Control device for a handling device

Abstract

A control device for a handling device includes a storage medium, a processing unit, an output for outputting signals, and an input for receiving signals from the handling device. A waiting phase is conducted before an actuation of an end-of-arm tool mounted to an end-of-arm of a handling arm. The signals received by the input represent a dynamic parameter of the end-of-arm and a threshold value corresponds to a specific dynamic parameter of the end-of-arm stored in the storage medium. The signals received by the input can be compared with the threshold value by a comparison unit of the control device, and an end of the waiting phase can be determined when reaching the threshold value. Depending on a curve of the dynamic parameter, the threshold value can be determined and the end of the waiting phase can be determined when reaching the threshold value.

Claims

1. A control device for a handling device, the control device comprising: a non-transitory computer-readable medium having stored thereon executable instructions; a processor; an output configured to output signals; and an input configured to receive signals from the handling device, wherein: the control device is configured to determine an end of a waiting phase when reaching a threshold value, the waiting phase being conducted before an actuation of an end-of-arm tool mounted to an end-of-arm of a handling arm of the handling device and the waiting phase serving to reduce oscillations of the end-of-arm of the handling arm of the handling device; the signals received by the input represent a dynamic parameter of the end-of-arm of the handling arm of the handling device and the threshold value corresponds to a specific dynamic parameter of the end-of-arm of the handling arm of the handling device stored in the non-transitory computer-readable medium; the executable instructions, when executed by the processor, cause the control device to function as a comparison unit configured to: (i) compare the signals received from the handling device with the threshold value and determine the end of the waiting phase when reaching the threshold value; or (ii) based on a curve of the dynamic parameter of each of multiple oscillating profiles of the end-of-arm of the handling arm of the handling device that are stored in the non-transitory computer-readable medium, determine the threshold value, which corresponds to a time limit, and determine the end of the waiting phase when reaching the threshold value; and the control device is configured to control the end-of-arm of the handling arm of the handling device based on the end of the waiting phase which has been determined.

2. The control device according to claim 1, wherein the control device is configured to output a continuation signal based on the end of the waiting phase which has been determined.

3. The control device according to claim 1, wherein the dynamic parameter is an oscillation value which is determined based on at least one of a speed, an acceleration, a deflection, a stress state or a position of the end-of-arm of the handling arm of the handling device.

4. A handling device for a molding machine, the handling device comprising: a handling arm which comprises an end-of-arm; an end-of-arm tool mounted to the handling arm for handling a molding part or a semi-finished product; and at least one drive device for the handling arm, wherein the handling arm comprises the control device according to claim 1.

5. The handling device according to claim 4, wherein the handling device comprises a handling control system, and the control device is signally connected to the handling control system or is integrated into the handling control system.

6. The handling device according to claim 4, wherein at least one procedure sequence for moving the end-of-arm along at least one movement axis is stored in the non-transitory computer-readable medium of the control device or in the handling control system.

7. The handling device according to claim 6, wherein the at least one procedure sequence comprises: a period of movement for moving the end-of-arm from a starting position to a handling position; the waiting phase; a handling phase initiated by a continuation signal; and a movement or transport phase for moving the end-of-arm from the handling position into an end position.

8. The handling device according to claim 6, wherein the at least one procedure sequence includes multiple procedure sequences, wherein the multiple procedure sequences differ from each other at least in speeds of the end-of-arm in a handling phase, and wherein for each procedure sequence, the threshold value is stored in the non-transitory computer-readable medium, the threshold value being dependent on an executed action of the end-of-arm tool of each handling phase.

9. The handling device according to claim 6, wherein, in each period of the at least one procedure sequence, the control device is configured to transmit corresponding signals via the output to the at least one drive device.

10. The handling device according to claim 4, further comprising at least one sensor, wherein the at least one sensor is configured to transmit values measured by the at least one sensor to the input of the control device as signals representing the dynamic parameter.

11. The handling device according to claim 10, wherein the at least one sensor is in an area of the end-of-arm or in an area of the end-of-arm tool.

12. The handling device according to claim 10, wherein the at least one sensor is an acceleration sensor.

13. A molding unit comprising: a molding machine; and the handling device according to claim 4.

14. The molding unit according to claim 13, wherein the molding machine comprises an injection device and a closing unit with a molding tool, wherein the handling device is configured to: (i) handle, in a handling phase, a molding part produced in the molding tool; or (ii) bring a semi-finished product into the molding tool.

15. The molding unit according to claim 13, wherein the molding machine comprises a machine control system, and a handling control system is signally connected to the machine control system or is integrated into the machine control system.

16. The molding unit according to claim 13, wherein the molding machine is an injection molding machine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further details and advantages of the present invention are described more fully hereinafter by means of the specific description with reference to the embodiments illustrated in the drawings, in which:

(2) FIG. 1 shows schematically a molding unit with a control device, a handling device and a molding machine,

(3) FIG. 2 shows schematically a second variant of the control device according to the invention,

(4) FIG. 3 shows a handling device in a perspective view,

(5) FIG. 4 shows a detail of FIG. 3,

(6) FIG. 5 shows exemplary program code according to the prior art,

(7) FIG. 6 shows exemplary program code according to the invention,

(8) FIG. 7 shows exemplary program code with an additional maximal waiting time,

(9) FIG. 8 shows the movement of the handling arm by means of a TCP,

(10) FIG. 9 shows a diagram of the velocity/time-progress of the acceleration of the end point and

(11) FIG. 10 shows a diagram of the velocity/time-progress of the acceleration of the end point in the case of a lower default velocity.

DETAILED DESCRIPTION OF THE INVENTION

(12) FIG. 1 schematically shows on the right side a molding unit 17. This molding unit 17 comprises a molding machine 11 and a handling device 2. In turn, the molding machine 11 comprises a closing unit 19 and an injection device 18. Also a machine control system 21 with a screen and an input unit (touch screen and/or keyboard) is provided. Starting material, preferably in the form of granulate, is melted in an injection unit 22 of the injection device 18, which starting material is introduced by means of a feed hopper 23. The melt is brought into a cavity formed in the molding tool 20 by means of the dashed illustrated injection channel 24, wherein the molding tool 20 comprises the two mold halves 20a and 20b. The two mold halves 20a and 20b are mounted to the moveable mold mounting plate 25 and to the fix mold mounting plate 26. The moveable mold mounting plate 25 is moveable along the frame 20 by a drive device 27 which is, for example, a toggle lever mechanism.

(13) The handling device 2 comprises a socket 29. The handling device 2 can also be mounted on or at the molding machine 11 by means of this socket 29. In this case, the handling arm 8 comprises three arm parts 8a, 8b and 8c. These arm parts 8a, 8b, 8c are moveable relative to each other along or around the movement axes X, Y and Z. These movement axes X, Y and Z can be formed rotational or linear. Each arm part 8a, 8b and 8c can be driven by a corresponding drive device 14a, 14b, and 14c. These three sub-drive devices form the drive device 14 for the handling arm 8. The handling arm 8 comprises and end piece which is referred to as end-of-arm 7. An end-of-arm tool 12 is mounted at the end of the handling arm 8. This handling arm tool 12 can also be referred to as manipulator or as transfer head. In the shown case, the end-of-arm tool 12 is formed as a pincer-like gripper. A molding part 13 is just removed from the cavity of the molding tool 20 by this gripper. Also, a—preferably fiber-reinforced—semi-finished product (e.g., a preform, a composite laminate or a roving) can of course be inserted into the cavity by this manner. In a handling control system 15 signally connected to the handling device 2, a procedure sequence B for the handling arm 8 of the handling device 2 is stored. Originating from this procedure sequence B, the single drive devices 14a, 14b and 14c are controlled. According to the movement phase M1, the end-of-arm 7 is moved from the starting position P1 into a handling position P2. Then, the waiting phase W follows. As soon as this waiting phase W has ended, the handling phase M2 by means of the end-of-arm tool 12 follows. Finally the transport phase M3 follows. After the procedure sequence B has been travelled, the end-of-arm 7 is in the end position P3. Also a sensor 16 is mounted in the area of the end-of-arm 7. A value is measured by this sensor 16, which value represents a dynamic parameter P.sub.dyn, e.g., an acceleration signal, of the end-of-arm 7.

(14) A (open-loop) control device 2 signally connected to the handling device 2 is schematically shown on the left side of FIG. 1. This control device 1 can be integrated into the handling control system 15. In the shown case, these structural components are separately formed. The control device 1 comprises a processing unit 4 and a storage medium 3. Further, there is an input 6 for receiving signals and an output 5 for outputting signals. The control device 1 receives a signal originating from the sensor 16 by means of the input 6, which signal represents the dynamic parameter P.sub.dyn of the end-of-arm 7. In a comparison unit 9 of the control device 1 this value is—in the case of the first variant according to the invention—compared with the threshold value G stored in the storage medium 3, which threshold value G corresponds to a dynamic threshold value G.sub.dyn comparable with the dynamic parameter P.sub.dyn. As soon as the dynamic parameter P.sub.dyn transmitted by the sensor 16 reaches the dynamic threshold value G.sub.dyn or exceeds the dynamic threshold value G.sub.dyn in a predetermined direction, the end of the waiting phase W is reached. Depending therefrom, a continuation signal F is the outputted. Thereby, the waiting phase W of a procedure sequence B is terminated. The procedure sequence B is preferably stored in the handling control device 15. This continuation signal F can directly be outputted from the control device 1 to the corresponding drive device 14 of the handling device 2. Preferably, it is provided that this is carried out indirectly by transmitting this continuation signal F—as shown—to the handling control device 15, whereby the procedure sequence F can be switched from the waiting phase W to the handling phase M2. In this handling phase M2, a signal is outputted to the end-of-arm tool 12 which correspondingly handles the molding part 13 (or the semi-finished product respectively).

(15) FIG. 2 schematically shows a second variant of the control device 1 according to the invention. The oscillating profiles are calculated in the calculation unit 10 of the control device 1. The oscillating profiles are based on the received dynamic parameters P.sub.dyn, from which each a curve V.sub.dyn of the dynamic parameter P.sub.dyn is generated. These calculated curves V.sub.dyn1 to V.sub.dynx are stored in the storage medium 3. For each of the curves V.sub.dyn1 to V.sub.dynx also an associated time threshold value G.sub.t1 to G.sub.tx is determined and stored.

(16) The waiting phase W is terminated by the control device 1, preferably by outputting a continuation signal F, as soon as—during the execution of the procedure sequence B of the handling device 2 in the waiting phase W—the threshold value G stored as a time limit is reached. In this case, it is (automatically or manually) considered which of the stored curves V.sub.dyn correspond to the current procedure sequence B and/or to the current characteristics of the handling device 2. Thus, that threshold value G.sub.t is used, which threshold value G.sub.t is stored for that oscillating profile which corresponds to the actual oscillation behavior or which comes nearest to this oscillation behavior. In the case of a curve V.sub.dyn with a strong oscillation behavior, thus, a threshold value G.sub.t with a later time limit for the outputting of the continuation signal F will be stored.

(17) FIG. 3 shows a handling device 2 in a perspective view. An elongated carrier 30 is mounted to the socket 29. The arm part 8a of the handling arm 8 is linearly moveable along this carrier 30 by means of the drive device 14a. The arm part 8b, in turn, is linearly moveable along this arm part 8a by means of the drive device 14b. The arm part 8c, consisting of the parts 8c1 and 8c2, is moveable in vertical direction relative to the arm part 8b. The arm part 8c is driven by the drive device 14c. The end-of-arm tool 12 is mounted to the end piece (end-of-arm 7). In this case the end-of-arm tool 12 is connected by means of a rotary axis ABC to the end-of-arm 7. There can also be several rotary axes ABC.

(18) In FIG. 4 the end-of-arm tool 12 is shown in details. This end-of-arm tool 12 comprises four suction elements 31 and four rods 32 by means of which a flat molding part 13 can be held well. A sensor 16 in the form of an acceleration sensor is mounted in the area of the end-of-arm 7. This sensor 16 detects the occurring accelerations on this position and, thus, enables a direct and model-based determination of the acceleration of the end-of-arm tool 12 in the control device 1.

(19) Generally, it is so that the positioning of the manipulator (end-of-arm tool 12) is carried out with a high dynamic, so that in particular protruding constructions cause an oscillation action subsequent to a positioning action. The duration of the oscillation action is depending on many parameters like position, weight distribution, position of the handling axes, used dynamic, etc. as well as on the precision requirements of the process. That is why according to the prior art the waiting time for the subsiding/decaying of the residual oscillation is empirically determined and is provided with tolerances in order to reach the desired process safety. In the following, the prior art of a program code of a control device of a handling device during taking or inserting a molding part or a semi-finished product shall be shown with reference to FIG. 5. Typically, an operation in the following form is advisable in this case: Outputting an instruction for moving to a preparation position (starting position P1) with a high velocity (MOVE Pos1) Outputting an instruction for moving to the target position (handling position P2) for the handling of parts with a reduced speed and outputting of an instruction for waiting till the default position corresponds to the target position (WAIT MOVE Pos2) Waiting until the residual oscillation has subsided (WAIT Waitingtime1) Outputting a control signal for the releasing or receiving of parts with the end-of-arm tool 12 and waiting until the handling is terminated successfully (Process) Outputting a signal for the movement into the next position, e.g., into the end position P3 (MOVE Pos3)

(20) In particular, in the case of the third instruction step mostly a fix time is used as there is no information about the state of the handling arm concerning the oscillations.

(21) By the use of sensor systems (sensor 16) at the end of the handling arm 8 or in its vicinity, it is possible to detect the state of the handling arm 8 concerning the dynamic (acceleration, velocity, deflection, stress state, vision systems, etc.). If now using one or multiple sorts of dynamic values (or values determined therefrom) as a decision criteria for the passing from the last robot position movement to the triggering of the end-of-arm tool, the yet predetermined time can be omitted. In particular, a parameter in the form of a limit for the decision criteria can be given to the new waiting condition. By the use of a sensor system, thus, a higher process safety is reached on the one hand and also a faster process run is reached on the other hand. Therefore, the new program code with robot instruction could appear as in FIG. 6. Accordingly, the difference to FIG. 5 is only in the third step. According to the third step, it is waited till the residual oscillation falls below a certain limit (threshold value G). In other words, there is a new waiting instruction instead of the empirically determined Waitingtime 1 according to FIG. 5, which waiting instruction waits for the falling below a limit representative for the end point acceleration. In addition, the limit can be chosen in such a way that it corresponds to the requirements of the process and is still valid in the case of changes in the planning of the travel path (position, dynamic) or even in the manipulator, that no damages are caused and that even a reduction of the cycle time is reached.

(22) FIG. 7 exemplarily shows a further program code. In this embodiment the waiting instruction has been complemented by the evaluation of a maximal waiting time (timeout). If the maximal waiting time is expired and the residual oscillation limit is not yet achieved, then it is branched to an alternative process. This process can represent a further try of the original process or can run to an error handling branch. Of course, also several tries, preferably in a loop, can be provided and the amount of tries can again be limited. All of these extensions have the aim to still increase the process stability and the error tolerance respectively.

(23) FIG. 8 shows an idealized movement of the TCP (tool center point) without oscillation of the TCP in the case of a programming as shown in FIG. 6. Also the three movement axes X, Y and Z are shown.

(24) FIG. 9 shows in a diagram the time progress of the end point acceleration. For this purpose, an interface module on the handling arm 8 is extended by an acceleration sensor (sensor 16). This sensor 16 enables the direct or modeled detection of the acceleration of the end point (end-of-arm) and the evaluation of the signal in the control device 1. In the procedure sequence B the acceleration is stored relative to the time (see dashed line “default”). The acceleration actually measured by the sensor 16 deviates from this default (see the continuous line “kinematic”). This controlled movement of the handling arm 8 corresponds to the movement phase M1. The waiting phase W joins to this movement phase M1. Oscillations are occurring by the predetermined abrupt braking of the movement of the handling arm 8, which oscillations subside by themselves with the time or by a damping introduced into the drive system. In order to pass on to the subsequent handling phase M2, a fix waiting time has been predetermined up till now (see dashed arrow). In doing so, however, an unnecessary deceleration of the cycle time has been accepted. In contrary, threshold values G (limit1, limit2) are now predetermined, which threshold values G are directly referring to the actual real oscillation behavior. As soon as this threshold value G is reached or undershot, the continuation signal F is outputted and, thereby, the handling phase M2 is started. As now the outputting of the continuation signal F is depending on a measured or calculated oscillation behavior, the switching reduces the next phase of the movement progress significantly (see shorter waitingtime1 and waitingtime2 respectively).

(25) If changing the robot acceleration default according to FIG. 10, for example during the start of a new product, or if setting changed threshold values, also the waiting times between the actual positioning of the robot and the possibility to start the subsequent process step change. The precise requirements are depending on each process, so that this process can be carried out with a swung out manipulator. According to FIG. 10, the maximal acceleration of the default is smaller than in FIG. 9, whereof the lower oscillation amplitudes result. For this reason, a still higher time saving compared to the predetermined waiting time is given in the case of the continuation signal outputting directly depending on the oscillation behavior.

LIST OF REFERENCE SIGNS

(26) 1 control device 2 handling device 3 storage medium 4 processing unit 5 output 6 input 7 end-of-arm 8 handling arm 8a-8c arm parts 8c1, 8c2 parts of the arm part 8c 9 comparison unit 10 calculating unit 11 molding machine 12 end-of-arm tool 13 molding part 14-14c drive devices 15 handling control system 16 sensor 17 molding unit 18 injection device 19 closing unit 20 molding tool 20a, 20b mold halves 21 machine control system 22 injection unit 23 feed hopper 24 injection channel 25 moveable mold mounting plate 26 fix mold mounting plate 27 drive device 28 frame 29 socket 30 carrier 31 suction elements 32 rods G threshold value G.sub.dyn threshold value on the basis of a dynamic parameter G.sub.t threshold value on the basis of a time limit F continuation signal W waiting phase P.sub.dyn dynamic parameter V.sub.dyn curve of the dynamic parameter B procedure sequence X, Y, Z movement axis M1 movement phase M2 handling phase M3 movement or transport phase P1 starting position P2 handling position P3 end position ABC rotary axis