DK171660B1 - System for deburring or grinding a workpiece using a manipulator and method of use at the same, as well as using the system and method - Google Patents

Description

DK 171660 B1

The invention relates to a system for deburring or grinding a workpiece using a manipulator, in particular a robot, of the kind set forth in the preamble of claim 1, and a method of use of the same kind as set forth in claim 4 and a use of the system. and the method.

In the prior art, deburring of molded articles has generally been performed by either passing the contour of the molded workpiece past a grindstone or other deburring tool or passing the deburring tool past the contour of the workpiece to be deburring. It has generally been the case that small items were passed past a grindstone, and for larger items the deburring tool was passed past the contour of the workpiece.

In the prior art, these processes have been sought automated, for example using robots.

15 When using robots, the robot must be controlled in some way in order to provide the desired degradation.

In the simplest designs, where the tool is guided around the workpiece to be deburred, the tool is simply passed through a particular web, or the workpiece is moved according to a specific movement profile without regard to the size of the burrs or the condition of the tool.

This has caused problems, as the tool or workpiece may be damaged at the meeting with large burrs or insufficient deburring if the tool has been worn. Therefore, it has been necessary to take these problems into account in robotic automated deburring, and this has led to complicated control and positioning systems.

EP-B1-410836 is an example of measures taken by a robot for deburring. In this specification, it is described that the pressure on a deburring tool carried by the robot arm around the contour of the workpiece can be controlled as a function of the rotational speed of the tool and shock absorbing means may be located between the tool 35 and the robot arm. Thus, with this tool, an advanced pressure control of the tool's system pressure has been required, and on the other hand, this requires that the position of the tool is sensed, as this position is otherwise unknown.

From US-A-4,894,597 there is known an equipment of the kind in which a robotic arm carries a grinding tool around the contour of a workpiece. To control the tool guide, the robot arm is provided with a touch-free sensor system that senses the contour of the workpiece to be degraded, and scanned values from this sensor system are used in conjunction with a pressure sensor system in the robot arm to control the grinding tool during degradation. Furthermore, since the sensor system cannot sense the current state of the grinding wheel / stone on the grinding tool, a grinding wheel diameter measuring tool is provided. This measurement tool is positioned separately relative to the workpiece and the robot arm and is used to calibrate the sensor system on the robot arm so that the sensor is displaced relative to the diameter of the grinding wheel.

Thus, with such equipment, optical scanning is required during degradation, which is complicated by the grinding dust being generated at the same time and guiding the grinding tool to a dedicated diameter measuring tool located separately from the normal working area to set the optical scanning. depending on the condition of the grinding stone, and being able to provide a good degradation.

A similar equipment is known from EP-A1-362,413 to 25 deburring of the ends of pipes. Here, the optical sensor system is replaced by a copy claw on the robotic arm that follows the tube surface in places where there are no burrs. The copy claw is used to apply a grindstone that constitutes the deburring tool on the robot arm.

To compensate for abrasion of the abrasive stone, the arm is moved to a dedicated calibration station where the copying claw is brought into contact with a base block, after which the abrasive stone is displaced on the robot arm for systems with a sensor element so that the abrasive surface occupies a given position 35 relative to the copying claw. on the robot arm.

In these known systems, the sensor system and the working surface of the deburring tool are set relative to each other at a separately arranged dedicated calibration station. In order to carry out this adjustment, this known equipment requires complicated equipment to be custom-made to be able to displace either the grindstone relative to the sensor or vice versa on the robot arm. Next, the deburring tool is moved to the workpiece, where the sensor (optical sensor system or copy claw) is used to control the deburring tool's migration relative to the workpiece.

Similarly, it is known in known systems of the kind in which a robotic arm guides the workpiece past a stationary deburring tool to design the deburring tool so that it can adjust the work surfaces of the deburring tool with the aid of measuring equipment and other equipment to compensate for abrasive wear. and stones.

15 The foregoing known techniques thus have the disadvantages of requiring equipment that is complicated to build and often needs to be custom made, making them costly. Furthermore, this prior art involves additional movable equipment which increases the danger of malfunctioning as well as necessitates 20 complicated dedicated calibration stations located outside the normal working area.

The invention aims to provide a single equipment of the kind passing the workpiece with a tool, significantly better accuracy and in particular reproduction accuracy, without requiring complicated equipment or extensive conversion, for example by a standard robot, or requiring separate calibration stations.

This is achieved by a system of the kind set forth in the preamble of claim 1 with the means disclosed in the characterizing part, and by a method of the kind specified in claim 4 and further by an application according to claim 9.

By designing the system as defined in claim 1, the use of pressure sensor-based positioning with associated costs and inaccuracies, including 35 continuous pressure over long travel, can be avoided, while degradation can be done with knowledge of the surface of the tool. This surface may be sensed from time to time by the individual means specified in the characterizing part of claim 1.

Further, in the embodiment of claim 2, the tool can be maintained with simple means so that the condition of the tool does not affect the degradation.

In addition, in the design according to claim 3, it is achieved that the tool which makes the alignment of the abrasive stone does not affect the quality 10 of the alignment during wear and thus ultimately the degradation itself.

In general, in the design as set out in claims 1-3, with simple means a precision of the deburring is obtained, which can otherwise only be achieved with complicated dedicated equipment.

Similarly, by the method of claim 4, the degradation process of a generally degradation machine can be substantially improved without substantial modification of standard equipment. Hereby, the tool which makes the deburring is further monitored, so that information on this can also be provided.

Furthermore, by carrying out the method as set out in claim 5, the quality of the deburring can be further improved by maintaining the deburring tool.

In the method of claim 6, the same deburring precision can be obtained for a single equipment, which is otherwise only provided with complicated equipment.

Furthermore, by carrying out the method as set forth in claim 7, the method can be adapted to experience-based basis so as to obtain optimum quality and quantity.

Furthermore, by failing to initialize the robot itself as set forth in claim 8, great accuracy is achieved in the degradation itself, without the need to change any standard program, or the precision of 35 in other work processes is disturbed by the method of the foregoing requirements.

DK 171660 B1 5

Furthermore, by using the system and method as defined in claim 9, the advantage is that a standard robot can lift heavy objects and place them in the room in a relatively simple manner, without any possible size of grating 5 having significant impact on the forces. to be used for this, whereas placement of tool on a manipulator generally requires special adaptation of the tool to the manipulator, transfer of continuous energy to the tool, and the tool will be exposed to large differences in pressure influence as a function of the grating size, which overall affects the quality of the deburring.

The drawing shows:

FIG. 1 is a top plan view of an integrated robot cell; FIG. 2 is a six-degree standard robot; FIG. 3 and 4 are the distal joints of a manipulator viewed from the side and from above, respectively; and FIG. 5 is a flow chart of a calibration routine according to the invention.

In FIG. 1, there is shown an integrated robotic cell 1 of 20 the kind which carries on a common ground plane element 15, 16 a manipulator 3 and any stationary tools 9, 11 or other for which to be precisely positioned.

The FIG. 1, the robot cell shown in Fig. 1 is built on a partially outlined bottom frame 16, on which is placed a bottom plate 15, which together constitutes the basic planar element.

At the rear end of this floor plan element, the control equipment 2 may optionally be located, but otherwise the manipulator 3 is located at the rear of this floor plan element. The base 30 of the manipulator, which at the same time constitutes the proximal reference 30, is here attached via attachment means 17 to the base frame 16 and the base plate 15, where it is where the greatest forces of force occur. Further in the robot cell, stationary tools 9, 11 are also located, which are also located on the base plate 15 and optionally on the base frame 16. In addition, there is also a front area 5 for incoming items and a outlet area 12 for outgoing objects 8. Advantageously, the deposition area 12 may be formed as a conveyor belt 12, as shown here, or a slit.

In this basic arrangement, the manipulator 3 can take a workpiece 8 from the outlet area 5 by its gripper or working head 4. Thereafter, the manipulator 3 moves the workpiece 8 to the first stationary tool 9, where the manipulator 3 moves the workpiece 8 as necessary to complete the first work process. Thereafter, the manipulator 3 10 moves the workpiece 8 to the next machine tool 11, where the manipulator 3 moves the workpiece 8 as necessary to carry out the work process here. Thereafter, the manipulator 3 moves the item 8 to the outlet area 12, where the manipulator 3 dispenses the item 8 to the outlet area 12. Thereafter, the manipulator 15 3 is ready to pick up a new item 8 from the input area 5 and complete a new duty cycle.

Of course, although the robotic cell is described herein and with one or two stationary tools 9, 11, there may be several.

In the work processes, the manipulator 3 moves the workpiece 8 to position by a machining tool 9, 11 and performs the necessary movements of the workpiece 8 to carry out this work process, this may be, for example, rotation and movement of the workpiece 8 relative to a desired end contour of the workpiece. 8, which is determined in relation to a cutting disc 9a, a grindstone 11a or the other working surface of the disc. As this work surface changes with wear or damage, it is necessary from time to time to correct this surface and / or shift the work movements in relation to this surface.

The manipulator itself may be a standard manipulator with five to six degrees of freedom, for example as shown in FIG. 2, which manipulator consists of a base 30 constituting the proximal reference, a first manipulator part 31 which is connected to the base 30 and can be rotated relative thereto in a direction A1, a second manipulator part or arm 32 which DK 171660 B1 7 can be rotated about a shaft 31a in a direction A2, a third manipulator part 33 which can be rotated about a shaft 32a in a direction A3, a fourth manipulator part or arm 34 which can be rotated in a direction A4, a fifth manipulator part 35, which can be rotated 5 about a shaft 34a in a direction A5 which sits on the front portion 37 of the manipulator arm 34, and a distal manipulator portion 36 which can rotate in a direction A6 relative to the manipulator portion 35. Attached to the manipulator portion 36 the working head 4, which may be a gripper, tool or the like. The link through which the manipulator portion 36 can rotate with respect to the manipulator portion 35 in the direction A6 is constituted by a rotary joint capable of rotating, for example, 720 °. The joint through which the manipulator portion 35 can be rotated relative to the manipulator portion 37 in the direction A5 is constituted by a pivot joint which can be rotated 15 by less than one turn, for example 240 ° or ± 120 °. The manipulator arm 34 with its anterior or distal portion 37 constitutes an elongated rigid manipulator element on which attachments can be attached, such as a welding transformer by welding robots. Standard robots and manipulators of this kind with five to six degrees of freedom are manufactured in large numbers for, for example, the automotive industry and therefore provide a very favorable price / quality ratio compared to custom made manipulators with fewer degrees of freedom.

Thus, when a standard robot is used in the integrated deburring cell, by default, more degrees of freedom and greater programming capabilities are provided than is immediately necessary for a deburring manipulator.

In the present invention, these degrees of freedom are utilized to perform control, calibration and straightening 30 of a rotary deburring means, for example, abrasives worn down by the deburring processes and thereby changing its work surface, so it is necessary from time to time to make a straightening and / or calibrating the surface of the abrasive stone to know its nature and / or location.

In a first embodiment of the invention, at least one sensor 52, 53 is located at the outside of one of the distal joints of the manipulator 3, as shown in FIG. 3 and 4, the signal of which is fed to the control equipment 2, optionally via a measurement processing circuit 54. Since the location of the individual 5 manipulator joints is known or can be calculated at any given time, the actual location of the sensor 52 is also known or can be calculated, since it has a fixed position relative to a manipulator part and since the position of this manipulator part is known or can be calculated based on the position of the 10 joints proximal to this part. Thus, in a calibration step, the manipulator can direct the sensor 52, 53 to the grinding stone or other to be calibrated, and by means of the manipulator, advance the sensor 52, 53 of a given path towards the grindstone to a point where the sensor senses a distance signal or where the sensor emits a detection signal whereby the manipulator stops its migration. If the grindstone has changed the working surface, this is detected as a difference in the position of the manipulator or in the distance between the manipulator and the working surface. This detection can be used to calculate a difference or offset between a reference position and the measured position, and this offset can be converted to an offset added to the manipulator's movements as the manipulator controls machining at the given tool without the need for 25 to initialize the manipulator's position, which would change the manipulator's location by other work processes. Furthermore, the signal from sensor 52 can be used to assess whether the grindstone should be straightened and / or replaced.

Further, when a straightener 51 is located at the outside of one of the distal portions of the manipulator, this straightener 51 can be advanced based on the data obtained by the calibration to align the abrasive with the manipulator 3, when and / or if necessary.

Since the shredder is also worn, it is advantageous to have an additional stationary sensor 57 which, in a shutter calibration step, can scan the distance to the shredder's work surface or detect it as the manipulator 3 advances the shutter 51 towards the sensor 57 to a given point in a similar manner as mentioned in the previous calibration step. Below, an offset can be calculated for the execution process and / or it is possible to decide whether the replacement should be replaced.

Advantageously there may be an additional sensor 53 at the outside of one of the manipulator distal parts if it is desirable to calibrate an additional tool and the first sensor 52 has a location which is inappropriate for this calibration.

The system for calibration and alignment can advantageously be built on a base plate 50 which can be attached to one of the distal parts 34, 37 of the manipulator 3, the manipulator 3 here being a standard manipulator which is made without a sensor or deflector by default. On this eraser base plate 50 there are located one or more sensors 52, 53 and optionally a eraser 51. These parts 51-53 are suitably placed 20 for the operations they are to perform, optionally the parts 51-53 and the base plate 50 may be designed so that the location can be changed, for example if new stationary tools are introduced. Further, a measuring processing circuit 54 may advantageously be placed on the base plate 50, 25 to which the signals from the sensors 52, 53 are fed via wires 55 and optionally also the control to the shutter 51, so that the signals can be processed before they have collected significant noise and possibly converted to signals which are compressed to the essential signals and / or are easier to process for the control equipment 2, furthermore, it makes the wiring simpler, since there is now only one unit to be connected, which is essential when the wiring is to be passed over the movable joints. .

Furthermore, the relative accuracy becomes extremely good when the calibration is performed in a position where the manipulator is near the position to which it is to use the calibration result, with wear and tear. may affect absolute accuracy over larger distances, but does not affect reproduction accuracy particularly over small distances, which is especially relevant for the calibrator calibration, since tool calibration by a manipulator is usually performed in a calibration range remote from the machining process.

The sensors used may be of any kind, but are preferably touchless sensors, which measure by an optical, capacitive, magnetic or ultrasonic principle, to avoid the wear and tear of a touch sensor.

By means of the invention it is easy to convert a standard manipulator to a special manipulator, especially if the technique from the applicant's simultaneously filed DK application: "Energy transfer connection to manipulator, especially robotic arm" (our ref. 55870). This special manipulator may, for example, be suitable for working under tight working conditions and can perform special operations such as 20 calibration and alignment of abrasive stones etc. This can be done by attaching a base plate 50, 60 with the necessary accessories in the form of energy converters 61, alignment, calibration or other units 51-54, and attaching this base plate 50, 60 to a standard manipulator arm at a location, e.g. a site intended for enhancement, and furthermore attaching a spacer unit 66 to a torsion joint, and attaching a unit with guide roller or guide rollers 65, 65a to a manipulator part, and optionally attaching a biasing unit 68 to a manipulator part which in the main case is held or held rigid with respect to the manipulator part where the base unit 50, 60 is secured.

In the special design of the particular cell specified in the applicant's simultaneous application, DK application: "Integrated deburring cell for deburring of support pieces" 35 (our ref. 55869), and energy transfer can be achieved increased speed, which is very important in degrading. Here, it should be noted that an automatic casting machine can often produce items eight times faster than they can be deburred, where the speed difference depends on the size of the workpiece. Thus, it is also advantageous for the cell to be easily moved, since in this way the number of cells can be varied by the individual foundry machine or casting hall, as needed.

The described calibration and alignment system and the technical solutions it encompasses, make it easy to customize a deburring cell to a customer's 10 wishes.

In this context, it is especially advantageous that the finished deburring cell can be easily moved. As the finished custom-adapted cell can be finalized at the manufacturer, where it can also be tested and run-in, so that no run-in time and post-adjustments are needed at installation by the user.

FIG. 5 shows an example of a calibration and alignment process which is solely for illustration purposes: DK 171660 B1 12 RI Start calibration and alignment program.

R2 Initialize the program and enter initial values.

R3 Go to the first calibration in block XI (R3-R8) during which tools are sensed and calibrated.

5 R4 Gives the calibration in response that the tool must be replaced if NO goes to R7, otherwise to R5.

R5 Is it a warning that the tool should be replaced soon if YES go to R6 or to R15 with status signal.

10 R6 Turn on the warning signal "tool to be replaced soon".

R7 Gives the calibration in response that must be executed if NO goes to R9 or goes to R8.

R8 Perform alignment.

R9 Are there other calibration procedures to be performed, 15 if YES go to RIO, otherwise go to Ril.

R10 Perform steps corresponding to XI for one or more tools.

Ril Count status counters.

R12 Is it the last calibration and alignment if YES

20 go to R13, otherwise go to R15.

R13 Wait for activation while other processes are performed.

R14 Must be calibrated if YES go to XI, otherwise go to Ril.

R15 When finished, save status and turn on status signals.

25 R16 Go to stop, wait, or return.

The above merely serves as an example, and it will be obvious to one skilled in the art to have block R13 at the top of the program, as well as to execute R9 and R14 such that any sequence Xn may be selected when desired in order of priority.

This can be done, for example, by letting R14 go to the point before R9 instead of after R9.

When the program is a sub-program under the manipulator control program itself, it is clear that R16 can be connected between R12 and R13, and that the program starts with R14 (after DK 171660 B1 13 initialization) and ends with R13. But of course there are many other options.

Object perception DK 171660 B1 14 1 Robot cell / deburring cell 2 Control equipment 5 3 Manipulator 4 Work head 5 Outlet area, input 6 Outer door 7 Inner door 10 8 Item 9 1. tool 9a Cutting disc 10 Slot 10a Box 15 11 2nd tool 11a Abrasive 12 , conveyor belt 13 Reading space 14 Door 20 15 Base plate, floor plan element 16 Bottom frame, floor plan element 17 Robot fastening, bolts 18 Lifting fastening, eye bolts 19 Rear wall 25 20 Front wall 21 Top 22 Side wall 23 Lift hole 30 25 Inspection window 26 Energy connection 27 Exit opening 28

List of items (continued) 15 GB 171660 B1 I Picking up item (8) II 1. machining 5 III 2. machining IV Delivery of item 30 Base (proximal ref. Manipulator) 31 1. manipulator part / arm part 10 31a Connector link 32 2. manipulator part / arm part 33 3. manipulator part / arm part 34 4. manipulator part / arm part 34a Connector joint 15 35 5. manipulator part / arm part 36 Fastening point for working parts.

37 Front part of 4th indent

All 1st degree of freedom, swivel joint 20 A2 2nd degree of freedom, swivel joint A3 3rd degree of freedom, swivel joint A4 4th degree of freedom, swivel joint A5 5. degree of freedom, swivel joint A6 6. degree of freedom, rotational joint 25 50 Base plate for drainage system 51 Straightener 52 2 sensor 30 54 Measuring machining circuit 55 Wiring 56 Fastening screws 57 Stationary sensor

List of objects (continued) 16 GB 171660 B1 60 Hydraulic / energy base plate 61 Energy source 5 62 Energy transfer connection / line 63 Pre-tensioning wheel 64 Turning wheel 65 Inner guide wheel 65a Outer guide wheel 10 66 Spacer assembly / member 67 Spacer shaft 68 Spring / balance 69 Wheel / balance 69 15 71 Arm (for rollers) 72 Mounting plate

Claims (9)

A system for deburring or grinding a workpiece (8) using a manipulator (3), in particular a robot, which manipulator is provided with gripping means (4) for gripping the workpiece to be degraded, whereby there is at least one rotating a deburring means (9, 9a, li, lia), for example, a grinding stone (9a, 11a), which is stationary, which is depreciated from time to time and thereby controlling the manipulator to guide the contour (s) of the blank; to be degraded, past the degradation means or means of proper bias and / or distance, whereby the degradation is carried out, characterized in that the manipulator is provided with at least one contactless sensor (52, 53), in particular optical or distance sensing for sensing an over -15 flat position on the deburring member (s) (9, 9a, 11, 11a). System according to claim 1, characterized in that the manipulator (3) is provided with at least one eraser unit (51) located on the working head (4) or a portion of the manipulator (34-36) which is proximal to the relationship. to the working head, in particular the second part proximal to a link to which the working head is located and that this straightener is used to execute the deburring means or means (9, 9a, 11, 11a). System according to claim 1 or 2, characterized in that at least one additional sensor (57), in particular optical or proximity sensing, is fixed in the vicinity of the deburring element (s) (9, 11). A method of deburring or grinding by a system according to one or more of claims 1-3, wherein a workpiece (8) is to be degraded using a manipulator (3), in particular a robot, which manipulator is provided with gripping devices ( 4) to grasp the workpiece to be degraded, whereby there is at least one abrasive (9a, 11a) or other rotating degradation means which is stationary, which first degradation means from time to time is set off and thereby the robot is guided to guide the contour (s) of the workpiece to degrade, past the grindstone with proper bias and / or distance, whereby the degradation is performed, characterized in that the manipulator in a first calibration step puts the manipulator in a given position which places a sensor (52, 53) located on the manipulator immediately outside the largest circumference which the grindstone may either have or was measured to have at the previous calibration, after which the nipulator moves the sensor against the abrasive surface until the surface is detected, which registration is subsequently used to either: adjust the starting position and / or bias of the manipulator in a subsequent degradation process, or 15 to determine whether to align the abrasive stone and / or to what size the alignment should be made, or to decide whether to replace the grindstone. Method according to claim 4, characterized in that in a straightening step, a straightening means (51) mounted on the manipulator (3) is brought to abutment with the surface of the abrasive stone (9a, 11a) and the straightening means is then introduced into a position determined from the previous record of the surface of the grindstone. Method according to claim 5, characterized in that, in a alignment calibration step, the manipulator (3) is placed in a given position which places a surface on a ridge (51) seated on the manipulator immediately outside a place-fixed sensor (57), in particular contact-free. located near the abrasive stone (9, 9a, 11, 11a), whereby the initial position of the surface is either predetermined, determined by the most advanced position the shredder can have, or determined as it was measured to by the previous calibration, after which the manipulator moves the rectifier against the sensor until the surface is recorded, which registration is subsequently used to either: adjust the starting position and / or the bias of the manipulator in a subsequent alignment process, 5 or to determine whether to replace the cutter. Method according to claim 6, characterized in that the first calibration step is performed at start-up and then continuously after a given number of intermediate degradation processes, wherein the intermediate degradation process is at least one, that a calibration calibration step is performed at start-up, that an alignment step is optionally carried out at start-up. that a calibration step is performed each time a given number of calibration steps is completed, with the given number of calibration steps being at least one, and that a calibration calibration step is performed each time a given number of calibration steps is performed, whereby the given number of alignment steps is at least one. Method according to one or more of claims 4 to 7, characterized in that the position registration at the calibration steps is used exclusively for the final positioning of the manipulator (3) in the said processing and calibration processes and not to initialize the manipulator itself. Use of the system and method according to one or more of claims 1-8 for deburring medium-heavy objects (8) of 1-500 kg, especially 15-200 kg.