DE102010060158B4 - Control device and method for controlling the stations of a production line - Google Patents

Abstract

The invention relates to a control device and a method for controlling a press line (10). The press line (10) has a plurality of processing stations (11) and at least one transfer station (14) for the workpiece transport between the processing stations (11). A station control unit 20 is assigned to each station. A system control unit (22) transmits a superordinate system control signal to all station control units (20). A local station control signal is generated in the station control units (20) for the respectively assigned station (11, 14). In addition, an assignment rule is stored in each station control unit (20), which defines the course of the local station control signal in relation to the higher-level system control signal. These assignment functions can be changed by an operator during operation of the press line (10). As a result, the chronological sequence of movements in at least one station (11, 14) can be changed compared to the superordinate system control signal by changing one or more assignment functions

Description

The invention relates to a control device and a method for controlling a production line, in particular a press line. The production line has a plurality of processing stations, which are sequentially traversed by a workpiece. For transporting the workpiece from one processing station to the other, at least one transfer station is provided.

Such a production line is for example from the DE 10 2005 040 762 A1 known. In such production lines there is a need to coordinate the work processes of the individual stations. The throughput of the entire production line depends on the slowest station.

Off at the production line DE 10 2005 040 762 A1 generates a master computer signals or setpoints depending on the detection of the operating state of at least one main processing station of the production line. The signals or setpoints are then transmitted to the other stations of the production line and taken into account there. Variations at the main processing station due to speed changes or slippage of the main drive, for example the main drive of a press, are then automatically taken into account in the other stations in the production line.

This production line works as it were in the "master-slave mode". A main processing stadium specifies the working cycle at which all other stations are automatically adjusted by a regulation. An optimization of the operation of a single station independent of the main processing station is not provided.

The company prospectus of Bosch Rexroth AG "Rexroth IndraMotion for Metal Forming - System Solutions for Forming Technology", pages 1 to 31, from the year 2008, shows that presses and transfer stations of a press line can be synchronized via a so-called "electronic cam" , Such "electronic cams" can be generated with a program that is described in the company prospectus of Bosch Rexroth AG "Rexroth IndraWorks 10VRS - CamBuilder", issue 02 from 2009 on pages 1 to 105.

The company prospectus of Bosch Rexroth AG "Rexroth IndraMotion MLC - Motion, Robot and Logic Control in an Innovative System Solution", pages 1 to 19, from the year 2008, generally describes a system architecture for motion control for three-dimensional trajectories.

From the company brochure of the Bosch Rexroth AG "Rexroth IndraMotion 10 VRS Technology Base Libraries", issue 02 from the year 2009, pages 1 to 363, describes various function blocks for a drive control. Presses are not mentioned.

From the company brochure of the Bosch Rexroth AG "Rexroth IndraDrive - Firmware for drive controllers MPH-04, MPB-04, MPD-04", issue 02 from 2008, pages 1 to 910, a closed-loop control with a master axis and following axes is known. The master axis is the drive that provides the master axis position for generating a synchronous position setpoint. The following axis forms a drive whose position control follows from the synchronous position setpoint.

Data of various drive controllers can be found in the company prospectus of Bosch Rexroth AG "Rexroth IndraDrive - Drive Controllers - MPx-02; MPx-03; MPx-04; MPx-05 ", issue 04 from 2007.

The article "What makes presses productive", Andreas Wenig in "Bands Sheet Pipes", issue 05/2005, pp. 60-62, describes the possibility of using Rexroth motion control and servo drives in presses to replace mechanical couplings between individual stations ,

DE 196 42 962 A1 relates to a hydraulic transfer press. The Presen- and Transfer control is done separately and is coordinated by a "virtual Leitwelle".

Out DE 10 2007 006 421 A1 For example, a method of operating controlled machines is known. The movement of a machine element is divided into profile segments. Each profile segment is influenced by a motion condition. Each motion condition has one or more triggering events and an action event. The action segment changes the profile segment. This allows the motion profile to be adjusted in real time when a triggering event occurs.

Out DD 296 451 B5 For example, a method and arrangement for coordinating axle drives for overlapping motions of flexible self-propelled sheet transport devices on presses is known. The aim of this device is to increase the press output performance through the highest possible collision-free movement overlay of press and automation device. There, the coordination of mutually influencing axis movements should not be done by constant adjustment of path deviations, but by Cyclic specification of complete trajectories, which are referred to there as driving jobs.

These travel jobs are then executed independently by the individual axle drives and take into account the dynamic performance of the final drive from the outset. Changes in the production line, for example fluctuations in the number of press strokes, are taken into account in a newly calculated travel job in order to avoid collisions. The necessary tolerances are estimated based on the ability to change within a work cycle. On the basis of a known clearance model, starting points, guiding functions in the form of speed-time curves for the final drives and monitoring functions as well as emergency routines are generated. If all generated data are available, the movement is released and processed on the basis of the calculated guidance function. This procedure requires a high degree of computing capacity. The motion sequences of the individual stations are cyclically recalculated in accordance with state fluctuations in the production process. As a result of the changing driving jobs, correspondingly new monitoring functions must also be generated. For an operator arise in the operation of the production line no interference options.

On this basis, it can be regarded as an object of the present invention to provide a control for a production line, which allows an operator an easy way of influencing the operation of individual stations of the production line.

This object is achieved by a method having the features of claim 1 and a control device having the features of claim 4.

The control device has a system control unit which generates a higher-level system control signal which is transmitted to all stations of the press line. As station, both the presses and the at least one transfer station of the press line are understood. Each station has a station control unit to which the system control signal is transmitted. The station control unit generates a station guidance signal for the associated station of the press line, depending on the system control signal and an assignment rule. In the station, a movement is performed depending on the station control signal. For example, in a press, the motion sequence may describe the stroke of a press ram. In a transfer unit, the movement sequence describes, for example, the movement of a gripper for transporting a workpiece. The time course of the sequence of movements is specified in each station by the station control signal.

According to the invention, at least one of the assignment rules, which describes the dependence of the local station control signal on the higher-level system control signal, can be changed. As a result of a change in one of the assignment specifications, at least one sequence of movements of a station with respect to the system control signal thereby changes. Preferably, all stations of the production line on a variable assignment rule. In one embodiment, at least one operating device is provided, with which one or more of the assignment rules is changeable. The assignment rule has several variable assignment parameters or is formed by them. The assignment parameter used is a scaling factor which can be set between a minimum value and a maximum value by an operator. This scaling factor allows you to set reduced movement speeds in the relevant station. The plunger speed of a press or the speed of movement of a gripper is at least partially reduced along a predetermined trajectory, so that the total time duration for the movement along the predetermined trajectory increases. This delay is varied based on the scale factor between zero and a maximum possible delay. In this way, the movement can also be varied comfortably during operation of the production line by an operator.

The spatial trajectories for the individual movements are fixed fixed immutable. With a scaling factor equal to the zero motion delay, the station operates at the maximum possible motion speed and generates the maximum possible throughput, depending on the station. If the delay is set to zero at all stations, this results in an operating state for the production line, in which a maximum possible number of workpieces per unit time is produced. This operating state is checked in advance in a simulation taking into account the clearances of the individual stations on collision freedom. The defined trajectories are preferably set so that the acceleration of the moving parts without jerk, ie without acceleration jumps. The spatially determined trajectories are defined, in particular for the transfer stations, in such a way that they have the lowest possible path curvature and thus the lowest possible accelerations. By changing the assignment rule and in particular the scaling factor, this spatial trajectory does not change. Only the speed of movement along the spatial trajectory is determined by the variable Matching rule adjusted. An adaptation is only possible in the direction of larger clearances. This can be used, for example, to first increase the clearances on the assignment rules during initial start-up of the production line and gradually increase the throughput of the production line. In this way, a review of the simulation model is possible. In addition, it is possible for an operator to consider changed states, for example when replacing a tool of a station, by adapting the assignment rule and, if necessary, to increase the clearances in order to rule out critical operating states.

The assignment rules and preferably the scaling factors for each station are changed by an operator. This operating device preferably has a display device and an input device. The assignment functions can be set or changed, for example, in an input mask of a software user interface. This may in particular be a graphical user interface. The user interface may be password protected to prevent unauthorized changes to assignment functions.

An assignment rule has several scaling factors. The spatially predetermined path curve is subdivided into a plurality of path sections, and the movement speed can be delayed on different path curve sections separately from one another via the respectively associated scaling factor starting from the maximum speed value. Flexibility is thereby further increased.

Advantageous embodiments of the invention will become apparent from the dependent claims and the description. The description is limited to essential features of the invention and other conditions. The drawing is to be used as a supplement. Show it:

1 a block diagram of an embodiment of a production line,

2 a user interface for changing the assignment rules for the stations of the production line in the embodiment according to 1 .

3 a schematic block diagram similar representation of the relationship between a higher-level system control signal and the local station control signals of the individual stations of the production line and

4 and 5 in each case a highly schematized representation of exemplary progressions of the system guidance signal, of a station guidance signal as well as of a trajectory respectively depending on the time.

1 shows the block diagram of an embodiment of a production line, here as Pressenstrasse 10 is executed. The press street 10 has several and example three processing stations 11 on, here by a press each 12 are realized. For transporting workpieces 13 between the workstations 11 is at least a transfer station 14 present and in the example described here are two transfer stations 14 intended. Every transfer station 14 has a gripper 15 for gripping the workpiece 13 on. The gripper 15 is from a multi-limbed arm 16 emotional. Between each two adjacent links of the arm 16 is a controllable axis 17 intended. The axes 17 are configured in the exemplary embodiment as a rotary actuators or part-turn actuators or buckling drives. As in 1 shown, the transfer station 14 five axes 17 on. The number of axes can vary. There can be up to six axes 17 be provided.

Every station 11 . 14 the press street 10 is a separate station control unit 20 assigned. The station control unit 20 Among other things, it serves to control the movement in the assigned station 11 . 14 to control or regulate. The station control unit 20 a press 12 controls the movement of a press ram 21 between an upper reversal point and a lower reversal point during the plunger movement. The station control unit 20 the transfer station 14 controls the spatial orientation and the spatial movement of the gripper 15 or of the workpiece to be transported 13 along a fixed spatial trajectory. The trajectory describes the movement and orientation of the gripper in space between a receiving location where the gripper 15 a workpiece 13 picks up and a depository where the gripper 15 the workpiece 13 again, as well as the return movement of the grapple 15 to the reception.

The movement of the press ram 21 or the gripper 15 is in the respectively assigned station control unit 20 specified. The time course of the movement in question is determined by a in the station control unit 20 predetermined local station control signal L determined. Depending on the number of stations 11 . 14 are in the press street 10 Therefore, correspondingly many station control signals L1 to Ln are provided.

A system controller 22 serves to coordinate the operation of the individual stations 11 . 14 the press street 10 , For this purpose, the System control unit 22 a system control signal S available to the individual station control units 20 is transmitted. Conversely, the local station control signals L1 to Ln to the system control unit 22 transmitted. In this way, the operation of each station 11 . 14 be coordinated with each other.

In every station control unit 20 a station 11 . 14 a variable assignment rule Z1 to Zn is given. The respective assignment rule Z1 to Zn describes the dependency and in particular the phase relationship between the higher-level system control signal S and the respective local station control signal L1 to Ln.

In the preferred embodiment, each assignment rule Z1 to Zn has at least one variable assignment parameter that can be set or changed by an operator in a predetermined range. An assignment parameter is, for example, a scaling factor F1 to Fn. In this case, each assignment rule Z1 to Zn can have one or more adjustable scaling factors F1 to Fn, wherein in the exemplary embodiment described here according to FIG 1 to 4 Each assignment function Z1 to Zn has a scaling factor F1 to Fn. The assignment function Z1 to Zn is preferably formed by an associated scaling factor F1 to Fn.

The assignment rule Z1 to Zn or the scaling factor F1 to Fn has the function of shifting the assigned local control signal Li relative to the respective other local control signals L1 to Li-1, Li + 1 to Ln and / or the higher-level system control signal S. In this way, the temporal movement of the individual station 11 . 14 be varied relative to each other and / or with respect to the higher-level system control signal S in a predetermined range. This serves, for example, to the movements of the press ram 21 the press street 10 relative to each other to the times of each maximum energy consumption of the presses 12 to shift against each other, giving the maximum value at a given time of the entire press line 10 required energy can be reduced. Because the maximum energy consumption of each press 12 does not occur at the same time, but staggered in time. Furthermore, by varying the assignment functions Z1 to Zn or the scaling factors F1 to Fn, the free movement at individual processing stations 11 be improved. This can for example when starting a press line 10 be used to maximize the free space initially and after the start of the press line 10 gradually and thereby reduce the number of press line 10 machined workpieces per unit time (throughput) to enlarge.

The press street 10 has at least one operating device 25 by means of which an operator can manually set or change the assignment functions Z1 to Zn and, according to the example, the scaling factors F1 to Fn. In the exemplary embodiment, it is provided that the scaling factors F1 to Fn can be set between a minimum value of 0 and a maximum value of 1. This is preferably done via a software user interface 26 as they are merely exemplary in 2 is illustrated schematically. The user interface 26 is in the embodiment after 2 designed as a graphical user interface. The stations 11 . 14 the press street 10 are shown schematically. Assigned to each station 11 . 14 is each an operating element 27 , in the present case a slider. About the control 27 the corresponding scaling factor F1 to Fn of the respectively assigned station 11 . 14 be set or changed. Each control 27 can be a numeric display 28 be assigned, which indicates the currently set value. The operating element 27 can be operated for example via a computer mouse, a touchpad, a trackball or another known per se computer control unit. Alternatively or additionally, a permissible numerical value in the field of the display 28 via a keyboard of the operating device 25 be entered.

In a modification to the described embodiment, the operator device 25 instead of a software user interface 26 have electrical and / or electronic control devices for setting or changing the assignment functions Z1 to Zn.

The operator is in this way also during operation of the production line or press line 10 able for each station 11 . 14 the local station control signal L1 to Ln very easy to vary, for example, with respect to the parent system control signal S.

The press street 10 is in a simulation and / or in a test on a minimum required clearance in all stations 11 . 14 designed. The trajectories of the press ram 21 or the gripper 15 are determined accordingly. It is the through the axes 17 the transfer stations 14 maximum dynamic available. Also, the trajectories are determined so that a smooth movement of the press ram 21 the presses 12 or the gripper 15 the transfer stations 14 he follows. The trajectories of the grapple 15 the transfer stations 14 are also defined to have a minimum curvature and thus a minimal acceleration of the gripper 15 or of the workpiece to be transported 13 occurs.

These spatial trajectories of the moving parts of the stations 11 . 14 are unchanging. By means of the adjustable scaling factor F1 to Fn, the station guide signal L1 to Ln determining the time profile of the movement along this path curve is changed, as shown by way of example and highly schematically in FIG 4 is illustrated. That is, the movement of that station 11 . 14 the press street 10 spatially unchanged, but changed over time. This causes the press ram 21 or the gripper 15 the predetermined spatial trajectory traverses at least in predetermined sections at a speed which is lower than the maximum permitted speed. Accordingly, the occurring accelerations can be reduced. The scaling factor F1 to Fn is the time delay of a movement cycle in the relevant station 11 . 14 specified. This time delay can be set between the value 0 and a maximum delay value. At the maximum possible delay, the assigned scaling factor F1 to Fn has the magnitude 1. Are all scaling factors F1 to Fn of the stations 11 . 14 the press street 10 set to the value 0, the press line is running 10 in an operating state with maximum possible throughput.

Will be at one or more stations 11 . 14 If the scaling factor F1 to Fn is set greater than 0, the cycle time at the relevant station is delayed 11 . 14 , Since the working cycle of the entire press line 10 always after the station 11 . 14 directed, which works with the largest cycle duration and thus the lowest operating speed, the higher-level system control signal S shifts accordingly and adapts to the maximum delayed station control signal L1 to Ln. This means that the system control signal S is directed to the local satationsignal L1-Ln, to which the largest scaling factor F1-Fn is assigned. All other local station control signals L1-Ln are phase-shifted with respect to the higher-level system control signal S. The size of the phase shift depends on the value of the scaling factor F1 to Fn.

In 4 schematically illustrates that the station control signal Li a station 11 . 14 the press street 10 is out of phase with the system control signal S by the relevant scaling factor F1. The station control signal Li is the temporal movement B given along the spatially fixed trajectory. This is schematically indicated by the dashed line in 4 illustrated.

In a modified embodiment according to 5 An assignment function Z1 to Zn has two scaling factors Fi1 and Fi2. The trajectory to be traversed is divided into two trajectory sections B1 and B2. Each of the trajectory sections B1, B2 is assigned a scaling factor Fi1 or Fi2. The phase shift of the local station control signal Li therefore takes place separately for the two trajectory sections B1, B2. It is understood that also more than two trajectory sections and correspondingly more scaling factors can be present in an assignment function Z1 to Zn.

The system control signal S and the local station control signals L1 to Ln are in the 4 and 5 shown as sinusoidal signals. This is just an example. The signals may also have any other arbitrary waveform for timing. For example, rectangular signals or triangular signals can also be used.

The invention relates to a control device and a method for controlling a press line 10 , The press street 10 has several processing stations 11 and at least one transfer station 14 for workpiece transport between the processing stations 11 on. Each station is a station control unit 20 assigned. A system controller 22 transmitted to all station control units 20 a higher-level system control signal S. In the station control units 20 is for the respective assigned station 11 . 14 generates a local station control signal L1-Ln. Also, in every station control unit 20 an assignment rule Z1 to Zn stored, which defines the course of the respective local station control signal L1-Ln with respect to the respective other station control signals L1 to Ln and / or the higher-level system control signal S. These assignment functions Z1 to Zn are during operation of the press line 10 changeable by an operator. This allows the temporal movement in at least one station 11 . 14 relative to the higher-level system control signal S by changing one or more assignment functions Z1 to Zn are changed.

LIST OF REFERENCE NUMBERS

10

press line

11

processing station

12

Press

13

workpiece

14

transfer station

15

grab

16

poor

17

axis

20

Workstation controller

21

press ram

22

System control unit

25

operating device

26

user interface

27

operating element

28

display

B

temporal movement

B1, B2

Trajectory section

F1 to Fn

scaling factor

L1 to Ln

Station pilot signal

S

System direct signal

Z1 to Zn

mapping function

Claims (6)

Method for controlling a press line ( 10 ) with several presses ( 12 ) and at least one transfer station ( 14 ) for transporting a workpiece ( 13 ) between successive presses ( 12 ), comprising the following steps: determining and predetermining a higher-level system control signal (S) for all stations ( 12 . 14 ), - Specifying a sequence of movements (B) for each station ( 12 . 14 ) depending on in each case a local station control signal (L1 to Ln), wherein the movement sequence (B) for each station ( 12 . 14 ) defines a spatially fixed predetermined trajectory, wherein the movement sequence (B) is divided into a plurality of movement sections (B1, B2), - predetermining an assignment rule (Z1 to Zn), the relationship between the higher-level system control signal (S) and at least one the local station control signals (L1 to Ln) and / or the local station control signals (L1 to Ln) to each other, said assignment rule (Z1 to Zn) has a plurality of variable scaling factors (Fi1, Fi2), each between a minimum value and a maximum value can be set by an operator and a scaling factor (Fi1, Fi2) is assigned to each movement section (B1, B2), changing at least one of the assignment rules (Z1 to Zn) by means of the at least one scaling factor (Fi1, Fi2) for changing at least one Sequence of movements (B) of one of the stations ( 12 . 14 ) with respect to the system control signal (S), - reducing the speed of movement of a plunger of a press ( 12 ) or a gripper ( 15 ) a transfer station ( 14 ) at least in sections along the predetermined path curve by means of a scaling factor (Fi1, Fi2) in the relevant station ( 12 . 14 ). A method according to claim 1, characterized in that the movement sequence (B) is determined in time by the local station control signal (L1 to Ln). A method according to claim 1, characterized in that the movement path is determined such that a jerk-free movement is given with minimum curvature. Control device of a press line ( 10 ), with several presses ( 12 ) and at least one transfer station ( 14 ) for transporting a workpiece ( 13 ) between successive presses ( 12 ), with a system control unit ( 22 ), which has a higher-level system control signal (S) for all stations ( 12 . 14 ), each with a station control unit ( 20 ) for each of the stations ( 12 . 14 ), the station control unit ( 20 ) a movement sequence (B) for the assigned station ( 12 . 14 ) depending on one for the station ( 12 . 14 ) predetermined station control signal (L1 to Ln), wherein the movement sequence (B) for each station ( 12 . 14 ) defines a spatially fixed predetermined path of movement and wherein the movement sequence (B) is divided into a plurality of movement sections (B1, B2), wherein the station control unit ( 20 ) specifies an assignment rule (Z1 to Zn) which determines the relationship between the higher-level system control signal (S) and the local station control signal (L1 to Ln) of the station (Z1 to Zn). 12 . 14 ), wherein the assignment rule (Z1 to Zn) has a plurality of variable scaling factors (Fi1, Fi2) which are each adjustable between a minimum value and a maximum value, wherein each movement section (B1, B2) is assigned a scaling factor (Fi1, Fi2), and with at least one operating device ( 25 ) by means of which at least one of the assignment specifications (Z1 to Zn) can be changed by setting at least one scaling factor (Fi1, Fi2) such that the speed of movement of a plunger of a press ( 12 ) or a gripper ( 15 ) a transfer station ( 14 ) at least in sections along the predetermined trajectory in the relevant station ( 12 . 14 ) is reduced. Control device according to claim 4, characterized in that the operating device ( 25 ) with the system control unit ( 22 ) and several and in particular all assignment rules (Z1 to Zn) of the stations ( 12 . 14 ) by means of the operating device ( 25 ) are changeable. Control device according to claim 4, characterized in that the at least one operating device ( 25 ) each with one of the station control units ( 20 ) and for changing the assignment rule (Z1 to Zn) of the assigned station ( 12 . 14 ) serves.

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