System monitoring method and device in multi-carrier system and multi-carrier system

Abstract

A system monitoring method for use in a multi-carrier system comprising a track (2) along which a plurality of individually drivable electric drive elements (5) are arranged, and at least one carrier (1) which can be driven by said drive elements (5) along said track (2), preferably in any one of two track directions. The method comprises simultaneously driving a plurality of said drive elements (5) such that their driving forces exerted on the carrier (1) counteract one another, simultaneously driving said drive elements (5), observing an electrical quantity, preferably a voltage or a current, at one or more or all of said drive elements (5) with one or more current sensors (23), and evaluating the observed electrical quantity and drawing conclusions on the actuation of the drive element and / or the actuation of the sensor on the basis of the evaluation.

Description

Technical Field

[0001] The present invention relates to a system monitoring method and device in a multi-carrier system and a multi-carrier system. Background Art

[0002] Figure 1a and 1b A multi-vector system in which the present invention may be used is schematically shown. Figure 1a The system comprises a track 2 along which one or more carriers 1 can move. The track 2 is elongated and may have a length, for example, greater than 1 or 2 or 5 or 10 meters. The track may have straight and / or curved sections. It may be e.g. Figure 1a As an application field, again by way of example, one may assume a manufacturing site in which carriers travelling along a track 2 pass through various processing stations for carrying out specific steps.

[0003] The carriers are individually drivable in terms of position, velocity and acceleration. Preferably, they can move in two directions along the track, e.g. Figure 1a As shown by the arrows L / R in FIG.

[0004] The drive is electromagnetic. Each carrier 1 comprises magnetic means, which may be passive and may for example comprise a horseshoe magnet, the opposite ends of which point towards the track and away from each other in the direction of the track. Figure 1b This is schematically indicated by number 4.

[0005] The track 2 comprises a plurality of drive elements 5 arranged along its length, which drive elements 5 may comprise electromagnets. Each of them may be driven individually at least by switching a current source on and off, and the polarity and intensity may also be selected. The drive elements 5 may be arranged at regular intervals p along the track 2. For example, more than 20 or 30 or 40 drive elements 5 may be included per meter of track length. This results in a pitch p of less than 5 or 3.33 or 2.5 cm. The distance a of the pole ends of the horseshoe in the carrier 1 may be set relative to said pitch. It may be different from an integer multiple of the pitch.

[0006] Therefore, a large number of drive elements 5 need to be controlled, and in order to present it, a hierarchical control structure can be provided. For each drive element 5, it can include a coil controller with a switch 22 and a current sensor 23. A coil group controller 21 can be provided, each connected to a plurality of coil controllers, for feeding them with individual power supply control signals and receiving current measurement signals from them. The coil group controller 21 can form a unit 6 together with the controlled coil controller 6.

[0007] Overall current control may be provided by pulse width modulation with an appropriate pulse frequency and selectable duty cycle, set according to certain target values ​​to be met. One or more segment controllers 7 may be provided, each segment controller 7 connected to a plurality of coil group controllers 21. The segment controllers may send current target values ​​to the connected coil group controllers 21 and may collect current measurement information from the coil group controllers 21.

[0008] A system controller 8 may be provided and may be connected to one or more segment controllers 7. It may send control target values, such as target position, target velocity or target acceleration, to the segment controllers for each of the plurality of carriers 1. It collects measurement information of the current from them. Furthermore, carrier tracking is performed for the entire system to understand the position of the individual carriers 1 along the system track 2.

[0009] Such a system may be used extensively and may be subject to mechanical shocks from the vehicle body 1 during acceleration or deceleration or when turning. Mechanical shocks and other factors may lead to system failures. A system failure may be a disconnection of the power supply line between the drive element 5 and the coil controller (in particular the switch 22). It may also include a current sensor failure. It is of interest to detect such system failures as early as possible and preferably actively, rather than having to conclude from vehicle control difficulties that such a failure may exist. Short circuits are another possible failure. Summary of the invention

[0010] An object of the present invention is to provide a system monitoring method and apparatus with improved fault detection.

[0011] The above objects are achieved by the features of the independent claims.

[0012] A system monitoring method has the features of claim 1. The system monitoring method operates in a multi-carrier system having a track along which a plurality of individually drivable electric drive elements are arranged, and one or more carriers drivable along the track in one or two track directions. The system monitoring method comprises testingly driving a plurality of said drive elements simultaneously so that the drive forces they exert on the carriers cancel each other out, observing electrical quantities, preferably currents, at one or more or all of said drive elements during said driving, evaluating the observed electrical quantities, and drawing conclusions about the operation of the drive elements and / or the operation of the sensors based on said evaluation.

[0013] When a plurality of drive elements are driven simultaneously so that the drive forces they exert on the carrier cancel each other out, the drive forces are reduced together and may cancel out completely, so that their driving influence on the carrier is reduced or virtually non-existent.

[0014] The simultaneous actuation of the plurality of drive elements is preferably performed when all carriers are not moving. This may be a system state that is explicitly set for monitoring, or it may be a state that would occur anyway, for example before regular operation begins at system startup. When the simultaneous actuation is performed during system stoppage, it is not superimposed on other system activities, nor is it disturbed by them. Furthermore, if motion or carrier displacement is still detected, this can be attributed to the test simultaneous actuation and can be further evaluated.

[0015] Thus, when the drive element is driven, a dynamic quantity of at least one carrier along the track can also be observed. The observed electrical quantity and the observed dynamic quantity can then be jointly evaluated. Based on the joint evaluation, conclusions can be drawn about the operation of the drive element and / or the operation of the sensor. The dynamic quantity can be a velocity value or a displacement value of the carrier along the track.

[0016] As previously mentioned, the multi-carrier system has a carrier tracking device for tracking the position of each carrier in real time as a dynamic quantity, and possibly other dynamic quantities such as velocity and acceleration. Tracking can be performed on each carrier, and the tracking can be or include position and / or velocity detection of each carrier. For example, it can include using detection signals from passing detectors arranged along the track, possibly in combination with some or all drive elements, interpolating the detected positions based on known carrier velocity curves and time lapse, evaluating the electromagnetic response of the drive elements 5 to the presence of the carrier 1, and possibly other techniques. The accuracy of the carrier position along the track can be better than the spacing of the drive elements 5, or better than 2 or 1 cm or 2 or 1 mm. The carrier velocity v can be obtained by calculation as the derivative of the carrier position with respect to time.

[0017] If during or after the test simultaneous drive, the change in the dynamic quantity is different from the change expected in response to the test simultaneous drive, this indicates that something is contrary to the assumption. This may be a faulty power supply to one of the drive elements, so that the forces applied to the carrier are not balanced as assumed, or this may be a tracking error. Vice versa, if the dynamics are as expected, but the observation of the electrical quantity indicates a fault, this may be an indication of an error in the current detection. In summary, more generally, dynamic quantity detection can be used for cross-checking with electrical quantity detection for more detailed system analysis.

[0018] A plurality of drive elements may be driven simultaneously for testing so that the total force exerted on the carrier by the driven drive elements in the direction of the track is less than an absolute or relative threshold value. The absolute threshold value may be a force value of 0.2 or 0.1 or 0.05 or 0.02 N. The relative threshold value may be 10% or 5% or 2% or 1% or 0.5% of the total amount of all forces exerted on the carrier, or may be 2% or 1% or 0.5% or 0.2% of the weight of the empty carrier 1.

[0019] Preferably, the forces acting on the carrier during the simultaneous test drive are small and, in the best case, completely cancel each other out. Numerically, this can be expressed as a fraction of the total force on the carrier in the track direction being smaller than the sum of all forces.

[0020] The driving of the driving element may be or include the generation or supply or reception or setting of a current target value or a driving pulse signal of the driving element, or may be or include turning on and off the power supply of the driving element, and may be performed using a PWM device component.

[0021] Therefore, the test simultaneous driving may involve any of a number of activities in the PWM structure from target value setting to switching. Vice versa, the test simultaneous driving does not require strict simultaneous switching of switches, etc.

[0022] The multi-carrier system may be designed such that, if driven simultaneously, the resultant force in the direction of the track exerted on the carrier by all drive elements of the system is independent of the carrier position along the track less than an absolute or relative threshold. The absolute threshold may be a force value of 0.2 or 0.1 or 0.05 or 0.02 N. The relative threshold may be 10% or 5% or 2% or 1% or 0.5% of the total amount of all forces exerted on the carrier, or may be 2% or 1% or 0.5% or 0.2% of the weight of the unladen carrier 1. Simultaneous driving comprises driving all drive elements of the system simultaneously.

[0023] In fact, an inherent property of many multi-carrier systems is that when all drive elements are driven simultaneously with the same polarity and the same amount, the carrier "encounters" a magnetic field distribution along the track that is more or less uniform, without gradients in one or the other track direction, so that although magnetic forces are present in all drive elements, they actually cancel and therefore do not move the carrier. In these systems, a test simultaneous drive can be such that all drive elements of the system are driven simultaneously with the same polarity and the same intensity. Again, this can be done in terms of PWM quantities and can be, for example, to provide the same current target value to all control structures of all drive elements at the same time.

[0024] Observing the electrical quantity may be or include observing a plurality of individual quantities of a plurality of corresponding individual drive elements. The observation of the plurality of quantities may be performed simultaneously, or in a time series, or in groups. The observation of the electrical quantity may be to check whether the instantaneous current value exceeds a threshold value, preferably within a defined observation time window, or may be a measurement of an average value, and a comparison thereof with a threshold value.

[0025] Preferably, electrical quantities such as current are obtained for each individual drive element. Preferably, they are obtained simultaneously if the hardware allows. This may include obtaining the information in an identifiable and assignable manner, meaning that the observation information is assigned or assignable to a certain drive element.

[0026] In many embodiments, the exact current value may be irrelevant. The observation may then be a check whether the current value (e.g. the instantaneous current value) or a related value exceeds a suitably defined threshold, and the observation is simply "yes" or "no" in conjunction with the identifier of the drive element associated with the observation. In addition to the instantaneous current value, other current values ​​may be monitored, and threshold comparisons may be performed, such as the average current value during a test simultaneous drive after the steady-state current is established. The threshold check and mean value calculation may be performed on the analog side using an operational amplifier and possibly a low-pass filter. But it may also be performed on the digital side after A / D conversion of the instantaneous value. The observations associated with a single drive element may ultimately be presented in a digital format including the identifier of the corresponding drive element.

[0027] Instead of driving all drive elements simultaneously for a test purpose, the method may comprise the step of selecting a plurality of drive elements to drive for monitoring purposes, selecting them so that when driven simultaneously, the resultant force in the direction of the track exerted by the selected drive elements on the carrier, taking into account the position of the carrier along the track, is less than an absolute or relative threshold value. The absolute threshold value may be a force value of 0.2 or 0.1 or 0.05 or 0.02 N. The relative threshold value may be 10% or 5% or 2% or 1% or 0.5% of the total amount of all forces exerted on the carrier, or may be 2% or 1% or 0.5% or 0.2% of the weight of the unladen carrier 1. This selection may be performed by calculation and may comprise setting individual current target values ​​Id* for a plurality of drive elements 5 with different indices i. i The selection may be made with reference to the known relative position of the respective carrier 1 with respect to all drive elements 5. The simultaneous drive may comprise that different drive elements receive different drive signals with the aim of generating reaction forces in the track direction and balancing their sum in the track direction below the mentioned threshold.

[0028] A system monitoring device that functions in a multi-carrier system, the multi-carrier system having a track and at least one carrier, along which a plurality of individually drivable electric drive elements are arranged, the carrier being drivable by the drive elements along the track in one or two track directions. The system monitoring device comprises: a drive device for driving a plurality of the drive elements simultaneously so that their drive forces on the carrier cancel each other out; an observation device for observing electrical quantities, preferably voltages or currents, at one or more or all of the drive elements while driving the drive elements; and an evaluation device for evaluating the observed electrical quantities and drawing conclusions about the operation of the drive elements and / or the operation of the sensors based on the evaluation. The drive device can be configured to drive all drive elements of the system simultaneously or to make a suitable force balance selection from them.

[0029] As a practical implementation, the monitoring device can be implemented together with the overall control structure of the multi-carrier system. Assuming that the important parts of the control structure are computer-implemented, this also applies to the monitoring device components. They can make use of the conventional drive hardware for the drive elements, in particular the PWM structure that may be provided. The monitoring activity can then be a special operating mode of the overall control structure, in which the provided hardware is used in a way that is different from the conventional drive mode. The modifications for presenting the monitoring device can be mainly on the digital and software implementation side of the control structure, and can activate the call of specific monitoring routines, which are then run instead of the routines usually used.

[0030] The device may also comprise means for observing a dynamic quantity (preferably position or velocity) of one or more or all carriers along said track.The evaluation means are then configured to jointly evaluate the electrical quantity and the dynamic quantity.

[0031] Dynamic quantity observation can utilize the conventional carrier tracking structure of global control. It can be configured to check whether the carrier has moved during the test simultaneous drive. It can be a query on whether the carrier has moved and / or obtained speed, and the answer to the query can be used for evaluation. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Hereinafter, features of the present invention are explained with reference to the accompanying drawings.

[0033] Figure 1a is a schematic multi-carrier system representation,

[0034] Figure 1b is a detailed view of the carrier 1 on the track member 2,

[0035] Figure 2a is a detailed schematic diagram of the drive elements and control structure components.

[0036] Figure 2bshows the possible signal flow in the control structure,

[0037] Figure 3a The magnetic related facilities in the carrier and the track are shown,

[0038] Figure 3b shows the resultant magnetic field that the carrier may experience,

[0039] Figure 3c shows the field properties,

[0040] Figure 4a is a representation of an example of the test current target value changing over time,

[0041] Figure 4b is a representation of the PWM voltage pulses, currents, and thresholds, and

[0042] Figure 5 The overall approach to system monitoring is shown. DETAILED DESCRIPTION

[0043] This has been explained to some extent Figure 1a and 1b .

[0044] Figure 1b The carrier 1 is schematically shown on a portion of a track 2. It may have some kind of wheels 3 with which it can roll along the track 2, which is Figure 1b The driving of the carrier 1 along the track 2 can be performed in one track direction, for example Figure 1b In the left direction, or in both directions, Figure 1b Left and right, and right-left.

[0045] For the track 2, schematically shown is a row of drive elements 5. The row has said drive elements 5 which are more or less juxtaposed and arranged in the track direction.

[0046] As mentioned above, more than 20 or 30 or 40 drive elements 5 can be set per meter of track length, and the drive element spacing p is less than 5 or 3.33 or 2.5cm. Each drive element 5 has its own controllable power supply. In addition, the polarity of the power supply is controllable. Figure 2 shows this in more detail. It is assumed that some groups of drive elements 5 can be driven by a coil group controller 21. In actual implementation, the number of drive elements in such a group is 3. But it can also be 2 or 4 or 5 or 6 or more. The coil controller of each coil includes a switch 22 for switching the electromagnetic coil of the corresponding drive element 5. The switch can be a semiconductor switch, such as a FET, IGBT, etc. The switch is connected to the corresponding coil 24 of the corresponding electromagnet via a wire 28. The coil 24 is wound on a magnetic core 25. For clarity, Figures 1 and 2 only show one switch wiring, while omitting the other and the common power supply, etc.

[0047] Likewise, each coil controller may include a measuring sensor for measuring the current of the corresponding coil. The measuring sensor may be an inductive tap, or may include a small-sized measuring resistor, such as a shunt, which generates a certain voltage drop when current passes through. FIG. 2 shows a control block 6g for a group of drive elements 5g1, 5g2, and 5g3, the control block 6g comprising a coil group controller 21 for the group and a coil controller for the group of electromagnets, in particular switches 22-1, 22-2, and 24-3 connected to the corresponding electromagnets 24-1, 24-2, and 24-3, which are wound around the cores 25-1, 25-2, and 25-3, and are connected by wires 28-1, 28-2, and 28-3. The current sensors are shown as 23-1, 23-2, and 23-3.

[0048] The coil group controller 21 outputs control signals to the various switches 21 and receives inputs from the various current sensors 23. The coil group controller 21 may be or include digital components and may include suitable D / A and A / D conversion elements at the interface to the coil controllers. As required, the coil group controller 21 may have suitable multiplexing capabilities for processing signals to and from or for the various coil controllers on the output side and / or the input side.

[0049] In addition, the coil group controller can have a recorded ID for identifying the monitoring results it sends elsewhere. The coil group controller 21 can add to the ID the identification of the individual drive element 5 from which the corresponding results are obtained. The coil group controller 21 can also have the ID optically readable attached, for example as a bar code or QR code or alphanumeric, so that it can be easily identified for maintenance.

[0050] The drive elements 5 each include an electromagnet 24, 25, which includes a respective core 25 around which a respective coil 24 is wound. Thus, it constitutes an elongated electromagnet, the length direction of which points upward from the track 2 to the carrier 1. A plurality of electromagnets 24, 25 of a plurality of drive elements 5 can be arranged closely juxtaposed to each other along the track direction, such as Figure 1b Shown and Figure 2a If the polarity of the power supply is not controllable, the arrangement may be such that when powered, all electromagnets 24, 25 show the same polarity towards the track, for example the N pole.

[0051] The coil group controller 21 can be arranged close to the respectively controlled drive element 5. The distance to each connected drive element 5 can be shorter than 20 or 10 cm. The coil group controller 21 can be provided as a unit 6 together with the switch and measuring facilities for the corresponding drive element. But similarly, the switch 22 and the measuring facilities (e.g. current sensor 23) can be constructed separately therefrom and can be constructed as a unit with the corresponding drive element 5.

[0052] Figure 2a Also shown is a segment controller 7 connected to the coil group controller 21. It is also functionally connected to other coil group controllers 21 along the track of the coil group controller 21 shown. The number of coil group controllers 21 connected to the segment controller 7 can be 2 or 3 or more than 3 or more than 5 or more than 10. It can be less than 50 or less than 20. The segment controller 7 can be a digital structure with digital communication capabilities toward the coil group controller 21 and toward the system controller 8. The segment controller 7 can also have an embedded ID for distinguishing it from other segment controllers 7. The segment controlled by the segment controller 7 can be a physically separable unit of the track 2. This segment can be physically and logically connected to other segments to form the entire track. The segment can form a track length of, for example, more than 20 or 50 or 100cm. It may be shorter than 200 or 150 or 100cm.

[0053] like Figure 1b As shown, the whole system may include a plurality of segment controllers 7 of the same nature communicating with a system controller 8. The system controller 8 may be a digital component, such as a microcomputer. It has knowledge about the system, in particular knowledge about the terrain and the control structure. It may also perform vehicle tracking of the vehicles 1 set along the track 2. It is able to send forward instructions and receive feedback information, such as observations. The system controller 8 itself may be connected to other components, possibly via a network. The system controller 8 may be connected to 1, 2, 3 or more than 3 or more than 5 or more than 10 segment controllers 7. It may be connected to less than 200 or 150 or 100 or 50 segment controllers 7.

[0054] Figure 2b The possibilities of signal flow in the control structure when system monitoring activities are carried out are shown. In the described hierarchy, only one of the possible multiple downstream connection components is shown respectively.

[0055] The start of monitoring activities may be decided by the system controller, for example periodically or at the start of system operation or at a user command, etc. Once it is decided to carry out monitoring activities, it may first be determined that all carriers are stationary at zero speed, if this is not the case. Then, test mode information may be sent from the downstream system controller 8 to the connected segment controllers 7, possibly together with a certain DC target value Id* for all segment controllers 7.

[0056] The segment controller 7 knowing that a test is to be performed can forward the current target value Id* to the connected group controller, or can create a suitable duty cycle command in the PWM control to meet the indicated DC target value Id*, and can send the duty cycle command again to the connected group controller together with the information that the test is to be performed.

[0057] If the group controllers 21 receive the current target value Id* from the segment controllers 7, they can determine the duty cycle and can implement this duty cycle by generating corresponding pulse sequences for all connected switches 22, or just implement the received duty cycle command by generating corresponding pulse sequences for all connected switches 22 of the connected drive elements 5. The relationship between the current target value Id* and the duty cycle can be a fixed feature, implemented by a formula to be calculated or a table to be accessed.

[0058] The current target value Id* and the synthetic duty cycle value are selected to call up a measurable current value in the possibly coarse and / or slow current sensor 23. The values ​​of the current target value Id* and / or the synthetic duty cycle may be greater than 0.2% or 0.5% of the possible maximum value, respectively. They may be lower than 20% or 10% or 5% or 2% of the maximum value.

[0059] The current target value Id* and / or the corresponding duty cycle of the PWM for the test simultaneous drive can be fixedly set or recorded in the system, or can be variably set automatically or manually as needed. The current generated in the test simultaneous drive can be adjusted with feedback control in closed-loop control or without feedback control in open-loop control. The latter has the advantage of simplicity, and for test purposes, the possible PWM duty cycle can be set directly without the need for the current target value Id*. The former has the advantage of accuracy, because the inaccuracy of the inductance, resistance, etc. in the system is eliminated by the control loop.

[0060] Electrical quantities, in particular the currents through the corresponding wires 28 to the corresponding electromagnets 24, can be monitored in a suitable manner by means of the corresponding current sensors 23 and the monitoring transmitted to the corresponding group controllers 21. These can be analog signals. In a suitable manner, they can be processed in the group controller, for example by threshold value comparison and produce corresponding inspection results and information about the corresponding drive elements 5, which are obtained from the corresponding drive elements 5. The group controller 21 can collect such inspection results from a plurality of connected drive elements 5 and can feed them back to the segment controller 7 together with its own ID ID21 for identifying the source of the information. In addition, certain tracking information can be forwarded here in a conventional manner to allow carrier tracking if necessary during the monitoring test.

[0061] For each carrier, tracking the carrier position can include one or more tracking detection signals from bypass detectors arranged along the track (for example, by position magnets attached to the carrier, which are detected by Hall sensors arranged along the track / guide rail), possibly in combination with some or all drive elements, interpolating the detected position based on a known carrier velocity profile and time lapse, and evaluating the electromagnetic response of the drive elements 5 to the presence of the carrier 5.

[0062] The segment controller 7 aggregates the results from a plurality of connected group controllers 21, may evaluate them, may add its own ID ID7 to the aggregated results and the resulting evaluation, and forwards it, possibly together with carrier tracking information, to the system controller 8. The system controller 8 then has the results from all drive elements 5 in the system, in particular observations of electrical quantities at said drive elements, and possibly also from conventional tracking information about the position of the carrier 1. This information may then be evaluated in the system controller 8.

[0063] It should be noted that the hierarchy does not have to be as shown in Figures 1 and 2. Both stages can be combined into one device. Figure 2b The communications between the various components shown in the hierarchical downward and upward directions may follow known protocols not described here. They may involve field bus protocols and / or network protocols. They may be analog and / or digital.

[0064] Figures 3a to 3c Electromagnetic relationships that can be used to perform the monitoring activities described above are shown. Figure 3aThe geometry in the track 2 and the carrier 1 is shown. The cores 25 of the multiple electromagnets of the drive element 5 are preferably juxtaposed at a regular pitch p. The carrier 1 itself has a magnetic facility 4 therein. It can be passive and can be the horseshoe magnet already mentioned. It can be assembled from single magnets 41, 42 of opposite orientation, which are away from each other in the track direction and connected to a yoke 43. The magnetic facility 4 in the carrier 1, in particular the lower surface of the horseshoe magnet, can have a distance d from the top surface of the core 25 of the electromagnet of the drive element 5. The horseshoe magnet 4 in the carrier 1 can have an opening in the track direction along the center of the pole. The distance a can be different from an integer multiple of the pitch p. This has the effect that the magnetic properties of each core 25 are not necessarily added at the carrier 1.

[0065] Figure 3b The magnetic field generated when the electromagnets of the drive elements are all driven simultaneously in the same way is shown. It is assumed that they receive all the same target value Id* for establishing the corresponding current through the corresponding coil 24. Then all electromagnets can, for example, present an N pole facing the carrier 1, and the carrier 1 experiences a practically uniform or consistent N pole from multiple electromagnets. The fields from multiple drive elements 5 are superimposed, so that the disturbance ΔB in the magnetic field B experienced by the carrier 1 is relatively low and almost zero, which also leads to a magnetic field gradient dB / dx in the track direction that is low to almost zero. In terms of force, the multiple magnetic forces exerted on the carrier by the multiple electromagnets cancel each other and add up to a low value or almost zero value.

[0066] Numerically, the cancellation can be expressed as the sum S(Fi) of all forces Fi acting on the carrier in the track direction. The forces Fi in the track direction are vectors with a sign of + or -. In order not to cause the carrier to move during the test drive, their sum should be low, e.g.

[0067] S(Fi) <Fth

[0068] Where Fth is a threshold force, for example 0.5 or 0.2 or 0.1 or 0.05 or 0.02 or 0.01 N. Similarly, the ratio r of the sum S(Fi) of all reaction forces Fi acting on the carrier 1 in the track direction to the sum S(|Fi|) of all forces Fi in the track direction can be considered. The magnitude of the force |Fi| is removed and is positive. The ratio r should be low, for example

[0069] r=S(Fi) / S(|Fi|) <rth

[0070] Where rth is a threshold ratio, such as 0.1 or 0.05 or 0.02 or 0.01 or 0.005. Alternatively, the offset can be expressed as a fraction of the total sum S(Fi) of all forces Fi in the track direction as the weight Fc of the unladen vehicle. The fraction should be so low that it hardly causes acceleration, for example

[0071] S(Fi) <f*Fc

[0072] Where f is 0.02 or 0.01 or 0.005 or 0.002.

[0073] As long as the switching of the various drive elements is not strictly simultaneous, short-term force imbalances occur. They average out in value over time and have a time constant in the range of the PWM switching frequency and are therefore much shorter than the time constant of the sluggish carrier 1 experiencing the imbalance, so that they do not lead to an acceleration of the carrier.

[0074] The overall effect is that, as long as the system is operating normally, the carrier 1 is not actually subject to any resultant driving force in the direction of the track, and the test simultaneous driving of all driving elements 5 for monitoring purposes will not change the position of the carrier 1 along the track and therefore will not interfere with normal use unless interruption time is required to perform monitoring activities.

[0075] Figure 3b A low magnetic disturbance ΔB is shown, where the solid line is above the top of the magnet. If one of the electromagnets 25 is faulty and, for example, receives no current, it will not generate a magnetic field. For example, if Figure 3b If magnet 25f is faulty and receives no current, the resulting overall magnetic field is less uniform and a significantly larger disturbance ΔBf will occur. Figure 3b Such a resultant magnetic field B is shown hatched. Most likely, this will have an effect on the nearby carrier, since, contrary to the previous situation, it will be subject to some driving force and will move. Such a movement during the test simultaneous drive may therefore indicate some error in the drive of the drive element 5. Carrier tracking as previously described will reveal such an error and can also be used as described further below.

[0076] Figure 3a The width w of the core 25 of the electromagnet in the track direction, the pitch p of the drive elements 5 and the distance d between the track 2 and the magnetic core surface of the carrier 1 are shown. Structural features that help to obtain the desired uniform magnetic field along the track direction during test simultaneous driving are that the width w may be greater than 20% or 30% or 40% or 50% of the pitch p between the cores 25, and / or the ratio d / p of the distance d to the drive element pitch p may be greater than 0.005 or 0.01. It may be lower than 0.1 or 0.05.

[0077] Figure 3c shows the distribution of the magnetic field B along the track direction x. Figure 3b , when all drive elements 5 are driven equally and simultaneously for testing, the magnetic field B varies with a disturbance in a range ΔB around a median or mean value Bm. The overall design may be such that, in correct operation, the ratio of the disturbance range ΔB measured and thus experienced on the underside of the carrier to the median or mean value Bm is less than a variance threshold vth, i.e.

[0078] ΔB / Bm <vth

[0079] vth is less than 0.2 or 0.1 or 0.05 or 0.02. This is achieved by the described mechanical design, but can also be achieved by other measures and kits for implementing the invention.

[0080] Figure 4a An example of the current target value Id* for the test simultaneous drive is shown. The duration of the test simultaneous drive is at the start time T S and end time T E The time interval may be relatively short in general and may last less than 200 or 100 or 50 ms. The current target value Id*(t) may be the start time T S and end time T E Constant value between Id* 0 , or may have a start time T S The rising slope between time T1, T2 and the end time T E The falling slope between T1 and T2 and the constant value Id* 0 ,like Figure 4a The constant value can be a fraction of the maximum possible system current. It is chosen based on the measurement requirements, the power supply requirements and the desire to minimize the impact on the carrier. The same applies to the duration of the test drive.

[0081] Figure 4a Also shown symbolically are individual PWM pulses Pi, which can be used to adjust the current target value Id* as a time average. As previously mentioned, the electromagnet can be driven with pulse width modulation (PWM) to switch on / off the individual control transistors constituting the switch 22, which results in resultant instantaneous and average current and voltage values ​​according to common considerations and physical laws.

[0082] Figure 4bTwo consecutive pulses Pn and Pn+1 along the time line t are shown in the upper figure, and the resultant current Id is shown in the lower figure. Given the case where the L / R time constant of the electromagnetic drive system of the drive element 5 having a total effective inductance L and a total effective resistance R (e.g., greater than 0.5 or 1 ms, such as 3 ms) is significantly longer than the PWM pulse cycle duration tp (e.g., less than 200 or 100 μs, such as 17 μs). Within this range, L / R>n*tp is applicable to the case where n is 10 or 20 or 50 or 100. Then, in normal operation, the actual current Id never reaches a constant value. Instead, it fluctuates around the target value Id*.

[0083] According to the current target value Id*, the pulse has a specific duration ti relative to the pulse period tp, the ratio ti / tp is called the duty cycle. The pulse frequency can be greater than 1 or 10 or 20kHz, for example 60kHz. Correspondingly, the pulse period tp is less than 1ms or 100μs or 50μs. According to the duty cycle, the pulse duration ti is a part of it.

[0084] In the case shown, the current evaluation can be performed relative to a lower current threshold Ith and / or a higher second current threshold Isth. They can be selected so that in normal operation, i.e. without line braking, without short circuit, the actual current Id fluctuates between the two thresholds without passing one of them. Vice versa, when one of them is passed, it may be an indication of a fault, i.e. line braking in the case of a current drop below the lower threshold Ith, or a short circuit in the case of a current exceeding the second threshold Isth.

[0085] In cases other than those shown, the timing of measurements and / or threshold checks for monitoring purposes can be synchronized at the PWM pulses or PWM pulse pauses. If within a meaningful measurable range, they can be synchronized at the on-time of the corresponding current drive for measurement at the rising edge, or at the off-time of the corresponding current drive for measurement at the falling edge, depending on the time constant. The measurement time and / or threshold check or current range check can be at or near the middle of each pulse or pulse pause.

[0086] The above-mentioned current measurement or evaluation and the threshold value check may constitute said observation of electrical quantities for checking whether the wiring towards the respective drive element 5 and possibly more generally the overall drive thereof is correct.

[0087] Noise and dynamic effects may lead to temporary or transient atypical values. In order to reduce their influence, a plurality of individual measured values ​​or threshold decisions may be averaged, for example at a plurality of pulses Pi. More than 1 or 2 or 5 measurements / decision may be averaged. Fewer than 50 or 20 or 10 may be taken. An average or majority determination may be used. This may be done in the respective drive element 5 or in the respective group controller 21 or in the respective segment controller 7 and may be done in each case. Figure 2b Report upward in layers.

[0088] The possibility of evaluating the above observations of electrical quantities is that if the measured current or its average value or majority vote meets the expectations, for example exceeds the threshold value Ith, then a correct connectivity is decided, otherwise an error is decided. This approach is suitable for many cases. For current evaluation, it is also possible to check whether the measured current is within the expected range around the expected current Ie, for example Ie plus or minus 30% or 20% or 10% or 5% of Ie.

[0089] The current measurement can always be performed at or near the middle timing of the PWM voltage pulse, such as at the middle timing of the pulse at the rising edge plus or minus 10% or 5% or 2% of the pulse duration, or at or near the middle timing of the pulse pause between two adjacent PWM voltage pulses, such as at the middle timing of the pulse pause at the falling edge plus or minus 10% or 5% or 2% of the pulse pause duration. In these cases, the measured current is approximately equal to the average current within the PWM pulse, and may also be equal to the average current within the pulse pause, depending on the time constant.

[0090] Figure 5 An overall view of the entire monitoring method is shown. The start can be commanded by the user, or periodically, or for example at certain system states such as system startup or system shutdown. After the start, if the system state at which the monitoring started does not yet give a quiescent state, all carriers 1 can be quiescent in step 51.

[0091] Then, in step 52, a test simultaneous driving of all or a plurality of selected drive elements 5 follows. During said driving, in step 53, at least an electrical quantity is acquired. It can be the current flowing in the coil 24 of the electromagnet or the result of the threshold comparison as described above. In particular, the currents of all simultaneously driven drive elements 5 and the coils 24 therein can be acquired. Likewise, dynamic information of the carrier 1, such as their position, can be acquired in a conventional manner.

[0092] The acquired quantities are evaluated in step 54. These may be threshold checks as explained above.

[0093] In step 55, the evaluation results are stored or output or sent over a network somewhere, or an alarm is generated and output / sent.

[0094] As previously described, the test simultaneous drive in step 52 can cause all system drive elements 5 to be driven simultaneously with the same current target value Id*. However, the drive elements 5 to be driven simultaneously can be selected, rather than driving all drive elements 5 of the system simultaneously. A "balanced selection" can be performed so that only selected drive elements 5 are driven, possibly with the same or different current target values ​​Id*, for obtaining the reaction force and actual counteracting force as described above from the selected drive elements 5 at the corresponding nearby carrier 1. Subsequent steps will then be performed on the selected drive elements 5. This selection will be performed before step 52 and can be performed by calculation taking into account the known position of the carrier. It may include setting a separate current target value Id* for the selected drive elements i , to obtain the desired quantitative cancellation result.

[0095] Features described in the present specification and / or claims and / or shown in the drawings should be considered to be combinable with each other, if their combination is not explicitly described, to the extent that the combination is technically feasible. Features described in a certain context, embodiment, figure or claim should be considered to be separable from the claim, context, embodiment or figure and should be considered to be combinable with each other figure, claim, context or embodiment to the extent that it is technically feasible. The embodiments and figures should not be understood to mean that they are necessarily mutually exclusive. Features described as part of an embodiment or a figure should be considered to be separable from the embodiment or figure and should be considered to be combinable with features of other embodiments or figures, as long as it is technically possible. The description of a method or a process or a method step or a process step should also be understood as a description of a device for implementing the method or a process or a method step or a process step, and / or should also be understood as a description of an article produced or modified by the method or a process or a method step or a process step, and / or should also be understood as a description of a data carrier storing program instructions suitable for implementing the method or a process or a method step or a process step, and vice versa. In this specification, references to the "invention" refer to the teachings of the inventor's subjective conception.

[0096] Reference numerals list

[0097] 1 carrier

[0098] 2 tracks

[0099] 3 rounds

[0100] 4Magnetic facilities

[0101] 5. Driving elements

[0102] 6 groups of controllers

[0103] 7-segment controller

[0104] 8 System Controller

[0105] 21 controllers

[0106] 22 Switches

[0107] 23 Current sensor

[0108] 24 coils

[0109] 25 cores

[0110] 28 wires

[0111] 41, 42 permanent magnet

[0112] 43 Yoke

[0113] 51–55 Method steps

Claims

1. A system monitoring method in a multi-carrier system, the multi-carrier system comprising a track and at least one carrier, a plurality of individually drivable electric drive elements being arranged along the track, the carrier being drivable along the track by the drive elements, The system monitoring method comprises (a) driving a plurality or all of the driving elements simultaneously so that the driving forces exerted by them on the carrier cancel each other out, (b) observing electrical quantities at one or more or all of the drive elements using one or more current sensors while driving the drive elements, and (c) evaluating the observed electrical quantities and drawing conclusions about the operation of the drive element and / or the operation of the sensor based on the evaluation. 2 . The method according to claim 1 , wherein the at least one carrier is drivable by the drive element along the track in either of two track directions of the track. The method according to claim 1 , wherein the electrical quantity is one of voltage and current.

4. A method according to claim 1, wherein the plurality of driving elements are driven so that the resultant force in the track direction applied by the driven driving elements to the carrier is less than an absolute threshold or a relative threshold, the absolute threshold being a value of 0.2 or 0.1 or 0.05 or 0.02 N, the relative threshold being 10% or 5% or 2% or 1% or 0.5% of the sum of all forces applied to the carrier, or being 2% or 1% or 0.5% or 0.2% of the weight of an unloaded carrier.

5. The method of claim 1, wherein driving the electrically driven element comprises turning power to an electromagnet on and off, and the driving may be achieved using a PWM device.

6. The method of claim 1 , used in a PWM control system, wherein the L / R time constant of the driven drive element satisfies L / R>n*tp, wherein tp is the PWM pulse period duration, and n is 5 or 10 or 20 or 50 or 100, and wherein observing the electrical quantity includes one or more threshold checks on the current flowing in the drive element.

7. A method according to claim 6, wherein the threshold check comprises a check in normal operation whether the current drops below a lower threshold and / or whether the current exceeds a second higher threshold.

8. A method according to claim 1, used in a multi-carrier system, the multi-carrier system being designed so that if driven simultaneously, the resultant force in the track direction exerted on the carrier by all driving elements of the system, independent of its position along the track, is less than an absolute threshold or a relative threshold, the absolute threshold being a value of 0.2 or 0.1 or 0.05 or 0.02 N and the relative threshold being 10% or 5% or 2% or 1% or 0.5% of the total amount of all forces exerted on the carrier, or being 2% or 1% or 0.5% or 0.2% of the weight of the unladen carrier.

9. The method of claim 1, wherein observing the electrical quantity comprises observing a plurality of individual quantities of a corresponding plurality of individual drive elements.

10. The method according to claim 9, wherein observing the plurality of quantities is performed simultaneously, or simultaneously in time sequence or in groups.

11. The method according to claim 10, wherein the observation of the electrical quantity is a measurement to check whether an instantaneous current value exceeds a threshold value or an average value.

12. The method according to claim 11, wherein the observation of the electrical quantity is to check whether the instantaneous current value exceeds a threshold value within a defined observation time window.

13. A method according to claim 1, comprising selecting a plurality of driven drive elements from all drive elements of the system so that when driven simultaneously, the resultant force in the track direction applied by the selected drive elements on a specific carrier, taking into account its position along the track, is less than an absolute threshold or a relative threshold, the absolute threshold being a value of 0.2 or 0.1 or 0.05 or 0.02 N, and the relative threshold being 10% or 5% or 2% or 1% or 0.5% of the total amount of all forces applied to the carrier, or being 2% or 1% or 0.5% or 0.2% of the weight of an unladen carrier.

14. A system monitoring device in a multi-carrier system, the multi-carrier system comprising a track and at least one carrier, a plurality of individually drivable electric drive elements being arranged along the track, the carrier being drivable along the track by the drive elements, the system monitoring device comprising: (a) a driving device for driving a plurality of the driving elements simultaneously so that their driving forces on the carrier cancel each other out, (b) an observation device for observing electrical quantities at one or more or all of the drive elements using one or more sensors when the drive elements are driven, and (c) an evaluation device for evaluating the observed electrical quantity and drawing conclusions about the operation of the drive element and / or the operation of the sensor based on the evaluation.

15. A system monitoring device according to claim 14, wherein the at least one carrier is drivable by the drive element along the track in either of two track directions of the track.

16. The system monitoring device according to claim 14, in, The system monitoring device is suitable for (a) driving a plurality or all of the driving elements simultaneously so that the driving forces exerted by them on the carrier cancel each other out, (b) observing electrical quantities at one or more or all of the drive elements using one or more current sensors while the drive elements are being driven, and (c) evaluating the observed electrical quantities and drawing conclusions about the operation of the drive element and / or the operation of the sensor based on the evaluation.

17. The system monitoring device according to claim 14, wherein the electrical quantity is one of voltage and current.

18. A system monitoring device according to claim 14, used in a multi-carrier system, the multi-carrier system being designed so that if driven simultaneously, the resultant force in the track direction applied by all drive elements of the system on the carrier is independent of its position along the track and is less than an absolute threshold or a relative threshold, the absolute threshold being a value of 0.2 or 0.1 or 0.05 or 0.02 N, and the relative threshold being 10% or 5% or 2% or 1% or 0.5% of the total amount of all forces applied to the carrier, or being 2% or 1% or 0.5% or 0.2% of the weight of the unladen carrier 1, and the drive means being configured to drive all drive elements of the system simultaneously.

19. The apparatus of claim 14, adapted for use in a PWM control system, wherein the L / R time constant of the driven drive element satisfies L / R>n*tp, wherein tp is the PWM pulse period duration, and n is 5 or 10 or 20 or 50 or 100, wherein the observation device comprises one or more threshold check devices for the current in the drive element.

20. The system monitoring device according to claim 14, integrated into a control system of a multi-carrier system.

21. The system monitoring device according to claim 14, wherein the ratio d / p of the distance d between the magnet surface of the track and the magnet surface of the carrier to the drive element pitch p is greater than 0.005 or 0.01, and less than 0.05 or 0.02 or 0.011, and / or the ratio w / p of the width w of the electromagnetic core facing the carrier to the drive element pitch p is greater than 0.2 or 0.

4.

22. A multi-vector system comprising A track along which a plurality of individually drivable electrically driven elements are arranged, at least one carrier capable of being driven along the track by the driving element, a control structure for driving the carrier along the track, a tracking device for tracking the position of a driven carrier in the multi-carrier system, and The system monitoring device according to claim 14.

23. A multi-carrier system according to claim 22, wherein the control structure is hierarchical and comprises a plurality of coil controllers, each coil controller being connected to a corresponding driving element for supplying power thereto and generating a current measurement signal, a plurality of coil group controllers, each connected to the plurality of coil controllers for feeding them with power control signals and receiving current measurement signals therefrom, one or more segment controllers, each connected to the plurality of coil group controllers for sending current target values ​​thereto and collecting current measurement information therefrom, and A system controller is connected to one or more segment controllers for sending carrier target speed values ​​or target position values ​​thereto, for collecting current measurement information therefrom and for carrier tracking.

24. The multi-carrier system of claim 23, wherein the plurality of coil controllers are configured to feed PWM power to corresponding drive elements.

25. The multi-carrier system of claim 23, wherein a plurality of coil group controllers are connected to a plurality of coil controllers for feeding PWM control signals thereto.

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