LINEAR MOTOR SYSTEM AND OPERATING METHOD FOR THE SAME

Abstract

A linear motor system, in particular to a transport system, e.g. a multi-carrier, including: a guide track having a plurality of electromagnets arranged distributed along the guide track; at least one carrier that is guided by and movable along the guide track and that includes a drive magnet for cooperating with the electromagnets of the guide track to move the carrier; and a control device for controlling the movement of the carrier relative to the guide track by a corresponding control of the electromagnets, wherein the control device is configured to detect an inertial response of the moving mass of the carrier during a movement of the carrier and to determine mass information relating to the mass of the carrier on the basis of the inertial response.

Claims

1. A linear motor system, comprising: a guide track having a plurality of electromagnets arranged distributed along the guide track; at least one carrier that is guided by and movable along the guide track and that comprises a drive magnet for cooperating with the electromagnets of the guide track to move the carrier; and a control device for controlling the movement of the carrier relative to the guide track by a corresponding control of the electromagnets, wherein the control device is configured to detect an inertial response of the moving mass of the carrier during a movement of the carrier and to determine mass information relating to the mass of the carrier on the basis of the inertial response.

2. The linear motor system in accordance with claim 1, wherein the linear motor system comprises an information feedback device for returning at least one piece of feedback information, which relates to the movement of the carrier and/or to the activity of the electromagnets during a movement of the carrier, to the control device.

3. The linear motor system in accordance with claim 1, wherein the control device is configured to regulate the movement of the carrier, on the basis of the feedback information, and to determine the mass information on the basis of a control deviation and/or a control response.

4. The linear motor system in accordance with claim 1, wherein the inertial response is detected on the basis of a position of the carrier relative to the guide track, including a position along the guide track.

5. The linear motor system in accordance with claim 1, wherein the inertial response is detected on the basis of a coil current of one of the electromagnets.

6. The linear motor system in accordance with claim 1, wherein the control device is configured to determine product information relating to a product to be moved by the carrier, relating to the mass of the product and/or a number of products or product parts, on the basis of the mass information.

7. The linear motor system in accordance with claim 1, wherein the control device is configured to control the carrier to perform a mass determination movement, to detect an inertial response during the mass determination movement, through feedback information, and to determine the mass information on the basis of said inertial response.

8. The linear motor system in accordance with at claim 1, wherein the mass information can be determined in at least one mass determination section with respect to the guide track, and wherein the mass determination section can be selected and a selection can be changed.

9. The linear motor system in accordance with claim 1, wherein the linear motor system comprises an interface for outputting the mass information, to a user device, and/or for inputting data and/or commands by a user and/or a user device.

10. A method of operating the linear motor system in accordance with claim 1, wherein the linear motor system comprises: a guide track having a plurality of electromagnets arranged distributed along the guide track; at least one carrier that is guided by and movable along the guide track and that comprises a drive magnet for cooperating with the electromagnets of the guide track to move the carrier; and a control device for controlling the movement of the carrier relative to the guide track by a corresponding control of the electromagnets, wherein the method comprises detecting an inertial response of the moving mass of the carrier during a movement of the carrier and determining mass information relating to the mass of the carrier on the basis of the inertial response.

11. The method in accordance with claim 10, wherein a first piece of mass information is determined during a first movement, and wherein a second piece of mass information is determined during a second movement, wherein a product is fed to the carrier or is discharged from the carrier between the movements.

12. The method in accordance with claim 11, wherein a difference of the mass information is determined.

13. The method in accordance with claim 10, wherein the mass information and/or a difference between two determined pieces of mass information, is compared with a desired value and/or a desired range.

14. The method in accordance with claim 13, wherein error information is determined on the basis of the comparison, wherein the error information comprises information as to whether a product is present at the carrier in the provided number and/or mass or not.

15. The method in accordance with claim 10, wherein the mass information is monitored in a plurality of sections of the linear motor system with respect to the guide track, over the total provided movement path of the carrier.

Description

[0045] The invention will be explained only by way of example in the following with reference to the schematic drawings.

[0046] FIG. 1 shows a linear motor system configured as a transport system;

[0047] FIG. 2 shows a curve section of the transport system of FIG. 1;

[0048] FIG. 3 shows a cross-section of the transport system of FIG. 1 with a sectional plane perpendicular to a guide track; and

[0049] FIG. 4 shows a plotting of different movement paths of a carrier.

[0050] A transport system 10 in accordance with the invention, which is configured as a multi-carrier system, is shown in FIG. 1. The transport system 10 comprises a plurality of linear motors 12 that are arranged in rows such that a continuous and in this case revolving movement of the carriers 14 along a guide track 16 is made possible. The transport system 10 further comprises a plurality of carriers 14 that form individual transport elements of the transport system 10 and that can be moved along the guide track 16, in particular independently of one another, by means of the linear motors 12.

[0051] FIG. 2 shows a curve section of the transport system 10 in an enlarged view. Only one carrier 14 is shown here, which is movable along the guide track 16, namely via the linear motors 12. Different electronic devices for controlling the linear motors 12 are visible at the side of the guide track 16 remote from the carrier 14, that is within the curve.

[0052] In FIG. 3, the transport system 10 is shown in a sectional view and enlarged. A carrier 14 is visible that is movably guided at the guide track 16. In this respect, the carrier 14 is movable along a guide axis 18 or a movement axis. For a movement along the guide axis 18, the carrier 14 is controlled by a plurality of electromagnets 20 that are arranged at the guide track 16 and that are uniformly distributed along it. The electromagnets 20 in this respect cooperate with a permanent magnet 22, which is arranged at the carrier 14 and which can also be designated as a drive magnet, for driving the carrier.

[0053] The carrier 14 is mechanically guided at the guide track 16, namely by a roller guide. Said roller guide comprises guide rollers 24 at the carrier 14 and guide rails 26 at the guide track 16. The carrier 14 is in this respect in particular held at the guide track 16 via the permanent magnet 22.

[0054] The transport system 10 furthermore comprises a position detection device 28. Said position detection device can, for example, be formed as a series of a plurality of magnetic sensors that extends along the guide track 16. A permanent magnet 30, which can also be designated as a position magnet and which is visible in FIG. 2, can be provided at the carrier 14, for example.

[0055] The transport system 10 furthermore comprises a control device that is not shown separately and that is configured to control the electromagnets 20 in a targeted manner in order to move the carrier 14 along the guide track 16 or the guide axis 18. In this respect, the position detection device 28 returns position information relating to the position of the carrier 14 with respect to the guide axis 18 to the control device. The control device regulates the movement of the carrier 14 on the basis of the position information.

[0056] When the carrier 14 is moved, an inertial response generally results. It can here be detected in a simple manner by the control device since an inertial response is expressed during an acceleration along the guide track 16 as part of the movement regulation. Thus, a control deviation and/or a control response is/are in particular dependent on the inertia. The inertial response is in this respect dependent on the moving mass. A control deviation can, for example, be easily detected by the position detection system. A control response, for example, results from an output value of a regulator of the control device, in particular from a coil current for at least one electromagnet.

[0057] If the mass is small, the control deviation is small and/or a control response is not particularly strong. If, in contrast, the mass is large, the control deviation and/or the control response is strong. Within the framework of the invention, this relationship is advantageously used to determine mass information relating to the mass of the carrier and/or to the mass of an object moved by the carrier. In this respect, it is often not even necessary to determine a certain or even an exact mass value. Rather, a particularly simple implementation comprises determining whether or not an object to be moved by the carrier 14 is present at the carrier, possibly in the correct number or quantity.

[0058] FIG. 4 shows a plotting of different movement paths of a carrier, wherein the abscissa represents the time and is designated as t, and wherein the ordinate represents the position of the carrier with respect to the guide track and is designated as x. The x direction thus corresponds to the guide axis 18 marked in FIG. 3.

[0059] A desired movement path 32 of an exemplary, regulated mass determination movement is shown. In this respect, the carrier is moved from a first position at a constant speed to a second position that differs from the first position.

[0060] An actual movement path 34 of a carrier is additionally shown. It has a control deviation 36 from the desired movement path 32 that is formed as a contour error here. A further actual movement path 38 of a carrier likewise has a control deviation 40 with respect to the desired movement path 32.

[0061] Mass information relating to the moving carrier can be determined based on a control deviation 36 or 40 since the control deviation is an inertial response of the system. The greater the control deviation 36 or 40, the greater the moving mass of the carrier. Based on the difference of the control deviations 36 and 40, it is also possible to conclude a difference of the moving masses of the respective carriers. If the movement paths shown relate to a certain carrier, an unloaded state and a loaded state of the carrier can, for example, be differentiated based on a difference in the control deviations 36 and 40. In this respect, the movement path 34 would correspond to the unloaded state and the movement path 38 would correspond to the loaded state.

[0062] The desired movement path 32 shown can, for example, represent a movement of the carrier which is anyway provided and during which the mass determination can be performed.

REFERENCE NUMERAL LIST

[0063] 10 transport system

[0064] 12 linear motor

[0065] 14 carrier

[0066] 16 guide track

[0067] 18 guide axis

[0068] 20 electromagnets

[0069] 22 drive magnet

[0070] 24 guide rollers

[0071] 26 guide rail

[0072] 28 position detection device

[0073] 30 position magnet

[0074] 32 desired movement path

[0075] 34 movement path

[0076] 36 control deviation

[0077] 38 movement path

[0078] 40 control deviation