AU2017217139A1

AU2017217139A1 - Input element with magnetic element and magnetic field sensor

Info

Publication number: AU2017217139A1
Application number: AU2017217139A
Authority: AU
Inventors: Matthias Alexander Weber
Original assignee: Siemens AG
Current assignee: Siemens AG
Priority date: 2016-02-12
Filing date: 2017-01-25
Publication date: 2018-07-26
Also published as: WO2017137253A1; DE102016202147A1; CN109496396B; CN109496396A; EP3414840A1; RU2691861C1

Abstract

An input element comprises a support element (140); an operating element (145) which is adjustable with respect to the support element; a locking device for holding the operating element in one or more predefined positions with respect to the support element; a magnetic element (165) which is mechanically coupled to the operating element; a magnetic field sensor (170) attached to the support element for sensing a magnetic field; and an analyser system for sensing a position of the operating element with respect to the support element on the basis of the magnetic field sensed by the magnetic field sensor.

Description

INPUT ELEMENT WITH MAGNETIC ELEMENT AND MAGNETIC FIELD SENSOR

The present invention relates to an input element and an input system, in particular for use on a rail vehicle such as a locomotive .

A locomotive has a steering position provided on it, which may be fitted to a driver's cab, in an engine room or in the outer region of the locomotive, for example. The steering position comprises a multiplicity of input elements, each of which is associated with a predetermined function of the locomotive. Each input element comprises an operator control element that can be moved translationally or rotationally by an operator. In this case, a predetermined number of positions of the operator control element is predetermined, and each of the positions can have an associated snap-action switch. If the operator control element has more than two positions, then it also comprises accordingly more snap-action switches.

The steering position can therefore comprise a large number of snap-action switches, which can require a relatively large installation space and usually also result in a relatively high weight. As a result of their mechanical complexity, input elements having the snap-action switches, in particular having multiple snap-action switches, can have increased susceptibility to error. The snap-action switches may be susceptible to corrosion, soiling, gumming or the penetration of foreign bodies in liquid or solid form. The function of the snap-action switch may be limited thereby. Each snap-action switch has one or more associated discrete lines that need to be connected within the scope of the steering position. The steering position may thus be complex to design, difficult to maintain and inflexible in the face of a later change.

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The invention is based on the object of providing an improved input element and an improved input system that overcome at least one of the disadvantages indicated above. The invention achieves this object by means of the subjects of the independent claims. Subclaims convey preferred embodiments.

An input element comprises a support element, an operator control element movable relative to the support element and a latching device in order to keep the operator control element in one of multiple predetermined positions relative to the support element. Further, the input element comprises a magnetic element, magnetically coupled to the operator control element, and a magnetic field sensor, fitted to the support element, for determining a magnetic field. Moreover, an evaluation device is comprised that is set up to determine a position of the operator control element relative to the support element on the basis of the magnetic field determined by means of the magnetic field sensor.

The use of a magnetic field sensor allows the input element to be of mechanically less complex design. A sensitivity of the input element toward corrosion, contamination or foreign bodies may be reduced. The magnetic field sensor can determine the position of the operator control element contactlessly, which means that wear in this region may likewise be reduced. It is, in particular, preferred for the evaluation device to be set up to determine the position of the operator control element only generally and not yet to map it onto one of the predetermined positions of the operator control element.

To this end, the evaluation device may be set up to determine the position of the operator control element in analog fashion or to provide an analog value indicating the position of the operator control element. In another embodiment, a digital value is used, the position being resolved with a higher resolution than the number of predetermined positions of the

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016Ρ013ΟOWOAU operator control element. By way of example, the position of the operator control element can be resolved with a resolution of 8 bits, corresponding to 256 different positions, while the operator control element is restricted to approximately 2 to 16 positions by means of the latching device. This allows an improved information base to be provided for a downstream, processing device. By way of example, a transition from one mechanical position to another can be tracked in improved fashion. It is also possible for the association of the determined position with one of the mechanically defined positions of the operator control element on the basis of an externally available system knowledge to be performed in improved fashion.

It is particularly preferred for the operator control element to be separable into a first and a second subunit, wherein the first subunit comprises the latching device and the magnetic element and the second subunit comprises the magnetic field sensor and the evaluation device. This allows a generic second subdevice to be provided that can be combined with different first subdevices. Using a specific instance of application, it is also possible for a first subunit to be replaced with a second subunit, for example if an increased number of mechanically defined positions on an input element becomes necessary or the purpose of the input element has changed.

In a further embodiment, a separating element is provided in order to separate the magnetic field sensor from the magnetic element. The separating element is preferably producible from a magnetically neutral material such as plastic, so that it does not adversely affect the operation of the input element. The separating element can prevent a contamination, which can penetrate the input element from the direction of the operator control element, in particular, from reaching the magnetic field sensor and damaging its operation. By way of example, it is thus possible for dust, liquids or residues of meals with

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016Ρ013ΟOWOAU which an operator is busy to be safely kept away from the magnetic field sensor. If the input element is inset in a control panel or a similar structure, for example, then the separating element may be fitted to the control panel, so that the separation between a control side of the input element with the operator control element and an evaluation side of the input element with the magnetic field sensor may be embodied in hermetic fashion. The latching element is preferably arranged on the input side.

In a particularly preferred embodiment, the input element is set up for redundantly determining the position of the operator control element. To this end, the input element can further comprise a further magnetic field sensor for determining a magnetic field and a further elevation device for determining the position of the operator control element on the basis of the magnetic field determined by means of the further magnetic field sensor. Preferably, measuring directions of the two magnetic field sensors form an angle of between 0° and 180° with one another.

If the movement of the operator control element of an input element from one predetermined mechanical position to another, for example, causes a translational movement by the magnetic element along a trajectory, then one of the magnetic field sensors may be fitted beside the trajectory and the other may be fitted at one of the ends of the trajectory. The magnetic field sensors in this case can determine different aspects of the respective local magnetic field influenced by the magnetic element. For the best possible separation, it is preferred for the measuring directions to form an angle of approximately 90° with one another.

Preferably, each magnetic field sensor has an associated evaluation device. In particular, the first magnetic field sensor may have an associated first evaluation device and the

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016Ρ013ΟOWOAU second magnetic field sensor may have an associated second evaluation device. The presence of a critical element whose failure can prevent the determination of the position by means of the two magnetic field sensors can thus be avoided in improved fashion. The strict separation of different measuring paths means that redundancy and hence failsafety of the input element can be increased distinctly.

In one embodiment, the input element is set up to be used in surroundings in which an increased safety demand level (e.g. SIL2) is called for.

The evaluation device can have an interface to a communication bus. If two evaluation devices are used, then each evaluation device may have an associated communication bus. The communication bus may in particular be designed on the basis of I2C, SPI or CAN. In particular, it is preferred for the communication bus to be embodied in serial fashion in order to decrease the number of lines to the input element. As a further preference, the communication bus allows addressing of individual terminals, so that in particular different input elements can be polled in succession.

It is thus possible, by way of example, for cyclic polling of multiple input elements to take place, or particular input elements can be polled more often than other input elements.

An input system comprises multiple instances of the described input elements, preferably in the embodiment having multiple magnetic field sensors, and a processing device connected to the input elements by means of a communication bus. In this case, the processing device comprises an interface for providing indications of positions of the input elements. The interface can comprise a further communication bus, in particular a serial communication bus such as IC2, SPI or CAN. Preferably, a message comprising indications of the positions

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016Ρ013ΟOWOAU of multiple input elements can be provided on the interface. The input system may be of simple design and flexibly alterable. Production and assembly costs can be reduced. The input system may be embodied in relatively lightweight and space-saving fashion. Each input element can be scanned redundantly in one of the embodiments, so that a determination certainty of the input system may be increased. The input system can therefore be used in improved fashion to control a safety-relevant system such as a locomotive.

The processing device is preferably set up to determine for the input elements a respective position of the operator control element in one of the predetermined positions on the basis of measured values transmitted via the communication bus from the magnetic field sensors. Expressed another way, the processing device is preferably responsible for performing mapping of a measured value from a magnetic field sensor onto one of multiple mechanical positions of an associated operator control element. In this case, it is in particular possible for a redundancy check or plausibilization to be performed if the input element has more than one magnetic field sensor. If, by way of example, it is determined that the positions of two magnetic field sensors of an input element are not as well matched to one another as predetermined or one of the determined positions does not match a predetermined mechanical position of the associated operator control element, then the determined position can be marked as invalid or set to a value associated with an invalid determination.

In a further embodiment, the processing device is set up to provide information indicating a determination quality for a position of an operator control element of an input element via the interface. This information can comprise an indication of the invalid determination described above. In a preferred embodiment, it is also possible for a value with a higher resolution to be managed for a determination quality.

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It is moreover preferred for the input system to comprise a central power supply for the input elements and the processing device. In an embodiment having multiple magnetic field sensors per input element, there may also be two central power supplies provided that are each associated with one of the magnetic field sensors. The input system may therefore be of improved consistently redundant design.

It is moreover preferred for the processing device to comprise a further interface for transmitting determined positions of the input elements. The further interface may be designed just like the aforementioned first interface or use a different medium, for example. In one embodiment, the first interface comprises an electrical medium, as specified for a parallel or serial bus, for example, while the second interface comprises a pneumatic medium, for example, or a discrete wired connection, that is to say a number of individual electrical conductors that are each associated with an input element or even a predetermined position of an operator control element of an input element.

The properties, features and advantages of this invention that are described above and the way in which they are achieved will become clearer and more distinctly comprehensible in connection with the description of the exemplary embodiments that follows, these being explained in more detail in connection with the drawings, in which

FIG. 1 depicts an input system for use in a locomotive;

FIG. 2 depicts variants of input elements for the input system of FIG. 1;

FIG. 3 depicts the input elements of FIG. 2 in an alternative embodiment with increased safety; and

FIG. 4 depicts a graph for determining a discrete position on the basis of an analog position.

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FIG. 1 shows an input system 100, in particular for use in a driver's cab, an engine room or an outer region of a locomotive. In particular, the input system 100 can be used to control a running state of a locomotive. The input system 100 comprises multiple input elements 105 and a processing device

110. The processing device 110 comprises an interface 115 for providing information indicating positions of the input elements 105. Optionally, there is also a further interface 115' provided, which is accordingly distinct. Preferably, one of the input elements 105 is connected to the processing device 110 by means of a communication bus 120. There may also be a further communication bus 120' provided, which may be connected to one of the input elements 105. In a preferred embodiment, the communication bus 120, 120' comprises a power supply for the input elements 105. In this regard, there may be dedicated power supply lines provided in the communication bus 120, 120', or information can be transmitted via power supply lines, for example by means of a data modulation method. The power supply may be embodied in redundant fashion in particular when second communication buses 120, 120' are used.

It is moreover preferred for a central power supply 125 to be provided that supplies the processing device 110 and the input elements 105 with power. In one embodiment, the central power supply 125 comprises the communication bus 120, that is to say that power that an input element 105 needs for its operation, for example, fitted a magnetic field sensor 170, which may preferably be embodied as a Hall sensor. The magnetic field sensor 170 is set up to determine the alteration of a distance or an orientation of the magnetic element 165 for the alteration of the position of the operator control element 145. In different embodiments, the magnetic field sensor 170 is set up to determine a magnetic field prevalent in its region in one or more directions.

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The magnetic field sensor 170 is connected to an evaluation device 175, which is preferably connected to the communication bus 120 by means of an interface 180. The evaluation device 175 is set up to take a measured value from the magnetic field sensor 170 as a basis for determining the position of the operator control element 145. In this case, it is preferred for the position to be determined without limitation to one of the mechanically prescribed positions 160. By way of example, an analog value can describe the position of the operator control element 145. In another embodiment, a digital value can be used that resolves the possible control path of the operator control element 145 to a higher extent than there are positions 160 defined. By way of example, 20 or fewer positions 160 may be mechanically defined, whereas the region of movement of the operator control element 145 is resolved with 6 bits, 8 bits, 10 bits or 12 bits. The position of the operator control element 145 as determined by the evaluation device 175 can then be transmitted to the processing device 110 via the interface 180 and the communication bus 120. The processing device 110 is preferably set up to perform mapping of the transmitted position onto one of the predetermined mechanical positions 160. This is described even more precisely below with reference to FIG. 4. The transmission of information between the evaluation device 175 and the processing device 110 can be initiated by the evaluation device 175 or via the processing device 110 in different embodiments.

In one embodiment, one of the input elements 105 has an associated further, additional magnetic field sensor 170' in order to determine the position of the operator control element 145 by means of the alteration of a magnetic field by the magnetic element 165. Preferably, each of the sensors 170' has an associated additional evaluation device 175' that is connected to the further communication bus 120' by means of an additional interface 180 (cf. FIG. 1). The magnetic field sensors 170, 170' are preferably fitted with reference to the

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016Ρ013ΟOWOAU magnetic element 165 such that they can determine the position of the same operator control element 145 in different ways. In particular, it is preferred for measuring directions of the magnetic field sensors 170, 170' to form an angle with one another that is greater than or equal to 0° and less than or equal to 180°, preferably around 90°. In one embodiment, one of the magnetic field sensors 170, 170' is fitted such that it determines a distance from the magnetic element 165, while the other magnetic field sensor 170, 170' determines an orientation or direction of the magnetic element 165. The fitting of the magnetic field sensors 170, 170' to the input element 105 is effected preferably on the basis of the chosen trajectory 150.

In another embodiment, the angle w may also be approximately 90° or approximately 180°, so that the measuring directions of the magnetic field sensors 170, 170' are aligned substantially parallel or antiparallel. By way of example, the magnetic field sensors 170, 170' may be fitted on different sides of a circuit board or as close to one another as possible on the circuit board.

In this embodiment, it is preferred for the processing device 110 to be set up not only to perform mapping of the position of an operator control element 145 of an input element 105 as determined on the basis of the magnetic field sensors 170 onto one of multiple predetermined mechanical positions 160, but also additionally to perform plausibilization. The plausibilization can in particular result in the determination of how well the determined (analog) positions match one another or the individual mechanical positions 160. If the determined positions are inconsistent with one another, then the position determined for the input element 105 can be set to a predetermined value that is not consistent with the mechanical position 160 but rather represents a failed position determination. Additionally or alternatively, an appropriate

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016Ρ013ΟOWOAU message indicating the failed position determination can be provided via one of the interfaces 115, 115'.

While it is preferred for the interfaces 115 and 115' to be of electrical design and moreover to be able to be consistent with a predetermined specification, for example for a serial transmission bus, another embodiment may have one of the interfaces 115, 115' designed differently than the other interface 115, 115' in order to provide a second path of action. In this regard, one of the interfaces 115, 115' can comprise dedicated wire connections for individual positions of an input element 105, for example, instead of the communication bus, or a pneumatic interface or a pneumatic actuator, for example. The interfaces 115, 115' are set up to be connected to a control device, which can perform safety-relevant control of an element, in particular. The element can relate to an engine or another device whose malfunction can result in personal injury or considerable material damage occurring. By way of example, the element can relate to a running function of a locomotive, in particular a speed control or a braking function .

FIG. 2 shows variants of input elements 105 for the input system 100 of FIG. 1. A first input element 105.1, a second input element 105.2 and a third input element 105.3 are each depicted in a plan view, as provided for an operator, and depicted in two longitudinal sections, each input element 105 being depicted in unoperated fashion in the first longitudinal section and in operated fashion in the second longitudinal section. The input elements 105 correspond in an exemplary manner to those of FIG. 1. For the purposes of better illustration, the input elements 105 are depicted incompletely (cf. FIG. 1).

In an exemplary manner, the first input element 105.1 comprises a rotary switch or rotary pushbutton switch, in the case of

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016Ρ013ΟOWOAU which the operator control element 145 can be rotated about an axis 205. The magnetic element 165, depicted in the form of a magnet by way of example, is fitted to an axial end of the operator control element 205 and changes its rotational alignment about the axis of rotation 205 when the operator control element 145 of the first input element 105.1 changes its position. The magnetic field sensor 170 is, by way of example, fitted axially in relation to the magnetic element 165 with reference to the axis 205 and set up to determine the alignment of the magnetic field caused by the magnetic element 165.

The exemplary second input element 105.2 comprises a pressure switch or pushbutton switch, in the case of which the operator control element 145 can be moved along an axis 205. The magnetic field sensor 170 is, in an exemplary manner, arranged with a lateral offset with reference to the axis 205 and set up to determine an alignment of the magnetic field caused by the magnetic element 165, or the strength of said magnetic field. The strength corresponds to the distance between the magnetic element 165 and the magnetic field sensor 170 and therefore indicates a position of the operator control element 145.

The third input element 105.3 depicted by way of example comprises a pivot lever that can be pivoted about an axis 205 that preferably runs parallel to the structure 130. The magnetic element 165 is fitted to the operator control element 145 outside the axis 205 and the magnetic field sensor 170 is mounted in a predetermined position with reference to the axis 205. When the operator control element 145 of the third input element 105.3 is pivoted about the axis 205, a strength and an alignment of the magnetic field caused by the magnetic element 165 can change in the region of the magnetic sensor 170.

In a further embodiment, a well 135 is further provided, configured in particular as a dirt well. The well 135 may, as

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016Ρ013ΟOWOAU depicted, be fitted beneath the input elements 105 or, in another embodiment, between the structure 130 and lower sections of the input element 105.

In a particularly preferred embodiment, the well 135 is fitted between various subunits of the input element 105, wherein a first subunit comprises the operator control element 145 and a second subunit comprises the magnetic field sensor. The well 135 itself can belong to one or to the other subunit in different embodiments. The input element 105 may be embodied so as to be separable along the well 135, so that the first and second subunits can be removed from one another.

In a preferred embodiment, an individual well 135 is provided for an input element 105. The well 135 can define two sides on the input element 105, namely an input side with the operator control element 145 and an evaluation side with the magnetic field sensor 170. The latching device 155 may also be situated on the input side. The well 135 may be connected to the structure 130 or fitted thereto. The well 135 may be embodied so as to be impervious to dust or liquid and may preferably be connected to the structure 130 in a manner impervious to dust or liquid. The well 135 may be cup-shaped, for example, in order to receive the operator control element 145 and ensure adequate mobility. Preferably, the well 135 comprises a nonmagnetic material such as plastic.

FIG. 3 depicts the input elements 105 of FIG. 2 in an alternative embodiment with increased safety. In addition to the elements depicted in FIG. 2, each input element 105 also comprises a further magnetic field sensor 170'. In an exemplary manner, the further magnetic field sensor 170' of the first input element 105.1 is fitted laterally beside the axis 205 and set up to determine a strength or alignment of the magnetic field caused by the magnetic element 165. The further magnetic field sensor 170' of the second input element 105.2 is, by way

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016Ρ013ΟOWOAU of example, fitted axially in relation to the magnetic element 165. When the operator control element 145 of the second input element 105.2 is moved along the axis 205, the distance between the magnetic element 165 and the further magnetic field sensor 170' changes. On the third input element 105.3, the further magnetic field sensor 170' is displaced relative to the magnetic field sensor 170 by a predetermined angle with reference to the axis 205.

In all cases, it is preferred for the magnetic field sensors 170 and 170' each to have a measuring direction, wherein the measuring directions of the magnetic field sensors 170, 170' form a predetermined angle with one another that is preferably in the region of approximately 90°. If the magnetic field sensor 170 is embodied as simple Hall sensor, for example, then the measuring direction is consistent with the direction run in order to be If the magnetic field in which a magnetic field needs to determined by means of the Hall sensor sensor 170 comprises a multidimensional magnetic field sensor, then it is preferred for it to comprise multiple single magnetic field sensors whose measuring directions are at a right angle in relation to one another. The measuring directions between magnetic field sensors 170 and 170' preferably form the predetermined angle in pairs in this case.

FIG. 4 shows a graph 400 for determining a discrete position 160 on the basis of an analog position. In the horizontal direction, a position of an operator control element 145 of an input element 105 with reference to a support element 140 is depicted, the position having been determined on the basis of a magnetic field measurement by means of a magnetic field sensor 170, as described above. This position can relate in particular to a translation along an axis 205 or a trajectory 150 or a rotation about an axis 205 or along a trajectory 150. In the vertical direction, a corresponding position is depicted that has been determined by means of a further magnetic field sensor

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170'. Moreover, mechanically prescribed positions 160 are shown that are prescribed by the latching device 155. Depicted around each mechanical position 160 is a region 405 in which the positions determined by means of the magnetic field sensors 170, 170' need to be in order to positively determine that the corresponding mechanical position 160 has been adopted by the operator control element 145. If the combination of the determined positions is outside one of the regions 160, then an invalid position can be determined. The positions determined by means of the different magnetic field sensors 170 and 170' then do not correspond to one another or to a predetermined mechanical position 160, which means that the determination is implausible .

Although the invention has been illustrated and described in more detail by the preferred exemplary embodiment, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by a person skilled in the art without departing from the scope of protection of the invention .

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