Method and conveyor device for operating a long stator linear motor
阅读说明：本技术 用于运行长定子线性马达的方法和输送装置 (Method and conveyor device for operating a long stator linear motor ) 是由 S·胡贝尔 D·瓦尔特 B·莱晨瓦尔纳 于 2019-07-25 设计创作，主要内容包括：本发明涉及一种用于运行以长定子线性马达为形式的输送装置的方法,该输送装置具有输送路线,至少两个运输单元沿着该输送路线依次运动,其中,在两个运输单元运动时检查,在两个运输单元之间是否遵守预定的最小间距,以避免两个运输单元的碰撞,其中,要遵守的最小间距根据两个运输单元沿着输送路线的位置而改变,其特征在于,所述最小间距由两个运输单元沿着输送方向的延伸长度来确定,并且至少一个运输单元在弯曲的输送区段上的延伸长度根据位置和/或根据运输单元的尺寸加上位置分量。此外本发明涉及一种以长定子线性马达为形式的输送装置。(The invention relates to a method for operating a conveying device in the form of a long-stator linear motor, having a conveying path along which at least two conveying units are moved in succession, wherein, during the movement of the two conveying units, it is checked whether a predetermined minimum distance is observed between the two conveying units in order to avoid a collision of the two conveying units, wherein the minimum distance to be observed varies as a function of the position of the two conveying units along the conveying path, characterized in that the minimum distance is determined from the extent of the two conveying units in the conveying direction, and the extent of at least one conveying unit over a curved conveying section is added to a position component as a function of the position and/or as a function of the size of the conveying unit. The invention further relates to a conveying device in the form of a long stator linear motor.)
1. Method for operating a conveyor device (1) in the form of a long-stator linear motor, having a conveying line (2) along which at least two transport units (TEi, TEi +1) are moved in succession, wherein, during the movement of the two transport units (TEi, TEi +1), it is checked whether a predetermined minimum distance (M) is observed between the two transport units (TEi, TEi +1) in order to avoid a collision of the two transport units (TEi, TEi +1), wherein the minimum distance (M) to be observed varies depending on the position of the two transport units (TEi, TEi +1) along the conveying line (2), characterized in that the minimum distance (M) is determined from the extent of the two transport units (TEi, TEi +1) in the conveying direction (x) and is determined depending on the position of the transport unit and/or depending on the transport unit (TEi, TEi +1), The size of TEi +1) adds the position component (Δ li, Δ li +1) to the extent of at least one transport unit (TEi, TEi +1) on the curved transport section (FAk, FAk + 1).
2. Method according to claim 1, characterized in that the minimum spacing (M) to be observed varies according to the dimensions of the two transport units (TEi, TEi + 1).
3. Method according to claim 1 or 2, characterized in that for a previously driven transport unit (TEi), the maximum extension of the transport unit (TEi) against the conveying direction (x) is determined with respect to a Reference Point (RPi) of the transport unit (TEi); and for a transport unit (TEi +1) travelling behind, determining a maximum extension of the transport unit (TEi +1) in the conveying direction (x) with respect to a reference point (RPi +1) of the transport unit (TEi + 1); and the minimum distance (M) is determined as the sum of the two lengths of the run along and against the transport direction (x) and at least one position component (Deltali, Deltali + 1).
4. Method according to claim 3, characterized in that the minimum spacing (M) is determined as the sum of the respective half-lengths (li/2, (li +1)/2) of the two transport units (TEi, TEi +1) in the transport direction (x) and the at least one position component (Δ li, Δ li + 1).
5. Method according to any one of claims 3 to 4, characterized in that the position components (Δ li, Δ li +1) before and after the transport unit (TEi, TEi +1) seen in the conveying direction (x) are different.
6. Method according to claim 1 or 2, characterized in that for a transport unit (TEi, TEi +1) on a curved conveying section (FAk, FAk +1), a radial projection through the centre point of the circle of curvature of the conveying section (FAk, FAk +1) is used to determine the projection of the transport unit (TEi, TEi +1) along the conveying direction (x) onto the transport unit (TEi, TEi +1)An extension (e) on the reference track (RA)i、ei+1) And using the extension (e) of the projectioni、ei+1) To determine said minimum spacing (M).
7. Method according to one of claims 1 to 6, characterized in that, for the case in which two transport units (TEi, TEi +1) which are driven in succession are driven through a switch (W) with two transport sections (FAk, FAk +1), wherein each of the two transport units (TEi, TEi +1) is moved in the region of the switch (W) over the other transport section (FAk, FAk +1), the transport unit (TEi) on the respective transport section (FAk) is projected onto the respective other transport section (FAk +1), and the compliance with the minimum spacing (M) between the projected transport unit (TEi') and the other transport unit (TEi +1) is checked.
8. A method as claimed in claim 7, characterized in that the geometry of the switch points (W) is taken into account in the determination of the minimum spacing (M) in the region of the switch points (W).
9. Conveying device in the form of a long-stator linear motor, having a conveying path (2) along which at least two transport units (TEi, TEi +1) are moved in succession, and having a collision monitoring unit (7) which checks for compliance with a predetermined minimum distance (M) when the two transport units (TEi, TEi +1) are moved in order to avoid a collision of the two transport units (TEi, TEi +1), wherein the minimum distance (M) to be complied with can be changed in the collision monitoring unit (7) as a function of the position of the two transport units (TEi, TEi +1) along the conveying path (2), characterized in that provision is made that the minimum distance (M) is determined by the extent of the two transport units (TEi, TEi +1) in the conveying direction (x) and in a curved conveying section (FAk, TEi +1), FAk +1) is added to the position component (Deltali, Deltali +1) depending on the position of the transport unit and/or depending on the size of the transport unit (TEi, TEi + 1).
10. Conveyor device according to claim 9, characterized in that the minimum distance (M) to be observed can be varied in the collision monitoring unit (7) depending on the size of the two transport units (TEi, TEi + 1).
Technical Field
The invention relates to a method for operating a conveyor device in the form of a linear motor with a long stator, having a conveyor path along which at least two transport units are moved in succession, wherein, during the movement of the two transport units, it is checked whether a predetermined minimum distance between the two transport units is observed in order to avoid a collision of the two transport units, wherein the minimum distance to be observed varies depending on the position of the two transport units along the conveyor path, and to a corresponding conveyor device.
Background
Long stator linear motors are often used as flexible conveyors in manufacturing, machining, assembly and the like. Long-stator linear motors are known which essentially comprise a long stator in the form of a plurality of drive coils arranged one behind the other and a plurality of transport units with exciter magnets (permanent magnets or electromagnets) which are moved along the long stator in such a way that the drive coils are correspondingly charged with current in the region of the transport units. A moving magnetic field is generated by a drive coil, which interacts with an exciter magnet on the transport unit in order to move the transport unit. The long stator thus forms a transport path along which the transport unit can be moved. This makes it possible to adjust each transport unit individually and independently of one another in its movement (position, speed, acceleration). For this purpose, each drive coil required for the movement can be actuated by an associated drive coil actuator, which can obtain a predetermined value (for example in the form of a setpoint value for the position or the speed) for moving the transport unit from a higher-level device control unit. In this case, switches of the long-stator linear motor can also be arranged along the conveying path in order to move the transport unit over different transport sections connected by the switches. The long stator is often also constructed in the form of transport sections, wherein each transport section forms part of the transport path and contains a number of drive coils. Usually, a section adjuster is provided for the transport section, which adjusts all drive coils of the transport section, for example by means of a coil adjuster of the next stage of each drive coil. Almost any conveying path can also be formed, for example with straight, curved, closed tracks or the like. The structural design of the long-stator linear motor, i.e. the design of the drive coils, the feed path, the transport unit, the guide of the transport unit, etc., for example, and the adjustment concept can naturally vary, but the basic operating principle of the long-stator linear motor can also be kept unchanged.
The transport device in the form of a long stator linear motor can be very complex and also comprise a plurality of transport sections which can be connected to one another at short points via switches. On which a large number of transport units can also be moved simultaneously. Such a conveying device therefore has high requirements with regard to the control of the movement of the individual transport units. In particular, precautions must often be taken so that the individual transport units do not collide with one another during movement.
The necessity of collision avoidance devices is also known from other conveying devices. For example, JPH05303423A shows a conveyor with vehicles that move along a conveying path. The distance between two vehicles running in succession on a straight line is monitored by means of a distance sensor on the vehicle. In a curve, the sensors are arranged on the vehicle or on the route in order to ensure that a minimum distance is observed between two vehicles travelling in succession. This approach requires high hardware costs on the additional sensors.
US8, 863, 669B2 describes a conveying device, for example in the form of a long stator linear motor, having a control of the movement of the transport unit. The transport path is divided into a plurality of zones, wherein the transport units are controlled in a zone based on a setpoint value as a function of a setpoint value and in a zone based on a limit value by means of maximum values for the end position and for the speed and acceleration. In the limit-value-based control, these predetermined values are converted into a movement curve with which the transport unit is moved. US8, 863, 669B2 also mentions avoiding collision of the transport units, but there is no description of how this can be achieved.
EP3196719a2 describes that the length of the transport unit in the direction of movement can be extended against the direction of movement by a predetermined minimum collision avoidance distance. The further transport unit travelling behind this transport unit must then at least comply with the spacing such that it can be stopped by controlled braking before the length of the transport unit, which is extended by the collision avoidance distance. The collision avoidance distance is configured here.
In EP3202612a1 it is proactively checked for the transport unit whether a stopping operation with a predetermined kinematics can be carried out, so that a collision with the transport unit which has previously traveled on it can be avoided, and if not, the stopping operation is initiated. Here, the minimum distance that can be achieved after the stopping operation is performed may also be required, wherein the safety margin and also the dimension of the transport unit in the transport direction may be described.
Here, the minimum distance and the collision avoidance distance are both considered as parameters to be predetermined, without giving any indication as to how they are determined. However, in order to reliably avoid possible collisions, these variables are usually set conservatively. This, however, results in the fact that in most cases the transport units which are driven one after the other cannot be driven one after the other as close as possible. This of course also limits the number of transport units that can move along the transport route per time unit, which is disadvantageous in many transport applications.
Disclosure of Invention
The object of the invention is to provide a method with which collisions of transport units moving along the transport path of a long-stator linear motor can be avoided in a simple manner and in this case the minimum distance to be observed between two transport units traveling one behind the other can be optimized.
This object is achieved by the features of claim 1. In this case, it is possible to adapt the minimum spacing to the respective position of the transport unit. When at least one transport unit is moved over a curved transport section, a different minimum spacing can be used than in the case of two transport units which are moved over a straight transport section. It is also possible to react accordingly to transport sections with different curves, with different minimum spacings being used depending on the curve or even depending on the position of the transport unit in the curve. As a result, the smallest distance that is as optimal as possible can always be used between two transport units that are traveling one after the other, depending on the respective position along the transport path, whereby the overall throughput of the transport units along the transport path can also be increased.
In addition, the minimum distance to be observed can also be varied depending on the size of the two transport units, whereby the respective size of the transport units and also the components to be transported can also be taken into account.
In one embodiment of the invention, the minimum distance is determined from the extent of the two transport units in the conveying direction and a position component is added to the extent of at least one transport unit on the curved conveying section, depending on the position and/or depending on the size of the transport unit. This can advantageously be carried out by determining the maximum extent of the transport unit with respect to the reference point of the transport unit against the conveying direction for a transport unit traveling ahead and the maximum extent of the transport unit with respect to the reference point of the transport unit along the conveying direction for a transport unit traveling behind, and by determining the minimum distance as the sum of the two extents along and against the conveying direction and of the at least one position component.
When using the center point of the transport units as a reference point, the minimum distance can be determined in a simplified manner as the sum of half the extension of the two transport units in the conveying direction and at least one position component.
In order to be able to better take into account the local conditions of the transport section, the position components before and after the transport unit, as seen in the transport direction, can also be different.
A design according to the invention that can be realized in a simple manner provides that, for a transport unit on a curved transport section, the extent of the transport unit projected onto the reference track along the transport direction is determined by means of a radial projection through the center point of the circle of curvature of the transport section, and the minimum distance is determined by means of the projected extent. This can be done by simple arithmetic operations, which also enable the minimum spacing to be calculated continuously during operation of the conveyor.
In order to be able to avoid collisions even in the region of a switch using the method according to the invention, it is provided that, for the case in which two transport units traveling in succession travel through a switch having two conveyor sections, wherein each of the two transport units is moved in the region of the switch over the other conveyor section, the transport units on the respective conveyor section are projected onto the respective other conveyor section, and the adherence of the minimum distance between the projected transport unit and the other transport unit is checked. In this case, it is advantageous to additionally take into account the geometry of the switch points when determining the minimum distance in the switch area.
Drawings
The invention is explained in detail below with reference to fig. 1 to 6, which show exemplary, schematic and non-limiting embodiments of the invention. Wherein:
figure 1 is an embodiment of a conveyor in the form of a long stator linear motor,
figure 2 is a cross-section through a transport route and a transport unit,
figure 3 is a section of the conveying path of a conveyor with two transport units,
figure 4 shows the spacing between two transport units in a straight section,
figure 5 is the spacing between two transport units over a curved section,
fig. 6 shows a switch of a transport route with two transport units.
Detailed Description
Fig. 1 shows an example of an arbitrary configuration of a conveyor 1 having a conveyor path 2 (indicated by a dashed line). The conveyor device 1 is designed as a long stator linear motor and is provided with a plurality of transport units TEi,the transport unit is movable along a transport path 2. The transport path 2 is essentially predetermined by the stationary long stator of the long stator linear motor 1. In the illustrated embodiment a series of conveying sections FSj are provided,
Each conveying section FSj comprises a number n of drive coils ASj, n,
The basic operating principle of long stator linear motors is sufficiently known and will not be discussed further. It is also not essential to the invention how the transport unit TEi, the conveying section FSj, the drive coils ASj, n, the field magnets EMi, m, etc. are structurally configured and shaped, and therefore will not be discussed in detail here.
For controlling the movement of the individual transport units TEi, a transport unit control device 3 (hardware and/or software) is provided, in which a setpoint value S for the movement of the transport units TEi is generated or determined. It goes without saying that a plurality of transport unit adjustment devices 3 can likewise be provided, which are each associated with a part of the conveyor 1, for example the conveyor section FAk, and which control the movement of the transport unit TEi on this part. A section control unit 4 (hardware and/or software) can additionally be provided, which is assigned to the transport section FSj (or to one of the transport sections FSj or to a part of the transport section FSj) and which converts the setpoint values for the assigned transport unit control devices 3 of the transport units TEi into a coil current for the assigned drive coils ASj, n, i.e., into a specific control variable, such as a coil voltage. However, the segment adjusting unit 4 can also be embodied or integrated in the transport unit adjusting device 3.
The control variable can then be used in power electronics, not shown, in order to generate an electrical variable, for example a current or a voltage, and to apply it to the drive coils ASj, n. As a setpoint value S, for example, the position p of the transport unit TEi along the transport path 2 can be predefined, or likewise the speed v can be predefined. This means that a new setpoint value S is calculated or predefined in each time step of the adjustment for each transport unit TEi, which is adjusted by the section adjustment unit 4. A suitable regulator is therefore implemented in the segment control unit 4, which converts the target setpoint value into a suitable control variable, for example into a precursor force or a coil current, and then determines, for example, a coil voltage for the respective drive coil ASj, n from this control variable.
The desired movement of the transport units TEi along the transport path 2 can also be predetermined by means of the transport regulating device 5 (hardware and/or software), wherein, for example, route calculations (for example, which way should the transport unit TEi be taken?, switch selections (for example, which switch?can the transport unit TEi), deadlock avoidance (for example, are two transport units TEi locked to one another?) and the like are carried out in order to move the transport unit TEi along the transport path 2 in a desired manner, for example, in order to carry out manufacturing, assembly or other processes. This movement specification for the transport unit TEi is converted in the transport unit adjustment device 3 into a theoretical specification for the transport unit TEi. For this purpose, a predetermined movement profile, for example a travel time profile, or a predetermined target position or target speed, from which the movement profile can be calculated, can also be predetermined for the transport unit regulating device 3.
In the transport conveyor 5 or in the transport unit regulator 3, it is to be ensured that impermissible states do not occur on the transport path 2. This firstly involves avoiding collisions of the two transport units TEi on the transport path 2. For this purpose, a separate collision monitoring unit 7 (hardware and/or software) may also be provided, which may also be implemented or integrated in the transport conveyor 5 or the transport unit controller 3. In order to avoid collisions, a certain minimum distance M is maintained between two transport units TEi, TEi +1 traveling in succession. The minimum distance M to be observed has hitherto been configured simply to avoid collisions.
The transport unit TEi is designed, for example, as shown in fig. 2. Fig. 2 shows a cross section through any part of the transport path 2, which has transport sections FAk, FAk +1 on both sides and transport units TEi moving thereon. The transport unit TEi in the exemplary embodiment shown comprises a base body 12 and a component holder 13 arranged thereon for holding the component 6 to be transported, wherein the component holder 13 can in principle be arranged at any point on the base body 12, in particular also on the underside for suspended components. On the base body 12, preferably on both sides of the transport unit TEi, a number of excitation magnets EMi, m are provided. The transport path 2 of the transport device 1 or of the transport sections FAk, FAk +1 is formed by a stationary guide structure 10, on which drive coils ASj, n, ASj +1, n are arranged. The base body 12 with the permanent magnets arranged on both sides as excitation magnets EMi, m is arranged in the exemplary embodiment shown between the individual drive coils ASj, n, ASj +1, n. Thus, the respective at least one excitation magnet EMi, m of the drive coils ASj, n, ASj +1, n (or a group of drive coils) is arranged opposite and thus co-acts with the at least one drive coil ASj, n, ASj +1, n to generate the front driving force Fv. The transport unit TEi can thus be moved between the guide structure 10 together with the drive coils ASj, n, ASj +1, n and along the transport path 2. It goes without saying that other arrangements of the drive coils ASj, n, ASj +1, n and the excitation magnets EMi, m interacting therewith are also conceivable. For example, it is possible to arrange the drive coils ASj, n, ASj +1, n inside and the field magnets EMi, m pointing inward and surrounding the drive coils ASj, n, ASj +1, n. Likewise, the drive coils ASj, n, ASj +1, n may also be arranged on the guide structure 10 on only one side (viewed in the conveying direction x) of the conveying sections FAk, FAk + 1.
Guide elements 11 (not shown or only depicted here for reasons of clarity) such as rollers, wheels, sliding surfaces, magnets, etc., can of course also be provided on the base body 12 and/or on the component holder 13 in order to guide the transport unit TEi along the transport path 2. The guide elements 11 of the transport unit TEi interact here for guidance with the stationary guide structure 10, for example in such a way that the guide elements 11 are supported on the guide structure 10, slide or roll thereon, etc. The guidance of the transport unit TEi can, however, also be realized (alternatively or additionally) by providing a guidance magnet in addition to the mechanical guidance.
Fig. 3 shows a part of the transport path 2 of the transport device 1. Shown is an arbitrary conveying section FAk having conveying segments FSj-1, FSj +1, wherein conveying segment FSj +1 is curved and the other conveying segments are linear. A drive coil ASj, n is arranged in succession as described above on each conveying section FSj-1, FSj + 1. The adjusting units 3, 4, 5 are not shown for reasons of clarity. The conveying sections FSj-1, FSj +1, or generally the conveying section FAk, are arranged in a stationary manner. Along the conveying sections FSj-1, FSj +1, or generally along the conveying section FAk, the transport units TEi, TEi +1 are moved in sequence at a determined pitch a. The distance a is of course a predetermined reference path RA along the transport path 2 relative to the transport unit TEi, for example the center between two transport sections FAk, FAk +1, which are arranged next to one another as viewed in the transport direction x (as shown in fig. 4), or the center of the air gap between the drive coils ASj, n, ASj +1, n and the exciter magnet EMi, m, or the side of the transport sections FAk, FAk +1 facing the transport unit TEi (as shown in fig. 5), and is given as an arc length over the curved section. On the reference track RA, a predetermined setpoint position is preferably also set for the movement of the transport unit TEi.
When the transport unit TEi moves along a curved section of the conveying path 2, the self-rigid transport unit TEi is diverted by being guided over the curved section. The point Pi on the transport unit TEi therefore follows a trajectory Ti as the transport unit TEi moves along the conveying path 2, which trajectory substantially depends on the size and curvature of the transport unit TEi. The components 6 transported by means of the transport unit TEi are taken into account here. That is, the components 6 are considered as a part of the transport unit TEi, which parts may be dimensioned together (when the components 6 protrude beyond the transport unit TEi, for example along and/or transversely to the transport direction x). Different points Pi on the transport unit TEi can naturally lead to different trajectories Ti. However, due to the deflection, the distance a between the transport units TEi, more precisely the distance between the point Pi of the transport unit TEi and the point Pi +1 of the transport unit TEi +1 running behind it, may decrease.
In order to avoid a possible collision between the transport unit TEi running ahead and the following transport unit TEi +1 in this case, the minimum distance to be observed between the two transport units TEi, TEi +1 is changed, generally increased, according to the invention in order to compensate for the steering.
The same applies when the transport unit TEi traveling ahead moves on a straight section and the transport unit TEi +1 traveling behind it moves on a curved section. In this case, it is also possible to bring the two transport units TEi, TEi +1 closer together only due to the deflection of the transport unit TEi +1 on the curved section, so that without countermeasures it may be impossible to avoid a collision.
However, even when both transport units TEi, TEi +1 are moved over a curved section, it may happen that the two transport units TEi, TEi +1 are undesirably close due to the turning of one (or also both) transport unit TEi, TEi + 1. In this case, it may also happen that the two transport units TEi, TEi +1 are only moved closer by the steering, so that a collision may not be avoided without countermeasures.
According to the invention, the minimum distance M between two transport units TEi, TEi +1 traveling in succession is therefore dependent on the position along the transport path 2. In particular, for the case in which the two transport units TEi, TEi +1 are moved over the straight transport section FAk, a different minimum distance M is used than for the case in which at least one of the two transport units TEi, TEi +1 is moved over the curved transport section FAk. In this case, the minimum distance M to be maintained in the second case is generally greater than in the first case. The minimum distance M between two transport units TEi, TEi +1 traveling in succession can thus be changed dynamically during operation of the conveyor 1. The minimum distance M to be observed between the two transport units TEi, TEi +1 (both moving on a straight section) can therefore be smaller than the minimum distance M to be observed between the two transport units TEi, TEi +1 (at least one of which moves on a curved section), for example.
It is of course also possible here for the minimum spacing M to depend not only on the position of the two transport units TEi, TEi +1 along the transport path 2, but also on the size of the transport units TEi, TEi +1 (optionally also taking into account the transported components 6). Transport units TEi, TEi +1 having different lengths li, li +1 and/or different widths and shapes along the transport direction x can of course cause different deflections in the curved transport section FAk, which can also be taken into account in the minimum spacing M to be observed.
The adaptation of the minimum distance M can be carried out continuously, i.e. for example at each respective position of the transport units TEi, TEi +1 in each predetermined time step of the movement adjustment of the transport units TEi, TEi + 1. However, the adaptation can also be carried out discontinuously. The first minimum distance M can be considered when, for example, two transport units TEi, TEi +1 are moved in succession on the linear transport sections FAk, FAk + 1. A further minimum distance M can be considered when at least one of the transport units TEi, TEi +1 traveling in succession moves over the curved conveying section FAk.
Fig. 4 shows, for example, a straight section of the transport path 2, on which the two transport units TEi, TEi +1 are moved in succession in the transport direction x. The minimum spacing M is relative to a reference point RPi, RPi +1 on the transport unit TEi, TEi +1, for example relative to a centre point (as shown in fig. 4) or relative to a foremost or rearmost point (seen in the conveying direction x), or relative to any further point. Likewise, the spacing a between the two transport units TEi, TEi +1 is relative to the reference points RPi, RPi + 1. As a reference path RA, for example, the center between two adjacent conveying sections FAk, FAk +1, viewed transversely to the conveying direction x, is considered, which, however, is not significant in the case of a straight conveying section FAk.
It is assumed that the transport units TEi, TEi +1 extend from the reference points RPi, RPi +1 to different extents in the conveying direction x and against the conveying direction x, which can be expressed by a factor q. The minimum distance M (in the example shown) is therefore at least M ═ q in the usual manneri+1·li+1+(1-qi)·li]And the spacing a must include at least the minimum spacing M. The distance a can be determined here, for example, from the current actual position (or also the theoretical position) of the two transport units TEi, TEi +1 (which in turn is known with respect to the reference points RPi, RPi +1) which is known in the movement control. For example, the current actual position is detected by means of a position sensor.
If at least one transport unit TEi, TEi +1 is moved over the curved transport section FAk, the minimum spacing M for the straight sections is no longer necessarily sufficient, as will be explained with reference to fig. 5. In this case, the two transport units TEi, TEi +1 move over a curved transport section FAk (for example in the form of a circular arc). The arc length between the two transport units TEi, TEi +1 (with respect to the reference points RPi, RPi +1) on the reference track RA (in this case the side of the conveying section FAk) is taken as the spacing a. The distance a can in turn be determined from the actual position (or also the theoretical position). Due to the turning of the transport units TEi, TEi +1, the two transport units TEi, TEi +1 approach radially inward. It is thus possible for the two transport units TEi, TEi +1 to come into contact radially on the inside, depending on the size and/or the curvature of the conveying section FAk, although the distance a does not exceed the minimum distance M for a straight section. In this case, the minimum spacing M to be observed is therefore increased as a function of position (for example the curvature of the curve at a given position) and/or as a function of size.
In order to vary the minimum spacing M as a function of position, for example, each transport unit TEi can increase the position component Δ li to an extent li along the transport direction x (shown in fig. 3) at the respective end of the transport unit TEi (viewed along the transport direction x) as a function of its position along the transport path 2. The position component Δ li is added to at least the rear end for the transport unit TEi traveling ahead and to at least the front end for the transport unit TEi +1 traveling behind. When a plurality of transport units TEi, TEi +1 are driven in succession, the position component Δ li may also be added to the transport units TEi at both ends in some cases. The position component Δ li can also be different here before and after the transport unit TEi, as seen in the transport direction x. The position component Δ li may also depend on the size of the transport unit TEi.
The minimum distance M to be observed between the two transport units TEi, TEi +1 (at least one of which moves over the curved transport section FAk) can then be determined analogously to the minimum distance for a straight section from the two extensions li, li +1 along the transport direction x and the position components Δ li, Δ li +1 at the respective ends of the two transport units TEi, TEi +1, i.e., M ═ q [ (q ═ q { (q {)i+1·li+1+Δli+1)+((1-qi)·li+Δli)]. If the two transport units TEi, TEi +1 extend the same distance in the transport direction x and counter to the transport direction x with respect to the reference points RPi, RPi +1, the determination of the minimum spacing M is for example simplified to M ═ li/2+ Δ li + li +1/2+ Δ li + 1. For a transport unit TEi +1 on a straight section, the position component Δ li +1 before and after the transport unit TEi +1 may be 0. For the transport unit TEi on the curved section, a certain position component Δ li (which may also be equal) before and after the transport unit TEi is determined.
Since the dimensions of the transport units TEi, TEi +1 (optionally with the transported components 6) and the geometry of the transport path 2 are of course known, the turning of the transport units TEi, TEi +1 at different positions along the transport path 2 can be calculated simply, optionally also depending on the dimensions of the transport units TEi, TEi + 1. The required position components Δ li, Δ li +1 can thus be determined for the transport units TEi, TEi +1 at each desired position or only for different transport sections FAk (for example straight, curved transport sections). The position components Δ li, Δ li +1 can then be stored for each transport unit TEi, TEi +1, for example in the control device of the transport device 1, for example in the transport control device 5 or in the collision monitoring unit 7 (hardware and/or software), as a function of the position and optionally also as a function of the size of the transport unit TEi, TEi + 1. Since only a defined number of different transport units TEi, TEi +1 are present, it can of course be simplified if only the position components Δ li, Δ li +1 of the different transport units TEi, TEi +1 are stored and then only the correct position components Δ li, Δ li +1 have to be read, which can be easily achieved. Alternatively, a formula or a mathematical model can also be stored in the control device, in order to calculate the respective current position component Δ li, Δ li +1 from the respective position (for example from the current curvature) and optionally also from the size of the transport unit TEi.
However, it is also possible to check when two transport units TEi, TEi +1 traveling one after the other (at least one of which moves over the curved conveying section FAk) collide, for example according to a simulation of the movement of the transport units TEi, TEi +1 along the conveying path 2. From this, the minimum distance M or the position component Δ li, Δ li +1 to be observed can also be determined.
The transport units TEi, TEi +1 can also be modeled by simple two-dimensional objects which respectively enclose the outer contour of the transport units TEi, TEi +1 (optionally together with the component 6). This results in an elongation li, li +1 or may simplify the simulation of the movement. Advantageously, a rectangle with an extension along the transport direction x and an extension against the transport direction x can be used, wherein the rectangle completely encloses the shape of the transport unit TEi. But other geometric objects are also contemplated. The actual shape of the transport units TEi, TEi +1 (optionally together with the components 6) can likewise be used in order to determine or determine the minimum spacing M or the position components Δ li, Δ li + 1.
A particularly simple design which can be implemented is illustrated in fig. 5. The transport units TEi, TEi +1 are considered here as rectangular, wherein other shapes are also conceivable. On the transport units TEi, TEi +1 toward the points Pi, Pi +1 radially inside one another, a simple radial projection is projected through the center point of the circle of curvature of the curved conveying section FAk onto the reference track RA (circle of curvature with radius r). This results in the extension e of the transport unit TEi, TEi +1 tangential to the projection of the curve with the radius ri，ei+1. The extension of the projection is simply made of
When the curved conveying section FAk is to have a varying curvature, in the simplest case, for the above-described determination of the minimum spacing M by means of a radial projection, a circle or a part thereof having the largest radius of curvature at the curved conveying section FAk can simply be used.
If, viewed in the conveying direction x, conveying sections FAk, FAk +1 are to be provided on both sides in a curve, it may be sufficient to consider the conveying section FAk which is radially inside in order to determine the minimum distance M to be observed in this curve.
In the manner described above, it is also possible to check the compliance of the minimum distance M when the transport units TEi, TEi +1 travel through the switch W, as will be explained with reference to fig. 6. In the region of the switch W, two conveying sections FAk, FAk +1 are always provided, at least one of which is curved. The travel of the two transport units TEi, TEi +1 on the same curved conveying section FAk, FAk +1 thus corresponds to the embodiment according to fig. 3 or 5 and can be handled in a simple manner as described above, in that the minimum distance M to be observed is determined and checked as a function of the position and/or the size of the transport units TEi, TEi + 1.
As shown in fig. 6, the travel of the two transport units TEi, TEi +1 through the switch over the different transport sections FAk, FAk +1 can be realized in that one transport unit TEi on the transport section FAk is projected onto the respective other transport section FAk +1, for example in the crash monitoring unit 7. As a result, the projected transport unit TEi' virtually appears at the respective other transport section FAk +1, so that the adherence to the minimum distance M can again be checked. For this projection, for example, the distance Di of a transport unit TEi from the switch point B on the transport section FAk can be considered and this transport unit TEi is projected onto the other transport section FAk +1 at the same distance Di from the switch point B. The switch starting point B is, for example, the point at which the two conveying sections FAk, FAk +1 start to separate in the region of the switch. In the region of the switch W, however, the minimum spacing M is usually determined differently in this case.
When the two transport units TEi, TEi +1 are moved in the region of the switch W on different conveyor sections FAk, FAk +1, at least one transport unit TEi, TEi +1 may again be deflected as a result of the movement on the curved section. This deflection can result in a change in the spacing between the two transport units TEi, TEi + 1. However, this state is also dependent on the geometry of the switch W itself, i.e. on the arrangement and geometry (in particular the curvature) of the two conveying sections FAk, FAk +1 in the region of the switch W. For example, a switch W with a straight conveyor section FAk and a curved conveyor section FAk +1 has different requirements for the minimum distance M than a switch with two curved conveyor sections FAk, FAk + 1. The minimum distance M to be observed between the two transport units TEi, TEi +1, which is determined by the geometry of the switch points, can be determined computationally or by simulation (for example again in two dimensions, surrounding the transport units TEi, TEi +1, optionally together with the object of the component 6).
In order to avoid collisions in the region of the switch W, for a specific combination of the transport units TEi, TEi +1, it can then be considered that the largest minimum distance M of the two minimum distances M passing over the same transport section FAk, FAk +1 or over different transport sections FAk, FAk +1 is considered as the minimum distance M to be observed. Alternatively, however, it is also possible to distinguish between the two cases and to use a correspondingly suitable minimum distance M for the switch travel.
Of course, the minimum spacing M can additionally also be increased by a safety spacing, for example to take account of adjustment errors (position errors) or defined safety margins. Likewise, the safety distance may also have a portion that is dependent on the current speed and braking variables (e.g., the maximum possible delay) of the transport units TEi, TEi +1, in order to ensure that the transport unit TEi +1 traveling behind can optionally also be stopped without a collision before the transport unit TEi traveling ahead.
The minimum distance M and/or the position component Δ li, Δ li +1 can be predetermined for different positions or position regions along the transport path 2 and optionally also for pairs of different transport units TEi, TEi +1 (due to the size and/or the transported components 6) and stored in a memory in order to be read as required during operation of the transport device 1. Alternatively, the minimum distance M to be maintained may also be determined continuously during operation of the conveyor 1, for example in each time step of the movement regulation of the transport units TEi, TEi + 1.
In this case, it can be checked at each time step of the adjustment whether the minimum distance M to be observed is observed by a currently predefined adjustment setpoint value (e.g., setpoint position or setpoint speed). If the minimum spacing M is not observed, certain, configured processing may be performed. For example, the movement of one transport unit TEi, TEi +1 may be limited, for example, in such a way that it is not adjusted to a desired theoretical speed or position, or even that the transport unit TEi, TEi +1 is stopped.