Method for Winding a Winding Material via a Brake Roller onto a Winding Body having a Non-Circular Cross Section

Abstract

A method for winding a winding material via a brake roller onto a winding body having a non-circular cross section for influencing a tensile force characteristic of the winding material, wherein a torque value is ascertained via a torque balance of the brake roller in dependence on a winding material speed and the ascertained torque value for the drive of the brake roller is specified.

Claims

1. A method for winding a winding material via a brake roller onto a winding body having a non-circular cross section for influencing a tensile force characteristic of the winding material, the method comprising: ascertaining a torque value via a torque balance of the brake roller in dependence on a winding material speed; and specifying the ascertained torque value for the drive of the brake roller.

2. The method as claimed in claim 1, wherein a torque characteristic curve as a torque setpoint value and current setpoint value derived therefrom is specified to a current controller for the specification of the ascertained torque value.

3. The method as claimed in claim 1, wherein a torque limit in the speed control loop is controlled using the ascertained torque value as a variable torque limit value for the specification of the ascertained torque value.

4. The method as claimed in claim 3, wherein the brake roller is controlled using a specifiable speed.

5. The method as claimed in claim 4, wherein the speed is specified to be approximately constant or the speed is specified from a speed characteristic.

6. The method as claimed in claim 4, wherein the speed is directed in a direction opposite to an unwinding direction.

7. The method as claimed in claim 5, wherein the speed is directed in a direction opposite to an unwinding direction.

8. The method as claimed in claim 1, wherein the torque value is ascertained via the torque balance with a counteracting tensile force component and an identically acting inertia component.

9. The method as claimed in claim 1, wherein the winding material speed is ascertained via geometric information relating to the winding body.

10. The method as claimed in claim 1, wherein the winding material speed is recorded via a test winding of the winding body with test conditions.

11. The method as claimed in claim 3, wherein the torque limit is controlled in real time.

12. The method as claimed in claim 8, wherein a tensile force or a tensile force characteristic is specified for the tensile force component.

13. The method as claimed in claim 8, wherein an inertia is specified, which is derived from a CAD system and specified, or is measured for the inertia component.

14. A control unit for a brake roller for winding a winding material onto a winding body, comprising: a processor; and memory; wherein the processor is configured to: ascertain a torque value via a torque balance of the brake roller in dependence on a winding material speed; and specifying the ascertained torque value for a drive of the brake roller.

15. A computer program, comprising commands stored in memory which, when executed by a computer, causes the computer to perform the method as claimed in claim 1, wherein the computer program is executed on a virtual controller.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The invention is explained in more detail below based on exemplary embodiments with reference to the figures, in which:

[0035] FIG. 1 shows a schematic illustration of a wire winding machine having a control concept in accordance with the prior art;

[0036] FIG. 2 shows a schematic illustration of a wire winding machine having a control concept in accordance with a first exemplary embodiment of the invention;

[0037] FIG. 3 shows a schematic illustration of a geometry of a non-circular winding body with relevant variables;

[0038] FIG. 4 shows a schematic illustration of a wire winding machine having a control concept in accordance with a second exemplary embodiment of the invention;

[0039] FIG. 5 shows a schematic illustration of a wire winding machine having a control concept in accordance with a third exemplary embodiment of the invention; and

[0040] FIG. 6 is a flowchart of the method in accordance with the invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0041] In the figures, elements having the same function are provided with the same reference signs, unless stated otherwise.

[0042] FIG. 1 shows a wire winding machine in accordance with the prior art, which involves winding a copper wire D onto a rectangular coil W with a constant tensile force. A geometry of a non-round winding body WK is therefore used as a basis for the coil W. FIG. 1 intends to illustrate how a wire D is wound slip-free onto a brake B driven by a brake motor Mb and made available to the process by a movement of the brake B. As depicted, the wire D is deflected once on a deflection roller U1 and guided on a wire guide U2. The coil W rotates at a constant speed, driven by the winding motor Mw. An encoder on the winder Gw ensures feedback into a current control loop having a current controller R_i_w for controlling a constant speed on the winder, here the coil W.

[0043] A speed characteristic for the brake B is calculated and controlled with the help of a geometric model of the winding body WK. An encoder Gb outputs the actual speed. The tensile force results from a position offset between the brake B and the winding body WK together with the wire stiffness. The position offset is controlled by an upstream force controller.

[0044] In order to keep the tensile force on the wire D at a setpoint tensile force F-soll, a force controller having a force controller R_f_b and feedforward controller C_f is placed upstream of a controller of the brake motor Mb having a current controller R_i_b and upstream speed controller R_n_b.

[0045] In accordance with a first exemplary embodiment, the brake B is controlled at a constant speed. FIG. 2 illustrates the exemplary embodiment, where the structure of the winder W having the deflection roller U1 and the wire guide U2 is identical to the structure shown in FIG. 1. The selected constant speed of the brake B is directed in the opposite direction to the unwinding direction, i.e., the speed would ensure that the wire D would be wound back onto the brake B. This ensures that the torque setpoint value of the brake B reaches the torque limit very quickly. The torque limit is controlled and selected in real time such that the acceleration phases of the wire D or of the brake B are compensated for.

[0046] The acceleration force to be compensated for is derived from the wire acceleration. The wire acceleration is obtained from the wire speed and this is calculated with the help of a geometric model:

[00001]$v_{Wire}\left(t\right)=r\left(\right)\stackrel{}{}$

[0047] Where is the angle of rotation of the winding body WK and r() is the effective radius. Both variables are explained with reference to FIG. 3.

[0048] FIG. 3 shows a non-round winding body WK around which a wire D is wound. The winding body WK rotates around a point o which at the same time forms the origin of a coordinate system, drawn for illustrative purposes, with an x-axis and a y-axis in the plane of rotation. The effective radius r() is the shortest distance between the center of rotation o of the winding body WK and the wire D. In the case of a simple geometry, such as a rectangle, this function can be concluded from user data.

[0049] The wire acceleration is obtained from the wire speed.

[00002]$a_{Wire}\left(t\right)=r\left(\right)\stackrel{.Math.}{}+\frac{dr}{d}\left(\right){\stackrel{}{}}^2$

[0050] The following torque balance applies to a rotating brake:

[00003]$F_{zug}{r}_B=J_B{\stackrel{.Math.}{}}_B+M_{{\mathrm{ist}}_B}$

[0051] Where r_B is the radius of the brake, F_Zug is the tensile force acting on the wire, J_B is the inertia of the brake and {umlaut over ()}.sub.B is the angular acceleration of the brake.

[0052] The angular acceleration of the brake can be replaced by the wire acceleration divided by the radius of the brake.

[00004]$M_{{\mathrm{ist}}_B}=F_{zug}{r}_B-\frac{J_B}{r_B}\left[r\left(\right)\stackrel{.Math.}{}+\frac{dr}{d}\left(\right){\stackrel{}{}}^2\right]$

[0053] The value M_ist_B ascertained in this way is then used as the torque limit value M_G, as illustrated in FIG. 2. The torque limit value M_G is controlled and is consistently reached at the provided torque limit G. Consequently, this limit is output as the setpoint to the current controller R_i_b. The conversion into a setpoint current that is specified to the motor takes place. In addition, a PI controller PI is provided in the speed control loop, for example.

[0054] In accordance with a second exemplary embodiment, instead of the torque limit with a controlled limit value, a torque setpoint value M_soll_b is specified to the current controller R_i_b. The value M_ist_B, as was ascertained in connection with the first exemplary embodiment described, is used as the torque setpoint value M_soll_b. In particular, this is a torque setpoint value characteristic which repeats itself almost in each cycle.

[0055] In accordance with the second exemplary embodiment, separator films and electrode films are wound onto a core for manufacturing a battery cell. Only one of the films that is to be wound one on top of another in layers is depicted.

[0056] In accordance with a third exemplary embodiment of the invention, the described concept of the torque value ascertained via the torque balance is used for the brake drive in a winding machine, in which the winding body WK of a coil or the like does not rotate but rather a kinematic system K winds the winding material onto the winding body WK. This can be advantageous, for example, in the case of flexibly interchangeable coil bodies in which the movement of the kinematic system K can compensate for the various geometries.

[0057] FIG. 6 is a flowchart of the method for winding a winding material D via a brake roller B onto a winding body WK having a non-circular cross section for influencing a tensile force characteristic of the winding material D.

[0058] The method comprises ascertaining a torque value via a torque balance of the brake roller B in dependence on a winding material speed, as indicated in step 610.

[0059] Next, the ascertained torque value for the drive Mb of the brake roller B is specified, as indicated in step 620.

[0060] Thus, while there have been shown, described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the methods described and the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps that perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.