METHOD FOR PRESSING A WORKPIECE WITH A PREDETERMINED PRESSING FORCE

Abstract

A method for pressing a workpiece with a predetermined pressing force uses a forming tool coupled with an electric motor via a spindle drive that converts the rotational movement of the electric motor drive shaft to a translational movement of the forming tool. The method includes: accelerating the electric motor in a first rotational direction to a predetermined maximal speed of rotation; operating the electric motor at the maximal speed until the drive shaft has completed a predetermined number of revolutions; reducing the speed of rotation of the electric motor to a predetermined reduced speed of rotation; operating the electric motor at the reduced speed until a pressing force increase exceeding a predetermined threshold value is detected by a measuring unit that follows the electric motor; forming the workpiece with constant detection of the pressing force by the measuring unit until the predetermined pressing force has been reached.

Claims

1: A method for pressing a workpiece (4) with a predetermined pressing force, by means of a forming tool (3), which is coupled by way of a gear mechanism, in particular a spindle drive (6), with an electric motor (2), wherein the gear mechanism converts the rotational movement of a drive shaft (8) of the electric motor (2) to a translational movement of the forming tool (3), and wherein the electric motor (2) is controlled by a regulator (5), characterized in that wherein the method comprises the following method steps: accelerating the electric motor (2) in a first direction of rotation, to a predetermined maximal speed of rotation, whereby the forming tool (3) is moved toward the workpiece (4); operating the electric motor (2) at the maximal speed of rotation until the drive shaft (8) of the electric motor (2) has completed a predetermined number of spindle revolutions or the forming tool (3) has reached a predetermined position, wherein during this method step, the forming tool (3) is freely moved toward the workpiece (4), without touching it; reducing the speed of rotation of the electric motor (2) to a predetermined reduced speed of rotation; operating the electric motor (2) at the reduced speed of rotation until a pressing force increase is detected by a measuring unit (12) that follows the electric motor (2), which increase exceeds a predetermined threshold value, wherein the pressing force increase occurs when the forming tool (3) comes to lie against the workpiece (4) to be formed; and forming the workpiece (4) with constant detection of the pressing force by means of the measuring unit (12) until the predetermined pressing force has been reached.

2: The method according to claim 1, wherein after detection of the pressing force increase, the electric motor (2) is braked to a predetermined minimal speed of rotation.

3: The method according to claim 2, wherein the electric motor (2) is operated at the minimal speed of rotation for a predetermined or predeterminable period of time, until vibrations that occur in the drive system due to the braking process from the reduced speed of rotation to the minimal speed of rotation have died out, to the greatest possible extent.

4: The method according to claim 1, wherein during forming of the workpiece (4), control of the electric motor (2) is set by the regulator (5) on the basis of the pressing force measured in the measuring unit (12).

5: The method according to claim 1, wherein the reduced speed of rotation amounts to between 0.1% and 100%, in particular between 0.5% and 99%, preferably between 50% and 80% of the maximal speed of rotation.

6: The method according to claim 1, wherein directly after detection of the pressing force increase, further control of the electric motor (2) is set by the regulator (5) on the basis of the pressing force, wherein after detection of the pressing force increase, the electric motor (2) is braked to a predetermined minimal speed of rotation, and in an initial period during the braking process, a pressing force based on a model calculation is superimposed on the pressing force detected in the measuring unit (12), and after the initial period, the pressing force detected by the measuring unit (12) serves as an input variable for the regulator (5).

7: The method according to claim 6, wherein in the model calculation, the mass inertia and/or the spring stiffness and/or the damping and the angular or linear accelerations of the individual components built into the drive train is/are taken into consideration.

8: The method according to claim 6, wherein the model calculation is adapted on the basis of the respectively previous cycles, in an iterative learning process, wherein for adaptation of the model calculation, the Time Progression of the measured value of the pressing force in the measuring unit (12), as well as of the motor moment and of the related angle of rotation of the drive shaft (8) in the electric motor (2) are used.

9: The method according to claim 6, wherein for superimposition of model calculation and pressing force detected in the measuring unit (12), an interference variable observer (19), in particular a Kalman filter is used.

10: The method according to claim 9, wherein superimposition between the actual force estimated in the interference variable observer (19) and the force detected in the measuring unit (14) is carried out.

11: The method according to claim 1, wherein a Piezo sensor is used as a measuring unit (12), which sensor is disposed in the region of the forming tool, so as to detect the pressing force.

12: The method according to claim 1, wherein directly after detection of the pressing force increase, further control of the electric motor (2) is set by the regulator (5) on the basis of a reference trajectory of the pressing force value, wherein the speed of rotation progression is calculated in a pre-controller, from the reference trajectory of the pressing force value.

13: The method according to claim 12, wherein in a first phase after detection of the pressing force increase, the pressing force value is estimated by means of an interference variable observer (19), and that in a second phase after detection of the pressing force increase, the pressing force is detected directly by the measuring unit (12), and serves as an input variable for the regulator (5).

14: The method according to claim 1, wherein the transition between different speeds of rotation of the individual method steps is set in such a manner that no sudden increases in acceleration occur.

Description

[0034] The figures show, each in a greatly simplified, schematic representation:

[0035] FIG. 1 a schematic representation of a possible structure of a press;

[0036] FIG. 2 a flow chart of a first regulation strategy for pressing of a workpiece;

[0037] FIG. 3 a structural circuit schematic of the mechanical model of the press;

[0038] FIG. 4 a force progression representation of the press;

[0039] FIG. 5 a structural circuit schematic of a regulation circuit for force regulation;

[0040] FIG. 6 an exemplary regulation distance of a force regulation unit;

[0041] FIG. 7 a flow chart of a further regulation strategy for pressing of a workpiece;

[0042] FIG. 8 a structural circuit schematic of a regulation circuit with interference variable observer and load pre-controller, force pre-controller, as well as inertia compensation;

[0043] FIG. 9 a structural circuit schematic of a regulation circuit with interference variable observer and force pre-controller as well as inertia compensation;

[0044] FIG. 10 a structural circuit schematic of a regulation circuit with interference variable observer and force pre-controller;

[0045] FIG. 11 a structural circuit schematic of a control circuit with interference variable observer and load pre-controller as well as force pre-controller;

[0046] FIG. 12 a structural circuit schematic of a control circuit with load pre-controller, force pre-controller, as well as inertia compensation;

[0047] FIG. 13 a structural circuit schematic of a control circuit with force pre-controller as well as inertia compensation;

[0048] FIG. 14 a structural circuit schematic of a control circuit with force pre-controller;

[0049] FIG. 15 a structural circuit schematic of a control circuit with load pre-controller as well as force pre-controller.

[0050] As an introduction, it should be stated that in the different embodiments described, the same parts are provided with the same reference symbols or the same component designations, wherein the disclosures contained in the entire description can be applied analogously to the same parts having the same reference symbols or the same component designations. Also, the position information chosen in the description, such as top, bottom, at the side, etc., for example, refer to the figure that is directly described or shown, and this position information must be transferred analogously to the new position in the case of a change in position.

[0051] FIG. 1 shows a schematic representation of a process press 1. The process press 1 comprises an electric motor 2, and a forming tool 3 coupled with the electric motor 2. The forming tool 3 can act on a workpiece 4 so as to be able to deform it. Such deformation can be embossing, for example. Furthermore, it is also conceivable that the workpiece 4 is bent, for example by means of the forming tool 3. The forming process of the workpiece 4 can take place in automated manner. The forming tool 3 can have the most varied shapes.

[0052] Furthermore, it can be provided that the electric motor 2 is structured as a servomotor. Such a servomotor can be a synchronous motor, for example. Furthermore, it can be provided that the electric motor 2 is connected with a regulator 5. Furthermore, it can be provided that a frequency inverter is formed, which interacts with the electric motor 2 and predetermines the speed of rotation of the electric motor 2.

[0053] As is further evident from FIG. 1, it can be provided that a spindle drive 6 is coupled with the electric motor 2. Such a spindle drive 6 can be configured as a threaded drive, for example, preferably as a ball screw drive. A ball screw drive has the advantage that it has low play. As a result, great precision of the process press 1 can be achieved.

[0054] By means of the spindle drive 6, the rotational movement of the electric motor 2 can be converted to a translational movement of the forming tool 3.

[0055] Furthermore, optionally it can also be provided that a gear mechanism 7 is disposed between spindle drive 6 and electric motor 2, by means of which the speed of rotation of the drive shaft 8 of the electric motor 2 can be stepped down.

[0056] If a gear mechanism 7 is provided in the drive train, then a spindle 9 of the spindle drive 6 is coupled with a gear mechanism output shaft 11 disposed on the gear mechanism output 10, and has the same speed of rotation as this shaft.

[0057] If no gear mechanism 7 is provided in the drive train, then the spindle 9 of the spindle drive 6 is coupled with the drive shaft 8 of the electric motor 2, and has the same speed of rotation as this shaft.

[0058] Furthermore, it is provided that a measuring unit 12 is disposed between spindle drive 6 and forming tool 3, which unit is configured for detecting the pressing force that is being applied to the forming tool 3. The measuring unit 12 can be configured, in particular, as a force sensor or as a force load cell. Preferably, it can be provided that the measuring unit 12 is configured as a Piezo sensor. The measuring unit 12 is coupled with the regulator 5.

[0059] Furthermore, it can be provided that a coupling 13 is provided for connecting electric motor 2 and gear mechanism 6 or for connecting gear mechanism 7 and spindle drive 6. The couplings 13 serve, in particular, for torque transfer between the individual components and are therefore disposed between the individual components.

[0060] Furthermore, it can be provided that the spindle 9 of the spindle drive 6 is mounted on a mounting 14, which serves for absorbing axial forces and radial forces introduced into the spindle 9. Furthermore, it can be provided that the spindle drive 6 comprises a threaded nut 15, which is coupled with the spindle 9 and converts the rotational movement of the spindle 9 to a translational movement of the threaded nut 15.

[0061] A carriage 16 can be coupled with the threaded nut 15, which carriage can serve to hold the forming tool 3. In particular, it can be provided that the measuring unit 12 is disposed between carriage 16 and forming tool 3.

[0062] In an embodiment variant that is not shown, it can be provided that the measuring unit 12 is integrated into the carriage 16.

[0063] Preferably, it can be provided that the forming tool 3 is coupled with the carriage 16 in removable manner. In this way, the result can be achieved that different forming tools 3 can be coupled with the carriage 16 for different usage requirements.

[0064] Furthermore, it can be provided that the carriage 16 is guided on a guide rail 17.

[0065] The general method of functioning of the process press 1 will now be explained using FIG. 1.

[0066] The forming tool 3 is moved toward the workpiece 4 by means of the spindle drive 6, wherein the spindle drive 6 is driven by the electric motor 2. In a first method step, in this regard, the forming tool 3 is moved freely toward the workpiece 4, wherein attention is paid to ensure that the forming tool 3 does not touch the workpiece 4. Stated in other words, this can also be spoken of as a setting process.

[0067] At the end of this setting process, a pressing surface 18 of the forming tool 3 comes into contact with the workpiece 4, and thereby the force acting on the forming tool 3 increases suddenly. Subsequently, the forming tool 3 is pressed into the workpiece 4, and thereby the workpiece 4 is deformed by means of the forming tool 3.

[0068] One can say that the pressing process is divided into two stages. The first stage is a setting process in which the forming tool 3 is moved freely toward the workpiece 4, but without touching it.

[0069] The second stage is a forming stage, in which the pressing surface 18 of the forming tool 3 lies against the workpiece 4 and the workpiece 4 is deformed by means of the forming tool 3, wherein increased torque needs to be applied to the drive shaft 8 of the electric motor 2.

[0070] During the setting process, it can be provided that the speed of the electric motor 2 can be regulated, in superimposed manner, until a predefined pressing force is exceeded or impact of the forming tool 3 on the workpiece 4 is detected using a gradient method. In the forming stage, it can be provided that the torque of the electric motor 2 can be regulated, in subordinate manner, wherein the measured pressing force serves for regulation of the electric motor 2.

[0071] In the forming stage, a predefined pressing force can be set using a cascaded regulator having two degrees of freedom. This cascaded regulator consists of an inner speed regulator, of a superimposed moment regulator or force regulator, and of a corresponding model-based pre-controller.

[0072] Using the model-based pre-controller, the pressing force that occurs is compensated to follow the load and the inertia of the drive. If the mechanical coupling between electric motor 2 and forming tool 3 is sufficiently stiff, then the pressing force detected at the measuring unit 12 can be used as a direct feed-back value for the moment regulator or force regulator.

[0073] The difficulty in regulation consists in keeping the process speed high and the pressing force within predetermined limits. If an ideal, interference-free segment is assumed, a progression of the motor speed of rotation can be found, which makes it possible to set a desired pressing force. In a real application case, however, interference and measurement noise must be expected in the measuring unit 12.

[0074] In order to achieve a defined pressing force and, at the same time, keep the process speed as high as possible, the regulation strategies according to the invention were developed.

[0075] As long as the forming tool 3 is moved freely toward the workpiece 4 and does not lie against it, no significant increase in the pressing force actually applied to the forming tool 3 is expected. It is therefore practical to directly set a motor speed of rotation profile without additional moment regulation or force regulation in this forming stage. Only once the pressing surface 18 of the forming tool 3 contacts the workpiece 4 does a rapid increase of the pressing force applied to the forming tool 3 occur, and the moment regulator or force regulator becomes active. In the forming stage, a motor speed of rotation profile is set, in which the different speed levels are constantly connected with one another. In this way, it is ensured that the mechanical components of the process press 1 are not subjected to unnecessary stress, and that excitation of vibrations in the system is kept low.

[0076] It is the goal of regulation to regulate the pressing force that is actually applied to the forming tool in such a manner that it achieves a defined value, also referred to as a predetermined pressing force.

[0077] The pressing force actually applied at the forming tool 3 is supposed to be measured using the measuring unit 12 and to serve as a feedback variable in regulation. However, it should be mentioned that the pressing force measured in the measuring unit 12 corresponds to the pressing force actually applied to the forming tool 3 only when the forming tool 3 is not being accelerated or braked at the time, and therefore dynamic effects occur on the basis of the mass inertia of the individual components. Stated in other words, the pressing force actually applied to the pressing tool 3 can be measured precisely by the measuring unit 12 when the forming tool 3 is at a standstill or is moving at a constant advancing speed, wherein this state also has to last for a certain period of time, so that vibrations have already died out.

[0078] FIG. 2 shows a flow chart of a schematic sequence of a first regulation strategy for pressing of the workpiece 4.

[0079] At decision paths, a plus (+) stands for condition has been met. A minus () stands for condition has not been met.

[0080] In method step 1, the drive shaft 8 of the electric motor 2 is accelerated to maximal speed of rotation. In order to accelerate the electric motor 2 to maximal speed of rotation, a specific time progression of the angular velocity or a specific acceleration ram can be set, by means of which the electric motor 2 is accelerated. In Query A, the question is asked whether the drive shaft 8 of the electric motor 2 has already completed a predetermined number of spindle revolutions, or, accompanying this, how far the forming tool 3 has already been moved by means of the spindle drive 6, in terms of its linear movement.

[0081] The electric motor 2 is operated at maximal speed of rotation until, in Query A, reaching the predetermined number of spindle revolutions or reaching the predetermined setting path of the forming tool 3 leads to fulfillment of the condition. The number of spindle revolutions that serves for a switch to the method step 2 is selected to be as high as possible, but so low that in all cases that are conceivable on the basis of the tolerance, it is guaranteed that the pressing surface 18 of the forming tool 3 does not come to lie against the workpiece 4 during this method step. During method step 1, it can be provided that the pressing force measured at the measuring unit 12 is not queried, or at least does not flow into the pressure regulation.

[0082] Subsequently, in method step 2, the electric motor 2 is operated at a reduced speed of rotation. The reduced speed of rotation serves to ensure that when a pressing force increase is detected in the measuring unit 12, sufficient time remains to reduce the motor speed of rotation or to change over to force regulation. The speed of rotation at the reduced speed of rotation is dependent on how quickly the electric motor 2 can be braked and the displacement path along which the forming tool 3 can still be displaced after it is set down onto the workpiece 4. This maximal displacement path is also called press-in depth. If the planned press-in depth is very great, for example, the reduced speed of rotation can have a high value, and can be approximately as great as the maximal speed of rotation, for example.

[0083] The transition from maximal speed of rotation to reduced speed of rotation can also take place in accordance with a predetermined time progression of the angular velocity. During operation of the electric motor 2 at a reduced speed of rotation, the measuring unit 12 is activated so as to be able to detect when the pressing surface 18 of the forming tool 3 comes into contact with the workpiece 4, whereby a sudden increase of the pressing force measured in the measuring unit 12 comes about. Query B, it is determined whether the pressing force detected in the measuring unit 12 has reached a specific predefined threshold value, and when the threshold value is reached, method step 3 is initiated.

[0084] Subsequently, in method step 3, force regulation as shown in the structural circuit schematic of the control circuit in FIG. 5 with the regulation segment in FIG. 6 is activated. By means of the force regulation, the electric motor 2 is controlled in such a manner that the predetermined pressing force is reached.

[0085] FIG. 3 shows a structural circuit schematic of the mechanical model of the process press 1. This serves as a basis for modeling of the process press 1. The input variable of the model represents the motor moment M.sub.m, which counteracts the friction moment M.sub.rm of the drive. The motor inertia moment is determined by .sub.m. The coupling 13 is modeled as a linear spring/mass damper element. This is characterized by the spring constant c.sub.k, the damping constant d.sub.k, and the inertia moment .sub.k, wherein the inertia moment is taken into consideration on the drive side and on the power take-off side, by half, in each instance. The moment after the coupling 13, which acts as the drive moment of the spindle 9, is referred to as M.sub.sp. The friction losses are taken into consideration with the moment M.sub.rs. .sub.sp indicates the inertia moment of the spindle 9. The ball screw drive transforms the rotational movement of the spindle 9 to a translational movement of the carriage 16. The translation ratio of this transformation is indicated with i.sub.g. The measuring unit 12, which connects the carriage 16 with the mass m.sub.1 and the forming tool 3 with the mass m.sub.2, is modeled with a linear spring/damper model having the spring constants c.sub.s and the damping constants d.sub.5. The position of the carriage 16 is indicated with s.sub.1 and the position of the forming tool 3 is indicated with s.sub.2. The transformed spindle moment causes the force F.sub.a, which acts on the carriage 16. The force F.sub.s indicates the measured value of the measuring unit 12, and F.sub.ext indicates the external force that occurs during pressing.

[0086] FIG. 4 shows an exemplary progression of the external force above the progression of the position of the forming tool 3. The exemplary progression of the external force can be determined by an experiment. This exemplary progression is also referred to as a load characteristic line.

[0087] In order to allow a wide field of pressing applications, and to guarantee simplicity of the model adaptation, the load model of the specific application cases is determined empirically. The goal is to detect a characteristic line using measurement technology, which line indicates the connection between the external force F.sub.ext and the position of the forming tool 3 s.sub.2. For this purpose, the forming tool 3 is moved at a constant velocity, in accordance with the application case, so far toward the workpiece 4 until a defined limit force has been reached.

[0088] The relationship between force and path determined in this way is shown in FIG. 4 and corresponds to that of a non-linear spring having the form F.sub.ext(s.sub.2)=k(s.sub.2)*s.sub.2 with the position-dependent spring stiffness k(s.sub.2). The characteristic line is divided into two regions. While the forming tool 3 moves freely, no significant increase in force occurs. For this process, F.sub.ext=ON is assumed. Only once the forming tool 3 impacts the workpiece 4 does a noticeable force increase come about. When this force increase F.sub.extF.sub.e>F.sub.trigger is detected, the forming stage begins. The related carriage position is indicated as s.sub.trigger.

[0089] FIG. 5 shows a structural circuit schematic of a control circuit for force regulation, wherein the force regulator is designed for the forming stage and is active during this stage.

[0090] In the case of some pressing processes, it can happen that the curve of the pressing force has a very steep increase. Stated in other words, the pressing force increases steeply in the case of only a slight movement of the forming tool 3. Therefore it can be necessary for the forming tool 3 to be brought to a stop within a short distance, in order to be able to achieve a predetermined value of the pressing force. Due to the inertia of the system or due to the inertia of conventional regulation of the electric motor 2, however, it can occur that the dynamics of the subordinate speed of rotation regulator of the electric motor 2 is not sufficient for this braking maneuver.

[0091] In order to circumvent this problem, not only a force pre-controller but also a motor speed of rotation pre-controller is used for inertia compensation and load compensation. This expanded control circuit is shown in FIG. 5. Due to the great stiffness in the relevant frequency range, .sub.m=.sub.sp=s.sub.2/i.sub.g is assumed for the design of the pre-controller and motor speed of rotation regulator, wherein .sub.m stands for the motor angle position of the electric motor 2, and .sub.sp stands for the spindle angle position of the spindle 9 of the spindle drive 6. At first, the translational total mass, i.e. m.sub.t=m.sub.1+m.sub.2 is added up, in accordance with the translation ratio i.sub.g, with the inertia moment of the drive train, to yield a total inertia moment =.sub.m+.sub.k+.sub.sp+m.sub.ti.sub.g.sup.2, wherein .sub.m represents the inertia moment of the electric motor 2, .sub.k represents the inertia moment of the coupling 13, and .sub.sp represents the inertia moment of the spindle 9. This results in the simplified draft model .sub.*.sub.m=M*.sub.mF.sub.exti.sub.g.

[0092] With F*=.sub.ext and M*.sub.FF=M*.sub.m, the motor speed of rotation pre-control is consequently M*.sub.FF=M*.sub.,FF+M*.sub.ext,FF. With the pre-control component M*.sub.,FF, subsequently the influence of the inertia moments and masses of the press can be compensated during the acceleration phases. The pre-control component for compensation of the external force F.sub.ext is M*.sub.ext,FF=F*i.sub.g. If the assumption of high stiffness is not justified, this simplified system does not apply, and the pre-control components must be calculated using the system in FIG. 3.

[0093] A substitute model for the controlled system G.sub.*.sub.m.sub.,F.sub.s(s) is shown in FIG. 6. The transfer function G.sub.m(s) with the motor moment M.sub.m as the input and the motor speed of rotation .sub.m as the output forms the output feedback .sub.m for the subordinate speed of rotation regulation circuit

[00002] $T_{} (s) = \frac{R_{} (s)}{1 + R_{} (s) .Math. G_{.Math. m} (s)}$

which, together with the transfer function G.sub.Fs(s) with the motor moment M.sub.m as the input and the sensor force F.sub.s as the output, depicts the entire controlled system

[00003] $G_{_{m}^{*}, F_{s}} (s) = \frac{F_{s}}{_{m}^{*}} = T_{} (s) .Math. G_{F .Math. s} (s)$

from the reference speed of rotation *.sub.m as the input to the sensor force F.sub.s as the output. A low-pass filter of the third order, having the form

[00004] $R_{F} (s) = \frac{k_{F .Math. P}}{{(1 + \frac{s}{_{F .Math. g}})}^{3}}$

is selected as a regulator. The limit frequency .sub.FG and the amplification k.sub.FP are adapted in such a manner that stable behavior occurs for the closed control circuit. The regulator parameters can be set using a Loop Shaping method.

[0094] FIG. 7 shows a flow chart of a schematic progression of a further regulation strategy for pressing the workpiece 4, wherein the first two method steps are the same as in the flow chart according to FIG. 2.

[0095] In method step 3, the electric motor 2 is operated at a minimal speed of rotation. The minimal speed of rotation can be different from process to process, and is predetermined on the basis of the current process parameters. In extreme cases, it can actually be necessary that the minimal speed of rotation is equal to zero or approaches zero. Braking from the reduced speed of rotation to the minimal speed of rotation should take place, within the scope of the strength values of the process press 1, as quickly as possible or abruptly. In method step 3, the electric motor 2 is operated at the minimal speed of rotation for such a time until the vibrations in the drive train, which occur due to the abrupt braking maneuver, have died out. For this purpose, a pre-calculated time period until the vibrations have died out is queried in Query C.

[0096] In an alternative variant, it can also be provided that the required time period until the vibrations have died out is not calculated on the basis of a model, but rather that this period is adapted in an iterative method, or that dying out of the vibrations is determined by means of detecting the motor torque in the electric motor 2 in comparison with the measured torque in the measuring unit 12.

[0097] Subsequently, in method step 4, force regulation as it is shown in the structural circuit schematic of the control circuit in FIG. 4 or in the controlled system in FIG. 5 is activated. By means of the force regulation, the electric motor 2 is controlled in such a manner that the predetermined pressing force is reached.

[0098] In FIGS. 8 to 14, different structural circuit schematics of possible control circuits for force regulation are shown. In order to avoid unnecessary repetition, reference is made to FIG. 5 and to the respective preceding figures.

[0099] In the exemplary embodiment according to FIG. 8, it is not the sensor signal Fs, as is the case in FIG. 5, that serves as the input variable for the force regulator R.sub.F, but rather an estimated force {circumflex over (F)}.sub.ext made available by an interference variable observer 19 is an input variable for the force regulator R.sub.F. Furthermore, a force pre-controller V.sub.F, a load pre-controller V.sub.ext, and an inertia compensation V.sub., are provided.

[0100] In the exemplary embodiment according to FIG. 9, a force {circumflex over (F)}.sub.ext estimated by the interference variable observer 19 serves as an input variable for the force regulator R.sub.F. Furthermore, a force pre-controller V.sub.F and an inertia compensation V.sub. are provided.

[0101] In the exemplary embodiment according to FIG. 10, a force Kraft {circumflex over (F)}.sub.ext estimated by the interference variable observer 19 serves as the input variable for the force regulator R.sub.F. Furthermore, a force pre-controller V.sub.F is provided.

[0102] In the exemplary embodiment according to FIG. 11, a force {circumflex over (F)}.sub.ext estimated by the interference variable observer 19 serves as an input variable for the force regulator R.sub.F. Furthermore, a force pre-controller V.sub.F and a load pre-controller V.sub.ext are provided.

[0103] In the exemplary embodiment according to FIG. 12, the sensor signal Fs serves as an input variable for the force regulator R.sub.F. Furthermore, a force pre-controller V.sub.F, a load pre-controller V.sub.ext, and an inertia compensation V.sub. are provided.

[0104] In the exemplary embodiment according to FIG. 13, the sensor signal Fs serves as the input variable for the force regulator R.sub.F. Furthermore, a force pre-controller V.sub.F and an inertia compensation V.sub. are provided.

[0105] In the exemplary embodiment according to FIG. 14, the sensor signal Fs serves as the input variable for the force regulator R.sub.F. Furthermore, a force pre-controller V.sub.F is provided.

[0106] In the exemplary embodiment according to FIG. 15, the sensor signal Fs serves as the input variable for the force regulator R.sub.F. Furthermore, a force pre-controller V.sub.F and a load pre-controller V.sub.ext are provided.

[0107] The exemplary embodiments show possible embodiment variants, wherein it should be noted at this point that the invention is not restricted to the specifically shown embodiment variants of the same, but rather, instead, diverse combinations of the individual embodiment variants with one another are also possible, and this variation possibility lies within the ability of a person skilled in the art of this field, on the basis of the teaching for technical action provided by the present invention.

[0108] The scope of protection is determined by the claims. However, the description and the drawings should be used to interpret the claims. Individual characteristics or combinations of characteristics from the different exemplary embodiments that are shown and described can represent independent inventive solutions on their own. The task on which the independent inventive solutions are based can be derived from the description.

[0109] All the information relating to value ranges in the present description should be understood to mean that this information comprises any and all partial ranges of them for example, the statement 1 to 10 should be understood to mean that all partial ranges, proceeding from the lower limit 1 and including the upper limit 10 are included, i.e. all partial ranges begin with a lower limit of 1 or more and end at an upper limit of 10 or less, for example 1 to 1.7, or 3.2 to 8.1, or 5.5 to 10.

[0110] For the sake of good order, it should be pointed out, in conclusion, that for a better understanding of the structure, some elements were represented not to scale and/or enlarged and/or reduced in size.

REFERENCE SYMBOL LISTING

[0111] 1 process press [0112] 2 electric motor [0113] 3 forming tool [0114] 4 workpiece [0115] 5 regulator [0116] 6 spindle drive [0117] 7 gear mechanism [0118] 8 drive shaft [0119] 9 spindle [0120] 10 gear mechanism output [0121] 11 gear mechanism output shaft [0122] 12 measuring unit [0123] 13 coupling [0124] 14 mounting [0125] 15 threaded nut [0126] 16 carriage [0127] 17 guide rail [0128] 18 pressing surface [0129] 19 interference variable observer

METHOD FOR PRESSING A WORKPIECE WITH A PREDETERMINED PRESSING FORCE

Assignee

Inventors

Cpc classification

Classification Explorer

B30B1/181

PERFORMING OPERATIONS; TRANSPORTING

Classification Explorer

B30B15/14

PERFORMING OPERATIONS; TRANSPORTING

Classification Explorer

B30B15/26

PERFORMING OPERATIONS; TRANSPORTING

Classification Explorer

B30B15/186

PERFORMING OPERATIONS; TRANSPORTING

Classification Explorer

B30B15/148

PERFORMING OPERATIONS; TRANSPORTING

International classification

Classification Explorer

B30B15/14

PERFORMING OPERATIONS; TRANSPORTING

Classification Explorer

B30B1/18

PERFORMING OPERATIONS; TRANSPORTING

Abstract

Claims

Description