iwith bevel for welding characteristic point at structured light sensor coordinate system L _xyzin coordinate, when welding arc scans groove with rotary motion form under additional transverse rotating magnetic field controls, arc sensor starts to adopt Hall element to gather welding current signal, Butterworth low pass ripple and wavelet filtering is adopted to carry out to welding current signal the filtering that pretreatment realizes interfering signal, and carry out signal amplification, adopt integration differential method, the welding current signal that characteristic harmonics method or extremum method are extracted after treatment carries out real-time welding torch posture information, airborne executing agency is according to obtained real-time welding torch posture information adjustment welding torch pose, make it aim at Weld pipe mill and maintain constant torch height, while airborne executing agency adjustment welding torch pose, arc sensor starts the arc energy signals collecting in next cycle, circulation like this, namely welding bead is realized from motion tracking,

3) according to bevel for welding characteristic point at structured light sensor coordinate system L _xyzin coordinate, carry out coordinate transform to basic cartesian coordinate system O _xyz, obtain the coordinate G of bevel for welding characteristic point i _i=(x _i, y _i);

4) according to step 2) and 3) solve the coordinate of a series of bevel for welding characteristic point successively, obtain a bevel for welding characteristic point coordinate sequence { G ₁, G ₂..., G _nand an offset distance array { E ₁, E ₂..., E _n, wherein

$N=\frac{\mathrm{\&lambda;}}{{\mathrm{vT}}_{op}}+1---\left(3\right)$

In formula: λ is the distance that structured light sensor is prepended to welding torch, determines according to welding bead trajectory geometry feature and welding process requirement, setting λ is the value between 30mm to 50mm, and v is speed of welding, T _opfor the bevel for welding characteristic point position information extraction cycle;

5) SPL (Catmull-Rom curve) is adopted to carry out the Fitting Calculation to bevel for welding characteristic point coordinate sequence, obtain lopcus function S (x) to be welded and carry out differentiate, solving the tangent slope k of each bevel for welding characteristic point on lopcus function S (x) to be welded in bevel for welding characteristic point coordinate sequence _i, i=1,2 ..., N, obtains comprising N number of bevel for welding characteristic point position auto―control P _i=[x _iy _iarctan (k _i)], i=1,2 ..., the set of N;

6) set threshold value σ with compare, and set threshold value ζ and Δ E compares, when or during Δ E> ζ, robot body performs the turning motion planning of side, welding torch place, i.e. continuous path Motion trajectory; When or during Δ E<-ζ, robot body performs the turning motion planning of side, non-welding torch place, namely around car body center pivot turn trajectory planning; When and during-ζ≤Δ E≤ζ, robot body performs point-to-point craspedodrome trajectory planning; Wherein

$\left\{\begin{array}{c}\mathrm{\&Delta;}E=E_N-E_1\\ \mathrm{\&sigma;}=L_m-L_s+\frac{1}{2}{L}_a,\frac{1}{2}{L}_a<L_m<L_a\\ \mathrm{\&zeta;}=\frac{1}{4}{L}_a\end{array}\right.---\left(4\right)$

In formula: E ₁and E _nbe respectively the 1st and N number of bevel for welding characteristic point and welding torch at structured light sensor coordinate system L _xyzon middle y-axis direction offset distance, L _sfor welding torch is at airborne executing agency coordinate system U _xyzin y coordinate, L _afor airborne executing agency is at airborne executing agency coordinate system U _xyzmaximum functional stroke on middle y-axis direction, L _mfor airborne executing agency is at airborne executing agency coordinate system U _xyzdefault impulse stroke on middle y-axis direction, according to actual welding structure and the size setting of airborne executing agency;

7) robot body is according to continuous path Motion trajectory, around car body center pivot turn trajectory planning or the adjustment of point-to-point craspedodrome trajectory planning execution pose, repeat step 2 simultaneously) ~ 6), carry out trajectory planning next time, namely realize the online Dynamic Programming of track in welding process and welding bead and follow the tracks of collaborative control.

Step 6) described in continuous path Motion trajectory, the method for employing is:

According to step 5) described in the set of bevel for welding characteristic point position auto―control, adopt following formula:

$\left[\begin{array}{c}{x}_{pi}\\ y_{pi}\\ {\mathrm{\&theta;}}_{pi}\end{array}\right]=\left[\begin{array}{c}{x}_i+\frac{1}{2}{L}_{a}sin\left(arctan\left(\frac{dS\left(x_i\right)}{dx}\right)\right)\\ y_i-\frac{1}{2}{L}_a\cos \left(arctan\left(\frac{dS\left(x_i\right)}{dx}\right)\right)\\ \arctan \left(\frac{dS\left(x_i\right)}{dx}\right)\end{array}\right],i=1,2,...,N---\left(5\right)$

Computing machine human body position auto―control U of i-th on robot body movement locus _pi: [x _pi, y _pi, θ _pi], (i=1,2 ..., N), wherein: S (x _i) be functional value upper i-th of lopcus function S (x) to be welded, x _pi, y _pito be respectively on robot body movement locus at i-th at basic cartesian coordinate system O _xyzin coordinate, θ _pifor robot body azimuth of i-th on robot body movement locus, adopt SPL (Catmull-Rom curve) to the coordinate (x of whole point on robot body movement locus _pi, y _pi), i=1,2 ..., N carries out interpolation calculation, generates continuous and level and smooth robot body movement locus; Adopt differential speed control method control left and right wheels, make it complete continuous path along path node and move, as shown in Figure 3,

U _p1: [x _p1, y _p1, θ _p1] be the starting point position auto―control of robot body on robot body movement locus,

U _pN: [x _pN, y _pN, θ _pN] be the terminating point position auto―control of robot body on robot body movement locus,

U _pi: [x _pi, y _pi, θ _pi], (i=2,3 ..., N-1) be the path node position auto―control of robot body on robot body movement locus;

Step 6) described in around car body center pivot turn trajectory planning, the method for employing is:

As shown in Figure 4, control machine human body left and right sides driving wheel, make driving wheel velocity magnitude equal, direction is contrary, realize robot body around the pivot turn of car body center, and make robot body central speed direction turning start with at the end of consistent with institute matching seam track tangential direction respectively, robot body angle of turn θ _remploying following formula calculates:

${\mathrm{\&theta;}}_R=arctan\left(\frac{dS\left(x_N\right)}{dx}\right)-arctan\left(\frac{dS\left(x_1\right)}{dx}\right).---\left(6\right)$

Step 6) described in point-to-point craspedodrome trajectory planning, the method for employing is:

As shown in Figure 5, U _p1for the initial pose of described robot body, U _pNfor described robot body object pose, keep robot body left and right sides driving wheel velocity-stabilization, make robot body be λ along current direction displacement length, translational speed size remains unchanged.

Realize the mobile welding robot system of method described in the present embodiment, as shown in Figure 6, it is characterized in that: it comprises a mobile robot (i.e. described robot body) 1, one structured light sensor 2 (comprises light source, video camera, filter, all do not draw in figure), one image pick-up card 3, one arc sensor (comprises a welding torch 4, one Hall element or signal transmitting device 5), one signal acquisition process module 6, one industrial computer 7, one motion control card 8, a set of airborne executing agency 9 (comprises balladeur train, slide block, motor, motor driver), one Movement Controller of Mobile Robot 10, one source of welding current 11.Described airborne executing agency is fixedly installed on described mobile robot 1.The end of described airborne executing agency 9 side is fixedly connected with described welding torch 4.One interface of the described source of welding current 11 is connected with workpiece 12 through described Hall element or signal transmitting device 5.Another interface of the described source of welding current 11 is connected with described welding torch 4, forms welding current loop.The output of described Hall element or signal transmitting device 5 connects the input of described signal acquisition process module 6, and the output of described signal acquisition process module 6 connects another input of described industrial computer 7.Described structured light sensor 2 is fixedly installed on the side of described welding torch 4 through a support, and the output of described structured light sensor 2 connects the input of described image pick-up card 3, and the output of described image pick-up card 3 connects an input of described industrial computer 7.The input that one output of described industrial computer 7 connects described motion control card 8 controls it and carries out work, and the output of described motion control card 8 connects described airborne executing agency 9.The input that another output of described industrial computer 7 connects described Movement Controller of Mobile Robot 10 controls it and carries out work, and the output of described Movement Controller of Mobile Robot 10 connects described mobile robot 1.

Described mobile robot adopts the one of wheeled mobile robot, mobile platform or mobile trolley, it is characterized in that: the pivot turn that radius of turn is zero can be realized, in the present embodiment, adopt the Pioneer3-AT robot car that ActivMedia company and Stanford University SIR laboratory are developed jointly.

Described welding torch adopts the one of the rotary welding torch of magnetic control, machinery rotating type welding torch, automatically controlled swing type welding torch or mechanical swinging type welding torch, adopts the rotary welding torch of magnetic control in the present embodiment.

Described industrial computer can be replaced by the one in single-chip microcomputer, DSP, PLC, ARM, FPGA or computer according to actual needs.

Claims (5)

1. in welding process, the online Dynamic Programming of track and welding bead follow the tracks of a collaborative control method, it is characterized in that described method comprises the steps:

1) set up mobile welding robot system coordinate system, comprising: basic cartesian coordinate system O _xyz, robot body coordinate system M _xyz, airborne executing agency coordinate system U _xyzwith structured light sensor coordinate system L _xyz, wherein, airborne executing agency coordinate system U _xyzwith structured light sensor coordinate system L _xyzx-axis forward consistent with the direction of robot body straight forward, z-axis forward is consistent with the direction of ground normal, and y-axis forward is determined by lefft-hand rule, airborne executing agency coordinate system U _xyzinitial point be positioned at the fixed connection place of airborne executing agency and robot body;

2) when welding arc scans groove with swing, rotation or swing-rotary composite movement form, adopt structured light sensor to extract the positional information of front, weld zone seam welds groove characteristic point i, comprise bevel for welding characteristic point i and welding torch at structured light sensor coordinate system L _xyzoffset distance E on middle y-axis direction _iwith bevel for welding characteristic point at structured light sensor coordinate system L _xyzin coordinate, adopt arc sensor to gather arc energy signal in real time simultaneously, integration differential method, characteristic harmonics method or extremum method is adopted to extract through signal filtering and the real-time welding torch posture information of amplifying in the arc energy signal after processing, welding torch pose is adjusted according to obtained real-time welding torch posture information by airborne executing agency, while airborne executing agency adjustment welding torch pose, arc sensor starts the arc energy signals collecting in next cycle, circulation like this, namely realizes welding bead and follows the tracks of;

3) according to bevel for welding characteristic point at structured light sensor coordinate system L _xyzin coordinate, carry out coordinate transform to basic cartesian coordinate system O _xyz, obtain the coordinate G of bevel for welding characteristic point i _i=(x _i, y _i);

4) according to step 2) and 3) solve the coordinate of a series of bevel for welding characteristic point successively, obtain a bevel for welding characteristic point coordinate sequence { G ₁, G ₂..., G _nand an offset distance array { E ₁, E ₂..., E _n, wherein

$N=\frac{\mathrm{\&lambda;}}{{\mathrm{vT}}_{op}}+1$

In formula: λ is the distance that structured light sensor is prepended to welding torch, v is speed of welding, T _opfor the bevel for welding characteristic point position information extraction cycle;

5) SPL is adopted to carry out the Fitting Calculation to bevel for welding characteristic point coordinate sequence, obtain lopcus function S (x) to be welded and carry out differentiate, solving the tangent slope k of each bevel for welding characteristic point on lopcus function S (x) to be welded in bevel for welding characteristic point coordinate sequence _i, i=1,2 ..., N, obtains comprising N number of bevel for welding characteristic point position auto―control P _i=[x _iy _iarctan (k _i)], i=1,2 ..., the set of N;

6) set threshold value σ with compare, and set threshold value ζ and Δ E compares, when or during Δ E> ζ, robot body performs continuous path Motion trajectory; When or during Δ E<-ζ, robot body performs around car body center pivot turn trajectory planning; When and during-ζ≤Δ E≤ζ, robot body performs point-to-point craspedodrome trajectory planning; Wherein

$\left\{\begin{array}{c}\mathrm{\&Delta;}E=E_N-E_1\\ \mathrm{\&sigma;}=L_m-L_s+\frac{1}{2}{L}_a,\frac{1}{2}{L}_a<L_m<L_a\\ \mathrm{\&zeta;}=\frac{1}{4}{L}_a\end{array}\right.$

In formula: E ₁and E _nbe respectively the 1st and N number of bevel for welding characteristic point and welding torch at structured light sensor coordinate system L _xyzon middle y-axis direction offset distance, L _sfor welding torch is at airborne executing agency coordinate system U _xyzin y coordinate, L _afor airborne executing agency is at airborne executing agency coordinate system U _xyzmaximum functional stroke on middle y-axis direction, L _mfor airborne executing agency is at airborne executing agency coordinate system U _xyzdefault impulse stroke on middle y-axis direction;

7) robot body is according to continuous path Motion trajectory, around car body center pivot turn trajectory planning or the adjustment of point-to-point craspedodrome trajectory planning execution pose, repeat step 2 simultaneously) ~ 6), carry out trajectory planning next time, namely realize the online Dynamic Programming of track in welding process and welding bead and follow the tracks of collaborative control.

2. the online Dynamic Programming of track and welding bead follow the tracks of collaborative control method in a kind of welding process according to claim 1, it is characterized in that: step 6) described in continuous path Motion trajectory, the method for employing is:

According to step 5) described in the set of bevel for welding characteristic point position auto―control, adopt following formula:

$\left[\begin{array}{c}{x}_{pi}\\ y_{pi}\\ {\mathrm{\&theta;}}_{pi}\end{array}\right]=\left[\begin{array}{c}{x}_i+\frac{1}{2}{L}_{a}sin\left(arctan\left(\frac{dS\left(x_i\right)}{dx}\right)\right)\\ y_i-\frac{1}{2}{L}_a\cos \left(arctan\left(\frac{dS\left(x_i\right)}{dx}\right)\right)\\ \arctan \left(\frac{dS\left(x_i\right)}{dx}\right)\end{array}\right],i=1,2,...,N$

Computing machine human body position auto―control of i-th on robot body movement locus: U _pi: [x _pi, y _pi, θ _pi], (i=1,2 ..., N), wherein: S (x _i) be functional value upper i-th of lopcus function S (x) to be welded, x _pi, y _pito be respectively on robot body movement locus at i-th at basic cartesian coordinate system O _xyzin coordinate, θ _pifor robot body azimuth of i-th on robot body movement locus, adopt SPL to the coordinate (x of whole point on robot body movement locus _pi, y _pi), i=1,2 ..., N carries out interpolation calculation, generates continuous and level and smooth robot body movement locus.

3. in a kind of welding process according to claim 1, the online Dynamic Programming of track and welding bead follow the tracks of collaborative control method, it is characterized in that: step 6) described in around car body center pivot turn trajectory planning, the method for employing is:

Control machine human body left and right sides driving wheel, makes driving wheel velocity magnitude equal, and direction is contrary, realizes robot body around the pivot turn of car body center, robot body angle of turn θ _remploying following formula calculates:

${\mathrm{\&theta;}}_R=arctan\left(\frac{dS\left(x_N\right)}{dx}\right)-arctan\left(\frac{dS\left(x_1\right)}{dx}\right).$

4. in a kind of welding process according to claim 1, the online Dynamic Programming of track and welding bead follow the tracks of collaborative control method, it is characterized in that: step 6) described in point-to-point craspedodrome trajectory planning, the method for employing is:

Keep robot body left and right sides driving wheel velocity-stabilization, make robot body be λ along current direction displacement length, translational speed size remains unchanged.

5. in a kind of welding process according to claim 1, the online Dynamic Programming of track and welding bead follow the tracks of collaborative control method, it is characterized in that: described welding torch adopts the one of the rotary welding torch of magnetic control, machinery rotating type welding torch, automatically controlled swing type welding torch or mechanical swinging type welding torch.