DD258382A1 - PROCESS FOR DRIVE CONTROL OF A PRESS AND A TRANSFER DEVICE - Google Patents

Abstract

The invention relates to a method for controlling the drive of a press and a transfer device with a drive independent of the press. With this method, a universal use of press and transfer device is achieved as a loosely coupled system by the Freigaengigkeitswinkel the press is fully utilized in its entire area. According to the invention, this is achieved by first detecting the actual press stroke number, determining the speed and acceleration parameters of the transfer drive units, and comparing the process data with the technical limits of the transfer, determining in a comparator block whether the process value is within the limits and thereafter outputting the start-stop commands and the set values for the transfer drive units and returning the process data to the control input. {Method; Traction control; Press; Transfer device; Freigaengigkeitswinkel}

Description

For this 3 pages drawings

Field of application of the invention

The invention relates to a method for controlling the drive of a press and a transfer device with drive independent of the press.

Characteristic of the known state of the art

According to DE-OS 2746161 a method for controlling the drive of a workpiece conveyor in processing machines with independent from the drive of the machine drive, in particular for controlling the drive of the gripper rails of a gripper rail device is known, according to which the drive of the workpiece conveyor depending on the path of a working means of the machine and / or the processing progress on the or a workpiece is controlled so that when reaching a certain waypoint of the working means and / or a particular processing stage, the workpiece conveyor reaches a likewise predetermined point of its trajectory. In the control of the drive of the gripper rails during pressing the path of the press ram is scanned and controlled by means of the manipulated variables thus obtained the gripper rail drive, wherein points of the trajectory of the press ram points of the travel curve of the gripper rails are assigned.

The disadvantage of this control is the electrically "rigid" connection between press and transfer movement, which excludes the single stroke as an important work regime for power and tool flexibility in the use of the press complex and is only valid after pre-set, coordinated motion sequences operate.

According to DE-OS 3425 006 a Steuerschaltungg, for example with microcomputer, known for a transfer device with two or three axes of movement, which has means to generate the strokes defining signals separately from the pressing movement, where with a press control device, due to the Outputs of the signal generating means provides press start and stop commands at respective times which do not disturb at least the longitudinal movement of the transfer means to effect intermittent pressing operations. In addition to the alternately intermittent operation of press and transfer device, it is also possible that the transfer device is operated continuously, while the start and stop operations of the press are carried out with a corresponding timing with respect to the material feed. Furthermore, the press can be operated continuously while the material feed proceeds intermittently with a corresponding timing with respect to the press movements. Although this solution also includes the technologically important one-stroke, this must be selected from the outside and does not result from the current parameters when operating the complex. Selecting specific strokes limits the flexibility of using different tool sets.

Object of the invention

The object of the invention is to provide a method of drive control, by which a collision-free movement between the press and automation device is ensured with the highest possible output of the press complex.

Explanation of the essence of the invention

The object of the invention is to optimize the movement parameters of the parts transport under the current conditions of workpiece, tool, press and stroke rate so that a maximum transport and storage security is achieved while minimizing dynamic load of the automation device.

According to the invention, the object is achieved in that the clearance angle of the press is fully utilized in its entire area, such that the press operates in the long stroke and the start-stop commands for the transfer device under hubzahl- and transfer increment-dependent calculation of the minimum possible acceleration and speed the transport movement are selected at fixed dynamic parameters for the closing and lifting movement. The start-stop commands for the closing and lifting movement of the transfer device are also selected under hubzahl- and Transferschrittweitenabhängiger calculation of their minimum possible acceleration and speed. When the maximum possible acceleration and speed parameters for the transfer movements are reached, an automatic transition into the individual stroke of the press is carried out and a sequential control is realized.

The solution is also valid for all other feeding, removal and transport devices that have independent drives the individual directions of movement.

embodiment

The invention will be explained in more detail with reference to drawings. The accompanying drawings show:

Fig. 1: sequence of movements for the closing and lifting stroke - speed over time

Fig. 2: Movement for the closing and lifting stroke - way over time

3: representation of a complex cycle

4 shows a block diagram for illustrating the method.

The conditions of the modern metalworking industry demand automation devices that are characterized by a high flexibility character. The present technical solution fulfills these conditions by means of a control which allows optimum workpiece, tool, machine and power flexibility. The transfer device is operated by independent hydraulic motors. The increments of all three movements are freely selectable. The movement sequence of closing-opening and lifting-lowering is optimized, for example, with fixed dynamic parameters and the transport movement after acceleration and speed.

Figures 1 and 2 show the movements for the lifting or closing movement at different stroke lengths. By specifying the acceleration and braking acceleration as well as the limit speed, any desired closing and lifting strokes can be realized by varying the switching points. If the main movement of the transfer device, the transport movement, is to be dynamically optimized, the question immediately arises of the available transport time. Of particular importance is the press locking angle, a technological size that is clearly defined by the press and tool parameters. Within this blocking angle, parts of the transfer device must not be in the space of the press described by the moving top tool. Thus, the locking angle becomes a tool-specific size. The following premises apply to an optimization:

1. Press works in the long-stroke, transfer in switching operation

2. Full utilization of the clearance angle

3. Hubzahlabhängige calculation of the minimum possible acceleration of the transport movement to ensure optimum smoothness and storage accuracy

4. When the maximum possible transfer parameters (speed and acceleration) are reached, automatic transition to the individual stroke of the press and thus subsequent operation

5. Realization of a class system for technologically slow transport processes or retraction regimes.

Based on these premises, the method for drive control, as shown in Figure 4. First, the free-running angle is determined by determining defined tool contours. A sensor determines the current press speed at every stroke of the press and determines the cycle time from it. The free angle and the cycle time result in the time available for the transfer movement. With the constant times for the closing and lifting movement, the time for the longitudinal movement follows from this. Under the condition of minimum acceleration, the optimized parameters of acceleration and velocity can be determined for each longitudinal stroke. In accordance with this described calculation algorithm, the following parameters are entered for the respective tool set via a terminal of the control:

- Beginning and end of the blocking angle

- Lifting stroke

- closing stroke

- Transport stroke

FIG. 3 shows the sequence of a complex cycle. Mean

(1) plunger movement

(2) closing movement (transverse)

(3) lifting movement (vertical)

(4) Transport movement (longitudinal).

After the press has been started, a measuring system records the current number of strokes and the internal control computer determines the optimized dynamic parameters for the main movement according to the algorithm described above. If the crank angle of the press reaches the end of the blocking angle, the start of the transfer is triggered. His movement is now tuned so that at the beginning of the blocking angle of the transfer leave the space described by the upper tool and also in time before the renewed switch-on has ended the entire cycle.

Thus, the press works in the long-stroke, the transfer in switching operation. If the press stroke is increased during the long stroke or in the disengaged state, this increase will be registered in the next stroke and new parameters calculated for the transfer.

If the determined speed or acceleration reaches or exceeds predefined limit values, then the movement of the transfer takes place with these limit values.

The controller registers this condition and interrupts the continuous stroke of the press at top dead center and initiates a sequence control in the single stroke.

In the transition from the continuous stroke in the single stroke, the output power of the complex goes back (loss time during the coupling operations). By increasing the stroke rate of the press, however, the maximum continuous stroke output can be reached or exceeded again.

For transport processes, which are to run slowly for technological reasons or for setup purposes, the automatic adjustment of the transfer cycle time to the press stroke number is ineffective. Therefore, a selectable class system consisting of fixed but low dynamic transfer parameters was included in the controller.

When calling one of these classes, the calculation algorithm is omitted and, for reasons of free movement, the complex operates in sequence control with single stroke. It can be achieved by a high Pressenhubzahl despite slow parts transport and optimum output. After determination of the optimized motion parameters or after calling the fixed values from the class regimes, the target value specification for the motion sequences, the actual value feedback and the required control according to known structures, which are not the subject of the patent.

The same applies to the safety circuit which monitors compliance with the clearance curves.

Claims (3)

Anspruch [en] A method of drive control of a press and a transfer device having a drive independent of the press, which is generated for the two- or three-dimensional movements according to a signal and depending on the clearance angle of the press by servo-actuators, characterized in that the clearance angle of the press is fully exploited in its entire range, such that the press operates in the long stroke and the start-stop commands for the transfer device are selected under Hubzahl- and Transferschrittweitenabhängiger calculation of the minimum possible acceleration and speed of transport movement at fixed dynamic parameters for the closing and lifting movement. 2. A method for driving control according to claim 1, characterized in that the start-stop commands for the closing and lifting movement of the transfer device are also selected under hubzahl- and transfer increment-dependent calculation of their minimum possible acceleration and speed. 3. A drive control method according to claim 1 and 2, characterized in that upon reaching the maximum possible acceleration and speed parameters for the transfer movements, an automatic transition to the individual stroke of the press and a sequence control is realized.