Method for operating laser plotter for cutting, engraving, marking and / or engraving workpiece, and laser plotter for engraving, marking and / or engraving workpiece

Abstract

The invention relates to a method for operating a laser plotter (1) for cutting, engraving, marking and / or engraving a workpiece (7), in which at least one radiation source (4) in the form of a laser (5, 6) is used in a housing (3) of the laser plotter (1), in which a laser beam (10) is guided to a focusing unit (12) via a deflection element (11) when the radiation source (4) is activated, wherein the control unit (13) is controlled on the basis of the set parameters and / or the loaded work (18), and wherein the machining table (9) or the machining space (8) is preferably detected by at least one camera (23) for recording the inserted workpiece (7). Data, in particular jobs (18), are received by a computer unit (27), and the calculation of the path plan is performed off-line by the computer unit (27) or externally by means of a cloud solution or component (15), then the path plan and other data are transferred to an SPS control device (26a) or a soft SPS (26b), subsequently, during a sampling period or sampling time (40), individual target data, in particular path planning and other data, such as speed, are transmitted step by step by the SPS control device (26a) or soft SPS (26b) via an industrial bus (25, 28), in particular an EtherCat bus, to modules (29, 30, 31) at least for shaft control and laser control, wherein at least the detected position and speed information (41), in particular the shaft position (41) and speed, is transmitted from the shaft module (29, 30) to the laser control module (31) at a periodic sampling time (40), and then one or more future shaft positions (42) are estimated (39) or calculated (39) by the laser control module (31) or by a universal board, in particular by a universal Trotec board, at a future time (43), in order to activate in time a control signal for laser control, in particular for activating the laser (5, 6) at a predefined estimated axis position (42) of the focusing unit (12).

Description

Technical Field

[0001] The invention relates to a method for operating a laser plotter for cutting, engraving, marking and / or inscribing workpieces and to a laser plotter for engraving, marking and / or inscribing workpieces as described in claims 1 and 12 . Background Art

[0002] A method for predetermining a processing position of a laser beam is known from DE 10 2004 043 175 A1, wherein a laser head is fastened to a robot arm, wherein the impact point of the laser beam on the surface of the workpiece is tracked by a camera. The actual position of the laser beam is derived from the camera position, and the processing position is determined from the deviation between the setpoint position and the associated actual position.

[0003] Furthermore, laser machines or laser plotters are known from the prior art, in which one or more radiation sources, in particular lasers, are operated. For this purpose, a laser beam is sent from the radiation source via a deflection element to a focusing unit, wherein the laser beam is deflected in the focusing unit in the direction of the workpiece and is preferably focused via an optical element, in particular a lens. In this case, the individual components, in particular the laser control module, the axis module, the suction device, the camera, etc., are controlled via a self-developed control unit, which processes the set and transmitted parameters or the sent jobs. In conventional architectures, due to the use of independent solutions for control and construction, it is common for the laser control module to be directly connected to the position sensor of the axis module or the axis control device. This makes it possible to trigger the laser pulse in time when a predetermined axis position is reached, i.e., the laser control module is constantly informed of the actual position of the processing head, in particular the focusing unit, by connection with the position sensor, and thus the laser or the laser pulse is activated in time to laser process the workpiece at the desired or predetermined position of the processing head, in particular the focusing unit.

[0004] A disadvantage in this context is that when developing a laser machine, in particular a laser plotter, stand-alone solutions involve a high level of hardware and software complexity. Summary of the invention

[0005] The object of the present invention is to provide a method for operating a laser plotter for cutting, engraving, marking and / or inscribing workpieces and a laser plotter therefor, which on the one hand avoid the above-mentioned disadvantages and on the other hand achieve a standardized design.

[0006] This object is achieved by the invention. Advantageous design and / or method measures are described in the dependent claims.

[0007] The object of the present invention is achieved by a method for operating a laser plotter for cutting, engraving, marking and / or inscribing workpieces, wherein data, in particular jobs, are received by a computer unit and the calculation of the path planning is performed offline by the computer unit or externally by a cloud solution or component, and then the path planning and other data are transferred to an SPS control device or a soft SPS, and then the SPS control device or the soft SPS sends the individual setpoint data, in particular the path planning and other data, such as speeds, step by step via an industrial bus, in particular an EtherCat bus to at least a module for axis control and laser control at sampling cycles or sampling times, wherein at least the detected position and speed information, in particular the axis position and speed, is sent from the axis module to the laser control module at periodic sampling times, and then one or more future axis positions are estimated or calculated by the laser control module or by a universal board, in particular by a universal Trotec board, at a future point in time in order to activate a control signal for the laser control, in particular for activating a predetermined estimated axis position of a focusing unit in a timely manner.

[0008] The advantage in this case is that the estimation of the position or axis position creates for the first time the possibility of using a standardized industrial bus for such laser machines, in particular laser plotters, without quality loss, since the laser can always be activated at the right time by “estimating” the position of the focusing unit. Usually, in the case of standardized industrial buses, the sampling times or sampling cycles are too high or indefinitely identical to be used for synchronizing the laser with the axis position of the focusing unit, i.e., the position of the focusing unit at the scanning time when the data, in particular the measured or detected axis position, is sent too early to activate the laser. According to the invention, this is solved in that an estimation of the axis position is performed between the scanning times or scanning cycles, so that the axis position at a future time can be determined, wherein the laser must be activated in order to hit the workpiece at the desired point or position, i.e., position data are generated or calculated within a time period, which are used for triggering the laser pulse. As a result, the high sampling times based on the estimation of the position have no effect. It can thus be said that the synchronization of the laser with the axis position is achieved based on the estimation.

[0009] Advantageous is a measure in which the axis module periodically transfers or sends the position and speed data obtained from the position sensor and the latest axis position to the laser control module via the industrial bus according to the calculated path plan at sampling times. This ensures that the planned final value is available for the estimated simulation or calculation, so that the direction of the calculation is predetermined, in particular whether the calculation is increasing or decreasing. As a result, only slight deviations from the planned path are always obtained.

[0010] The following measure is advantageous, in which the laser control module or the universal board, in particular the universal Trotec board, calculates or estimates a plurality of future system states, in particular future axis positions, at future times based on the data transmitted by the axis modules on the basis of a numerical time integration method, in particular the Runge-Kutta 4-schema. This makes it possible to use integration methods proven in the prior art. This results in a simple software-based integration.

[0011] The following measure is advantageous, in which the number of future calculated estimates, in particular the calculated axis positions at future calculated points in time, is settable or can be set. This makes it possible to simply adapt the number of estimates for different applications. In this case, the more estimates are set, the higher the quality of the laser processing, because the points in time and the axis positions for triggering the control signal for activating the laser are given more accurately. If fewer estimates are set, the time step Δt between the individual points in time increases, whereby the control signal for the laser can no longer be triggered so accurately. For example, the laser used has a laser frequency of 200 kHz, so that at a sampling time of 200 μs for the industrial bus, in the best case, i.e. at the highest resolution, 40 different estimates can be performed or calculated, i.e. an estimate of the axis position can be made every 5 μs.

[0012] The following measure is advantageous, in which the estimation at the beginning of a simulation cycle corresponds exactly to the measured or transmitted axis position, wherein the difference between the planned axis position and the simulated axis position is obtained with successive simulation times. This ensures that only very small differences or deviations of the estimated axis position relative to the planned axis position are always obtained. A simulation cycle is the duration between two sampling times of the industrial bus.

[0013] However, the following measure is also advantageous, in which the difference is automatically corrected by taking over the measured or known axis position at each sampling time. This achieves that the axis position is automatically corrected after each sampling time, so that only small differences of deviation always occur. In this case, the position sent at the beginning of the estimation is used as the new position for the estimation.

[0014] The following measure is advantageous, in which the time of the SPS control or soft SPS is synchronized with the time of the modules, in particular the axis control or axis module and the laser control or laser control module or universal Trotec board. In this case, the SPS control or soft SPS sends a synchronization message so that the SPS time runs synchronously with the slave device clock, in particular the axis module and the laser control module.

[0015] However, the following measure is also advantageous, wherein the sampling time is between 150 μs and 300 μs, in particular 200 μs, in the case of the industrial bus used, in particular the Ethernet Cat-Fast bus, so that data can be sent from the master to the slave or from the slave to the slave or from the slave to the master according to the sampling time.

[0016] The following measure is advantageous, wherein the time interval between the time points, in particular a plurality of time points, for estimating the shaft position is smaller than the time interval between the sampling times. This achieves that at least one, preferably a plurality of, time points between the sampling times are used to estimate or calculate the shaft position.

[0017] Measures are advantageous in which the deviation of the estimate of the axis position is dependent on the measurement accuracy of the starting state and / or on the selection of the effects taken into account in the model and / or on the accuracy of the values ​​used for the model parameters, in particular geometry, inertia, friction and elasticity, and / or on the duration of the simulation. This allows the deviation of the estimate from the planned or actual axis position to be kept low due to the parameters involved.

[0018] Measures are advantageous in which the results of the path planning are transmitted at the sampling time, in particular positions, speeds, accelerations, laser powers, etc. This ensures that the relevant information is always transmitted at the sampling time.

[0019] Furthermore, the object of the invention is achieved by a laser plotter for engraving, marking and / or inscribing workpieces, wherein a computer unit is arranged for taking over and processing data, in particular jobs or graphics and / or texts, said computer unit being connected to an SPS control or soft SPS, wherein at least one axis module and a laser control module are connected to the SPS control or soft SPS via an industrial bus, wherein the laser control module or a universal board, in particular a universal Trotec board, is designed to estimate or calculate the future axis position at a future point in time based on the detected position and speed information, in particular the axis position and speed of the axis module, and then the laser can be activated at the correspondingly defined axis position. In this case, it is advantageous that by estimating the axis position at a future point in time, the point in time with the corresponding estimated axis position can be shortened, so that for the first time the possibility is created that the laser plotter can be operated with an SPS control or soft SPS and an industrial bus.

[0020] A design is advantageous in which the position sensor is arranged on the axis module. This allows standardized modules to be used, thereby avoiding the costs of developing expensive individual solutions.

[0021] Finally, a configuration is advantageous in which a computer unit, preferably a Windows-based computer unit, is integrated into the laser plotter, thereby enabling a simple data connection to external components.

[0022] The problem when using an industrial bus is that the sampling time for sending the data lasts much longer or the time interval between the samplings is too long, so that the laser cannot be controlled accordingly according to the transmitted axis position, because when using standardized components, especially SPS control devices or soft SPS and industrial buses, the position sensor of the axis module is not directly connected to the laser control module, so that the laser control module only transmits information, especially the axis position, during the scanning time. However, due to the large sampling time, the application is impossible without the solution according to the invention for estimating the axis position. By estimating the axis position, the time point for generating the control signal for the laser can be determined as accurately as possible. Therefore, by estimating or calculating the axis position, the synchronization of the laser control module or the universal board, especially the universal Trotec board, with the position sensor of the axis module is simulated. In the case of the prior art, a separate solution is used, in which the position sensor is directly connected or coupled to the laser control module, so that the laser control module is constantly informed of the position of the focusing unit and can thus generate the control signal for activating the laser in a timely manner. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention is described below in the form of exemplary embodiments, wherein it is pointed out that the invention is not limited to the exemplary embodiments or solutions shown and described, but can be transferred to equivalent solutions.

[0024] Figure 1 A laser machine, in particular a laser plotter, for processing workpieces is shown in a simplified schematic diagram with a camera system on the cover;

[0025] Figure 2 A block diagram showing a control device for a laser plotter with a computer unit and an SPS control device is shown in a simplified schematic diagram;

[0026] Figure 2a Another block diagram of a control device for a laser plotter with a soft SPS in a computer unit is shown in a simplified schematic diagram;

[0027] Figure 3 A schematic diagram showing calculation of an estimate between two sampling periods;

[0028] Figure 4 A schematic diagram showing multiple estimates in multiple consecutive sampling periods. DETAILED DESCRIPTION

[0029] It should be understood by way of introduction that in different embodiments, identical parts are provided with identical reference numerals or identical component names, wherein the disclosure contained in the entire specification can be transferred to identical parts with identical reference numerals or identical component names in a meaningful manner. The orientation descriptions selected in the specification, such as top, bottom, lateral, etc., also relate to the described figures and can be transferred to the new orientation in a meaningful manner when the orientation changes.

[0030] exist Figures 1 to 4 Detailed Description of the Invention An exemplary embodiment of a laser machine 1 , in particular a laser plotter 1 , is shown in which, for example, a camera system 2 is integrated and a method for operating a laser plotter 1 for cutting, engraving, marking and / or inscribing workpieces is carried out.

[0031] In the case of the laser plotter 1 shown, at least one, preferably two, radiation sources 4 or laser sources 4 in the form of lasers 5, 6 are arranged in a housing 3. The lasers 5 and 6 preferably act alternately on a workpiece 7 to be processed. The workpiece 7 is positioned or is positioned in a processing space 8 of the laser plotter 1, in particular on a processing table 9, wherein the processing table 9 is preferably adjustable in its height. The laser beam 10 emitted by the radiation source 4, in particular the laser 5 or 6, is sent via a deflection element 11 to at least one movable focusing unit 12, by which the laser beam 10 is deflected in the direction of the workpiece 7 and focused for processing. The control, in particular the position control, of the laser beam 10 relative to the workpiece 7 is carried out by software running in a control unit 13, wherein the workpiece 7 is processed by adjusting a carriage 14 in the XY direction, preferably via a belt drive, on which the focusing unit 12 is also movably arranged. In this case, it is possible, for example, to adjust the carriage 14 row by row in the case of the “intaglio printing” process, while in the case of the “cutting” process the carriage 14 is moved according to the contour to be cut, ie not row by row.

[0032] Graphics 16 and / or texts 16 are created or loaded at an external component 15, in particular a computer, laptop or control device, by means of commercially available software 17, such as Core1Draw, Paint, etc., or by means of own application software 17, in particular Ruby 17, which are preferably exported or transferred to the control unit 13 of the laser machine or laser plotter 1 in the form of a job 18. Preferably, the data to be transferred are converted by the same or different software so that the control unit 13 can process the job 18. However, it is equally possible that the data are converted by software in the control unit 13 or in a cloud solution. Of course, it is also possible that the input can be made directly at the laser plotter 1 by means of existing input devices 19, such as a touch screen 19 or input keys, or that the corresponding job 18 can be loaded from a storage medium 20, such as a cloud 20a, a USB stick 20b, etc. After the data, in particular the one or more jobs 18, have been transferred or directly created or loaded from the storage medium 20, the job 18 is processed by the laser machine 1, in particular its control unit 13. It is possible here that a plurality of jobs 18 can be stored simultaneously in the laser machine 1, in particular the laser plotter 1, and can be processed one after the other. In principle, it should be mentioned that the application software 17, in particular Ruby 17, can also be called up via the cloud 20a, so that the graphics 16 and / or texts 16 can be created via the cloud 20a, i.e. the application software 17, in particular Ruby 17, can be installed in the cloud 20a and can be called up from a web browser on a computer, so that the graphics 16 and / or texts 16 can then be created or can be loaded, and then a job 18 is created for the laser plotter 1, which is sent directly to the laser plotter 1 or can be stored in the cloud 20a, so that it can be loaded at a later point in time, as is shown in the example of FIG. Figure 2a , wherein the direct connection of the computer 15 to the laser machine 1 is also shown by a dotted line.

[0033] In the case of such a laser machine 1, in particular a laser plotter 1, safety requirements require that in order to start the work 18 to be processed, in which the laser beam 10 acts on the workpiece 7, a cover 21 or door 21, which is preferably at least partially transparent, must be closed, as in the case of a laser machine 1, which is preferably at least partially transparent. Figure 1. Subsequently, the operator can manually or also automatically position a laser spot or laser pointer 22, in particular a laser pointer spot 22a, on the inserted workpiece 7, which is coupled into the beam path of the lasers 5, 6 and deflected in the direction of the processing table 8 by the focusing unit 12, and then the operation 18 for processing the workpiece 7 can be started. At the end of the operation 18, the carriage 14 and the focusing unit 12 are then preferably adjusted to the starting position, so that the finished workpiece 7 can be removed, and then a new processing can be started by inserting a new workpiece 7 or blank 7 to be processed. In this case, it is advantageous to indicate the end of the processing optically or acoustically, so that the user does not have to constantly observe the laser machine 1. For the sake of completeness, it is mentioned that it is possible to adjust the focusing unit 12 with an activated laser pointer 22 even when the cover 21 is open, but the lasers 5, 6 cannot be activated.

[0034] Furthermore, it is possible that at least one camera 23 can be provided in the camera system 2, wherein the camera 23 is located in the cover 21. The camera 23 is provided to record the processing space 8, in particular the processing table 9, so that the inserted workpiece 7 can be identified. However, it is also possible that two or more cameras 23 are arranged in the cover 21 or the housing 3. The position of the inserted workpiece 7 is detected by means of the camera 23 and is preferably displayed on an external component, in particular a laptop. In this case, the position of the workpiece 7 is preferably detected before processing or starting the processing process, so that the focusing unit 12 can be positioned accordingly by the laser pointer 22. For the sake of completeness, it is pointed out that it is also possible to identify the position of the workpiece 7 even when the cover 21 is open.

[0035] In the case of the novel laser plotter 1 or laser machine 1, it is now provided that a novel electronic architecture, in particular the structure of the control unit 13, is provided, as in Figure 2 and 2a This can be seen schematically in the block diagram.

[0036] For this purpose, the control unit 13 now consists of a plurality of preferably standardized modules, which are connected as so-called slaves 24 (24a, b, c, d, ...) via an industrial bus 25, in particular an EtherCat bus 25, to a master 26, wherein the master 26 consists of a plurality of preferably standardized modules, Figure 2 The standardized SPS control device 26a shown in FIG. Figure 2aIn order to be able to transfer data to the host device 26, the host device is connected to a computer unit 27 or directly integrated into the computer unit 27. The computer unit 27 can also be connected to an external component 15, in particular a laptop or a storage medium 20 via a data connection, so that the created job 18 or the created or loaded graphics 16 and / or text 16 can be transferred to the computer unit 27 in the laser plotter 1, that is, the computer unit 27 receives the job 18 or graphics and / or text 16 from the external component 15, in particular a laptop 15 or a storage medium 20, in particular a cloud 20a, and then the computer unit 27 processes the received data. Here, path planning, in particular the calculation of the path and / or position of the focusing unit 12 and / or the movement process / pattern of the focusing unit 12 and / or the results of the path planning consisting of position, speed, acceleration, laser power, etc., is performed by a computer unit 27 or externally via a cloud solution or offline by component 15 for processing the workpiece 7, so that all positions, paths, speeds, accelerations, laser activations, laser powers, etc. are known at the beginning of the working process. The path planning is then transferred from the computer unit 27 to the SPS control device 26a or the soft SPS 26b, in particular the master device 26, and then the path planning, in particular the path and / or position and / or motion process / mode and / or result is applied to the industrial bus 25 step by step for the sampling cycle 40 or sampling time 40, that is, the path planning is calculated offline by the computer unit 27 or externally through a cloud solution or component 15 and transferred to the master device 26, in particular the SPS control device 26a or the soft SPS 26b, and then the first result of the path planning, in particular the position, speed, acceleration, laser power, etc., is transferred from the device 24 to the SPS control device 26a or the soft SPS 26b for the sampling time 40 or sampling cycle 40, and then the next result of the path planning is sent for the next sampling cycle 40 or the next sampling time 40, etc. In this case, synchronization information is also sent together so that the slave device time is synchronized or runs synchronously with the master device time. Preferably, a Windows-based computer unit 27 is used, but other operating systems such as Linux macOS can also be used. The computer unit 27 is preferably implemented by a PC (Personal Computer), so that a simple external communication with the component 15 or the storage medium 20 is possible. In this case, a wired and / or wireless connection to the storage medium 20, in particular to the cloud 20a and / or the external component 15, such as Ethernet, Wlan, etc. can be used.

[0037] In the embodiment shown, the master device 26 or SPS control device 26a or soft SPS 26b has two industrial buses 25 and 28, one of which (EtherCat-Fast) has a fast sampling time 40 of about 200 μs, while the other industrial bus 28 (EtherCat.Slow) has a much slower sampling time. Therefore, the slave device 24 is connected to the two industrial buses 25 and 28 as required, wherein the axis control device 29, 30 or axis module 29, 30 for at least the X and Y axes and the laser control device 31 or laser manipulation module 31 are connected to the fast industrial bus 25 (EtherCat-Fast). Other slave devices 24 or modules 32-34, such as safety module 32, input / output module 33, sending axis module 34, etc., do not need a fast periodic sampling time 40, so that the other slave devices 24 or modules 32-34 can be connected to the slower industrial bus 28 (EtherCat-Slow). Of course, it is possible that the SPS control device 26a or the soft SPS 26b can be used or operated with only one industrial bus 25 or 28, so that all modules 29-34 are controlled via this one industrial bus 25 or 28. It is also possible to arrange the laser control module 31 on a universal board, in particular a universal Trotec board, on which other components or modules can also be arranged, which can, for example, take over individual working steps of the laser control module 31, wherein time delays can be avoided here by the direct connection via the universal board.

[0038] Due to the use of standardized components, in particular SPS control devices 26a or soft SPS 26b with industrial buses 25, 28 (EtherCat), it is not possible to shorten the sampling time 40 for sending and receiving data. Such high sampling times 40 of standardized industrial buses 25, 28 cause the lasers 5, 6 to be ignited either too early or too late at the desired axis position, in particular the position of the focusing unit 12, so that the quality, in particular the gravure printing quality, suffers. In the case of the industrial bus 25 EtherCat-Fast used, the fastest possible sampling time 40 is 200 μs, so that data can only be sent and received every approximately 200 μs, that is, only at the sampling time 40 or sampling cycle 40, that is, every approximately 200 μs, the detected position and speed information of the axis modules 29, 30 can be sent to the laser control module 31 for activating the lasers 5, 6, wherein the activation of the lasers 5, 6 only requires a small part of the scanning time 40, so that when the position is sent, the lasers 5, 6 will be ignited much earlier in the case of the solution not according to the invention.

[0039] In order to correctly control the laser control module 31 to ignite or activate the lasers 5, 6 during the processing of the workpiece 7, especially in the gravure printing mode, it is necessary to synchronize the control signals for the laser control module 31 with the position of the processing head or the focusing unit 12, especially with the axis modules 29, 30. It is common in conventional laser plotters 1 known from the prior art that the laser control module 31 is directly electrically connected to the position sensors 35, 36 of the axis modules 29, 30. This allows the laser pulse to be triggered in time, especially a few μs before reaching a predetermined position, so that at the exact time when the position of the processing head is reached, the lasers 5, 6 are also activated according to the path planning.

[0040] In the case of the laser plotter 1 according to the invention, due to the use of standardized components, there is no direct connection between the position sensors 35, 36 of the axis modules 29, 30 and the laser control module 31. The position sensors 35, 36 of the axis or drive 37, 38 are connected to the axis modules 29, 30, at which the position information is present, so that it can only be transmitted according to the sampling time 40, that is, the position and speed information is transmitted from the axis modules 29, 30 to the laser control module 31 via the industrial bus 25 cyclically at the sampling time 40, so that the actual position of the axis or focusing unit 12 is always known to the laser control module 31 at the sampling time 40. However, in the case of a standardized industrial bus 25, the sampling time 40 is so large that it cannot be guaranteed that the laser control module 31, in particular the laser 5, 6, is controlled in time when a specific position is reached. The size of the sampling time 40 is limited downward by technical facts, such as computing speed, transmission time, transmission delay, and in the case of the EtherCat bus used is approximately 200 μs, so that the measured position and other information of the position sensors 35, 36, such as speed, acceleration, laser power, etc., can only be sent every approximately 200 μs.

[0041] In order to activate the lasers 5, 6 now in time or to generate control signals for laser control, an estimation 39 or calculation 39 of the system state, in particular an estimation 39 of the position of the focusing unit 12, is performed at a future point in time between two sampling times 40 or sampling periods 40, as schematically shown in FIG. Figure 3 For this purpose, the path or position calculated according to the path planning is plotted in the position-time diagram as a solid line, and the estimate 39 of the path or position is plotted as a dashed line.

[0042] Starting from the current point in time, i.e. the first sampling time 40a, the known or measured axis position 41a transmitted from the axis module 29, 30 to the laser control module 31 or the universal board, in particular the universal Trotec board, at the sampling time 40a is used, and then an estimate 39 or calculation 39 of the unknown future axis position 42a-e is made at future points in time 43a-e until the next sampling time 40b. At the next sampling cycle 40b or sampling time 40, the known or measured axis position 41b is again transmitted from the axis module 29, 30 to the laser control module 31 or the universal board, in particular the universal Trotec board, and is used as a starting value for the new estimate 39. In this case, at the beginning of the simulation cycle, the estimate 39 exactly corresponds to the measured or transmitted axis position 41, wherein the difference between the planned axis position and the simulated axis position 42 is obtained with the successive simulation times. However, this difference is automatically corrected after each sampling period 40 since, after expiration of the sampling time 40 , the known or measured value or shaft position 41 is sent again and used as initial value for a new simulation or estimation 39 .

[0043] The estimation 39 is based on a mathematical-physical model of the electromechanical axis system including the control unit, which contains the relevant properties and effects, such as geometry, inertia, friction, elasticity, quantization of position measurement, time delays of processing, closed-loop control circuits and path planning. The model is mathematically described, for example, by a set of difference equations. For example, the system of equations can be used for the purpose of estimating 39 or calculating 39 the future axis position 42 by time integration methods, in particular explicit numerical time integration methods such as the Runge-Kutta 4 scheme used. For the sake of completeness, it is mentioned that the estimation 39 is performed directly by the laser steering module 31 or a universal board, in particular a universal Trotec board.

[0044] Due to the lasers 5, 6 used, which have a laser frequency of, for example, 200 kHz, in the best case 40 different position estimates 42 or estimated shaft positions 42 can be determined with a sampling time 40 of 200 μs, i.e. an estimate 39 of the estimated shaft position 42 is calculated every 5 μs. Of course, it is also possible to provide fewer than 40 estimates 39 for a sampling time 40 of 200 μs. Figure 3, in which, for the sake of simplicity, only five estimates 39 of the shaft positions 42a-e are provided within two sampling times 40a, b of 200 μs, wherein the actually measured shaft position 41 is always transmitted at the sampling time 40. In this case, it is advantageous that the measured shaft position 41 of the path planning and the most recent shaft position 44 are always transmitted at the sampling time 40, i.e. the transmitted shaft position 41 represents the initial state at the beginning of the estimation 39 and the second desired shaft position 44 at the end of the estimation 39 according to the path planning, wherein the further position estimates 39 of the shaft position 42 located between them are determined by integration, in particular the Runge-Kutta 4 scheme, so that the laser control module 31 or the universal board, in particular the universal Trotec board, is informed in time by the planned or estimated shaft position 42 and the lasers 5, 6 can therefore be activated in time so that they are ignited in the desired end position.

[0045] In this context, the estimation 39 of the axis position 42 is important, since the ignition of the laser 5, 6 requires a fraction of the time or time interval of the transmission of the measured axis position 41 according to the sampling period 40 or sampling time 40. Therefore, based on the estimation 39 of the axis position 42 at a shorter point in time 43 in the future, a synchronization of the laser 5, 6 with the estimated axis position 42 is actually achieved, so that the laser 5, 6 can be activated for the estimated axis position 42 by the control signal, so that for the correct point in time 43 and axis position 42, the laser beam 10 is applied to the workpiece 7. In this case, the resolution of the estimation 39 performed, i.e. the number of estimations 39, can be set, wherein the best possible resolution is achieved with the maximum achievable estimation 39 out of 40, since the laser 5, 6 is actually activated, for example, with the last estimation 39, and is therefore ready at the correct time. If, however, fewer estimations 39 are performed or set, the laser 5, 6 is activated slightly too early.

[0046] The estimation 39 makes it possible to shorten the time intervals in which no value is present for the axis position or the duration between two sampling times 40, wherein a corresponding estimation 39 of the axis position 42 is performed at a defined time point 43. It is thereby possible to continuously inform the laser control module 31 or a universal board, in particular a universal Trotec board, about the position of the focusing unit 12 based on the estimated axis position 42, so that the control signals for the lasers 5, 6 are activated as a function of a specific position, so that the laser beam 10 strikes the workpiece 7 to be processed for the desired position.

[0047] In addition, Figure 4In FIG, a position-time diagram with a plurality of paths or positions of path planning and the associated estimates 39 of the axis positions 42 is shown by dashed lines, wherein a plurality of consecutive sampling time intervals are plotted. It is important here that, in order to correctly control the radiation source 4, in particular the laser 5, 6, during processing / in particular in gravure mode, the control signals for the radiation source 4, in particular the laser 5, 6, are synchronized with the position of the focusing unit 12, which is carried out by estimating 39 or calculating the axis position 42 between the sampling times 40. Furthermore, it can be seen that at each sampling time 40, the transmitted axis position 41 is used for a new estimate 39, i.e. at the start of the estimate 39, the transmitted axis position 41, in particular measured by the position sensors 35, 36, is used, so that the difference occurring between the measured axis position 41 and the estimated axis position 42 is kept as low as possible. For the sake of completeness, it should be mentioned that, for the sake of clarity, at Figure 4 In FIG. 3 , the individual shaft positions 42 with the time points 43 are not plotted during the estimation 39 .

[0048] In principle, it can be said that according to the invention a method for operating a laser plotter 1 for cutting, engraving, marking and / or inscribing workpieces 7 is described, wherein at least one radiation source 4 in the form of a laser 5, 6 is used in a housing 3 of the laser plotter 1, wherein when the radiation source 4 is activated, the laser beam 10 is guided via a deflection element 11 to a focusing unit 12, wherein the control is performed by a control unit 13 based on set parameters and / or a loaded job, wherein preferably a processing table 9 or a processing space 8 is detected by at least one camera 23 for recording an inserted workpiece 7, wherein data, in particular a job 18, is received by a preferably Windows-based computer unit 27, wherein the calculation of the path planning is then performed offline by the computer unit 27 or externally via a cloud solution or component 15, and the path planning is then transferred to the computer unit 27. The plan and other data are transferred to the SPS control device 26a or the soft SPS 26b, and then the SPS control device 26a or the soft SPS 26b gradually sends the various rated data to the modules 29, 30, and 31 for axis control and laser control via the industrial bus 25, especially the EtherCat bus, wherein at a periodic sampling time 40, especially every approximately 200 μs, the detected position and speed information 41 is sent from the axis control device or the axis module 29, 30 to the laser control device or the laser manipulation module 31, and then the laser manipulation module 31 estimates 39 or calculates 39 one or more axis positions 42 at a future time point 43, so as to timely activate or trigger the control signal for laser control, especially for activating the laser source or laser 5, 6 at a predetermined position of the focusing unit 12.

[0049] For this purpose, the laser plotter 1 is designed for engraving, marking and / or inscribing a workpiece 7, and comprises a processing space 8 for positioning the workpiece 7, at least one, but preferably two, radiation sources 4 in the form of lasers 5, 6, corresponding deflection elements 11, a preferably movable focusing unit 12 and a control unit 13 for controlling a carriage 14, which is moved via a preferably belt drive and has the focusing unit 12 arranged movably thereon, wherein a computer is arranged for taking over and processing data, in particular a job 18 or graphics 16 and / or texts 16. Unit 27, the computer unit is connected to the SPS control device 26a or the soft SPS 26b, wherein at least one axis module 29, 30 and a laser control module 31 are connected to the SPS control device 26a or the soft SPS 26b via the industrial bus 25, 28, wherein the laser control module 31 is constructed to estimate 39 or calculate 39 the future axis position 42 at a future time point 43 based on the detected position and speed information, in particular the axis position and speed of the axis modules 29, 30, and then the laser 5, 6 can be activated for the correspondingly defined axis position 42.

[0050] It is important for the problem-free functioning of the individual modules 29, 30, 31, and in particular the laser control module 31, that all slave clocks run synchronously with the master clock. For this purpose, a synchronization message is sent by the master.

[0051] The soft SPS 26b (programmable logic controller in software 26b) is a software program that imitates a conventional programmable logic controller (SPS control device 26a). This includes not only functionality but also non-functional aspects, such as robustness and real-time behavior. The soft SPS 26b consists of at least a PC (usually an industrial PC, an embedded PC or a box PC), SPS software, and E / A components and / or an industrial bus. The soft SPS 26b is integrated in or can be integrated in the computer unit 27.

[0052] A SPS control device 26a (memory programmable control device (Speicher ProgrammierbareSteuerung) 26a) is a device for controlling or regulating a machine or a facility and is programmed on a digital basis. In the simplest case, the SPS control device 26a has inputs, outputs, an industrial bus, an operating system and interfaces via which user programs can be loaded. The SPS control device 26a can be implemented in very different ways, for example as a single device ("module"), as a PC plug-in card, as a software simulation, etc.

[0053] For the sake of completeness, it is mentioned that path planning is usually carried out "offline", i.e. before the work or marking process, but it is also possible that the work or marking process is already started or carried out while the path planning is not yet completed, i.e. the work or marking process is already started during the calculation with a time delay relative to the path planning.

[0054] In principle, it can be said that the path planning corresponds to the real movement process, while the estimation corresponds to the simulated position. It is also possible that the solution according to the invention can also be applied and used in other laser machines, in particular in galvanometer lasers or galvanometer marking lasers.

[0055] For the sake of clarity it is pointed out here that the invention is not limited to the embodiment variants shown but can also include other designs and structures.

Claims

1. A method for operating a laser plotter (1) for cutting, engraving, marking and / or inscribing workpieces (7), wherein at least one radiation source (4) in the form of a laser (5, 6) is used in a housing (3) of the laser plotter (1), wherein when the radiation source (4) is activated, a laser beam (10) is guided via a deflection element (11) to a focusing unit (12), wherein the control is performed by a control unit (13) based on set parameters and / or a loaded job (18), wherein the processing table (9) or the processing space (8) is preferably detected by at least one camera (23) for recording the inserted workpiece (7), characterized in that Data, in particular jobs (18), are received via a computer unit (27), and the calculation of the path planning is performed offline by the computer unit (27) or externally via a cloud solution or component (15), and the path planning and other data are then transferred to an SPS control device (26a) or a soft SPS (26b), and then the SPS control device (26a) or the soft SPS (26b) gradually sends the individual setpoint data, in particular the path planning and other data, such as speed, via an industrial bus (25, 28), in particular an EtherCat bus, to at least one of the control devices for axis control and laser control in a sampling cycle or sampling time (40). A control module (29, 30, 31) is provided, wherein at least the detected position and speed information, in particular the axis position (41) and the speed, is sent from the axis module (29, 30) to the laser control module (31) at periodic sampling times (40), and then the laser control module (31) or a universal board, in particular a universal Trotec board, estimates (39) or calculates (39) one or more future axis positions (42) at a future point in time (43) in order to activate a control signal for laser control, in particular for activating the laser (5, 6) at a predetermined estimated axis position (42) of the focusing unit (12) in time.

2. The method according to claim 1, characterized in that The axis modules (29, 30) periodically transfer or send the position and speed data obtained from the position sensors (35, 36) and the latest axis position (44) to the laser control module (31) via the industrial bus (25) at sampling time (40) according to the calculated path plan.

3. The method according to claim 1 or 2, characterized in that: The laser control module (31) or the universal board, in particular the universal Trotec board, calculates or estimates (39) a plurality of future system states, in particular future axis positions (42), at future time points (43) based on data transmitted by the axis modules (29, 30) based on a numerical time integration method, in particular the Runge-Kutta 4 scheme.

4. The method according to any one of the preceding claims, characterized in that The number of future calculated estimates (39), in particular calculated shaft positions (42) at future calculated points in time (43), is predeterminable or can be predetermined.

5. The method according to any one of the preceding claims, characterized in that At the beginning of a simulation cycle, the estimate (39) corresponds exactly to the measured or transmitted shaft position (41), wherein the difference between the planned shaft position and the simulated shaft position (42) is obtained with the successive simulation times.

6. The method according to claim 5, characterized in that The difference is automatically corrected by taking over the measured or known shaft position (41) at each sampling time (40).

7. The method according to any one of the preceding claims, characterized in that The time of the SPS control device (26a) or the soft SPS (26b) is synchronized with the time of the modules (29, 30, 31), in particular the axis control device or the axis module (29, 30) and the laser control device or the laser manipulation module (31).

8. The method according to any one of the preceding claims, characterized in that In the case of the industrial bus (25) used, in particular the EtherCat Fast bus, the sampling time (40) is between 150 μs and 300 μs, in particular 200 μs.

9. The method according to any one of the preceding claims, characterized in that The time interval between the time points (43), in particular the plurality of time points (43a to 43e), for the estimation (39) of the shaft position (42) is smaller than the time interval between the sampling times (40).

10. The method according to any one of the preceding claims, characterized in that Deviations in the estimation of the axis position depend on the measurement accuracy of the starting state, on the choice of effects taken into account in the model, on the accuracy of the values ​​used for the model parameters, in particular geometry, inertia, friction and elasticity, and on the simulation duration.

11. The method according to any one of the preceding claims, characterized in that The results of the path planning, in particular the position, speed, acceleration, laser power, etc., are transmitted at the sampling time (40).

12. A laser plotter (1) for engraving, marking and / or inscribing a workpiece (7), comprising a processing space (8) for positioning the workpiece (7), at least one, preferably two, radiation sources (4) in the form of lasers (5, 6), corresponding deflection elements (11), a preferably movable focusing unit (12) and a control unit (13) for controlling a carriage (14) with a movably arranged focusing unit (12) which is moved via a preferably belt drive, characterized in that A computer unit (27) is arranged for taking over and processing data, in particular jobs (18) or graphics (16) and / or texts (16), which is connected to an SPS control device (26a) or a soft SPS (26b), wherein at least one axis module (29, 30) and a laser control module (31) are connected to the SPS control device (26a) or the soft SPS (26b) via an industrial bus (25, 28), wherein the laser control module (31) or a universal board, in particular a universal Trotec board, is designed to estimate (39) or calculate (39) a future axis position (42) at a future time point (43) based on detected position and speed information, in particular the axis position and speed of the axis modules (29, 30), and then the laser (5, 6) can be activated at the correspondingly defined axis position (42).

13. The laser plotter (1) according to claim 11, characterized in that: The position sensors (35, 36) are arranged on the axis modules (29, 30).

14. The laser plotter according to any one of the preceding claims 11 to 12, characterized in that The computer unit (27), preferably a Windows-based computer unit (27), is integrated in the laser plotter (1).

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