System and method for machining body parts, wherein robots are synchronised with a conveyor belt

The invention relates to a processing method and a method A processing installation, in particular a joining installation with the Characteristics within the scope of the procedure Device main claim.

Such joining systems for the car body building are off Practice. They consist of a tactical one Working conveyor for the workpieces, eg as Stroke shuttle. The joining system is in this case Several along the conveyor or the transfer line Ordered stations, in which at the dormant Workpiece different joining tasks of robots Are carried out in the stations One or more sides of the transfer line Are arranged. This construction has the disadvantage that A relatively high number of robots is required, wherein The robots and also the tools are not optimal Are loaded. Through the station binding and the Work on the stationary tool consists of a fixed The robot also has only one Limited workspace. In the total act of the In addition to working hours, Transportation time is decisive, resulting in efficiency . In addition, the station is connected to the An increased distance between the Robots, which increases the space requirement. After the robots Only partial areas must be machined on the standing workpiece For similar tasks on the front and back of the Workpiece several robots and also several similar Tools.

From DE 195 20 582 C1 an assembly is mounted on moving parts Bodies. The montage robot moves in In this case on an additional driving axis in Direction of transport synchronized with the body and For this purpose to the body conveyor. After Completion of the assembly job, the robot must be returned to Its initial position. This brings one Increased space requirements in the conveying direction. In addition Can not have multiple robots closely next to each other in Promotion.

DE 35 16 284 A1 also deals with the Carry out assembly work on a moving Vehicle body. Also here are Montageroboter with An additional linear axis, which is connected to the Conveyed vehicle synchronously Completion of the job.

DE 199 31 676 C2 teaches measuring a body, Which is stationary during the measuring process. Of the Measuring robot has an additional linear axis, with which it His working position can change. On the new It must be measured using stationary calibration marks Again.

DE 101 36 691 A1 deals with the compensation of Position errors of a robot by means of a laser measuring instrument. This is merely a calibration process. The measuring instrument can also be used as a measuring instrument Welding tool and a work piece Can be calibrated, which simplifies the calibration process And accelerated.

DE 24 30 058 A1 discloses a position measuring system for And is used for calibration and calibration Of a robot with compensation of its axis errors.

US Pat. No. 4,254,433 A1 discloses a joining system for bodywork construction, wherein Workpieces are continuously transported by a conveyor, and wherein a stationary workpiece Arranged in its axis movements with the conveying movement Is synchronized by means of a sensor system detecting the position of the workpieces. In This document describes the movements of the robot to the speed of the robot But the conveyor is not connected to the robot by a conveyor Central control system.

It is an object of the present invention to provide a better Machining process including processing plant and In particular a joining system for the car body building As well.

The invention solves this problem with the features in the Main claim. With the claimed method and the joining system, the Eg in the preferred embodiment as a so-called respot welding system Can be a higher Efficiency and better utilization of the robots used And their tools. Also the Stations can be canceled. The space requirement And the construction cost is reduced. The number of Can be used because of their functional and functional Spatial scope Can be minimized.

Through the continuous conveyor and the processing Of the workpieces during the conveying movement Time linkage. The performance of the Joining system is increased. The robots can According to their function and their processing tasks Optimally positioned. Superfluous free spaces, such as They were present in the previous station binding, Can be avoided. The space requirement of the joining plant Decreases accordingly.

For synchronizing the stationary With the conveying movement of the workpieces Is a suitable sensor system for movement and movement Position detection of the workpieces, which are carried out with a For example superordinated or into a Robotic control integrated control system . This makes the conveyor central And control and synchronize the robots. Preferably There is also a monitoring system which Compliance with the synchronization in the work area of ​​the Robot monitors and in collaboration with the central Or decentralized control system possibly for a Adjustment of the conveyor movement and / or the Robot movement.

The subclaims are further advantageous Embodiments of the invention.

The invention is illustrated in the drawings, by way of example, in: Schematically. In detail:<dl tsize="14"><dt>FIG. 1:</dt><dd>A processing plant with a Central control system in one schema rendering,</dd><dt>FIG. 2:</dt><dd>An enlarged top view of the Jointing system of FIG. 1,</dd><dt>3 and 4:</dt><dd>Functional representations of one 2 of the joining system of FIG Synchronized robots,</dd><dt>FIG. 5:</dt><dd>A variant of the joining system of FIG. 2 and</dd><dt>FIG. 6:</dt><dd>A joining plant according to the state of the Technology.</dd></dl>

FIG. 6 shows a processing installation (1) for the Car body building in an education according to the Practice known prior art. The processing plant (1) is designed as a joining system in bodywork construction, in particular As a respot welding system for vehicle body Body parts. It is divided into Several successively along a transfer line (3) Staged stations A to D. The vehicle body bodies (2) are conveyed by means of an overlapping conveyor (5) from station to station. This is a For example, a lifting shuttle. For The entire joining system (1) is subject to a fixed pre - set Work cycle that takes place in machining times and Transport times. Within stations A to D Are inserted one or both sides of the transfer line (3) A plurality of stationary robots (7, 8) are arranged which support the (2) during the processing, Eg with spot welding pliers or other welding tools Welding out. The robots (7, 8) are spatially limited Working areas on the body (2), on each A robot (7,8) in the front And a different robot (7, 8) in the rear body region. For Such as spot welding Corresponding to the tools, in particular welding tools, Several times.

Between the individual stations A to D Usually a free space is left, whereby in this The neighboring robots (7, 8) have a larger Distance d than within the individual stations A To D. The previously known joining unit (1) with the Station concept therefore needs considerable space in Transfer direction and is characterized by the strict work in Efficiency.

FIGS. 1 to 5 show a device according to the invention Processing plant (1), in particular in the form of a And especially a respot welding system. In the (1), one or more conveyors (5) Which are used as continuously operating conveyors And the workpieces (2), in particular Vehicle bodies or body parts in one Continuous and preferably continuous movement in Direction of transport (4).

The conveying motion can be at constant speed Be regulated. Alternatively, the conveying speed When using several conveyors (5) locally vary and on (5) is accelerated or decelerated will. This allows the distances between the workpieces (2) locally (so-called "breathing" of the workpieces). A Increase in distance, for example, creates space in the front and rear Rear area for machining operations. With a Followed by the delay Original distance restored.

The workpieces (2) can be placed directly on the conveyor (5) Can be arranged. Alternatively, they can also be applied to carriers, In particular pallets (6) in a predetermined position Held and tensioned, and with these carriers (6) be transported.

The individual conveyor (5) can be one-piece. He can Alternatively divided into several conveying sections be. The conveyor (s) have respective conveyor sections Suitable controllable drives, which are schematically illustrated in FIG As motors M are shown. The conveyor (5) can be used in Optionally as a roller conveyor, Chain conveyors or the like.

The robots (7, 8) process the transported ones Workpieces (2) during their conveying movement. To this end The robot movements with the conveying movement Synchronizable. The robots (7, 8) are arranged in Dependency on position and transport speed of the Workpieces (2). For this purpose, the joining unit (1) A suitable sensor system (13) for movement and movement Position detection of the workpieces (2) and / or their Carrier (6).

The robots (7, 8) are in the form of stationary articulated arm robots Formed during their activity with their base Stationary on the ground. The robots (7,8) have Several rotational axes, preferably six axes. They are, for example, trained as industrial robots in which On the stationary base a carousel around the first Vertical axis I, turning at the carrousel a swingarm About a horizontal second axis II , At the end of which a boom is arranged around a horizontal third Axis III. The boom carries on End of a multi-axis robot hand, preferably a so- Central hand with three intersecting rotary axes IV, V And VI. The aforementioned synchronization with the Conveying movement is usually caused by several axes Overlapping changes of the rotational movements of the Rotatory axes.

In addition, a monitoring device (11) is provided, To the process of adhering to the synchronization monitor. For this purpose, the monitoring system (11) can, for example, One or more devices, in particular cameras for the Optical imaging and evaluation. Over this It is possible to determine, for example, whether the operating conditions associated with the conveying movement Synchronized robots (7, 8) with their tools (10) Actually synchronized with the workpiece (2) during the Joining operation and / or their delivery or Reset movements. In addition, (10) with collision edges on the Work piece (2). Also the Collision - free mutual matching of adjacent ones The robot (7,8) can be monitored.

During the joining process, compliance with the Synchronization also in other ways, eg by A force measurement on the robot (7, 8) and / or on the tool (10) be monitored. If the robot movement is not synchronous To the conveying movement, a relative movement is produced which A change in the forces acting in the process Which, in turn, act on the robot axes And here by momentary or current monitoring of the Axle drives or other means, eg by forces and / Moment sensors.

The robots (7, 8) preferably have in their Robot control a specific processing program for Their operations are stored on the workpiece (2). This can Eg a workpiece (2) which is stationary on static operation, Programmed processing program to be used at the Execution corresponds to the conveying movement Dynamic component is superimposed. At this Overlay can affect any changes in the Conveying speed or the position of the Workpieces (2) are reactivated immediately and online. Alternatively, the editing program can display the dynamic Already contain a component Movement. In this case, The synchronization monitors whether the specified Dynamic conditions are respected or whether a Adjustment is required online.

The joining unit (1) has at least one control system (12), which preferably is central and plants Overlapping. To the control system (12) Preferably all the robots located in the system (1) (7, 8). Also the sensor system (13), the Monitoring system and the drives of the conveyor (5) or Of the conveyor sections are connected to the central control system (12). To maintain synchronization Can depend on the conveying movement and in particular the position And the speed of the workpieces (2) , Wherein the robots (7, 8) are arranged in their Working and delivery movements synchronized accordingly will. In this case, the conveyor (5) can also be moved to a Preset, especially when the robot (7,8) already have dynamic processing programs in their Control.

The joining unit (1) can be a station on the entrance side (14) in which the conveyor (5) or the conveyor belt Carrier (6) is loaded with workpieces (2). In this Station (14), tensioning functions can also be performed By, for example, clamping devices on the carrier (6) Creating appropriate energy and control connections Are actuated. When transported through the installation (1) These energy and control connections can be released again will. The station (14) is preferably also for this purpose Via a corresponding control component to the central control unit Control system (12). Finally, in the Station (14), control operations are performed, To ensure the correct positioning of the workpiece (2) on the Conveyor (5) or the carrier (6) as well as the function of the Tensioners and possibly other machine components check.

On the output side of the joining unit (1), a Similar station (15), on which the conveyor (5) or the carriers (6) from the machined workpieces (2) are unloaded. Again, here again Control operations are carried out to conclude Compliance with the correct clamping position of the workpieces (2) during the previous plant run And, if necessary, a (1) quality inspection of the plants listed in Appendix Joining operations.

FIG. 5 schematically shows a variant of the joining system (1) Of FIG. 2. In FIG. 2, the robots (7, 8) are connected to both Sides of the transfer line (3) Workpieces (2) the plant (1) only once and in one Direction. In the variant of FIG The workpieces (2) in a loop or a Roundabout through a suitably trained Conveyor (5). Here, only one side of the Transferring line (3) robots (7), which are arranged in the same direction Between the two by the loop or the (3). The Robots (7) work on the way to the right Side of the vehicle parts (2) and on the return path thereof left side. The robots (7) can alternately be moved to the Front and rear.

FIGS. 3 and 4 show in a schematic representation the Synchronized robot operations. As shown in FIG The robot (7) does not work with it The rear of the (4) in front of the workpiece (2) He there for example several welding points with a Point welding pliers. Once the operation is finished Or the workpiece (2) the working space (9) of the robot (7), the robot (7) pivots into the dashed line Drawn position and edit the next one Distance the following workpiece (2) Processing operations on the front side thereof. The robot (7) can thus move on the workpiece which has moved past (2) different regions with corresponding Different processes.

The processing operations run in arbitrary Spatial path movements, the robot hand and The tool can be moved in several axes. Accordingly Is the synchronization of the axis movements of the Robots (7,8). In contrast to pure assembly operations, Eg a side wheel mounting on the vehicle, in which The robot the self-propelled tool, eg one Screwdrivers, only with simple kinematics on a straight Path synchronously along the conveying direction, and The tool will provide the transversal assembly operations Its own drive and without strain of Robot axes themselves, it is necessary with the Complex processing operations and the Optimized interplay of several side by side Standing robots (7, 8) of a much more complicated one Kinematics. The robot movements and their synchronization Depend on the process and component requirements.

A transverse or oblique to the conveying direction and possibly also Still running with vertical component Processing path, eg welding or adhesive seam, Welding point line, etc., requires trajectory tracking With a robotic welding tool at each Change of direction Axis movements. This goes beyond a pure straight Carry along along the conveying direction because the Robot (7, 8) and its tool tracked spatially And with arbitrarily changing directions and curvatures Respectively.

The robot (7) can also use the Change tool if necessary. The robot is therefore optimal , Wherein also the inserted tools (10) Better utilized and optimized in number. In this way, similar joining operations of A robot (7) on the whole side facing it Of the workpiece (2) moved by. The robot (7) can be, for example, all or at least in FIG A large part of the weld points on the right side of the Place the vehicle body (2).

As FIGS. 1 and 2 illustrate, the robots (7, 8) Along the transfer line (3) Substantially equidistant. The Working areas of the robots (7) on the workpieces (2) Can be compared with previously known systems So that fewer robots (7.8) are needed. The distance between the robots (7, 8) along the transfer line (3) can be optimized and according to the process requirements set to. Rigid dimensions and spacing as In the prior art according to FIG. FIG. 6 no longer exists. In the joining system (1) according to the invention, moreover, falls Preferably the station binding away, so that the Existing security and freerooms between the Stations are dispensable. Correspondingly denser The robots (7, 8) are arranged. The system length Shortened accordingly.

FIG. 4 illustrates in another view the Synchronized movement of the robots (7, 8) with the Workpiece transport. The robot (7), for example, welds at (2) to the left of the workpiece Stem of the body. During the continuous Workpiece transports, the robot (7) rotates around its axis Vertical base axis I with and also changes the Other axis positions, for example, a series of Welding points on the stem. Through appropriate Axis motion, the robot (7) also moves in this case During welding operations with closed Welding tongs synchronously with the body part (2). The The infeed movement to the next welding point is also found Synchronized instead. FIG. 4 shows in dashed lines Aborted representations the feed of the Body part and the corresponding synchronous Tracking movements of the robot (7). The workpiece (10) Is not shown for the sake of clarity. Also the The position of the robot (7) is better Clarity.

The robots (7, 8) are Stationary and in a preferred embodiment on the ground and on one or both sides of the Transfer line (3) or of the conveyor (5). In addition, robots can be attached to one within the plant (1). In Another modification, the robots can be one or more Additional axles, for example, one along the transfer line (3) Oriented driving axle.

Modifications of the embodiments shown are shown in FIG Variously possible. This applies, on the one hand, to the Number, arrangement and formation of the robots (7,8). Also the Conveyor (5) and the sensor system (13) used as well as the Monitoring device (11) can be constructed in a constructive manner Can be modified.

Also variable is the control system (12), which Also consist of several individual control components Can In this case, it is also possible to control the control system (12) completely or partially into one or more Robotic controls, whereby, for example, a single Robots (7, 8) or a group of robots (7, 8) The conveyors (5) in his or her working area Controls. As a result, the conveying movement can be locally optimal On the processing requirements or the robot properties Be adjusted. Furthermore, it is possible to select the central Plant control into a robot control.

REFERENCE LIST

<dl tsize="2" compact="compact"><dt>1</dt><dd>Processing plant, joining plant</dd><dt>2</dt><dd>Workpiece, vehicle body</dd><dt>3</dt><dd>Transfer line</dd><dt>4</dt><dd>direction of transport</dd><dt>5</dt><dd>Conveyors</dd><dt>6</dt><dd>Carrier, pallet</dd><dt>7</dt><dd>robot</dd><dt>8th</dt><dd>robot</dd><dt>9</dt><dd>working space</dd><dt>10</dt><dd>Tool</dd><dt>11</dt><dd>monitoring system</dd><dt>12</dt><dd>control system</dd><dt>13</dt><dd>sensor technology</dd><dt>14</dt><dd>Loading, tensioning and control station</dd><dt>15</dt><dd>Control and discharge station</dd></dl>