System for supporting condition-based maintenance of a vehicle access arrangement and corresponding access arrangement

Abstract

System for supporting condition-based maintenance of an access arrangement of a vehicle, preferably a public transport vehicle, wherein the access arrangement (2) comprises a movable element (3) and an electric motor (4) and the movable element (3) is adjustable by means of the electric motor (4) during an adjustment process, comprising: a detection unit (21) configured to detect at least one operating parameter (I) of the access arrangement (2) and to generate n measured values ​​of the at least one operating parameter (I) during the adjustment process, wherein n is a natural number, a distance measurement unit (22) which is communicatively connected to the detection unit (21) for receiving measured values ​​and is configured to determine a deviation measure based on a difference vector,wherein the difference vector is based on an actual vector (v→actual) and a target vector (v→target) and wherein the actual vector (v→actual) comprises the measured values ​​received by the acquisition unit (21) in the actual vector elements (vist,i) and the target vector (v→target) corresponding reference values ​​in the target vector elements (vtarget,i), and an evaluation unit (24) configured to determine a maintenance condition based on the deviation measure.

Description

The invention relates to a system for supporting state-based maintenance of an access arrangement of a vehicle, preferably of a public transportation vehicle, wherein the access arrangement comprises a movable element and an electric motor and the movable element is adjustable by means of the electric motor during an adjustment process. The invention further relates to a corresponding access arrangement.In principle, in the case of practically all technical devices, degradation takes place with increasing operating time, which degradation leads to a failure over a short or long period and thus to the device having to be repaired or replaced overall or essential parts of the device before continued operation of the device is possible and permitted. Such a failure is particularly disadvantageous if it occurs surprisingly and thus both interrupts the ongoing operation and requires the use of a replacement device for maintaining the operation for the duration of the repair or replacement. Both the lack of anticipability of such failures and the resulting need to provide a correspondingly large reservoir of replacement devices results in high costs. In addition, frequent purchase of spare parts can further increase costs. This problem also applies, and in particular in the field of vehicles for public transportation and there particularly with respect to access arrangements such as door and slide entry systems.The above problem is addressed by the fact that service intervals determined on an operating time basis are provided after which individual components are to be respectively maintained or replaced. However, the safety factor required in the calculation of the service intervals, in the event of an effective prevention of failures, leads to the tendency for such maintenance to take place too frequently and also to parts being exchanged which could still be used in per se for a considerable time before a failure.Another approach is to dimension the components such that failure does not occur practically during a common lifetime. However, this approach requires the use of particularly high-quality and low-wear materials, so that very expensive devices are thereby produced. This approach is thus often not possible.Another approach is state-based maintenance (also known as condition-based maintenance-CBM). Since degradation regularly originates from gradually proceeding processes, a prediction about an imminent failure can be made by measuring and evaluating these gradually proceeding processes. As a result, the component in question can be scheduledly maintained or replaced shortly before the failure.U.S. Pat. No. 6,636,814 B1 describes a predictive diagnostic system for a motor-driven automatic door system. The operating behavior of the door system is recorded and the energy and time consumption during operation is determined. These consumption data are compared with historical consumption data and based on this comparison the degradation rate of the door system is determined with the aim of being able to determine more accurate service times. For this purpose, an artificial neural network is trained by running as many series of tests as possible with door systems. In this way, the artificial neural network can learn and recognize failure patterns independently.DE 10 2017 130 002 A1, DE 10 2020 116 022 A1 and DE 10 2020 130 512 A1 each use a simulation model for describing an access arrangement. With this simulation model, variables to be expected are calculated and compared with actually present variables. If the calculated, expected variable deviates too far from the actually present variable, a need for maintenance is deduced. Even if reliable statements about the need for maintenance can be made in this way, these approaches are comparatively computation- and / or memory-intensive.The object of the invention is to provide a system and an access arrangement of the type mentioned at the beginning, with which state-based maintenance of an access arrangement can be carried out as reliably and as cost-effectively as possible.This object is achieved by the combinations of features of the subordinate claims. Further embodiments of the invention are disclosed in the respective dependent claims.An embodiment of the system disclosed herein for supporting state-based maintenance of an access arrangement of a vehicle, preferably of a public transportation vehicle, comprises:a detection unit configured to detect at least one operating variable of the access arrangement and to generate n measurement values of the at least one operating variable during an adjustment process of the access arrangement, wherein n is a natural number,a distance determination unit which is connected to the detection unit in a communicating manner for receiving measurement values and is designed for determining a deviation measure based on a difference vector, wherein the difference vector is based on an actual vector and a target vector, and wherein the actual vector comprises the measurement values received from the detection unit in the actual vector elements and the target vector comprises corresponding reference values in the target vector elements, andan evaluation unit configured to determine a maintenance state based on the deviation amount.One configuration of the access arrangement disclosed here for a vehicle, preferably a public transportation vehicle, comprises a movable element, an electric motor, a control unit controlling the electric motor and a system according to the present disclosure, wherein the movable element is adjustable by means of the electric motor during an adjustment process and wherein the system for detecting at least one operating parameter is connected in communication with the control unit and / or the electric motor.It should be noted that the features listed individually in the claims can be combined with one another in any desired, technically expedient manner and reveal further configurations. The description additionally characterizes and specifies the invention, in particular in conjunction with the figures.It should also be noted that a conjunction "and / or" used herein, between two features and linking them to one another, should always be interpreted in such a way that in a first configuration only the first feature can be present, in a second configuration only the second feature can be present, and in a third configuration both the first and the second feature can be present.It has been recognized that, in order to determine an emerging need for maintenance, no complicatedly trained neural networks and no modelling of access arrangements are required. This is because at least individual operating variables of the access arrangements have typical time profiles and / or typical position-dependent profiles during an adjustment process of the movable element, which profiles depend in each case on the maintenance state of the respective access arrangement. This can go so far that it is possible to infer the failure of a specific component and its expected remaining running time from a temporal and / or position-dependent profile of an operating variable and a comparison with a reference profile. Therefore, according to the present disclosure, a temporal and / or position-dependent profile of measured values of at least one operating variable is compared with a temporal and / or position-dependent profile of a corresponding reference variable, and a deviation measure is determined using a difference vector. In this way, a maintenance state and a possible maintenance requirement can be deduced.To exploit this principle, a system according to the present disclosure includes at least a detection unit, a distance determination unit, and an evaluation unit. The detection unit is designed to detect at least one operating variable of the access arrangement and to generate n measured values of the at least one operating variable during an adjustment process, wherein n is a natural number. The distance determination unit is communicatively connected to the detection unit and can receive measurement values generated by the detection unit. In addition, the distance determination unit is designed to form a difference vector based on an actual vector and a desired vector and to determine a deviation measure using this difference vector. This deviation measure can be transmitted to the evaluation unit connected to communicate with the distance determination unit. From a received deviation measure, the evaluation unit can determine a maintenance state. Depending on the ascertained maintenance state, it is possible to infer an existing maintenance requirement.The number n of measured values should be selected such that the temporal and / or position-dependent profile of the operating variable is depicted sufficiently. This requirement is certainly not applicable for only one or a few measured values. The number of measured values should therefore be "not too small", since otherwise a temporal or position-dependent profile of the operating variable cannot be mapped sufficiently. What means "not too small" should depend on the particular application scenario. In one embodiment, n is greater than or equal to 25, in another embodiment greater than or equal to 50, in another embodiment greater than or equal to 100. At the same time, n should be "not too large", since otherwise the computing effort and the memory requirement become too large and cannot be related to an additional gain of information. A number of tens of exchanged measured values should usually be too much. Therefore, n is less than or equal to 10,000 in one embodiment, less than or equal to 5,000 in another embodiment, and less than or equal to 1,000 in another embodiment. In many application scenarios, it may be advantageous if the number of measured values n is a power of 2, for example 128, 256, 512 or 1024.A "time profile of an operating variable" describes how the operating variable changes over time. A "position-dependent profile of an operating variable" describes how the operating variable changes as a function of a position. The position can be formed, for example, by the position of the electric motor, the position of the movable element, a coupling element or the like. Since the position usually also has a dependence on time, a position-dependent profile is not rarely also a temporal profile or vice versa.For further evaluation of the n measured values, these are arranged in the vector elements of an "actual vector". It is thereby expedient if the individual measured values maintain their temporal or position-dependent sequence in the actual vector. This can mean that the vector element v ist,i has been detected temporally or positionally after the vector element v ist,j if j is greater than i. A reverse sequence is also conceivable. In both cases, the evaluation of the measured values can thereby be simplified.Corresponding reference values are arranged in the vector elements of a "desired vector". This means that a vector element v soll,i of the desired vector corresponds to a vector element v ist,i of the actual vector. In this way, a direct assignment between a measured value and an associated reference value is possible. The "difference vector" can thereby directly indicate the deviation of the temporal and / or position-dependent profile of the measured values from the temporal and / or position-dependent profile of the reference values.When arranging the measured values in the actual vector, it is not absolutely necessary for all detected measured values to be included in the actual vector. For example, measured values identified as "outliers", which deviate considerably from an expected measured value by a measurement error, cannot be used and thus cannot be included in the actual vector. It is thereby expedient to omit the corresponding reference values even for the desired vector.In one embodiment, the "difference vector" is a difference--made of the actual vector and the target vector The difference vector can, however, also be based in another manner on the actual vector and the target vector. Thus, the desired vector and / or the actual vector can still be modified before the difference formation, for example by scaling, filtering or the like. Accordingly, in another embodiment, the "difference vector" may be a difference in another embodiment, a difference, and in yet another embodiment, a difference, wherein the deleted vectors are each modified versions of the difference vector.The "measured values" can be obtained in a wide variety of ways. Thus, a dedicated sensor may be present, which measures an operating variable during an adjustment process. However, it is also conceivable for the access arrangement or the vehicle as a whole already to have sensors of this type and for the measured values obtained there to be supplied to additional use. In addition, the measured values do not have to be measured directly. A measurement value can also be calculated or even estimated from other measurement values. As long as the measured values indicate the time-dependent and / or position-dependent profile of the operating variable, this is usable at least in principle in the present disclosure.Depending on the manner in which the measured values are obtained, the function and mode of operation of the detection unit should also differ. In the simplest case, the acquisition unit only "collects" measured values from other units. In other cases, the acquisition unit can control and / or perform the acquisition of the measurement values and can also comprise analog-to-digital converters, filters and / or the like or interact with such components.Likewise, the "reference values" can originate from a wide variety of sources. Thus, the reference values can originate, for example, from measurements on the most varied access arrangements of the same type and can be formed, for example, by averaging from the individual measurements. In one embodiment, the reference values are obtained at the access arrangement to be evaluated according to the present disclosure. Since the present disclosure is intended to reveal degradation of the maintenance state, the state of the access arrangement upon detection of the reference values is of minor importance as long as the access arrangement upon detection of the reference values can be referred to as "ready for use". Ideally, however, the reference values are obtained when the access arrangement is in a new or new-valued state, since a defined initial state is then present. This can mean that the access arrangement has been put into operation for the first time shortly before the reference values are detected or has only undergone so few adjustment processes after a first put into operation that degradation is practically absent. For the detection of the reference values, a plurality of adjustment processes can be carried out, in which the at least one operating variable is measured in each case. The reference values can then be determined from the measured values, for example by averaging corresponding measured values. In this way, the quality of the reference values can be improved and possible measurement errors can be calculated out.In principle, all that is considered as the "deviation measure" reflects a distance between the actual vector and the target vector, that is to say specifies a measure for a deviation of the temporal or position-dependent curves between measured values and reference values. The determination of the deviation measure can be carried out in a wide variety of ways, as long as a deviation measure with the properties mentioned here can arise. In one embodiment, vector operations are used. In this way, a simple calculability can be achieved.In this case, the "deviation measure" can specify a deviation between the actual state and the desired state in a wide variety of ways. The deviation measure may indicate the amount of deviation (the greater the different) or the amount of agreement (the greater the similar). The deviation measure may be merely a number which represents a measure of the total deviation. The deviation measure can also specify in more detail at which point of the temporal and / or position-dependent profile which deviation between the actual state and the desired state is present. The deviation measure may include one or more absolute values, one or more related values, or one or more relative values. The deviation measure can also be a percentage specification. This non-exhaustive and non-limiting enumeration shows how flexible the deviation measure can be used.A "maintenance state" of the access arrangement indicates how well the access arrangement is maintained or how far degradation has advanced. A "maintenance requirement" indicates whether the degradation has advanced to such an extent that maintenance or even replacement of components of the access arrangement or of the access arrangement as a whole is required for a short time. In this case, a need for maintenance can be present, for example, if the access arrangement should fail within a defined period of time, that is to say, for example, a remaining operating duration of one week or one month is estimated.The "evaluation unit" is generally designed to evaluate the ascertained deviation measure and to obtain information about the maintenance state of the access arrangement from the deviation measure. This can be the information that the access arrangement operates without problems and does not threaten a timely failure. However, this can also be the information that the access arrangement threatens to fail in a time period t A for example within one month or within two weeks. In this case, the information about the maintenance state can also indicate which specific component of the access arrangement is imminent to fail. This evaluation can be carried out in a wide variety of ways.Since the deviation measure specifies a distance between measured values and reference values, an evaluation of the deviation measure can comprise, for example, the evaluation of the distance.In principle, the maintenance state can be determined during each adjustment process. As a result, current values about the maintenance state would always be present. To reduce the computing effort, however, it may also be appropriate not to determine the maintenance state during each adjustment process. In this case, a determination of the maintenance state can be triggered by a number of adjustment processes, for example after 100 closing processes or 500 opening processes. However, it is also conceivable that a determination of the maintenance state is triggered in a time-based manner, for example once per hour, once per day or once per week. In addition, a combination of the two possibilities mentioned can also be carried out, for example after 750 opening-closing cycles, but at the latest once a day.The present disclosure may be used for a wide variety of "vehicles" and "access arrangements.". It is important that at least one movable element is moved by at least one electric motor during an adjustment process and an increasing degradation is thereby caused. In one configuration, the vehicle is a vehicle for public transportation, for example a bus, a train, a wagon, a traction car, a ferry, a ship or the like. The access arrangement is preferably formed by a sliding door, a pivotable sliding door, a sliding gate, a ramp or the like. It should also be noted here that these enumerations are neither exhaustive nor restrictive.In the present case, an "adjusting process" is generally understood to mean a process in which a movable element of the access arrangement is displaced by the electric motor from a first position into a second position. This first position can be an initial position and the second position an end position, or vice versa. In one embodiment, an adjusting process is an opening process, in another embodiment a closing process. In a further embodiment, an adjusting process is a phase of an opening and / or closing process, for example a locking, an unlocking, a linear movement, an acceleration, a braking, a stop and / or a similar movement process. In this case, the movable element can undergo a wide range of movements during an adjustment process, for example translatory, rotatory, tilting, pivoting or combinations thereof, to name just a few possible examples.The present disclosure provides the advantage that a measure of a maintenance state and / or a maintenance requirement can be easily obtained and state-based maintenance can thus be supported. In this case, the present disclosure does not necessarily require a neural network or other artificial intelligence. In addition, it is not absolutely necessary for modelling of the access arrangement to be carried out. As a result, an inexpensive assessment of an access arrangement that makes do with relatively small resources can be carried out. Nevertheless, the maintenance state and / or the maintenance need can be reliably estimated.The system disclosed herein may be implemented in various ways. In one embodiment, the system is fully implemented by hardware. In another embodiment, the system is implemented by a combination of hardware and software. The hardware can comprise, for example, sensors, analog-to-digital converters, filters (for example high-pass filters, low-pass filters, band-pass filters), processors (for example microcontrollers, digital signal processors or ASIC (application specific integrated circuit)) and / or a programmable logic circuit (for example an FPGA (field programmable gate array) or CPLD (complex programmable logic device)). Furthermore, one or more memories can be present, for example RAM (random access memory), ROM (read only memory) or flash memory, which can be accessed by other hardware components. Software may control the respective components of the system, for example the processor or parameter of an analog-to-digital converter.In one configuration, the distance determination unit is designed to determine the deviation measure on the basis of a p-norm of the difference vector, wherein the p-norm of the difference vector is defined by:Here, p is a real number greater than or equal to 1 and less than infinity. For p = ∞, the p norm is known as the maximum norm. By using a p-standard, a distance measure between an actual state and a desired state can be reliably determined, wherein each measured value is inherently compared to its corresponding reference value. At the same time, the determination of this deviation measure can be implemented and calculated relatively easily. In a development, here too, modified versions of the desired vector and / or of the actual vector can be used in the formation of the p-norm.In a development, the distance determination unit is designed to use a 1-norm-sum norm-with p=1, a 2-norm-Euclidean distance-with p=2 or a ∞ norm-maximum norm, wherein the ∞ norm is defined by:The 1-norm offers the advantage that the calculation manages without powers and is thus particularly resource-saving. The 2-norm offers the advantage that large deviations are weighted more strongly than small deviations, so that the norm provides good statements about the distance. The 2-norm provides a high level of relevance and can be calculated at the same time with reasonable effort. The ∞ standard provides information about the maximum deviation of the associated measurement and reference values. In a development, here too, modified versions of the desired vector and / or of the actual vector can be used in the formation of the p-norm.In one embodiment, the distance determination unit is designed to normalize measured values received by the detection unit before calculating the p-norm, preferably by dividing the received measured values with another p-norm, particularly preferably with a ∞ norm. In this way, the comparison between measured values and reference values is improved. Each measured value or reference value thus has an amount of less than or equal to 1.In one embodiment, the evaluation unit is designed to compare the deviation measure with a threshold value in order to ascertain a maintenance state, wherein a maintenance requirement is decided on when the threshold value is reached or exceeded. In this way, a particularly simple evaluation with simultaneously high significance can be achieved.In one embodiment, the evaluation unit is designed to evaluate a temporal and / or position-dependent profile of the deviation measure in order to determine a maintenance state by comparing a currently determined deviation measure with a deviation measure determined for earlier adjustment processes. In this way, it is possible to determine whether and how much degradation proceeds. This makes it possible to improve a statement about an estimated remaining running duration. In addition, the comparison of the determined deviation measures can provide supplementary information about the maintenance state. At least some degradation effects have a manageable level for some time after initial start-up. Thus, for example, after the installation of a linear guide, degradation is low for a certain time, since, for example, lubricants slide the components well and only after prolonged operation are there increasingly wear of the components due to a deteriorated lubrication quality.In one embodiment, the evaluation unit is designed to evaluate a derivative of the temporal and / or position-dependent profile of the deviation measure in order to determine a maintenance state by determining a speed of a change in the deviation measure relative to deviation measures determined for earlier adjustment processes. In this way, it can be determined how quickly the maintenance state changes. This can provide a statement about the progress of degradation, since at least some degradation effects accelerate with increasingly progressive degradation. This may have an effect on the estimated residual time.In one embodiment, the distance determination unit and / or the evaluation unit is / are designed to detect phases of an adjustment process, to evaluate at least two of the detected phases separately from one another and to infer from evaluation results for the individual phases preferably a type of emerging defect. It has been found that some degradation effects become visible differently in different phases of an adjustment process. Thus, a linear guide that fails should have a stronger effect during an acceleration phase of the movable element or during a phase with a substantially constant speed than during a deceleration phase. In a locking phase, the effect of the failing linear guide can even be negligible. This will look quite different if a lock for the movable element is imminent. Here, only an unlocking and / or locking phase should be meaningful. These two simple examples show that by evaluating different phases of an adjustment process, deepening information about the type of an occurring defect can be achieved. In this case, only two phases can be evaluated separately from one another. In principle, however, it is also possible to distinguish and evaluate three or even more phases.In one configuration, the detection unit detects, as the at least one operating variable, an electric current consumed by the electric motor, an electric voltage applied to the electric motor, an electric power consumed by the electric motor and / or a rotational speed of the electric motor. The use of the electric current drawn offers the advantage that the electric current is directly influenced by the mechanics of the access arrangement and the kinematics of the drive of the movable element. Thereby, the maintenance state can have a direct influence on the electric current consumed by the electric motor. The same applies to the voltage present at the electric motor or the power consumed by the electric motor, since both voltage and electric power are related to the current. The speed may also provide indications of the maintenance condition. Thus, an increasing degradation can lead to an increased load torque of the electric motor, which in turn can influence the rotational speed.In one embodiment, the system can be placed in an initialization state, wherein the system in the initialization state is designed to record the at least one operating variable during at least one adjustment process, preferably during several adjustment processes, and to determine and store a vector based on the recorded at least one operating variable. By obtaining the reference values by means of the access arrangement to be evaluated later, errors can be reduced. This is because tolerances of the installation situation, the sensors, the electric motor, the gears, etc. are identical or at least deviate from one another in a defined manner both during the reference value acquisition and during the later evaluation of the maintenance state. It may be appropriate to record the reference values during a plurality of adjustment processes and to summarize the results of the individual measurements, for example by averaging. This can reduce the effects of measurement errors during individual measurements and / or adjustment processes. For example, 10 adjustment processes can be carried out and both opening processes and closing processes can be detected. In this case, the reference values for the opening processes and the closing processes can be used to form separate desired vectors.In one embodiment, the system additionally has an output interface, with which a maintenance requirement can be signaled and / or a maintenance state can be output. In this way, a central processing unit within the vehicle can be informed of a need for maintenance, for example. This information can also be transmitted to a central management system, for example a fleet management system. Thus, a recognized maintenance requirement can immediately trigger maintenance or also an ordering of a replacement part.In one embodiment, the detection unit and / or the distance determination unit is designed to clean and / or filter the measured values, preferably to eliminate outliers. In this way, interference can be reduced and the effects of measurement errors can be minimized.In one embodiment, points in time of a detection of measured values are defined by reaching defined positions of the movable element and / or of the electric motor. For example, one revolution of the electric motor can trigger the acquisition of a measured value. It would also be conceivable for the movement of the movable element to be detected with a sensor and for a measured value detection to be triggered when the movable element is adjusted by a defined distance and / or angle. In this way, a relationship between reference values and measured values can be defined and controlled more accurately.Further features and advantages of the invention will become apparent from the following description of exemplary embodiments of the invention, which are to be understood as non-limiting and are explained in more detail below with reference to the drawings. In this drawing, the following are shown schematically: FIG. 1 shows a schematic illustration of a rail vehicle of public transportation by persons with two access arrangements in the form of plug-and-socket doors, each having a movable element and an electric motor driving this movable element, FIG. 2 shows a diagram with an exemplary profile of a current consumed by the electric motor during an opening process of the access arrangement, FIG. 3 shows a diagram with an exemplary profile of a current consumed by the electric motor during a closing process of the access arrangement, FIG. 4 is a block diagram of an embodiment of a system according to the present disclosure, FIG. 5 shows a diagram with an exemplary course of a current absorbed by the electric motor during a closing operation with an increasing degradation of a linear guide, FIG. 6 shows a diagram with an exemplary course of a current consumed by the electric motor during a closing process with an increasing degradation of an angle transmission, and FIG. 7 shows a diagram with an exemplary change over time of the 1-norm, 2-norm and ∞-norm of a difference vector of actual vector and target vector.In the different figures, parts which are equivalent in terms of their function are always provided with the same reference symbols, so that they are generally also described only once.The vehicle 1 illustrated in FIG. 1 is a rail vehicle for public transportation with a plurality of passenger doors fastened to the vehicle 1, of which two are shown here as access arrangements 2 a, 2 b, by way of example. Each access arrangement 2 a, 2 bincludes in each case a movable element 3 a, 3 b, which is here a door leaf, and an electric motor 4 a, 4 bfor adjusting the door leaf. The electric motors 4 a, 4 bare each a direct current machine.The electric motors 4 a, 4 bare each controlled by control signals 5 a, 5 bwhich originate from a respective control unit 6 a, 6 b. The vehicle 1 further comprises measuring devices 7 a, 7 bon each access arrangement 2 a, 2 b, wherein the measuring devices 7 a, 7 brespectively generate measuring signals 8 a, 8 band transmit them to the respective control device 6 a, 6 b. These measurement signals 8 a, 8 bdescribe operating variables of the access arrangement 2 a, 2 b, for example an electric current I consumed by the electric motor 4 a, 4 b, the speed of the respective movable element 3 a, 3 band / or the power consumed by the electric motor 4 a, bwhen the respective movable element 3 a, bis adjusted.During an opening process or a closing process, the electric motor 4 a, 4 bacquires a current I, as is illustrated by way of example in FIGS. 2 and 3. In the example shown, the current I is represented in amperes above a position p of the movable element 3. The positions p are marked with a number between 0 and 255. Thus, n=256 measurement values can be generated. It should be noted that, by means of the representation selected here about the position in FIG. 2-opening process-in the diagram the time for the measurement value acquisition runs from left to right and in FIG. 3-closing process-from right to left.In the diagrams shown, the sliding gate door passes through a total of three phases: an unlocking / locking phase 9, a linear phase 10 and a so-called buckle phase 11. During the closing process (FIG. 3 ), the movable element 3 is first accelerated in the buckle phase 11, is held at an approximately constant speed in the linear phase 10 and is brought to the lock in the locking phase 9 and is finally locked. In this case, a current profile 12 is in each case established, as is illustrated by way of example in FIGS. 2 and 3.FIG. 4 shows an embodiment of a system according to the present disclosure. The system 20 illustrated comprises a detection unit 21, a distance determination unit 22, a memory 23 with a desired vector, an evaluation unit 24 and an output interface 25. The actual vector is transferred from the detection unit 21 to the distance determination unit 22 via a communicating connection. The distance determination unit 22 loads the target vector from the memory 23 and forms a difference vector from the actual and target vectors, and a deviation amount is then determined using the difference vector. The distance determination unit 22 passes on the determined deviation measure to the evaluation unit 24, which determines a maintenance state and / or a maintenance requirement therefrom. The maintenance state and / or the maintenance requirement can be given "to the outside" via the output interface 25. This "outward" may be, for example, a light display in the access arrangement, a central control computer of the rail vehicle or a fleet management system. The system 20 may be implemented in the control unit 5, for example, or may be connected to the control unit 5.FIG. 5 shows a current profile during a closing process, as occurs with increasing degradation and imminent failure of the linear guide. The higher the current, the greater the degradation. It can be seen that a particularly pronounced deviation occurs in particular in the linear phase 10 and the locking phase 9.FIG. 6 shows a current profile during a closing process, as occurs with increasing degradation and imminent failure of the angle transmission. Here, the differences are less. Nevertheless, in the locking phase and the linear phase, distinct differences of the curves can be recognized.FIG. 7 shows a diagram with the 1-norm (diamond-shaped), 2-norm (plus sign) and ∞ norm (circular) in the case of a linear guide that fails / fails. In this case, the standards are each standardized using the ∞ standard, i.e. the respective values are divided by the ∞ standard. The acquisition days are plotted in the abscissa direction, the lines on the abscissa indicating a period of six weeks in each case. It can clearly be seen that the 1-norm and the 2-norm rise significantly in the first two-thirds. When the values drop to 0, the linear guide has been replaced, after which the 1-norm and 2-norm drop again clearly.With regard to further advantageous configurations, reference is made to the general part of the description and to the appended claims in order to avoid repetitions.Finally, it should be expressly pointed out that the exemplary embodiments described above serve merely for explaining the claimed teaching, but do not restrict it to the exemplary embodiments.List of reference characters1 Vehicle 2 Access arrangement 3 Movable element 4 Electric motor 5 Control signals 6 Control unit 7 Measuring device 8 Measurement signals 9 Unlocking / locking phase 10 Linear phase 11 Buckle phase 12 Current profile 20 System 21 Detection unit 22 Distance determination unit 23 Memory 24 Evaluation unit 25 Output interfaceReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedU.S. Pat. No. 6,636,814 B1

[0006] DE 10 2017 130 002 A1

[0007] DE 10 2020 116 022 A1

[0007] DE 10 2020 130 512 A1

[0007]

Claims

System for supporting state-based maintenance of an access arrangement of a vehicle, preferably of a public transportation vehicle, wherein the access arrangement (2) comprises a movable element (3) and an electric motor (4) and the movable element (3) is adjustable by means of the electric motor (4) during an adjustment process, comprising: a detection unit (21) which is designed to detect at least one operating variable (I) of the access arrangement (2) and to generate n measurement values of the at least one operating variable (I) during the adjustment process, wherein n is a natural number, a distance determination unit (22) which is connected to the detection unit (21) in a communicating manner for receiving measurement values and is designed to determine an amount of deviation based on a difference vector, wherein the difference vector is based on an actual vector (v→is t) and a target vector (v→s o l l) and wherein the actual vector (v→is t) comprises the measured values received from the detection unit (21) in the actual vector elements (v ist,i) and the target vector (v→s o l) corresponding reference values in the target vector elements (v soll,i) and an evaluation unit (24) which is designed to determine a maintenance state based on the deviation measure.The system according to claim 1, characterized in that the distance determination unit (22) is configured to determine the deviation measure based on a p-norm of the difference vector ( v → i s t - v → s o l l ) wherein the p-norm of the difference vector ( v → i s t - v → s o l l ) is defined by: d p ( v → i s t, v → s o l l ) = ≅ v → i s t - v → s o l l ≅ p = ( ∑ i = 1 n ( | v → i s t, i - v → s o l, i | ) p ) 1 p The system according to claim 2, characterized in that the distance determination unit (22) is configured to use a 1-norm - sum norm - with p = 1, a 2-norm - euclidean distance - with p = 2 or a ∞ norm - maximum norm - wherein the ∞ norm is defined by: d ∞ ( v → i s t, v → s o l l ) = ≅ v → i s t - v → s o l l ≅ ∞ = i ∈ { 1,..., n } max { | v i s t, i - v s o l, i | } System according to one of Claims 1 to 3, characterized in that the distance determination unit (22) is designed to normalise measured values received by the detection unit (21) before the calculation of the p-norm, preferably by dividing the received measured values with a p-norm, particularly preferably with a ∞ norm.System according to one of Claims 1 to 4, characterized in that the evaluation unit (24) is designed to compare the deviation measure with a threshold value in order to determine a maintenance state, a maintenance requirement being decided on when the threshold value is reached or exceeded.System according to one of Claims 1 to 5, characterized in that the evaluation unit (24) is designed to evaluate a temporal and / or position-dependent profile of the deviation measure in order to determine a maintenance state by comparing a currently determined deviation measure with a deviation measure determined for earlier adjustment processes.System according to one of Claims 1 to 6, characterized in that the evaluation unit (24) is designed to evaluate a derivative of the temporal and / or position-dependent profile of the deviation measure in order to determine a maintenance state by determining a speed of a change in the deviation measure relative to deviation measures determined for earlier adjustment processes.System according to one of Claims 1 to 7, characterized in that the distance determination unit (22) and / or the evaluation unit (24) is / are designed to identify phases (9, 10, 11) of an adjustment process, to evaluate at least two of the phases (9, 10, 11) separately from one another and to infer preferably a type of an occurring defect from evaluation results for the phases (9, 10, 11).System according to one of Claims 1 to 8, characterized in that the detection unit (21) detects, as the at least one operating variable (I), an electric current absorbed by the electric motor, an electric voltage applied to the electric motor, an electric power absorbed by the electric motor and / or a rotational speed of the electric motor.The system according to any one of claims 1 to 9, wherein the system is displaceable into an initialization state, wherein the system (20) in the initialization state is configured to detect the at least one operating variable (I) during at least one adjustment process, preferably during a plurality of adjustment processes, and to determine and store a vector v → s o l l based on the detected at least one operating variable (I).The system according to any one of claims 1 to 10, wherein the system additionally has an output interface (25), with which a maintenance requirement can be signaled and / or a maintenance state can be output.System according to one of Claims 1 to 11, characterized in that the detection unit (21) and / or the distance determination unit (22) is designed to clean and / or filter the measured values, preferably to eliminate outliers.System according to one of Claims 1 to 12, characterized in that points in time of a detection of measurement values by reaching defined positions (p) of the movable element (3) and / or of the electric motor (4) are defined.Access arrangement for a vehicle, preferably a public transportation vehicle, having a movable element (3), an electric motor (4), a control unit (6) controlling the electric motor (4) and a system (20) according to one of Claims 1 to 13, wherein the movable element (3) is adjustable by means of the electric motor (4) during an adjustment process and wherein the system (20) is connected to the control unit (6) and / or the electric motor (4) in a communicating manner for detecting at least one operating parameter (I).

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