Abstract
A linear motor system, in particular a transport system, for example a multi-carrier system, includes a guide track having a plurality of electromagnets arranged distributed along the guide track. The linear motor system furthermore includes a first and a second carrier that are guided by and movable along the guide track and that each include a drive magnet for cooperating with the electromagnets of the guide track to move the carriers; and a control device for controlling the movement of the carriers relative to the guide track by a corresponding control of the electromagnets. Furthermore, the linear motor system includes at least one energy transmission element that is fastened to the first and/or second carrier and that transmits energy from the first carrier to the second carrier.
Claims
1-15. (canceled)
16. A linear motor system comprising: a guide track having a plurality of electromagnets arranged distributed along the guide track; a first and a second carrier that are guided by and movable along the guide track and that each comprise a drive magnet for cooperating with the electromagnets of the guide track to move the carriers: a control device for controlling the movement of the carriers relative to the guide track by a corresponding control of the electromagnets; and at least one energy transmission element that is fastened to the first and/or second carrier and that is configured to transmit energy from the first carrier to the second carrier.
17. The linear motor system in accordance with claim 16, wherein the energy transmission element is configured to transmit the energy from the first carrier to the second carrier when the first and/or the second carrier enters/enter into an active region of the energy transmission element.
18. The linear motor system in accordance with claim 17, wherein the acceleration of the second carrier attributable to the control device is at least not negative in the active region and/or deviates by at most 15% or 10% from the acceleration attributable to the energy transmission element.
19. The linear motor system in accordance with claim 16, wherein the control device is configured to adapt the control of the movement of the second carrier to an acceleration curve of the second carrier caused by the energy transmission element.
20. The linear motor system in accordance with claim 16, wherein the control device is configured to set the control of the movement of the second carrier such that an approximately triangular or trapezoidal acceleration curve of the second carrier is achieved by the control.
21. The linear motor system in accordance with claim 18, wherein an optimal start spacing d.sub.opbetween the second carrier and the first carrier is determined by means of an iteration method, wherein the iteration method comprises: (1) a first start spacing d.sub.1 between the first carrier and the second carrier being defined, at which first start spacing d.sub.1 a first minimum distance d.sub.min,1 between the carriers results that is smaller than an optimal minimum distance d.sub.min,opt, wherein the start spacing defines a distance between the first carrier and the second carrier, with the first carrier starting to brake and the second carrier starting to accelerate on a falling below of said distance; (2) a second start spacing d.sub.2 between the first carrier and the second carrier being defined, at which second start spacing d.sub.2 a second minimum distance d.sub.min,2 results that is greater than an optimal minimum distance d.sub.min,opt, (3) a third start spacing being calculated and a corresponding third minimum distance d.sub.min,3 being determined; (4) d.sub.1 and d.sub.2 being updated as follows: d.sub.1:=d and d.sub.2:=d.sub.3 if (d.sub.min,1−d.sub.min,opt).Math.(d.sub.min,3−d.sub.min,opt)<0; or d.sub.1:=d.sub.3 and d.sub.2:=d.sub.2 if (d.sub.min,2−d.sub.min,opt).Math.(d.sub.min,3−d.sub.min,opt)<0. (5) steps (3) and (4) being repeated if d.sub.min,2−d.sub.min,opt>epsilon and d.sub.3 is not equal to 0; (6) the optimal start spacing d.sub.opt resulting as follows: d.sub.opt=d2 or d.sub.opt=d3 if d.sub.min,3−d.sub.min,opt=0.
22. The linear motor system in accordance with claim 16, wherein the energy transmission element comprises a spring.
23. The linear motor system in accordance with claim 22, wherein a spring constant D.sub.spring of the spring is represented by the equation: where D.sub.spring represents the spring constant of the spring, s.sub.deflection represents the deflection distance of the spring at a maximum spring deflection, and E.sub.pot,spring represents the potential energy stored in the spring at a maximum spring deflection, wherein E.sub.pot,spring is determined as follows: where m is the mass of a carrier and v.sub.start is the speed of the first carrier when contacting the spring.
24. The linear motor system in accordance with claim 23, wherein the deflection distance of the spring at a maximum spring deflection s.sub.deflection is determined as follows: where s.sub.L1 represents a traveled braking distance of the first carrier, s.sub.L2 represents a traveled acceleration distance of the second carrier, and a represents the magnitude of the acceleration of the first and/or second carrier.
25. A linear motor system in accordance with claim 16, wherein the energy transmission element can at least regionally be recessed in the carrier to which the energy transmission element is fastened.
26. A linear motor system in accordance with claim 16, wherein the energy transmission element is attached along a center of mass line that extends in the direction of travel through a center of mass of the first and/or second carrier.
27. The linear motor system in accordance with claim 16, wherein the linear motor system is a transport system.
28. The linear motor system in accordance with claim 27, wherein the transport system is a multi-carrier system.
29. A method of operating a linear motor system, wherein the linear motor system comprises: a guide track having a plurality of electromagnets arranged distributed along the guide track; a first and a second carrier that are guided by and movable along the guide track and that each comprise a drive magnet for cooperating with the electromagnets of the guide track to move the carriers; and a control device for controlling the movement of the carriers relative to the guide track by a corresponding control of the electromagnets, wherein the method comprises transmitting, at least partly, energy of the first carrier to the second carrier by an energy transmission element fastened to the first and/or second carrier.
30. The method in accordance with claim 29, wherein the first carrier is decelerated on the transmission of the energy to the second carrier and the second carrier is accelerated on the transmission of the kinetic energy.
31. The method in accordance with claim 29, wherein a braking of the first carrier and an acceleration of the second carrier start when both carriers are located in the active region of the energy transmission element, and the braking of the first carrier and the acceleration of the second carrier end when both carriers have left the active region of the energy transmission element.
32. The method in accordance with claim 29, wherein the linear motor system is a transport system.
33. The method in accordance with claim 29, wherein the linear motor system further comprises: the energy transmission element.
34. A carrier for a linear motor system, the linear motor system comprising: a guide track having a plurality of electromagnets arranged distributed along the guide track; a first and a second carrier that are guided by and movable along the guide track and that each comprise a drive magnet for cooperating with the electromagnets of the guide track to move the carriers; a control device for controlling the movement of the carriers relative to the guide track by a corresponding control of the electromagnets; and at least one energy transmission element that is fastened to the first and/or second carrier and that is configured to transmit energy from the first carrier, the carrier comprising: a drive magnet for cooperating with the plurality of electromagnets of the guide track of the linear motor system to move the carriers; and at least one energy transmission element for transmitting kinetic energy.
Description
[0070] The invention will be presented purely by way of example with reference to the drawings in the following. There are shown:
[0071] FIG. 1 a linear motor system configured as a transport system;
[0072] FIGS. 2A to 2D the transmission of energy from a first carrier to a second carrier;
[0073] FIG. 3 a plan view of the linear motor system;
[0074] FIG. 4 an acceleration curve caused by the energy transmission element and an acceleration curve of a carrier caused by the control device;
[0075] FIG. 5 acceleration courses of a carrier and corresponding current courses; and
[0076] FIGS. 6A to 6C different embodiments with respect to the energy transmission elements.
[0077] A linear motor system 10, which is configured as a multi-carrier system, is shown in FIG. 1. The linear motor system 10 comprises a plurality of linear motors 12 that are arranged in a row so 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 comprises a plurality of carriers 14 that form individual transport elements of the transport system 10 and that can be moved independently of one another along the guide track 16 by means of the linear motors 12. A control device 17 in this respect controls the movement of the carriers 14 along the guide track 16.
[0078] FIG. 2A shows a front view of a section of the linear motor system 10. A first carrier 18 is visible that is guided on the guide track 16 at a speed v.sub.L1 and that moves towards a second carrier 20. An energy transmission element in the form of a spring 22, which faces in the direction of the first carrier 8, is fastened to the second carrier 20 along a center of mass line 21 that extends through the center of mass in the direction of travel. Between the first carrier 18 and the second carrier 20, there is a distance D that can, for example, be determined by means of sensors, not shown.
[0079] As soon as a predetermined distance between the two carriers 18, 20 is fallen below by the first carrier and the first carrier 18 thus enters into an active region 19 of the spring 22 or comes into direct contact with the spring 22, as shown in FIG. 2B, the control device 17 starts to decelerate the movement of the first carrier 18 and simultaneously to accelerate the movement of the second carrier 20. In this respect, the control of the movement of the first carrier 18 and/or the movement of the second carrier 20 is adapted to an acceleration curve that was, for example, previously determined via an iteration method and that can be attributed to the spring 22 independently of the control device 17.
[0080] Due to the spring 22, at least some of the kinetic energy of the first carrier 18 is transmitted directly to the second carrier 20 and/or stored in the spring 22 as potential energy and is subsequently transmitted as kinetic energy to the second carrier 20. Thus, the first carrier 18 is decelerated and the second carrier 20 is accelerated by the energy transmission. This effect is enhanced by controlling the movement of the first and second carriers 18, 20 by means of the control device 17. The spring 22 is compressed up to a point of the maximum spring deflection, as shown in FIG. 2C, so that the two carriers 18, 20 have a minimum distance from one another in a maximum compressed state of the springs 22. At the moment of the maximum spring deflection, energy is stored in the spring 22 that corresponds to half the kinetic energy of the first carrier 18 shortly before or exactly on the entry into the active region 19. As soon as the state of the maximum spring deflection is reached, the spring 22 at least partly transmits the potential energy stored in the spring 22 in the form of kinetic energy to the first and/or second carrier 18, 20 so that the second carrier 20 is accelerated and the first carrier 18 is decelerated.
[0081] As can be seen in FIG. 2D, after the transmission of the energy, the second carrier 20 is guided on the guide track 16 at a constant speed v, while the first carrier 18 continues to be decelerated or is at rest.
[0082] The control device 17 is in particular configured to determine the acceleration curve or braking curve of the second or first carrier 18, 20 attributable to the spring 22 and to adapt a control of the movement of the first and second carriers 18, 20 to that effect.
[0083] FIG. 3 shows a plan view of the linear motor system 10 in which loads 24 are transported by a respective two carriers 14. The first carrier 18 transports a load 24 together with a third carrier 23, while the second carrier 20, to which a spring 22 is fastened, transports a further load 24 together with a fourth carrier 25. In this respect, the carriers 14 transporting a common load are connected only by the load 24 that is fastened to the two carriers. Alternatively, two carriers 14 that jointly transport a load 24 may, for example, be connected via a connection element so that the two carriers 14 are connected to one another. For example, the two carriers 14 can be connected so that the two carriers 14 have a fixed spacing from one another. The first and third carriers 18, 23 move toward the second and fourth carriers 20, 25 at the speed v, wherein the first and third carriers 18, 23, when contacting the first carrier 18 and the spring 22 fastened to the second carrier 20, at least partly transmit energy, and in particular kinetic energy, to the second and fourth carriers 20, 25 via the spring and accelerate the second and fourth carriers 20, 25 while the first and third carriers 18, 23 are being decelerated.
[0084] FIG. 4 shows two acceleration curves of the second carrier, wherein the first acceleration curve 26 is attributable to an acceleration by the spring 22 (i.e. would occur if only the spring 22 were considered in the acceleration), while the second acceleration curve 28 is attributable to an acceleration by the control or control device 17 (i.e. would occur if only the acceleration caused by the electromagnets and controlled by the control device 17 were considered). The first acceleration curve 26, which is caused by the spring 22, has an approximately sinusoidal course and can, for example, be known, be determined by an iteration method by the control device 17, and/or be measured by means of sensors. The first acceleration curve 26 in particular depends on the properties of the spring 22 and on the speed and mass of the first and/or second carrier 18, 20. The second acceleration curve 28 corresponds to an acceleration acting on the second carrier 20 by the control device 17. As shown in FIG. 4, the second acceleration curve 28 has a triangular or trapezoidal course (indicated by a dashed line) to replicate and/or to approximate the sinusoidal acceleration course caused by the spring 22 as closely as possible. The second acceleration curve 28 or the acceleration produced on the second carrier 20 by the control device 17 is in particular adapted to the first acceleration curve 26. It is preferred that the acceleration curve 28 caused by the control deviates by at most 15 or 10% from the first acceleration curve 26 so that the control device 17 assists or at least does not reduce the acceleration of the second carrier 20 caused by the spring 22.
[0085] FIG. 5 shows an acceleration course of a carrier 14 and a current course corresponding to this acceleration course. The current course is in particular shown for an acceleration process 30 (left) of a carrier 14 and for a braking process 32 (right) of a carrier 14 with the use of a spring 22 as an energy transmission element and without the use of a spring 22. In this respect, it can be seen that the current course (graphs 2 and 4) of a carrier 14 is proportional to the acceleration course (graphs 1 and 3). It can also be seen that the required current for an acceleration process 30 of a carrier 14 with a spring 22 is less than in an acceleration process 30 without a spring 22. It is in particular shown in FIG. 5 that the maximum current value for an acceleration of a carrier 14 with a spring 22 is approximately 7 amperes (see acceleration process, graph 4) while the maximum current value for an acceleration without a spring 22 is 12 amperes (see acceleration process, graph 2). It can furthermore be seen that the required current is also smaller in the braking process 32 of the carrier 14 with a spring 22 than in the braking process 32 without a spring 22. In a braking process 32 of the carrier 14 with a spring 22, the magnitude of the maximum current value is approximately 6 amperes (see braking process, graph 2), while the magnitude of the maximum current value is 9 amperes in a braking process 32 of the carrier 14 without a spring 22 (see braking process, graph 4). Consequently, the current consumption of a linear motor system 10 comprising an energy transmission element such as a spring 22 is significantly lower than in the case of a linear motor system without a spring 22. Due to the lower current values, the demands on the system can further be reduced.
[0086] FIGS. 6A to 6C show different embodiments of the linear motor system 10. FIG. 6A shows a first carrier 18 and a second carrier 20 that are guided on a guide track 16, wherein the energy transmission element or the spring 22 is attached to the first carrier 18.
[0087] FIG. 6B shows an embodiment of the linear motor system 10 in which a first spring 34 and a second spring 36 are fastened to the second carrier 20, wherein the first spring 34 and the second spring 36 are arranged axially symmetrically to a center of mass line 21.
[0088] FIG. 6C shows an embodiment of the linear motor system 10 in which the first spring 34 is fastened to the first carrier 18 and the second spring 36 is fastened to the second carrier 20, wherein the springs 34, 36 are arranged such that they are axially symmetrical to the center of mass line 21 of the carriers 34, 36 during the contact with a carrier 34, 36.
REFERENCE NUMERAL LIST
[0089] 10 linear motor system [0090] 12 linear motors [0091] 14 carrier [0092] 16 guide track [0093] 17 control device [0094] 18 first carrier [0095] 19 active region [0096] 20 second carrier [0097] 21 center of mass line [0098] 22 spring [0099] 23 third carrier [0100] 24 load [0101] 25 fourth carrier [0102] 26 first acceleration curve [0103] 28 second acceleration curve [0104] 30 acceleration process [0105] 32 braking process [0106] 34 first spring [0107] 36 second spring
