WO2024045120A1

WO2024045120A1 - System and method for self-adjustable welding

Info

Publication number: WO2024045120A1
Application number: PCT/CN2022/116467
Authority: WO
Inventors: Chi Hung Lai
Original assignee: Squaredog Robotics Limited
Priority date: 2022-09-01
Filing date: 2022-09-01
Publication date: 2024-03-07

Abstract

An integrated, fully-automated welding path planning and welding operation system for joining at least two adjacent workpieces by welding, The fully-automated welding path planning and welding operation system is ealized by a robotic control mechanism integrated into the present system to be operable with the welding apparatus and optical scanner. Also related a method for joining the same with a self-adjustable scanning mechanism to re-position an optical scanner responsible for performing each optical scanning cycle until obtaining an optimal welding path in the absence of any human intervention prior to actual welding.

Description

SYSTEM AND METHOD FOR SELF-ADJUSTABLE WELDING

TECHNICAL FIELD

The present invention relates to a system and method for self-adjustable welding, in particular, to self-adjusting a welding path along a target welding seam based on a series of sensed spatial and optical data for a subsequent robotic welding operation.

BACKGROUND

Welding processes involve various techniques, materials, and conditions for joining at least two metal portions in metal fabrication and repair industries. Those techniques involved in welding as such include, but not limited to, arc welding, gas welding, flow welding, carbon induction welding, resistance welding, thermit welding, etc. Depending on the purpose of the welding joint, there are five common types of welding joints, which are butt joint, lap joint, corner joint, edge joint, where the most commonly used among them is butt joint for joining edges of two plates or surfaces in approximately the same plane. For heavy sections, grooved butt joint with different types of edge preparations is used, where the edges are prepared by flame cutting, shearing, flame grooving, machining, chipping, carbon arc cutting or gouging. For plate thickness from 3/8 to 1/2 inches, single-V or single-U grooved butt joint can be used; for heavier sections, e.g., from 1/2 to 2 inches, double-V grooved butt joint may be used; and for thickness of 3/4 inches or up, double-U grooved butt joint should be used. It is generally considered to be better in heavy sections when butt joints are prepared on both sides, i.e., double-V or double-U grooves, than only one side. However, welding on both sides can sometimes be impractical under certain circumstances, e.g., when repairing fixtures on a vertical wall.

In terms of the joint anatomy of butt joints, the most commonly used bevel is plain bevel with a usual wall thickness of about 4 to 22 mm. Another type of bevels in butt joints is compound bevel with a wall thickness of more than 22 mm.

In the context of welding two plates in vertical position on a wall while a longitudinal axis of the weld is in a relatively horizontal orientation, a weld line between two adjacent edges of two plates which a corresponding welding apparatus follows during welding operation is usually scanned manually by an operator of the welding apparatus to roughly estimate the profile of the weld bevel. However, the exact geometry of the weld joint is difficult to be measured by bare eyes.

Therefore, some prior arts attempted to provide some automated welding devices or methods to measure the weld joint and/or estimate the geometry of the actual weld joint prior to welding operation. US 2011/0155711 is one of those, where a line type laser sensor was used to project a “laser line” within a fixed operating window and produce a reflective position of anything that the laser line “sees” within that operating window, in order to estimate the distance of an object from the laser along the laser line, and certain parts of the weld bevel were thereby targeted for estimating the geometry thereof. The measured data were then used to adjust the welding parameters in operating the welding equipment.

US 9,221,118 disclosed an adoptive control hybrid welding system including a seam tracker and control system to measure seam property of adjacent workpieces prior to welding and to modify welding parameters of a laser and electric arc welder or the spacing between the laser and the arc responsive to the measured seam property, in which the seam property is the variable gap along the seam.

US 10,448,692 disclosed a head mounted augmented or mixed reality displays for welding operation incorporated with an optical sensor to collect an image of a weld environment and an AR controller to determine position and perspective a simulated object (e.g., one or more lasers) , an interaction between the wearer and the simulated object, and response to the interaction by the wearer. The displays are mainly for training and learning purpose, instead of adjusting welding path along an axis of the welding plane between the two toes of the workpieces prior to welding operation.

Some other prior arts focused on machining bevels or adjusting bevel edge geometry of a workpiece during facing, such as US 10,537,940.

However, none of them has provided a specific solution to correct errors arising from a misalignment between a virtual welding path and an actual welding path substantially perpendicular to the root of a weld, e.g., a groove weld, and to couple with a fully automated welding apparatus to realize a welding operation without human intervention.

A need therefore exists for an improved system and method to at least diminish or substantially eliminate the disadvantages and problems described above.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a system and a related method for self-adjusting a welding path of a target seam from one end to an opposing end along a longitudinal axis of a weld between at least two workpieces based on a pre-determined two-dimensional profile data obtained from an optical device.

In one aspect, the present method includes using the optical device to scan along a virtual weld line between the two respective surfaces of work of at least two adjacent workpieces starting from the one end of the welding path of the target seam, defining a geometry of the weld bevel, and determining an intersection between the virtual weld line and a longest edge of the toe section of the weld bevel at each spot of welding. If the intersection substantially forms a right angle on the plane between the weld line and the longest edge of the toe section of the weld bevel, the optical device will continue to move on to a subsequent spot of welding along the welding path which is substantially perpendicular to the actual weld line until reaching the opposing end of the welding path; otherwise, the system will self-adjust the position of the optical device and repeat the scanning procedure at the same spot of welding until the intersection substantially forms a right angle on the plane between the weld line and the longest edge of the toe section of the weld. A two-dimensional profile of the whole weld joint between the two workpieces will be obtained prior to the actual welding operation.

In one embodiment, the optical device is selected from a line scanner.

The line scanner in certain embodiments can be used to scan along the weld line on each spot of welding from one toe section of the weld bevel toward another toe section thereof. As long as the intersection on the plane between the weld line and the longest edge of each of the toe sections of the weld bevel substantially forms a right angle, the line scanner will move on to a subsequent welding spot along the welding path of the target seam. Otherwise, the line scanner will be re-positioned based on the spatial and optical data obtained in a preceding scan to ensure the intersection on that plane forms substantially a right angle between the weld line and the longest edge of each of the toe sections of the weld bevel.

In certain embodiments, the re-positioning of the line scanner is fully automated.

In certain embodiments, the re-positioning, linear and angular motions of the line scanner are assisted by a robotic control module.

After completion of scanning the whole weld joint between the two workpieces along the virtual welding path, a corresponding two-dimensional profile of the whole weld joint will be generated based on one or more lines of pixel data obtained by the line scanner moving on a x-y plane across the whole weld joint, where the y-axis direction is defined by two opposing ends of the virtual welding path.

In certain embodiments, the virtual welding path along which the line scanner travels in a y-axis direction is substantially parallel to the longest edge of the two workpieces, while a self-adjusted weld line along which the actual welding apparatus will travel in a x-axis direction that is substantially perpendicular to the virtual welding path.

In certain embodiments, the system of the present invention includes:

a weld end module;

a robotic control module; and

a computer processor.

In certain embodiments, the weld end module includes a plurality of optical units including a light emitting unit and an optical sensing unit.

In certain embodiments, the light emitting and optical sensing units are accommodated in a scanner housing.

In certain embodiments, the weld end module further includes a movable shield device for shielding at least the light emitting and optical sensing units when needed.

In certain embodiments, the movable shield device includes a motor and a cover shield, where the motor is configured to pivotably move the cover shield to or away from where a window of the scanner housing is disposed for allowing light emissions or reflections leaving or entering the weld end module according to different operational states of the system.

In certain embodiments, the weld end module further includes a welding apparatus including a welding gun and a welding gun holder for accommodating the welding gun.

In certain embodiments, the weld end module further includes a robotic arm connection unit for communicating with the robotic control module.

In certain embodiments, the robotic control module includes at least a robotic arm pivotably movable in one or more orientations to navigate the linear or angular motion of the weld end module.

In certain embodiments, the system further includes one or more algorithms to be executable by the computer processor to calculate the best welding path based on the sensed spatial and image data obtained by the optical sensing units.

The computer processor can be integrated or separated from any of the modules. In the case where it is separated from any of the modules, they will be communicated via any wireless communication protocols.

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. Other aspects of the present invention are disclosed as illustrated by the embodiments hereinafter.

BRIEF DESCRIPTION OF DRAWINGS

The appended drawings, where like reference numerals refer to identical or functionally similar elements, contain figures of certain embodiments to further illustrate and clarify the above and other aspects, advantages and features of the present invention. It will be appreciated that these drawings depict embodiments of the invention and are not intended to limit its scope. The invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which:

FIG. 1 schematically depicts a method of using the self-adjustable welding system according to an embodiment of the present invention in an example weld bevel of two adjacent workpieces substantially erected vertically, in which the upper panel depicts an optical device of the present system responsible for scanning the geometry of weld bevel before self-adjustment and the lower panel depicts the scanning of the weld bevel geometry by the optical device after self-adjustment; dashed lines denoted by 101a represent the light emission spectrum by the optical device 101 along a weld line (104a, 104b) in an y-axis direction;

FIG. 2 shows some key steps of a method of using the self-adjustable welding system according to an embodiment of the present invention as a flowchart;

FIG. 3 shows key elements of the self-adjustable welding system according to certain embodiments of the present invention as a block diagram;

FIG. 4A schematically depicts from a front perspective view the self-adjustable welding system according to an embodiment of the present invention;

FIG. 4B schematically depicts from a rear perspective view the self-adjustable welding system according to the same embodiment as in FIG. 4A;

FIG. 5A schematically depicts a non-welding operational state of the present system according to certain embodiments of the present invention;

FIG. 5B schematically depicts a welding operational state of the present system according to certain embodiments of the present invention;

FIG. 6A shows images of an example weld bewel profile scanned by the present system (left panel) and a projected weld line according to the scanned weld bewel profile (right panel) ;

FIG. 6B shows images of another example weld bewel profile scanned by the present system (left panel) and a projected weld line according to the scanned weld bewel profile (right panel) .

Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been depicted to scale.

DEFINITION

The term “root” of a weld described herein may refer to the point at where the bottom of the weld intersects the base metal surface.

The term “face” of a weld described herein may refer to an exposed surface of a weld made by any arc or welding approach on the side from which the welding is done.

The term “leg” or its plural form of a weld described herein may refer to the distance from the root of the joint to the toe of a fillet weld, where there are two legs in a fillet weld.

The term “toe” of a weld described herein may refer to the junction between the face of a weld and the base metal.

The term “theoretical throat” of a weld described herein may refer to a perpendicular distance of a weld and the hypotenuse of the largest right triangle that can be inscribed within the cross-section of a fillet weld.

The term “actual throat” of a weld described herein may refer to a distance from the root of a fillet weld to the centre of its face.

The term “reinforcement” of a weld described herein may refer to the weld metal on the face of a groove weld in excess of the metal necessary for a specified weld size.

The term “groove weld” or alike described herein may refer to the size of a weld is the depth of chamfering plus the root penetration when specified.

The term “fusion zone” or “filler penetration” described herein may refer to the area of the base metal melted determined in the cross-section of a weld.

References in the specification to “one embodiment” , “an embodiment” , “an example embodiment” , etc., indicate that the embodiment described can include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

The term “a” or “an” are used to include one or more than one and the term “or” is used to refer to a nonexclusive “or” unless otherwise indicated. In addition, it is to be understood that the phraseology or terminology employed herein, and not otherwise defined, is for the purpose of description only and not of limitation. Furthermore, all publications, patents, and patent documents referred to in this document are incorporated by reference herein in their entirety, as though individually incorporated by reference. In the event of inconsistent usages between this document and those documents so incorporated by reference, the usage in the incorporated reference should be considered supplementary to that of this document; for irreconcilable inconsistencies, the usage in this document controls.

Value in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a concentration range of “about 0.1%to about 5%” should be interpreted to include not only the explicitly recited concentration of about 0.1 wt. %to about 5 wt. %, but also the individual concentrations (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.1%to 0.5%, 1.1%to 2.2%, and 3.3%to 4.4%) within the indicated range.

In the methods of preparation or using the system, device, apparatus, or alike described herein, the steps can be carried out in any order without departing from the principles of the invention, except when a temporal or operational sequence is explicitly recited. Recitation in a claim to the effect that first a step is performed, and then several other steps are subsequently performed, shall be taken to mean that the first step is performed before any of the other steps, but the other steps can be performed in any suitable sequence, unless a sequence is further recited within the other steps. For example, claim elements that recite “Step A, Step B, Step C, Step D, and Step E” shall be construed to mean step A is carried out first, step E is carried out last, and steps B, C, and D can be carried out in any sequence between steps A and E, and that the sequence still falls within the literal scope of the claimed process. A given step or sub-set of steps can also be repeated.

DETAILED DESCRIPTION OF THE INVENTION

It will be apparent to those skilled in the art that modifications, including additions and/or substitutions, may be made without departing from the scope and spirit of the invention. Specific details may be omitted so as not to obscure the invention; however, the disclosure is written to enable one skilled in the art to practice the teachings herein without undue experimentation.

Turning to FIG. 1, the upper panel and lower panel show the respective positions of a line scanner 101 being an optical device of the present system for scanning weld bevel geometry along a weld line of a welding spot before and after self-adjustment computed by a computer processor with one or more corresponding algorithms based on spatial and image data obtained by the line scanner. For illustration purpose, the upper and lower panels of FIG. 1 just present one spot of welding along a virtual welding pathway of two adjacent workpieces, but it should be understood as non-limiting to that spot of welding. In FIG. 1, it shows an example under a situation where the two adjacent workpieces to be joined by welding are vertically oriented on an erected structure such as a permanent wall panel (not shown in FIG. 1) . In this example, a single V-grooved butt joint is presented. Again, it should be understood that the present system is not limited to be applied to this kind of weld joint, but is applicable to other kinds of weld joint as well.

As shown in the upper panel of FIG. 1, the line scanner 101 initially moves along a potential weld line 104a in an x-axis direction starting from an x-y plane surface of a first workpiece, first intersecting a longest edge 102 of the first workpiece at a junction with a first toe of the weld, towards a root 106 of the weld along a first original surface of work 104, and then from the root 106 of the weld to a second original surface of work 105, second intersecting a longest edge 103 of a second workpiece at a junction with a second toe of the weld, until reaching an x-y plane surface of the second workpiece. During each scanning cycle, light emissions 101a will be generated alongside the scanning along the weld line. If the initial scan could not establish an incident angle of 90° between the potential weld line (in y-axis direction) and the longest edge of the first /second workpiece (in x-axis direction) , where the measurement of the incident angle is based on the spatial and pixel data obtained by the line scanner, a computer processor of the present system (not shown in any figures) will send instructions or command to a corresponding moving mechanism responsible for controlling the motion (linear and/or angular) of the line scanner to self-adjust the scanning position of the line scanner prior to a subsequent scan of the same spot of welding. Preferably, an tolerable accuracy of this incident angle is within ±0.5 degrees.

As shown in the lower panel of FIG. 1, after self-adjustment of the angle (θ) between a central axis 107 of the line scanner 101 and the vertical axis of the x-y plane surface 108 of the first /second workpiece (102, 103) , e.g., to adjust the central axis 107 of the line scanner 101 to be substantially parallel to the vertical axis of the x-y plane surface 108 of the first /second workpiece (102, 103) , the potential weld line 104b will substantially be parallel to the central axis 107 of the line scanner 101, thereby establishing an incident angle of 90° between the potential weld line 104b (in y-axis direction) and the longest edge (102, 103) of the first /second workpiece (in x-axis direction) . As long as the incident angle of 90° adjacent to the first and second toes of the weld is established, that means an optimal weld line at a particular welding spot along the welding path is obtained, the moving mechanism for controlling the linear/angular motion of the line scanner will move the line scanner to a subsequent spot of welding in the x-direction along the welding path until reaching the opposing end of the target seam.

It should be understood that a groove weld can include a root penetration (which is not shown in FIG. 1, but an example is shown in the left panel of FIG. 6A) . The moving mechanism used in the example of FIG. 1 or other embodiments described herein can include a robotic arm controlled by a robotic system, where the robotic arm is physically connected to a welding apparatus and the line scanner (an example will be described hereinafter and shown in FIGs. 4A and 4B) . Besides using line scanner, any optical device capable of scanning a sufficiently large area and sensing corresponding data for generating a two-dimensional profile of the weld joint between two adjacent workpieces can alternatively be used as the optical device of the present system.

Turning to FIG. 2, using the line scanner depicted in FIG. 1 as the optical device of the present system for scanning an optimal weld line of each of the welding spots along the welding path, an operator of the present system initially defines start and end points (or spots) of the welding path of a target seam (s201) . The line scanner scans along a weld line in a vertical (or y-direction as in FIG. 1) at each welding spot from the start point to obtain corresponding spatial and image data along that weld line including geometrical data of the weld such as bevel angle of each of the original surfaces of work against a virtual central axis from the root of the weld (or a theoretical throat of a fillet weld) , depth or size of the weld, etc. (s202) . The sensed data will then be fed to a corresponding computer processor with a software component to estimate whether a scanned weld line results in an optimal weld line in terms of the best angle and welding distance along that weld line (s203) . As depicted in FIG. 1, the best angle to result in the best distance of welding along the weld line may be obtained by determining whether an intersect point between the weld line and the longest edge of the first /second workpiece on the x-y plane is substantially a right angle or not. In certain embodiments, the optimization of the weld line and estimation of weld seam profile are computed by a software component with respect to the relative position between the weld seam and the weld gun in order to correlate the weld seam profile with the robot arm position. The computation by the software component involves using the global position of the scanner (i.e., x-, y-, and z-coordinates) , angular motion of the scanner (rx, ry, rz) , and linear distance from the weld seam to the scanner (y ₁, y ₂, y ₃ …. y _n) . If an optimal weld line is obtained, the robotic arm connected to the welding apparatus and the line scanner for scanning the weld lines along the target seam will move the welding apparatus and the line scanner to a subsequent spot of welding to repeat the steps s202 and s203 at the subsequent spot (s204) until reaching the pre-defined end point of the welding path of the target seam. However, if an optimal weld line of a particular welding spot is not obtained, the robotic arm will self-adjust the position of the line scanner, e.g., adjust a tilting angle of the line scanner, based on a two-dimensional profile obtained in the preceding scan, and then repeat steps s202 and s203 at that particular welding spot (s207) until an optimal weld line is obtained before moving on to a subsequent spot of welding. After the weld line at each of the welding spots along the welding path of the target seam is obtained, an optimal welding path and two-dimensional (2D) contour map re-constructing the geometry of the weld along the whole welding path will be obtained (s205) . Based on the optimal welding path and the 2D contour map, the robotic arm under the control by the corresponding control mechanism will actuate/navigate the connected welding apparatus of the present system to perform welding following the optimal welding path under the operational parameters corresponding to the corresponding geometry of the weld at each welding spot (s206) . The operational parameters may vary from one to the other welding spots along the welding path in terms of the depth, bevel angle, materials of the workpiece and/or other morphological characteristics of the weld. FIGs. 6A and 6B show two different spots on a prospective welding path with different weld bewel geometries (one with a root penetration whereas the other without a root penetration) , respectively, and their corresponding projected/estimated weld line after the self-adjustment.

Turning to FIG. 3, the architecture of the present system can be mainly divided into a weld end module or apparatus 30 and a robotic control module 40. Within the weld end module 30, it includes an optical complex 300 including an optical scanner 321 disposed in a scanner housing 320 for measuring surface parameters of objects detected during scanning of multiple weld lines along the welding path, and a movable shield device 310 mainly for selectively shielding the optical scanner 321 when needed. The movable shield device 310 includes an optical switch 311 and a motor 312, where the optical switch 311 is configured for light emission and receiving light reflections from objects, while the motor 312 is for controlling a pivotal movement of an associated cover shield to substantially cover a window of the scanner housing 320 from where the optical scanner 321 receives image signals from any scanned objects. Adjacent to the optical complex 300, a welding apparatus includes a welding gun holder 330 and a welding gun 331. The welding apparatus also includes a handle (332 as shown in FIG. 4A) . Associated with the optical complex 300 and the welding apparatus, there is a connection 340 for engaging one end of a robotic arm 410 of a robotic control module 40. The connection 340 includes a plurality of engagement members (341 as shown in FIG. 4B) complementary to those at the one end of the robotic arm 410 for securing the connection between the optical complex/welding apparatus and the robotic control module. In a preferred embodiment, the optical complex 300 and welding apparatus are detachably connected with each other. During weld line/welding path scanning, the optical complex 300 and the welding apparatus are driven to move in the same degree of motion and direction according to the movement of the connected robotic arm. In other embodiments, the welding apparatus can be detached from the optical complex 300 such that they do not necessarily align to each other when the robotic arm moves.

Turning to FIGs. 4A and 4B, front and rear perspective views of the present system according to certain embodiments are shown, corresponding to the key elements depicted in FIG. 3. In FIG. 4A, the weld end module 30 includes an optical complex 300, a welding apparatus, and a connection for engaging a corresponding robotic control module 40. The optical complex 300 includes a plurality of optical units including an optical switch 311 and optical scanner 321 which are disposed in separate housings in these embodiments. A motor 312 pivotally connected to a cover shield 310 affixed on two opposing external walls of the scanner housing 320 is configured to control the movement of the cover shield between its top and front orientations, as depicted in FIGs. 5A and 5B, respectively. A main purpose of the cover shield 310 is to protect the optical units of the present system from any potential damages arising from the welding operation, as usually heat will be applied during the welding operation. Therefore, during scanning of weld line and welding pathway, the cover shield 310 is at its upright position, as in FIG. 5A, whereas during welding operation, that is the welding gun 331 is in operation, the cover shield 310 is moved by the motor 312 from its upright position to a front position (or by almost 90° as in FIG. 5B) such that an open end or window of the scanner housing 320 corresponding to a light sensing zone of the optical scanner and the optical switch is almost completely covered by the cover shield 310.

Along the same central axis as the optical complex 300, the welding apparatus is disposed adjacent to the optical complex 300 for welding operation subsequently to scanning of weld lines/welding pathway, which includes a welding gun holder 330 for securing or holding the welding gun 331. Welding materials including metal and non-metal compounds can be stored in the welding gun holder 330. An optional handle 332 is incorporated into the welding apparatus and disposed under the welding gun holder 330 for an operator of the present system to control the welding operation manually when needed. Preferably, movement of the welding apparatus along the welding path is fully automated which is realized by a robotic arm engaged with a corresponding connector 340 disposed adjacent to the welding apparatus and on the same central axis as those of the optical complex 300 and welding apparatus. To enable a more accurate measurement and determination of the most optimal welding path/welding profile, from optical scanning to welding operation, movement and/or self-adjustment of any of the modules of the present system is/are preferably performed under the control by the robotic control module 40. Under some circumstances, the optical scanner and/or welding apparatus can be manually controlled by the operator with the assistance by a welding path guiding mechanism such as a projected welding path on a target seam visually available to the operator that is computed by the computer processor of the present system based on the sensed data of one or more preceding scans. To secure the robotic arm 410 to the connector 340 of the present system, a number of engagement members 341 having a shape and dimension complementary to the same number of receiving members (not shown in any figures) are provided at a connection end of the connector 340 (FIG. 4B) .

Since some weld joints in which the present system is intended to be used are relatively large in scale and limited by the orientation of two adjacent workpieces and/or the target seam, a line scanner is preferably selected as the optical scanner of the present system for obtaining corresponding image data of the whole weld region. A two-dimensional contour map of the weld bevel geometry throughout the whole weld region is thereby generated and analyzed by one or more algorithms to be implemented by the computer processor of the present system in order to find the optimal welding path prior to actual welding. Other data such as spatial and/or temperature information of the line scanner during welding path and/or weld line scans may be obtained simultaneously by other sensors including but not limited to IMU and thermal sensors to assist the welding path finding and generation of the weld bevel contour map of the target seam.

The body of any modules and/or connector of the present system can be made of one or more of metal or non-metal materials, or a combination thereof, including but not limited to steel, aluminum and polyoxybenzylmethylenglycolanhydride (or known as Bakelite) . Preferably, one or more lighter, weather-resistant and thermal-resistant material (s) is/are selected as at least the scanner housing and cover shield associated therewith to enable the protection of the optical units disposed therein from the welding operation and/or from the surroundings since the present system may more frequently be used in outdoor settings.

Although the invention has been described in terms of certain embodiments, other embodiments apparent to those of ordinary skill in the art are also within the scope of this invention. Accordingly, the scope of the invention is intended to be defined only by the claims which follow.

Claims

An integrated, fully automated welding path planning and welding operation system, the system comprising:

a weld end module;

a robotic control module; and

a computer processor,

the weld end module comprising:

a plurality of optical units for optically scanning a weld joint region along a target seam,

welding apparatus for performing said welding operation, and

a complementary connector for engaging the robotic control module;

the robotic control module comprising one or more movement mechanisms for enabling multi-plane movements of the weld end module;

the computer processor comprising one or more algorithms for processing and analyzing sensed data by one or more of the optical units during said optically scanning, self-adjusting at least one of the optical units based on the processed and analyzed data, and/or directing linear and/angular motions of said welding apparatus along an actual welding path during said welding operation.
The system of claim 1, wherein the plurality of optical units comprises at least a light emitting unit and an optical sensing unit.
The system of claim 2, wherein the optical units are accommodated in a scanner housing, wherein the scanner housing is physically connected with the welding apparatus.
The system of claim 1, wherein the welding apparatus comprises a welding gun and a welding gun holder, wherein the welding gun holder comprises a compartment for storing and transferring welding materials for generating the weld joint to the welding gun.
The system of claim 3, wherein the weld end module further comprises a movable shield device capable of shielding the optical units accommodated in the scanner housing from the surroundings by substantially covering an opening of said scanner housing with a cover shield at where the corresponding optical units emit light beams and receive light reflections from any scanned objects during said optically scanning.
The system of claim 5, wherein the opening of said scanner housing is covered by the cover shield during said welding operation.
The system of claim 1, wherein the one or more movement mechanisms of the robotic control module are one or more robotic arms, wherein the multi-plane movements of the weld end module are enabled with respect to linear or angular motion of the most proximal robotic arm engaging the weld end module through the complementary connector.
The system of claim 2, wherein the optical units further comprise a line scanner for said optically scanning the weld joint region along the target seam, and wherein the light emitting unit is selected from an optical switch.
A method for welding at least two adjacent workpieces in a fully automated manner, comprising:

using the system of any one of claims 1 to 8 to define an optimal welding path to be of a target seam based on sensed data obtained in a series of optical scanning cycles;

an operator of the system starting a first cycle of optical scanning from a starting spot of the optimal welding path to be of the target seam and repeating the optical scanning cycle at each subsequent spot until a last spot on the optimal welding path to be of the target seam;

during a preceding cycle of optical scanning, if a corresponding weld line scanned by one of the optical units between two adjacent workpieces is not substantially perpendicular to a longest edge of each of the two adjacent workpieces, said optical unit responsible for performing said preceding optical scanning cycle will be re-positioned prior to a subsequent round of optical scanning until an optimal weld line is obtained at the same spot;

based on the sensed data obtained throughout the optimal welding path to be of the target seam, generating a two-dimensional contour map corresponding to surface geometry of the weld between the two adjacent workpieces to identify a shortest path between the starting spot and last spot above a weld joint region as the optimal welding path of the target seam; and

according to the optimal welding path so identified, welding at the weld joint region along the optimal welding path from the starting spot until the last spot thereof in the absence of any human intervention,

said sensed data comprising spatial and optical data of the weld bevel along the optimal welding path to be of the target seam;

said optical unit for performing the series of optical scanning cycles being an optical scanner capable of obtaining pixel data of any scanned object line-by-line perpendicular to the optimal welding path to be of the target seam; and

the longest edge of each of the two adjacent workpieces being at a junction between a plane surface of a first workpiece or second workpiece and a first or second toe of the weld bevel, respectively.
The method of claim 9, wherein the weld bevel comprises single or double groove bevels, and fillet bevels; the two adjacent workpieces are vertically oriented on an erected structure.