Method for controlling an electrically adjustable seat assembly and electrically adjustable seat assembly
Patent Information
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- BROSE FAHRZEUGTEILE GMBH & CO KG
- Filing Date
- 2024-08-14
- Publication Date
- 2026-06-24
Smart Images
Figure EP2024072881_20022025_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] Method for controlling an electrically adjustable seat assembly and electrically adjustable seat assembly
[0003] The invention relates to a method for controlling an electrically adjustable seat assembly. The invention also relates to an electrically adjustable seat assembly.
[0004] The interior of a motor vehicle typically contains at least one vehicle seat, designed as a single seat. Such a vehicle seat is typically part of a seat assembly, which is initially prefabricated and later installed in the interior of the motor vehicle.
[0005] In most cases, the seat assembly comprises, in addition to the vehicle seat, two pairs of rails over which the seat assembly is mounted in the interior of the vehicle and over which the vehicle seat can be moved or adjusted in a longitudinal direction. Such a seat assembly can be found, for example, in DE 102016 123 836 A1.
[0006] The object of the invention is to provide an advantageously designed electrically adjustable seat assembly and an advantageous method for controlling an electrically adjustable seat assembly.
[0007] With regard to the method, the object is achieved according to the invention with the features of claim 1, and with regard to the electrically adjustable seat assembly with the features of claim 12. Advantageous embodiments and refinements are the subject of the subclaims. The advantages and embodiments cited with regard to the method are also transferable to the seat assembly, and vice versa.
[0008] The method according to the invention is designed to control an electrically adjustable seat assembly according to the invention.
[0009] The electrically adjustable seat assembly according to the invention is, in turn, designed and configured to carry out the method according to the invention in at least one operating mode. Furthermore, the electrically adjustable seat assembly, i.e., the electrically adjustable seat assembly according to the invention, is designed for a motor vehicle, in particular a passenger car. It is typically initially prefabricated and later installed in the interior of the motor vehicle.
[0010] Independently of this, the seat assembly, i.e., the electrically adjustable seat assembly, includes a vehicle seat. The vehicle seat is typically designed as a single seat, for example, a driver's seat or a passenger seat.
[0011] The seat assembly also features two electric drive units. Each of the two electric drive units, in turn, features an electric motor. Thus, the seat assembly features two electric motors. Depending on the application, the electric motors are designed, for example, as so-called brushless motors.
[0012] In addition, the seat assembly has a control and evaluation unit that is signal-connected to the two electric motors for the purpose of controlling these electric motors. Depending on the design variant, this control and evaluation unit may be a separate control unit, for example. According to an alternative variant, each of the two aforementioned electric motors is part of a unit with integrated control electronics, for example, part of a motor unit consisting of the aforementioned brushless motor and control electronics. In such a design variant, the control electronics of the two units are typically linked in a master-slave configuration and are usually connected via a data bus. The control electronics with the master function then functions as the aforementioned control and evaluation unit.According to another alternative design variant, each of the two aforementioned electric motors is part of a unit with integrated control electronics, but the control electronics of both units are connected to a higher-level control unit. In such a case, the higher-level control unit expediently functions as the aforementioned control and evaluation unit.
[0013] Independently of this, the electrically adjustable seat assembly also has an adjustment mechanism. The two electric motors mentioned above are coupled to the adjustment mechanism in such a way that they interact via the adjustment mechanism. The adjustment mechanism and the two electric motors are expediently part of an adjustment device by means of which the vehicle seat of the electrically adjustable seat assembly can be adjusted. Depending on the application, the adjustment mechanism is designed for a longitudinal adjustment of the vehicle seat, i.e., an adjustment of the longitudinal position of the vehicle seat, for an adjustment of the height of the vehicle seat, for an adjustment of the inclination of the vehicle seat, or for an adjustment of the inclination of a seat back of the vehicle seat.
[0014] During the execution of the method, at least one of the two electric motors is controlled by the control and evaluation unit, and during this control, a measured variable is recorded that is functionally related to the torque of the controlled electric motor. Preferably, the measured variable is a current that is functionally related to the current supplied to the electric motor.
[0015] Such a method is advantageous, among other things, because the measured value typically provides information about how the adjustment mechanism and electric motors interact. Therefore, conclusions can usually be drawn as to whether distortions are present. Such distortions can occur, for example, if high tolerances are permitted during assembly of the seat assembly and / or installation of the seat assembly in the aforementioned motor vehicle.
[0016] It is also advantageous if, during the execution of the method, several measured values are determined for the measured variable, in particular for different adjustment positions of the adjustment mechanism or for different rotor positions of a rotor of one of the electric motors, if a measured value curve is determined based on the measured values, and if a local or global extreme value is determined for the measured value curve. This allows additional information to be obtained.
[0017] In an advantageous development, during the execution of the method, at least one virtual reference value, for example a virtual zero position or a virtual zero position, is specified or modified based on the determined local or global extreme value. This at least one virtual reference value is then selected in particular such that the aforementioned stresses are reduced. Preferably, at least one virtual reference value for at least one of the electric motors is further specified or modified based on the determined local or global extreme value. Alternatively, at least one virtual reference value for the adjustment mechanism is specified or modified.
[0018] As already explained above, the adjustment mechanism is designed in at least one application for a longitudinal adjustment of the vehicle seat, i.e., an adjustment of the longitudinal position of the vehicle seat. In such a case, the adjustment mechanism and thus the seat assembly expediently comprises two pairs of rails elongated in a longitudinal direction. Each pair of rails comprises a floor rail and a seat rail connected to the floor rail. The floor rail is connected to the seat rail, at least in an installed state of the seat assembly, for example, via a plain bearing or in another known manner, so that the seat rail is displaceable in the longitudinal direction relative to the floor rail.Furthermore, each pair of rails is assigned one of the two electric drive units, so that the seat rail can be moved longitudinally relative to the floor rail by means of the electric motor of the assigned electric drive unit. The control and evaluation unit is then configured to control the electric drive units for the purpose of adjustment such that the vehicle seat, which is connected to the seat rails, can be moved longitudinally relative to the floor rails under the control of the control and evaluation unit and is thus longitudinally adjustable. The seat assembly thus implements a longitudinal adjustment, namely an electric longitudinal adjustment.
[0019] The aforementioned floor rails are also designed for attachment to a floor assembly in the interior of the vehicle. After appropriate attachment, the two floor rails are typically aligned approximately parallel to each other and parallel to the longitudinal direction. However, a flush arrangement is not mandatory. Rather, in some cases, due to installation tolerances, there may be a significant offset between the two floor rails in the longitudinal direction, for example, an offset of 5 mm.
[0020] According to at least two advantageous method variants, the method is now used to compensate for a possible offset of the floor rails in the longitudinal direction.
[0021] According to one of these process variants, compensation occurs during each adjustment. This essentially constitutes live compensation.
[0022] According to the other method variant, the electric drive units are controlled in such a way that a calibration is first performed to compensate for a possible offset of the floor rails in the longitudinal direction. In this case, the measured variable is expediently recorded during the calibration, and in particular only during the calibration, the local or global extreme value is determined, and preferably at least one virtual reference value is specified, in particular for at least one of the electric motors. Subsequently, the electric drive units are typically simply controlled synchronously by the control and evaluation unit when the vehicle seat is to be adjusted in the longitudinal direction.
[0023] This is based on, among other things, the following considerations. In the future, at least some motor vehicles will likely be equipped for fully autonomous driving. "Fully" means that it will no longer be necessary for a driver to supervise the vehicle. This opens up new possibilities for interior concepts, particularly those involving vehicle seats with even more extensive adjustment options. For example, longitudinal adjustment with a significantly greater adjustment range than previously possible will be provided.
[0024] When using two pairs of rails with a larger adjustment stroke, mechanical synchronization, as provided in DE 10 2016 123 836 A1, is no longer readily feasible. Thus, as in at least one embodiment of the seat assembly according to the invention, an electric drive unit must be provided for each pair of rails. However, if, for example, due to installation tolerances, there is a significant offset in the longitudinal direction between the two floor rails, this typically results in tension, which generally negatively impacts function and / or leads to increased wear in the electric longitudinal adjustment.
[0025] To avoid or at least mitigate these disadvantages, it is planned to compensate for any misalignment between the two floor rails and thus reduce any potential distortion. For this purpose, the aforementioned live compensation or the previously described calibration is performed. In principle, this can achieve various advantages. Among other things, it is possible to reduce costs, particularly through reduced tooling costs, since larger installation tolerances can be accepted as long as compensation is performed via calibration. Functional reliability can also be increased because any potential distortion is compensated. Furthermore, a reduction in wear can be achieved.
[0026] During calibration, for example, at least one of the longitudinal positions of the two seat rails is adjusted, i.e., one of the positions of the two seat rails along the longitudinal direction. In particular, the relative distance between the longitudinal positions of the two seat rails is reduced. Alternatively or additionally, at least one virtual reference value, for example, a virtual zero position, is specified for at least one of the electric motors, or at least one previously specified virtual reference value is changed.
[0027] Subsequently, the electric drive units are typically simply controlled synchronously by the control and evaluation unit when the vehicle seat is to be adjusted in the longitudinal direction. This means that, for example, essentially identical electrical signals, in particular essentially identical voltage signals, are simultaneously supplied to the two electric drive units by the control and evaluation unit. In this way, longitudinal adjustment with electrical synchronization is then realized.
[0028] Depending on the application, calibration is still performed before each longitudinal adjustment of the vehicle seat. Alternatively, calibration is performed at specific intervals.
[0029] Preferably, however, the calibration is only performed before a first longitudinal adjustment of the vehicle seat, for example, before a first longitudinal adjustment after installation of the seat assembly, after replacing a component of the seat assembly, or after resetting the control and evaluation unit. It is further expedient if, during the calibration, one of the two electric drive units, hereinafter referred to as the first electric drive unit, is controlled by the control and evaluation unit in such a way that the associated seat rail, hereinafter referred to as the first seat rail, is moved back and forth along the longitudinal direction starting from an initial position, so that it successively assumes several different longitudinal positions.
[0030] According to an advantageous embodiment, a current intensity is determined for each of these longitudinal positions of the first seat rail for the electric motor of the first drive unit. In an advantageous further development, a current intensity curve is then determined based on the determined current intensity, and a local or global extreme value is determined for the current intensity curve.
[0031] Furthermore, the offset of the floor rails in the longitudinal direction is preferably determined as the difference between the starting position and the longitudinal position of the extreme value. The offset thus determined is then conveniently compensated during calibration.
[0032] It is also advantageous if, during the calibration, the other of the two electric drive units, hereinafter referred to as the second electric drive unit, is controlled by the control and evaluation unit in such a way that the associated seat rail, hereinafter referred to as the second seat rail, is held in its position while the first seat rail is moved back and forth.
[0033] As already explained above, live compensation is carried out as an alternative to calibration, i.e. compensation during an adjustment of the longitudinal position of the vehicle seat. In this case, control is typically such that initially one of the two seat rails increasingly leads the other seat rail, then the other seat rail catches up again and finally increasingly leads itself. In the reference system of one of the two seat rails, this is comparable to the previously described back-and-forth movement of the other seat rail along the longitudinal direction. During this time, a position-dependent current measurement is expediently carried out, or a current measurement dependent on a relative position between the two seat rails or between the current virtual zero positions of the two electric motors or the rotors of the two electric motors.
[0034] Alternatively, a clock-controlled current measurement is performed, for example, in the readout cycle of the aforementioned control electronics or control unit. Each clock interval is then typically assigned a rotation angle of a rotor of one of the electric motors. For example, if a current measurement is performed in a 20 ps cycle, approximately 30 to 40 current readings are determined per rotor revolution, with one rotor revolution typically corresponding to 1 mm of adjustment travel in the longitudinal direction.
[0035] Preferably, at least one of the virtual zero positions is then adjusted or redefined. This is preferably done during ongoing operation or, alternatively, during the next adjustment.
[0036] For this purpose, for example, a virtual zero position is varied by a small increment, e.g. 90° rotor position, or by several such increments.
[0037] Such live compensation is advantageous, among other things, because it also allows for the compensation of changing influences, e.g. due to temperature expansion.
[0038] Irrespective of this, it is preferred if the compensation described above is carried out automatically by the control and evaluation unit. This means that the control and evaluation unit is then designed and configured to carry out the compensation automatically.
[0039] It is also advantageous if, alternatively or additionally, a permissible adjustment range or stroke is adjusted based either on the determined extreme value or on the determined offset. Such a permissible adjustment range or stroke is typically specified by so-called soft stops, i.e., virtual limits. Such virtual limits are usually intended to prevent physical limits, such as mechanical stops, from being reached.
[0040] Exemplary embodiments of the invention are explained in more detail below using a schematic drawing. In the drawing:
[0041] Fig. 1 shows a side view of a seat assembly with two pairs of rails, with a base unit and with a vehicle seat,
[0042] Fig. 2 shows in a perspective view the rail pairs together with associated drive units,
[0043] Fig. 3 shows a block diagram of the base unit together with electric motors of the drive units,
[0044] Fig. 4 shows a diagram of a current intensity as a function of a longitudinal position, as well as
[0045] Fig. 5 shows a top view of the rail pairs with markings to explain calibration.
[0046] Corresponding parts and sizes are always provided with the same reference symbols in all figures.
[0047] A seat assembly 2 described below as an example is shown in a side view in Fig. 1. It is designed for a motor vehicle not shown, for example, a passenger car. The seat assembly 2 is preferably initially prefabricated and later installed in a not-shown interior of the motor vehicle.
[0048] In the exemplary embodiment, the seat assembly 2 has two elongated pairs of rails 4 which, at least in an installed state of the seat assembly 2, are aligned parallel to one another and parallel to a longitudinal direction 6. This is indicated in Fig. 2. Each pair of rails 4 has a floor rail 8 and a seat rail 10 connected to the floor rail 8. The floor rail 8 is designed, in a manner not shown in detail, for fixing to a floor assembly (not shown) in the interior of the motor vehicle and, at least in the installed state of the seat assembly 2, is connected to the seat rail 10 in such a way that the seat rail 10 is displaceable relative to the floor rail 8 in the longitudinal direction 6.
[0049] Furthermore, each pair of rails 4 is assigned an electric drive unit 12, so that the seat rail 10 can be moved in the longitudinal direction 6 relative to the floor rail 8 via the assigned electric drive unit 12. Each of the electric drive units 12 has its own electric motor 14.
[0050] In the exemplary embodiment, at least the electric motors 14 of the electric drive units 12 are housed in a base unit 16 of the seat assembly 2. This base unit 16 is fixed to the seat rails 10 and supports a vehicle seat 18. In an alternative embodiment not shown, the seat assembly 2 does not have such a base unit 16. Instead, the vehicle seat 18 is fixed directly to the seat rails 10. In both embodiments, the vehicle seat 18 is preferably designed as an individual seat.
[0051] In the exemplary embodiment, the two electric drive units 12 and in particular the two electric motors 14 are further connected for signaling purposes to a control and evaluation unit 20, which in the exemplary embodiment according to Fig. 3 is integrated into the base unit 16. The control and evaluation unit 20 is configured to control the electric drive units such that the vehicle seat 18, controlled by the control and evaluation unit 20, can be moved longitudinally relative to the floor rails and thus is longitudinally adjustable. In the seat assembly 2, a longitudinal adjustment, namely an electric longitudinal adjustment, is thus realized.
[0052] As previously explained, the floor rails 8 are designed for attachment to the floor assembly in the interior of the motor vehicle, and after appropriate attachment, the two floor rails 8 are then aligned parallel to one another. However, a flush arrangement of the two floor rails 8 is not mandatory. Rather, in some cases, due to installation tolerances in the longitudinal direction 6, an installation offset 22 may occur between the two floor rails 8. This is evident from Fig. 2. Here, the installation offset 22 is indicated on the right-hand side by dashed lines with long dashes.
[0053] Such an installation offset 22 typically entails disadvantages, which is why the aforementioned control and evaluation unit 20 is configured, for example, to automatically perform a calibration during its initial commissioning, by means of which the effects of the installation offset 22 are at least partially compensated. After calibration, the electric drive units 12 are then simply controlled synchronously by the control and evaluation unit 20 each time the vehicle seat 18 is to be adjusted in the longitudinal direction 6. The control and evaluation unit 20 is configured accordingly for this purpose.
[0054] In the exemplary embodiment, during the calibration, at least one virtual reference value, namely a virtual zero position, is changed for at least one of the seat rails 10, which was determined, for example, during a so-called standardization run by the manufacturer of the seat assembly 2. For this purpose, one of the two electric drive units 12, hereinafter referred to as the first electric drive unit 12, is first controlled by the control and evaluation unit 20 such that the associated seat rail 10, hereinafter referred to as the first seat rail 10, is moved back and forth along the longitudinal direction 6 starting from an initial position XA, so that it successively assumes several different longitudinal positions x.
[0055] Meanwhile, the other of the two electric drive units 12, hereinafter referred to as the second electric drive unit 12, is controlled by the control and evaluation unit 20 such that the associated seat rail 10, hereinafter referred to as the second seat rail 10, remains in its position. For each of these longitudinal positions x, a current intensity I is determined for the electric motor 14 of the first drive unit 12. Based on the determined current intensity I, a current intensity curve l(x) is then determined, and a local or global extreme value IE is determined for the current intensity curve l(x). This is indicated in Fig. 4. Furthermore, the difference is determined between the starting position XA along the longitudinal direction 6 and the longitudinal position XE of the extreme value IE.
[0056] This difference is finally defined as the drive offset 24, and the aforementioned virtual zero position is shifted by the drive offset 24. Depending on the design variant, either the virtual zero position of the first seat rail 10 is shifted or the virtual zero position of the second, stationary seat rail 10 is shifted. In Fig. 2, the drive offset 24 is indicated by dashed lines with short dashes.
[0057] According to an alternative design variant, the drive offset is distributed proportionally to both seat rails 10 and the zero positions of both seat rails 10 are then changed accordingly.
[0058] Further preferred embodiments are those in which the manufacturer of the seat assembly 2 provides so-called soft stops S. As indicated in Fig. 5, each of the floor rails 8 typically forms a mechanical stop M at each end, wherein the two mechanical stops M of a floor rail 8 limit the possible travel path of the associated seat rail 10 along the floor rail 8. However, due to the previously described installation offset 22, the mechanical stops M of the two floor rails 8 are also offset from one another, so that the possible travel path MV of the vehicle seat 18 is reduced compared to the possible travel paths of the seat rails 10.
[0059] However, approaching mechanical stops M is usually undesirable, as this is generally detrimental to acoustics and also typically compromises durability. Therefore, it is preferable to approach such a mechanical stop M only once, if possible, for the purpose of determining the position.
[0060] After such a start, soft stops S are preferably automatically defined by the control and evaluation unit 20, usually depending on the position when approaching the mechanical stop M. These soft stops S are typically defined for both floor rails 8 and at least provisionally limit the permissible travel paths, wherein the provisional permissible travel path of the vehicle seat 18 is in turn reduced compared to the provisional permissible travel paths of the seat rails 10. The soft stops S are virtual reference values, wherein in the embodiment according to Fig. 5 the soft stop S of each floor rail 8 shown on the left functions as the virtual zero position or zero position of the corresponding floor rail 8.
[0061] During the calibration described above, in the exemplary embodiment shown in Fig. 5, the front soft stop S of the upper floor rail 8 is shifted by the determined drive offset 24 toward the calibrated front soft stop KS. Thus, the aforementioned zero position is shifted. In addition, however, the rear soft stop S of this floor rail 8, shown on the right, is also shifted by the determined drive offset 24 toward the calibrated rear soft stop KS, with the two calibrated soft stops KS subsequently limiting the final permissible travel path ZV of the vehicle seat 18.
[0062] This ensures that, despite the installation offset 22, none of the four mechanical stops M is encountered, neither on one floor rail 8 nor on the other floor rail 8. It should be noted that, during the aforementioned position determination, the control and evaluation unit 20 typically only detects that a mechanical stop M has been encountered, but not which one. In the exemplary embodiment according to Fig. 5, the vehicle seat 18 is moved all the way to the left to determine the position, whereby the mechanical stop M of the floor rail 8 shown below is encountered. The soft stops are then defined relative to this.
[0063] List of reference symbols
[0064] 2 Seat assembly
[0065] 4 pairs of rails
[0066] 6 Longitudinal direction
[0067] 8 floor rail
[0068] 10 seat rail
[0069] 12 Drive unit
[0070] 14 Electric motor
[0071] 16 base unit
[0072] 18 Vehicle seat
[0073] 20 Control and evaluation unit
[0074] 22 Installation offset
[0075] 24 Drive offset x longitudinal position
[0076] XA starting position
[0077] XE Longitudinal position extreme value
[0078] I Current l(x) Current curve
[0079] IE extreme value
[0080] M mechanical stop
[0081] MV possible travel path
[0082] 5 Soft stop
[0083] ZV permissible travel
[0084] KS calibrated soft stop
Claims
Claims 1. A method for controlling an electrically adjustable seat assembly (2) comprising a vehicle seat (18) and two electric drive units (12), wherein - each of the two electric drive units (12) has an electric motor (14), - the electrically adjustable seat assembly (2) has a control and evaluation unit (20) which is connected to the electric motors (14) by means of signals for the purpose of controlling the electric motors (14), - the electrically adjustable seat assembly (2) has an adjustment mechanism (4), - the electric motors (14) are coupled to the adjustment mechanism (4) so that they interact via the adjustment mechanism (4), - at least one of the electric motors (14) is controlled by the control and evaluation unit (20) and - during the control, a measured variable (I) is recorded which is functionally related to a torque of the controlled electric motor (14).
2. Method according to claim 1, wherein a plurality of measured values (I) are determined for the measured variable (I), wherein a measured value curve (l(x)) is determined based on the determined measured values (I), and wherein a local or global extreme value (IE) is determined for the measured value curve (l(x)).
3. The method according to claim 2, wherein a virtual zero position for one of the electric motors (14) is specified based on the determined local or global extreme value (IE).
4. Method according to one of claims 1 to 3, wherein - the adjustment mechanism (4) has two pairs of rails (4) elongated in a longitudinal direction (6), - each pair of rails (4) has a floor rail (8) and a seat rail (10) connected to the floor rail (8), - each pair of rails (4) is assigned one of the electric drive units (12), so that the seat rail (10) can be moved in the longitudinal direction (6) relative to the floor rail (8) via the assigned electric drive unit (12), - the control and evaluation unit (20) is designed to control the electric drive units (12) for the purpose of adjustment such that the vehicle seat (18), which is connected to the seat rails (10), can be moved in the longitudinal direction (6) relative to the floor rails (8) and can thus be adjusted longitudinally under the control of the control and evaluation unit (20).
5. The method according to claim 4, wherein the electric drive units (12) are controlled in such a way that first a calibration is carried out to compensate for an offset (22) of the floor rails (8) in the longitudinal direction (6) and that subsequently, for a longitudinal adjustment of the vehicle seat (18), the electric drive units (12) are controlled synchronously by the control and evaluation unit (20), wherein in the course of the calibration the measured variable (I) is recorded, the local or global extreme value (IE) is determined and the virtual zero position for one of the electric motors (14) is specified.
6. The method according to claim 5, wherein the calibration is carried out only before a first longitudinal adjustment of the vehicle seat (18).
7. The method according to claim 5 or 6, wherein during the calibration one of the two electric drive units (12), namely a first electric drive unit (12), is controlled by the control and evaluation unit (20) in such a way that the associated seat rail (10), namely a first seat rail (10), is moved back and forth along the longitudinal direction (6) starting from an initial position (XA) so that it successively assumes several different longitudinal positions (x).
8. The method according to claim 7, wherein for each of these longitudinal positions (x) of the first seat rail (10) for the electric motor (14) of the first drive unit (12) a current intensity (I) is determined as a measured value (I) for the measured variable (I).
9. The method according to claim 8, wherein a current intensity profile (l(x)) is determined based on the determined current intensities (I), wherein a local or global extreme value (IE) is determined for the current intensity profile (l(x)), and wherein the difference between the starting position (XA) and the longitudinal position (XE) of the extreme value (IE) is determined as the offset (22) of the floor rails (8) in the longitudinal direction (6).
10. The method according to claim 9, wherein during the calibration the two electric drive units (12) are controlled in such a way that the determined offset (22) is compensated.
11. Method according to one of claims 7 to 10, wherein during the calibration the other of the two electric drive units (12), namely a second electric drive unit (12), is controlled by the control and evaluation unit (20) in such a way that the associated seat rail (10), namely a second seat rail (10), is held in its position.
12. Electrically adjustable seat assembly (2) designed and configured to carry out a method according to one of the preceding claims in at least one operating mode.