DE202019000816U1 - Planar rotor position measuring system - Google Patents

Abstract

Passive rotor position measuring system,
comprising an active planar stator (1), a translational passive planar rotor (2) and a sensor unit (3),
the active planar stator (1) having a planar stator tooth structure (7) and motor coils (8),
wherein the stator tooth structure (7) is arranged in a stator X axis (4) and a stator Y axis (5) of a stator plane (6) and is formed by stator teeth (9) and stator tooth gaps (10),
wherein the motor coils (8) are assigned to the stator tooth structure (7) and the stator tooth structure (7) and motor coils (8) are designed to form a movable stator magnetic field (11),
the passive planar rotor (2) being linearly movable in relation to the stator x-axis (4) and the stator y-axis (5) in the stator plane (6) and having permanent magnetic magnetic poles (12),
the permanent magnetic magnetic poles (12) forming a rotor magnetic field (13),
wherein the permanent magnetic magnetic poles (12) of the same polarity form magnetic pole lines (14) in a rotor X-axis (4) and in a rotor Y-axis (5), magnetic pole lines (14) of different polarity being arranged alternately,
wherein magnetic poles (12) of different polarity intersect magnetic pole diagonals (15) diagonally to the rotor X-axis (4) and the rotor Y-axis (5) and wherein the magnetic poles (12) form magnetic zero lines (16) which are each arranged between two magnetic pole diagonals (15),
and the magnetic poles (12) form increments,
The sensor unit (3) is arranged on the planar stator (1) and is designed to detect an absolute position of the planar rotor (2), the sensor unit (3) having a sensor arrangement (17), an evaluation unit (18) and a voltage source (19) ,
wherein the sensor arrangement (17) has at least five sensors (20), at least three sensors (20) being arranged in the stator X-axis and three sensors (20) in the stator Y-axis,
the sensors (20) detecting the rotor magnetic field (13),
wherein the evaluation unit (18) is connected to the sensors (20) and is designed by means of an X-axis increment count and the detection of an intra-incremental X-axis position to record an X-axis absolute position and by means of a Y-axis increment count and Detection of an intra-incremental Y-axis position, recording an absolute Y-axis position,
XY coordinates of an absolute position of the planar rotor in the stator plane (1) can be determined from the axis absolute positions
and wherein the voltage source (19) supplies the sensors (20) and the evaluation unit (18).

Description

The invention relates to a planar rotor position measuring system for a planar motor with an active stator for determining a position of a planar rotor.

Systems for determining a position of an electrically driven rotor of a planar motor with a permanent magnetic stator magnetic field are known from the prior art. The position of the rotor can be determined by its position relative to the stator magnetic field. The disadvantage of these solutions is that they are only of limited use in an active stator due to the variable magnetic field of the stator. There is also the disadvantage that when the stator magnetic field is switched off, the position of the rotor can no longer be determined and, moreover, the rotor must carry out a calibration run to a zero position after each restart.

The object of the invention is to show a passive rotor position measuring system for planar motors with an active stator, with which a position of the rotor can be determined at any time, which is simple and inexpensive to manufacture and does not make any particular demands on the operating states of the planar motor.

The object is achieved by the features listed in protection claim 1. Preferred further developments result from the subclaims.

According to the invention, the passive rotor measuring system has an active planar stator, a translational passive planar rotor and a sensor unit.

The active planar stator is also referred to below as the planar stator. According to the invention, it has a stator tooth structure. This is arranged planar in a stator X axis and a stator Y axis of a stator plane. The stator x-axis and the stator y-axis are preferably arranged orthogonally to one another and in each case parallel to the stator plane.

The stator tooth structure is formed in a manner known per se by stator teeth and stator tooth gaps. The stator teeth consist of an electrically magnetizable material, which is preferably particularly soft magnetic.
The stator teeth are shaped such that they protrude from the stator plane preferably perpendicular to the stator plane and thus at the same time perpendicular to the stator X axis and the stator Y axis. The geometrical shape of the stator teeth is not specified here. Preferably, a shape is used that is easy to manufacture and has a similar symmetry in the X and Y directions.
The stator tooth gaps are located between the stator teeth and are preferably filled with a non-magnetizable material, for example with a polymer or a ceramic. By filling the stator tooth gaps, the stator teeth are mechanically stabilized and protected from contamination and can thus also be integrated into the load-bearing layer of roadways. Formations of the stator tooth structure are also possible, which are composed of linear structures in the stator Y axis and linear structures in the stator X axis in the stator plane. In this way, several linear stator units can be interconnected to form an active planar stator, with which the planar rotor can be moved in the stator x-axis, in the stator y-axis and in directions with portions of both axes.

According to the invention, the planar stator also has motor coils. These are assigned to the stator tooth structure.
The motor coils are preferably wound along the stator teeth and consist of a winding of an electrical conductor. When a current is applied, the stator teeth are magnetized. The motor coils are switched in such a way that an electrical current can preferably be applied to them independently of one another.

According to the invention, the stator tooth structure and the motor coils are designed to form a movable stator magnetic field. By changing the direction of flow and the strength of the current applied to the individual stator teeth, a stator magnetic field can be generated which can be modulated in a targeted manner in terms of its alignment and magnetic flux density.

The specific design of the stator tooth structure and the motor coils is not essential for the invention, since the stator magnetic field generated thereby is only relevant for driving the planar rotor, but not for determining the position of the planar rotor.

According to the invention, the translational passive planar rotor, abbreviated also referred to as planar rotor, has permanent magnetic magnetic poles and can be moved linearly to the stator X axis and to the stator Y axis in the stator plane.

The translational passive planar rotor can be integrated in a holder or superordinate device or can be the carrier of devices which are not part of the measuring system according to the invention. For example, the holder can be designed, the translational passive planar rotor on balls, rollers, wheels or an air cushion at a desired height above the active planar stator.

The permanent magnetic magnetic poles of the planar rotor face the active planar stator.

According to the invention, the permanent magnetic magnetic poles form a rotor magnetic field. The planar rotor is arranged so that the rotor magnetic field is spatially superimposed on the movable stator magnetic field and interacts with it. By modulating the movable stator magnetic field, a directed force is generated on the planar rotor by the electromagnetic interaction of the magnetic fields, whereby the planar rotor is moved accordingly.

According to the invention, the permanent magnetic magnetic poles of the same polarity form magnetic pole lines in the rotor X-axis and the rotor Y-axis. Magnetic pole lines of different polarity are arranged alternately with one another.

According to the invention, magnetic poles of different polarity form intersecting magnetic pole diagonals which are arranged diagonally to the rotor X axis and to the rotor Y axis. The magnetic poles are essentially arranged such that a magnetic pole of one polarity sits in the middle of an imaginary square and there are four magnetic poles of the other polarity at the four corners of the same square.

According to the invention, the magnetic poles form magnetic zero lines, which are each located between two magnetic pole diagonals. The magnetic zero lines run between and parallel to the magnetic pole diagonals. The magnetic zero lines denote the areas in which there is essentially no magnetic flux.

According to the invention, the magnetic poles form increments. Due to the regular distances between the magnetic poles, an arbitrarily large length can be calculated from the number of magnetic pole pairs traveling over and from their distance. This applies to both the rotor x-axis and the rotor y-axis. Here, a pair of magnetic poles is preferably formed from two adjacent magnetic poles of the same polarity. An increment preferably corresponds to the distance within a pole pair or a multiple thereof. An increment can also be formed by any two periodically repeating points in the rotor magnetic field. For example, the distances between the magnetic zero lines, the magnetic pole lines, the magnetic pole diagonal, their intersections and multiples thereof can also be used.

According to the invention, the sensor unit has a sensor arrangement, an evaluation unit and a voltage source and is arranged on the planar stator. At least the sensor arrangement is in a fixed positional relationship to the planar stator.

The sensor unit can preferably also have a plurality of sensor arrangements which are preferably arranged at regular intervals from one another. The planar stator is preferably composed of a plurality of subfields which are interconnected and thus transfer the planar rotor to one another and take it over from one another as it moves. In this case, each subfield preferably has a sensor arrangement. The size of the planar stator or its subfields, the size of the planar rotor and the position of the sensor arrangement or the sensor arrangements are coordinated such that the planar rotor always covers at least one sensor arrangement. The distances between the sensor arrangements are smaller than the simple edge length of the planar rotor. In the case of spatially large planar runners and spatially small subfields, it is therefore possible that not every subfield, but for example in every extension in the X or Y direction, has only every second or third subfield a sensor arrangement. Conversely, it is possible that in the case of spatially small planar rotors and spatially large subfields, one subfield has several sensor arrangements.

It is also possible to realize an irregular distribution of the sensor arrangements. For this purpose, their arrangement is stored in the evaluation unit and included in the calculation of the planar runner position.

According to the invention, the sensor unit is designed to detect a position of the planar rotor.

According to the invention, the sensor arrangement has at least five sensors, at least three sensors being arranged in the stator X axis and three sensors being in the stator Y axis. The arrangement of the sensors can preferably be realized in a cross or an L shape, the sensor being designed at the intersection of the stator X and Y axes to measure both in the X and Y directions.

The distance between the two outer sensors for one direction is equal to or less than the distance between the magnetic poles of a magnetic pole pair of the planar rotor. For example, the distance between the magnetic poles of a pair of magnetic poles in the rotor X-axis is the distance between a north magnetic pole and the neighboring north magnetic pole.

The use of three sensors enables the increments to be counted as well as the intra-incremental detection of the rotor magnetic field. Intra-incremental detection is understood to mean the detection of the magnetic field within an increment for determining the position in this increment.

According to the invention, the sensors detect the rotor magnetic field. The sensors are aligned and arranged so that they detect the rotor magnetic field when the planar rotor is above them.

The at least three sensors per axis provide at least three values for the magnetic field strength per axis. The position on the sinusoidal curve of the course of the magnetic field is clearly defined by three values. This applies to each of the two axes.

According to the invention, the evaluation unit is connected to the sensors and is designed to record an X-axis absolute position by means of an X-axis increment count and the detection of an intra-incremental X-axis position. The evaluation unit is also designed according to the invention to record an absolute Y-axis position by means of a Y-axis increment count and the detection of an intraincremental Y-axis position.

The evaluation unit is data-connected to the sensors and receives the measurement data from the sensors.
The evaluation unit uses the measurement data of the sensors to determine a count of entire increments that have been run over and the intraincremental position in the last, not completely passed over increment. The evaluation unit calculates the X-axis absolute position and the Y-axis absolute position of the translational passive planar rotor from the sum of the increments passed and the intraincremental position.

The evaluation unit is preferably formed by a controller or computer which additionally has a memory.

According to the invention, the XY coordinates of a position of the planar rotor in the stator plane are determined from the two axis positions. For this purpose, the XY coordinates of a position of the planar rotor are calculated from the two axis positions of the planar rotor. The evaluation unit calculates the respective distances to an intersection of the two axes. This intersection is preferably the coordinate origin. Furthermore, it is also possible to determine a position of the planar rotor which is only relative to another position, so that information about a distance traveled is then available. The solution thus offers the possibility of determining an absolute position as well as relative positions.

According to the invention, the voltage source supplies the sensors and the evaluation unit.

It is essential for the invention that the sensor unit is arranged in the planar stator and uses the permanent magnetic rotor magnetic field for the position determination. It works as an advantage regardless of the stator magnetic field. Another particular advantage is that the permanent magnetic rotor magnetic field is available regardless of the operating state of the planar motor.
One advantage is that in an embodiment with several sensor arrangements, an absolute position can be determined by means of a short calibration run even after the voltage supply has been switched off. This is based on the following. The evaluation unit loses the information in which increment the planar runner is. However, the position of the planar rotor is known from the position of the sensor arrangement, which detects the planar rotor after it is switched on, to the extent that it is located above which sensor arrangement. Now a movement in the stator X axis and in the stator Y axis is carried out until the planar rotor enters the detection range of the adjacent sensor arrangement. Since the positions of the adjacent sensor arrangements are also known, the absolute position of the planar rotor is now known without the planar rotor having to be moved to a specific zero position of the planar stator.

According to an advantageous development, the sensor unit has a plurality of sensor arrangements. Here, the evaluation unit is connected to all sensor arrangements.
The sensor arrangements are arranged relative to one another in such a way that the translational passive rotor is detected in each case when the vehicle is run over. Their spacing and number are matched to the dimensions of the translational passive planar rotor. The distances between the sensor arrangements are smaller than the simple edge length of the translational passive planar rotor.
The advantage is that even with large planar extensions of the planar stator, the planar rotor is detected by the sensor arrangements in every position and movement.

According to a further advantageous development, the voltage source is designed as a permanent voltage source.

According to the invention, the permanent voltage source supplies the sensors and the evaluation unit. The permanent voltage source supplies the sensors and the evaluation unit with electrical energy independently of a main system. The main system is understood in particular to be the energization of the magnetic coils in order to modulate the stator magnetic field in order to bring about the movement of the planar rotor. The permanent voltage source can access an energy store such as batteries or have a permanent power supply connection.

Thus, even when the main system is switched off, the sensors record movements of the translational passive planar rotor in the stator plane and the absolute positions are retained after a system restart.
This means that calibration runs that are otherwise required can be avoided. In combination with the permanent voltage supply of the sensor unit, the planar rotor position can thus be determined at any time and in particular also after passive movements of the planar rotor.

According to an advantageous development, the permanent voltage source has a rechargeable energy store. The advantage of using a rechargeable energy store for the permanent voltage source is the greatly reduced maintenance effort for the active planar stator.
In the event of a power failure, the absolute positions determined are not lost in the evaluation unit. By using two accumulators it is possible to charge one while the other provides its energy.

• 1 Passivläuferpositionsmesssystem (Draufsicht)
• 2 Passivläuferpositionsmesssystem in alternativer Statorausbildung (Draufsicht)
• 3 Passivläuferpositionsmesssystem (Seitenansicht)
• Fig.°4 translatorischer passiver Planarläufer (detaillierte Draufsicht)
• Fig.°5 mögliche Sensoranordnungen (Detailansicht) näher erläutert.

The invention is used as an embodiment based on

• 1 Passive rotor position measuring system (top view)
• 2nd Passive rotor position measuring system in alternative stator design (top view)
• 3rd Passive rotor position measuring system (side view)
• Fig. 4 translational passive planar rotor (detailed top view)
• Fig. 5 possible sensor arrangements (detailed view) explained in more detail.

In 1 the passive rotor position measuring system is shown in plan view. It is the active planar stator 1 , the translational passive planar runner 2nd and the sensor unit 3rd shown.
The active planar stator 1 becomes from the stator level 6 and the tooth structure 7 educated. The tooth structure 7 again turns out of the stator teeth 9 and the stator tooth gaps 10th educated. The stator teeth 9 consist of a soft magnetic metal and are with the motor coils 8th wrapped around.
The motor coils are only in 2nd shown. Between the stator teeth 9 are the stator tooth gaps 10th , which is cast with a filling compound in this version. This creates a smooth surface in the stator plane 6 . The stator plane extends in the stator X axis 4 and the stator Y axis 5. In the stator tooth spaces 10th are the sensors 20 the sensor arrangements 17th arranged. In this embodiment, the sensor arrangements are 17th cruciform.
The sensors 20 the sensor arrangements 17th are with the evaluation unit 18th data connected.
The evaluation unit 18th and the sensors are powered by a voltage source 19th , which is designed in the exemplary embodiment as a permanent voltage source, with electrical current from a rechargeable energy store 21 provided. The translational passive planar runner 2nd has permanent magnetic poles 12th on.

2nd shows a passive rotor measuring system with an active planar stator 1 in an alternative education. The stator teeth 9 are arranged in linear subunits, which together form a planar arrangement of the stator tooth structure. In this exemplary embodiment, there are two subunits in an X orientation, also called X bridges, and two subunits in a Y orientation, also called Y bridges. The X bridges make up the part of the planar rotor that moves 2nd in the X direction and the Y bridges the movement share of the planar rotor 2nd in the Y direction.

The passive planar runner 2nd is in 2nd not shown in the operating position, but shifted upwards to the right to provide a view of the sensor arrangement 17th with the sensors 20 to release. The sensor arrangement 17th has nine sensors in this embodiment 9 in a preferred arrangement of three times three sensors 20 on. The sensor arrangement 17th is advantageous in this embodiment due to the special arrangement of the stator teeth 9 formed free space arranged.

The planar runner is in the operating position 2nd with the permanent magnetic magnetic poles 12th over the sensor array 17th positioned so that the sensors 20 that of the permanent magnetic magnetic poles 12th rotor magnetic field formed (reference symbol 13 according to 3rd ) capture. The evaluation unit with voltage source is in for simplification 2nd not shown.

The 3rd shows the passive rotor position measuring system in a side view. In this figure is illustrates how the passive rotor position measuring system works.
The active planar stator 1 exhibits the tooth structure already described 7 on. The stator teeth 9 are with the motor coils 8th wrapped around. Will the motor coils 8th A moving stator magnetic field is applied at different times with an electric current 11 generated. This interacts with the rotor magnetic field 13 ; which is due to the permanent magnetic magnetic poles 12th is generated and causes a movement of the translational passive planar rotor 2nd over the stator level 6 . The accelerating force and its direction of action can be set by controlling the current strength and the direction of flow of the electrical current. By optimally controlling the motor coils 8th can be the translational passive planar runner 2nd any in the stator X axis 4 and the stator Y axis 5 in the stator plane 6 be moved. In 2nd only the stator X-axis 4 is shown. However, an analog structure is present in the stator Y axis 5.

The sensor unit 3rd consists of an evaluation unit 18th and a sensor arrangement 17th .

In order to detect the increments passed and the intraincremental position, the sensor arrangement 17th at least three sensors for each axis 20 needed. In this version, a total of five sensors 20 in the sensor arrangement 17th used and the middle sensor 20 detects the rotor magnetic field 13 in the rotor X and rotor Y axes, which creates a sensor 20 can be saved. The sensors 20 send the recorded data to the evaluation unit 3rd . In this version, an increment corresponds to the distance between two permanent magnetic magnetic poles 12th .

The evaluation unit 3rd has a voltage source 19th as a permanent voltage source with a rechargeable energy storage 21 on. The voltage source 19th draws electrical energy from the rechargeable energy storage 21 and thus supplies the evaluation unit 3rd and the sensors 20 .
The evaluation unit 3rd uses that from the sensors 20 acquired data to an axis absolute position of the translational passive planar rotor 2nd to be determined on the stator X-axis 4 and the stator-Y-axis 5. From the axis absolute positions, the evaluation unit uses the XY coordinates to determine an absolute position of the translational passive planar rotor 2nd to calculate.

In 4th is the translational passive planar runner 2nd presented in more detail. Because the sinusoidal curves of the strength of the magnetic flux both in the rotor X-axis 22 as well as in the rotor Y axis 23 are arranged, a mountain range of the strength of the magnetic flux is formed, which has the following characteristic lines.
It will be in 4th the characteristic lines of the rotor magnetic field 13 shown. For a better overview, the courses of the field lines are not shown. In the following, the terms "line" and "diagonal" represent a relative alignment to the rotor x-axis 22 and the rotor y-axis 23 represents.
The permanent magnetic magnetic poles 12th of the same polarity are each on a magnetic pole line 14 and the permanent magnetic magnetic poles 12th different polarity are on a magnetic pole diagonal 15 arranged. On the magnetic pole line 14 and the magnetic pole diagonals 15 the extremes of the magnetic field strength lie directly above the permanent magnetic poles 12th . The zero crossings of the magnetic field strength are between the magnetic poles 12th and in interaction form magnetic zero lines 16 between the magnetic pole diagonals 15 lie out.

The extrema as maxima above the magnetic poles and as minima at the zero crossings in the gaps form striking points in the periodic rotor magnetic field, which are suitable for defining an increment. In this version, the extremes are above the magnetic poles 12th used with the same polarity for the definition of an increment.

In 5 are the different variants of the arrangement of the sensors 20 in the sensor arrangement 17th shown. Here, only one of the sensors is used 20 provided with an exemplary reference number.

Variants a) to c) show the use of five sensors, each with the sensor 20 is formed at the intersection of the linear arrangements to detect the rotor magnetic field in the rotor X-axis and in the rotor Y-axis. There are three ways of arranging five sensors. According to variant a) they can be arranged in a cross shape, according to variant b) T-shaped and according to variant c) L-shaped.
Variant d) shows an arrangement of six sensors (three for each axis). The arrangement of six sensors according to variant d) has two rows of three perpendicular to each other (one row of three for each axis). The rows of three can be arranged to each other as long as the vertical alignment of the rows of three to each other is maintained and the size of the planar rotor is not exceeded.

Variant e) also shows a particularly preferred arrangement with nine sensors. Three sensors are available three times in each axis, so that a particularly precise and reliable calculation of the planar rotor position is possible. Each of the sensors 20 is thus designed to detect the rotor magnetic field in the rotor X-axis and in the rotor Y-axis.

Reference list

1

active planar stator

2nd

translational passive planar runner

3rd

Sensor unit

4th

Stator X axis

5

Stator y-axis

6

Stator level

7

Stator tooth structure

8th

Motor coils

9

Stator teeth

10th

Stator tooth gaps

11

movable stator magnetic field

12th

permanent magnetic magnetic poles

13

Rotor magnetic field

14

Magnetic pole lines

15

Magnetic diagonal

16

magnetic zero lines

17th

Sensor arrangement

18th

Evaluation unit

19th

Voltage source

20

Sensors

21st

rechargeable energy storage

22

Runner X axis

23

Runner Y axis

Claims (4)

Passive rotor position measuring system, comprising an active planar stator (1), a translational passive planar rotor (2) and a sensor unit (3), the active planar stator (1) having a planar stator tooth structure (7) and motor coils (8), wherein the stator tooth structure (7) is arranged in a stator X axis (4) and a stator Y axis (5) of a stator plane (6) and is formed by stator teeth (9) and stator tooth gaps (10), wherein the motor coils (8) are assigned to the stator tooth structure (7) and the stator tooth structure (7) and motor coils (8) are designed to form a movable stator magnetic field (11), the passive planar rotor (2) being linearly movable in relation to the stator x-axis (4) and the stator y-axis (5) in the stator plane (6) and having permanent magnetic magnetic poles (12), the permanent magnetic magnetic poles (12) forming a rotor magnetic field (13), wherein the permanent magnetic magnetic poles (12) of the same polarity form magnetic pole lines (14) in a rotor X-axis (4) and in a rotor Y-axis (5), magnetic pole lines (14) of different polarity being arranged alternately, wherein magnetic poles (12) of different polarity intersect magnetic pole diagonals (15) diagonally to the rotor X-axis (4) and the rotor Y-axis (5) and wherein the magnetic poles (12) form magnetic zero lines (16) which are each arranged between two magnetic pole diagonals (15), and the magnetic poles (12) form increments, The sensor unit (3) is arranged on the planar stator (1) and is designed to detect an absolute position of the planar rotor (2), the sensor unit (3) having a sensor arrangement (17), an evaluation unit (18) and a voltage source (19) , wherein the sensor arrangement (17) has at least five sensors (20), at least three sensors (20) being arranged in the stator X-axis and three sensors (20) in the stator Y-axis, the sensors (20) detecting the rotor magnetic field (13), wherein the evaluation unit (18) is connected to the sensors (20) and is designed to record an X-axis absolute position by means of an X-axis increment count and the detection of an intraincremental X-axis position and by means of a Y-axis increment count and the Detection of an intra-incremental Y-axis position, recording an absolute Y-axis position, XY coordinates of an absolute position of the planar rotor in the stator plane (1) can be determined from the axis absolute positions and wherein the voltage source (19) supplies the sensors (20) and the evaluation unit (18). Passive rotor position measuring system according to Claim 1 , characterized in that the sensor unit (3) has a plurality of sensor arrangements (17) and the evaluation unit is connected to these sensor arrangements (17). Passive rotor position measuring system according to one of the preceding claims, characterized in that the voltage source (19) is designed as a permanent voltage source. Passive rotor position measuring system according to Claim 3 , characterized in that the Permanent voltage source (19) has a rechargeable energy store (21).

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