Longidutinal adjustment device for a vehicle seat

Abstract

The invention relates to a longitudinal adjustment device (1, 1') for a vehicle seat (2), said longitudinal adjustment device comprising: a first adjustment element (11A) guided on a rail (10A); a second adjustment element (11B) guided on a rail (10B); a first drive device (12A) by means of which the first adjustment element (11A) can be adjusted along the rail (10A) on which the first adjustment element (11A) is guided; and a second drive device (12B) by means of which the second adjustment element (11B) can be adjusted along the rail (10B) on which the second adjustment element (11B) is guided, wherein a control unit (120A) of the first drive device (12A) is communicatively connected to a control unit (120B) of the second drive device (12B).

Description

[0001] Longitudinal adjustment device for a vehicle seat

[0002] Description

[0003] The invention relates to a longitudinal adjustment device for a vehicle seat and a vehicle seat with such a longitudinal adjustment device.

[0004] Longitudinal adjustment devices in vehicle seats are typically used to adjust a seat section and a backrest along a vehicle's longitudinal direction, for example to give the vehicle seat occupant more or less legroom as needed. Motorised longitudinal adjustment devices, in which the adjustment is effected by an electric motor, offer a great deal of comfort. Typically, longitudinal adjustment devices have at least two rails spaced apart in a transverse direction, each with an adjustment element guided on it. The adjustment elements can be designed as seat rails that engage with the respective rail. In practice, an electric motor is regularly arranged, for example, in a free space between the two rails and is operatively connected to the adjustment elements via a shaft in each case, so that the electric motor can adjust the two adjustment elements along the rails.

[0005] In some applications, however, it is desirable to leave a space between the rails free; or the space between the rails is blocked by fixed parts. In both cases, a mechanical coupling of one electric motor with the two adjustment elements is typically not feasible or only possible with considerable effort.

[0006] Therefore, in some cases it may be appropriate to provide two electric motors, one for each of the two adjustment elements.

[0007] A longitudinal adjustment device with two separate drive units, each with a drive motor, is described in DE 198 60 910 B4. To ensure that the rotary movements of the two drive motors run synchronously, this document proposes the use of a mechanical synchronization shaft between the two drive motors. However, this offers little advantage over a drive driven by a single motor. Alternatively, the document proposes providing a control unit that is electrically connected to both drive motors and to the respective devices for detecting a relative position. However, this typically requires increased cabling complexity.

[0008] The solution described in DE 10 2008 007 267 B4 has similar disadvantages. There, two motors are connected in series or parallel and controlled via switches.

[0009] The task is to provide an improved longitudinal adjustment device.

[0010] This object is achieved by an article having the features of claim 1.

[0011] According to this, a longitudinal adjustment device for a vehicle seat comprises a first adjustment element guided on a (e.g., a first) rail, a second adjustment element guided on a (e.g., a second) rail, a first drive device by means of which the first adjustment element can be adjusted along the rail on which the first adjustment element is guided, and a second drive device by means of which the second adjustment element can be adjusted along the rail on which the second adjustment element is guided. It is provided that a control unit of the first drive device is communicatively connected to a control unit of the second drive device.

[0012] By providing two separate drive units, one for the first adjustment element and one for the second adjustment element, the space between the rails can be used for other purposes. Furthermore, since each of the two drive units is controlled by its own control unit, the cabling for the communication connection between the control units can be adapted particularly flexibly to the specific application and can be simple, for example, using a few wires with a small cross-section or an optical cable. Alternatively, it is even possible to implement the communication connection wirelessly. Furthermore, the communication infrastructure already present in the vehicle can be used, which enables particularly simple connection.

[0013] The control unit of the first drive device controls, for example, a drive motor of the first drive device. The control unit of the second

[0014] Drive device controls, for example, a drive motor of the second

[0015] Drive device, e.g. based on data received via the communicative connection.

[0016] The control unit of the second drive device can be configured to synchronize a movement of the second adjustment element with a movement of the first adjustment element using the communicative connection. Thus, the first drive device specifies a movement, and the second drive device takes over this movement. The first drive device thus operates as a "master," and the second drive device as a "slave." The second drive device follows the control of the first drive device.

[0017] Optionally, the control unit of the first drive device is configured to determine a position of the first adjustment element along the first rail and communicate the position to the control unit of the second drive device. This enables efficient control and communication. The control unit of the second drive device, for example, controls a drive motor of the second drive device based on the position communicated by the control unit of the first drive device. This enables precise control.

[0018] For example, the control unit of the second drive device is configured to calculate a target speed for the drive motor of the second drive device based on the position communicated by the control unit of the first drive device. Based on this target speed, the drive motor of the second drive device can be controlled. This enables the second adjustment element to follow the first adjustment element quickly and precisely. Furthermore, the control unit of the second drive device can be configured to use the position communicated by the control unit of the first drive device as the target position for the second adjustment element along the second rail. In this way, the second control unit always moves to the last communicated position. This allows precise and robust control. Optionally, the control unit of the second drive device is configured (e.g.A pulse-width modulation signal is calculated based on the calculated target speed. This can be used, for example, to control a brushless direct current (BLDC) motor as a drive motor.

[0019] For example, the control unit of the first drive device is communicatively connected to the control unit of the second drive device via a gateway, e.g., in the form of a control unit, in particular a seat control unit. The gateway, in particular the seat control unit, can, for example, establish communication between the control units. For example, the gateway, in particular the seat control unit, provides a clock for communication. The gateway, in particular the seat control unit, can comprise a LIN bus commander; the control units can be implemented as simple LIN bus responders.

[0020] The control units of the drive devices can be configured to adjust the adjustment elements in a standardization run in order to save a respective zero-point position. The control units of the drive devices can also be configured to then relate actual and / or target positions to the stored zero-point position. The zero-point position can thus serve as a reference for actual and / or target positions along the respective adjustment path, i.e., along the respective rail. In this way, precise adjustment can be achieved over a long service life. It can be provided that an adjustment can only be activated when all drive devices are standardized and / or none of the drive devices reports an error.

[0021] The control units of the drive devices can be configured to move all adjustment elements of the longitudinal adjustment device against a respective stop into a stop position during the standardization travel. This means that all of the adjustment elements can rest against the respective stop at the same time. The control units can also be configured to save their respective stop positions as the zero point position. Due to tolerances in the manufacture of the individual parts of the longitudinal adjustment device or in the assembly of these individual parts, it is possible that the individual adjustment elements do not strike the respective stops at exactly the same time, but one after the other. This can lead to (slight) tension in parts of the vehicle seat, whereby its bearings can be kept free of play via the longitudinal adjustment device.The stop of a given adjustment element can be configured such that the given adjustment element moves to its stop before the other adjustment element during the standardization run (or before the other adjustment elements if there are more than two adjustment elements). All control units can be configured to store the respective zero point position in the stop position of the given adjustment element. For example, the stop position of the given adjustment element is located before the other stop positions, e.g., by installing a stop offset from the other stops. This can prevent tension in the vehicle seat.

[0022] Furthermore, it can be provided that the control units are configured to store a respective zero point position as soon as any of the adjustment elements first reaches its stop position. As soon as a first of the adjustment elements hits the corresponding stop, all drive devices stop and store the respective actual position as the zero point position (even if they have not yet hit the respective stop). For example, the corresponding control unit detects a hit against the stop by the fact that the angular position of a corresponding drive motor no longer changes or no longer changes as expected. After detecting a hit, the corresponding control unit can send messages to the other control unit(s) so that they also stop the respective drive motors.

[0023] One of the control units can be configured as the primary control unit to communicate control commands to the other, secondary control unit (or, in the case of more than two drive devices, to the other, secondary control units). This enables a particularly simple design and also simple programming, especially of the secondary control unit(s).

[0024] The control commands can each include a speed and / or a position. This allows the secondary control unit(s) to efficiently and precisely control or regulate the position of the respective adjustment element. The speed can be a target speed of the primary control unit, which then serves as the target speed for the secondary control unit. The position can be an actual position of the primary control unit, which then serves as the target position for the secondary control unit.

[0025] The primary control unit can be configured to first communicate a control command to the secondary control unit to start a movement (as a result of which the secondary control unit starts the corresponding drive motor) before the primary control unit, after a predetermined delay following this communication, controls the drive motor of the drive device of the primary control unit. This can compensate for any latency when starting up the drive device of the secondary control unit, so that all drive units start up synchronously. This latency can be caused, for example, by a diagnosis required before starting up, in which the secondary control unit checks, for example, whether there is no short circuit and / or whether a supply voltage is within a predetermined range or the like.This allows a diagnosis to be performed while the primary control unit is waiting to control the drive motor of the primary control unit's drive device.

[0026] The communication of a control command may involve a communication latency. Therefore, there may be a time period between the sending and receiving of the control command, which can be known. In this case, the primary control unit may be configured to calculate the future actual position of the adjustment element of the primary control unit after the communication latency has elapsed. Furthermore, the primary control unit may be configured to communicate a control command with the calculated future actual position as the target position for the secondary control unit to the secondary control unit. This allows the communication latency to be compensated, enabling improved synchronization.

[0027] Alternatively, the primary control unit can be configured to communicate a control command with the current actual position of the adjustment element of the primary control unit as the target position for the secondary control unit to the secondary control unit. The secondary control unit can be configured to operate its drive motor based on that target position and / or the communication latency. For example, based on the received target position, the secondary control unit extrapolates the actual current actual position of the adjustment element of the primary control unit as the target position, taking into account the current adjustment speed, in particular rotational speed, and the communication latency. This also allows the communication latency to be compensated, enabling improved synchronization.

[0028] The control units can be configured to increase the speed of the respective drive device according to a respective speed ramp when a movement starts. The speed ramps can be the same or different from one another, in particular, they can have a different gradient. Alternatively or additionally, the speed ramps can be offset (in time) from one another. This makes it easy to compensate for latencies, for example, by a steeper increase in speed. Furthermore, one or more speed ramps for one or more of the drive devices can be communicated via target speed specifications. Latency can also be taken into account here, as described.

[0029] It can be provided that the control commands each include a timestamp, which, for example, indicates the time of the actual position of the adjustment element of the primary control unit. Based on this, the secondary control unit can precisely control or regulate the position of the corresponding adjustment element.

[0030] The primary control unit can be configured to store an actual position of its drive device at the moment a control command is sent to the secondary control unit. Alternatively or additionally, the secondary control unit can be configured to store an actual position of its drive device at the moment a control command is received from the primary control unit. These values ​​can be used to prevent jitter resulting from a sampling frequency of the actual position. Communication can be controlled via a clock, e.g., a seat control unit, while the periodic sampling of the position takes place via a clock of the control unit. These clocks can have different frequencies and can also be offset from one another.

[0031] The secondary control unit can be configured to pause the execution of a program code by means of an interrupt the moment a control command is received from the primary control unit in order to save the actual position of its drive device. This can significantly reduce the described jitter.

[0032] The primary control unit (e.g., of the first drive device) can communicate with the secondary control unit (e.g., of the second drive device) unidirectionally or bidirectionally. With a bidirectional communication connection, the secondary control unit can, for example, transmit feedback on performed adjustment movements and / or an error to the primary control unit. This can further improve functionality and robustness. The primary control unit can be configured to send control commands to the secondary control unit more frequently than it receives feedback information from the secondary control unit (in a given period of time). This can further reduce delays due to communication.

[0033] One or more, e.g. all, of the control units can each be set up to control a respective drive motor using a torque-generating voltage. This can be done in particular without speed and current control. Such Uq control (open loop), e.g. of a BLDC motor, instead of a closed loop control (e.g. speed control with adjustment of the target speed by means of position comparison) enables behavior similar to DC motors, with synchronization taking place via a motor characteristic curve. Apart from a start command, no further synchronization or communication is required. It can therefore be provided that the control units no longer communicate except for a start command until a target position is reached. This enables particularly simplified communication.For example, a torque-generating voltage is specified by the control unit(s) and after commutation with Park and / or Clarke transformation, the phase voltages U, V, W are obtained, which are ultimately applied directly to the drive motor.

[0034] The longitudinal adjustment device can comprise more than two, e.g., three or four, drive devices, each with a control unit, by means of which an adjustment element can be adjusted, e.g., each along its own rail. The control units of the drive devices can communicate with each other and / or with a seat control unit. In this way, for example, several vehicle seats or a seat bench can be adjusted.

[0035] Optionally, the control unit of the first drive device is communicatively connected to the control unit of the second drive device by means of a bus system. This enables a particularly simple design because such a bus system is often already present and can often be connected using short distances. For example, the bus system is designed in the form of a LIN bus system (Local Interconnect Network). This enables a particularly simple design. Alternatively, a CAN bus could also be used as the bus system. Also conceivable is, for example, a bus system according to CAN FD, FlexRay, Ethernet, K-line or MOST. The described longitudinal adjustment device enables electronic synchronization by means of a low-bandwidth bus system. It is possible to use an existing bus system, which enables particularly low expenditure. Several parallel bus systems can be provided.A control unit for the longitudinal adjustment system, e.g., a seat control unit, can provide multiple parallel, independent bus systems, particularly in the form of two LIN bus lines. This allows parallel communication with multiple secondary control units, enabling close synchronization.

[0036] For example, the control unit (or alternatively, e.g., the primary control unit of the first drive device) can be configured to send control commands via broadcast in parallel to the secondary control units of the remaining drive devices. This allows for particularly good synchronization.

[0037] The control unit of the (primary) first drive device can be configured to communicate data frames containing control data to the secondary control unit(s) at time intervals. This allows the secondary control unit(s) to gradually replicate the movements controlled by the primary control unit. In a further development, the secondary control unit(s) is / are configured to interpolate the control data contained therein for a period between two consecutive data frames. This enables particularly consistent control, even when the communication channel between the control units, e.g., the LIN bus system, is heavily utilized.

[0038] The secondary control unit(s) can be configured to detect a fault and communicate it to the control unit of the primary drive device. This enables particularly high levels of safety and robustness of the longitudinal adjustment device. The fault could be, for example, a defect in the drive device or an activated anti-pinch function. The communicated message regarding the anti-pinch function causes, for example, a stop of all drive devices.

[0039] According to one aspect, an adjustment device, in particular a longitudinal adjustment device, a fitting arrangement or the like, e.g. for a vehicle seat, is specified, in particular according to any of the above-described embodiments, comprising a first adjustment element guided (e.g. on a, for example, first, rail), a second adjustment element guided (e.g. on a, for example second, rail), a first drive device, by means of which the first adjustment element can be adjusted along the rail on which the first adjustment element is guided, and a second drive device, by means of which the second adjustment element can be adjusted along the rail on which the second adjustment element is guided, wherein a control unit of the first drive device and a control unit of the second drive device are connected to one another and / or to a further control device, e.g.a seat control unit, are in communicative connection, for example via a bus system.

[0040] It should be noted that all of the embodiments described herein as examples for a longitudinal adjustment device, particularly with regard to communication, can also be used in other adjustment devices, e.g. the fitting arrangement already mentioned, to which the corresponding description applies analogously. In particular, it can be provided that the adjustment device is designed in the form of a longitudinal adjustment device for adjusting a longitudinal position of the vehicle seat, in the form of a seat height adjustment device for adjusting a seat height of the vehicle seat, in the form of a seat inclination adjustment device for adjusting an inclination of a seat part of the vehicle seat (e.g. relative to a vehicle floor) or in the form of a backrest inclination adjustment device (e.g. the fitting arrangement) for adjusting an inclination of a backrest of the vehicle seat relative to the seat part.

[0041] According to one aspect, a vehicle seat is provided with a seat part, a backrest, and the adjustment device, e.g., the longitudinal adjustment device, according to any embodiment described herein. It can be provided that at least the seat part (in particular the seat part and the backrest) is mounted on the adjustment elements of the longitudinal adjustment device.

[0042] The attached figures illustrate possible embodiments of the proposed solution.

[0043] Here we show:

[0044] Fig. 1 shows a vehicle with a longitudinally adjustable vehicle seat;

[0045] Fig. 2 shows a longitudinal adjustment device of the vehicle seat according to Fig. 1;

[0046] Fig. 3 Control units of the longitudinal adjustment device according to Fig. 2, which are in communicative connection with each other;

[0047] Fig. 4 shows a control of a drive motor of the longitudinal adjustment device according to Fig. 2; Fig. 5 shows a sequence of messages sent via a bus system between the control units of the longitudinal adjustment device according to Fig. 3;

[0048] Fig. 6 a longitudinal adjustment device for a vehicle seat;

[0049] Fig. 7 Positions of two adjustment elements of the longitudinal adjustment device according to Fig. 2 against time;

[0050] Fig. 8 shows a time sequence of a periodic transmission of control commands and a scanning of an actual position of an adjusting element by a control unit of the longitudinal adjustment device according to Fig. 2;

[0051] Fig. 9 shows a time sequence of communication between a primary control unit and three secondary control units of the longitudinal adjustment device according to Fig. 6;

[0052] Fig. 10 shows a time sequence of communication between a primary control unit and three secondary control units of the longitudinal adjustment device according to Fig. 6 when using two parallel communication channels;

[0053] Fig. 1 1 shows a time sequence of communication between a primary control unit and three secondary control units of the longitudinal adjustment device according to Fig. 6 when using broadcast messages; and

[0054] Fig. 12 Speeds of drive motors of the longitudinal adjustment device according to Fig. 2, which are approached with different ramps from a standstill to a desired speed.

[0055] Fig. 1 shows a vehicle 3, for example, in the form of a passenger car. The vehicle 3 comprises several vehicle seats 2, one of which is shown in Fig. 1.

[0056] The vehicle seat 2 comprises a seat part 20 and a backrest 21. In the example shown, the backrest 21 is pivotally mounted on the seat part 20. Furthermore, the vehicle seat 2 comprises a longitudinal adjustment device 1.

[0057] By means of the longitudinal adjustment device 1, the seat part 20 and the backrest 21 can be displaced along a longitudinal axis. For this purpose, the longitudinal adjustment device 1 comprises two rails 10A, 10B, of which a first rail 10A is visible in the side view of Fig. 1. A second rail 10B runs parallel to the first rail 10A (and spaced apart from the first rail 10A), as can be seen, for example, in Fig. 2.

[0058] The rails 10A, 10B are fastened to a substructure 31 of the vehicle 3. The substructure 31 represents part of the body of the vehicle 3 or, alternatively, is fastened thereto, for example. On each of the rails 10A, 10B, an adjustment element 11A, 11B is guided so as to be displaceable along the respective rail 10A, 10B. A first adjustment element 11A is thus guided on the first rail 10A, and a second adjustment element 11B on the second rail 10B. The first adjustment element 11A is visible in the side view of Fig. 1, and the second adjustment element 11B can again be seen in Fig. 2.

[0059] In the present case, the adjustment elements 11A, 11B have a rail-shaped section which engages the respective rail 10A, 10B in a longitudinally displaceable manner, as can be seen in Fig. 2. A support section of each adjustment element 11A, 11B is firmly connected to the respective rail-shaped section. The two support sections of the adjustment elements 11A, 11B extend through a vehicle floor 30 in the present case. The vehicle floor 30 comprises, for example, a carpet. This makes it possible for the rails 10A, 10B to be arranged beneath the vehicle floor 30 and thus not visible to a passenger. Such a construction facilitates cleaning of the vehicle 3 and also allows the formation of particularly long rails 10A, 10B. This enables particularly wide adjustment paths, which allows great freedom in the use of the vehicle interior.However, this embodiment is merely exemplary and the rails could also be mounted on the vehicle floor 30 (in particular on the carpet).

[0060] A stop 14 is fixed to each of the rails 10A, 10B, e.g., attached to or formed thereon. The stop 14 limits the adjustment path of the respective adjustment element 11A, 11B along the rail 10A, 10B. The adjustment elements 11A, 11B can strike their respective stop 14.

[0061] The seat part 20 is supported on the adjustment elements 11A, 11B, in the example shown via a seat height adjustment device 6A for adjusting the seat height of the vehicle seat 2 relative to the vehicle floor 31. The seat part 20 is mounted on the adjustment elements 11A, 11B (here height-adjustable). The seat part 20 can be fastened to the adjustment elements 11A, 11B. The seat height adjustment device 6A comprises a plurality of adjustment elements in the form of pivot levers and two drive devices (indicated by a circle), each with a drive motor and a control unit for controlling the respective drive motor (in this case on each side of the vehicle seat 2, left and right), wherein the control units are, for example, communicatively connected to one another and / or to another control device 130, for example via a bus system. The drive devices are each configured to adjust (at least) one of the pivot levers.

[0062] The vehicle seat 2 further comprises, for example, a fitting arrangement 22, by means of which the backrest 21 can be pivoted relative to the seat part 20. The fitting arrangement 22 comprises two (e.g., identical) fittings, each with a drive motor (illustrated by a circle) and a control unit for controlling the respective drive motor, wherein the control units are communicatively connected to one another and / or to the further control unit 130, e.g., via the bus system. The fitting arrangement 22 represents a backrest inclination adjustment device 6B for adjusting the inclination of a backrest 21 of the vehicle seat 2 relative to the seat part 20. Each of the drive devices serves to adjust an adjustment element, each in the form of a fitting part.

[0063] Furthermore, the vehicle seat 2 comprises, for example, a seat inclination adjustment device 6C for adjusting an inclination of the seat part 20 of the vehicle seat 2 relative to the vehicle floor 31. The seat inclination adjustment device 6C comprises two adjustment elements in the form of side parts of a seat pan part shown in dashed lines and two drive devices (illustrated by a circle), each with a drive motor and a control unit for controlling the respective drive motor (in this case on each side of the vehicle seat 2, left and right), wherein the control units are, for example, communicatively connected to one another and / or to the further control unit 130, for example via the bus system. The drive devices are each configured to adjust one of the adjustment elements.

[0064] The communication and control in the case of the longitudinal adjustment device 1 is explained below; however, this also applies, for example, to the seat height adjustment device 6A, the backrest inclination adjustment device 6B and the seat inclination adjustment device 6C (and other possible adjustment devices).

[0065] Fig. 2 shows the longitudinal adjustment device 1 in a view along the longitudinal extent of the rails 10A, 10B. In Fig. 2 it can also be seen that the longitudinal adjustment device 1 further comprises a first drive device 12A, by means of which the first adjustment element 11A is adjustable along the first rail 10A, and a second drive device 12B, by means of which the second adjustment element 11B is adjustable along the second rail 10B.

[0066] Each of the drive devices 12A, 12B comprises its own drive motor 121. The longitudinal adjustment device 1 thus has two drive motors 121, which are optionally identical in construction, as in the example shown.

[0067] Each of the drive motors 121 drives (via a gear) a shaft 122. The respective shaft 122, in turn, drives a worm 123, which meshes with a respective spindle nut 124. In the example shown, the spindle nuts 124 are each rotatably mounted on the corresponding adjustment element 11A, 11B and engage with a spindle 124, which here is arranged on the corresponding rail 10A, 10B and fixed relative thereto. Activating the drive motor 121 of the first drive device 12A thus causes the spindle nut 124 to be screwed along the corresponding spindle 124. The spindle nut 124 thereby carries the first adjustment element 11A with it. Activation of the drive motor 121 of the second drive device 12A analogously causes the corresponding spindle nut 124 to be screwed along the associated spindle 124, whereby this spindle nut 124 carries the second adjustment element 11A with it.It should be noted at this point that this arrangement is only exemplary. Alternatively, for example, the worm 123 could mesh with a gear (or similar) attached to a spindle mounted rotatably relative to the corresponding rail 10A, 10B, so that the spindles would be set in rotation by means of the then stationary drive motors. A respective spindle nut engaging the corresponding spindle would then be attached to the corresponding adjustment part 11A, 11B.

[0068] The drive motor 121 of the first drive device 12A is arranged adjacent to the first adjustment element 11A (and to the first rail 10A), the drive motor 121 of the second drive device 12B is arranged adjacent to the second adjustment element 11B (and to the second rail 10B). The drive motor 121 of the first drive device 12A is arranged closer to the first adjustment element 11A (and to the first rail 10A) than the drive motor 121 of the second drive device 12B. The drive motor 121 of the second drive device 12B is arranged closer to the second adjustment element 11B (and to the second rail 10B) than the drive motor 121 of the first drive device 12A.

[0069] By providing two independent drive motors 121, no torque transmission between the drive devices 12A, 12B and the adjustment elements 11A, 11B is necessary (and also not provided). Due to the described arrangement, a space between the two rails 10A, 10B is therefore free and can be used for other purposes, for example by part of a traction battery, a fan duct, or the like. An obstacle H is schematically illustrated in Fig. 2 as a representative example. In contrast, a mechanical coupling of the drives of the adjustment elements 11A, 11B would have to be moved along the longitudinal axis in the region of the obstacle H.

[0070] In order to be able to effect a joint movement of the two adjustment elements 11A, 11B despite the absence of mechanical torque transmission, a control unit 120A of the first drive device 12A is communicatively connected (directly or indirectly, e.g., via a gateway) to a control unit 120B of the second drive device 12B. The two control units 120A, 120B can exchange data with each other, in this case, for example, bidirectionally. The control unit 120A of the first drive device 12A is configured to send data to the control unit 120B of the second drive device 12B, which is configured to receive and process the data.In the described example, the control unit 120B of the second drive device 12B is also configured to send data to the control unit 120A of the first drive device 12A, which is also configured to receive and process the data sent to it.

[0071] For this purpose, the two control units 120A, 120B are connected to a communication system. Generally, a wired, optical, or wireless communication system would be conceivable. In the example shown, the control units 120A, 120B are connected to a common bus system 13.

[0072] The bus system 13 in this case is a LIN bus. A LIN bus has a simple structure, is relatively inexpensive, and is already present in many vehicles. This allows the two control units 120A, 120B to be communicatively linked with each other in a particularly simple manner. The two control units 120A, 120B communicate via a predefined transmission protocol. In this case, the two control units 120A, 120B exchange data packets in the form of data frames. Depending on the design of the communication system, the data packets could be exchanged directly between the two control units 120A, 120B. In the present example of the bus system 13 designed as a LIN bus, a gateway in the form of a seat control unit 130 is provided in the bus system 13, which transmits the data frames between the two control units 120A, 120B.The control unit 120A of the first drive device 12A is thus communicatively connected to the control unit 120B of the second drive device 12B via the seat control unit 130. As a result, the control units 120A, 120B do not require a precise clock generator (e.g., a separate quartz clock generator, as included by way of example in the seat control unit 130), which can simplify the structure of the control units 120A, 120B. Alternatively, however, it could also be provided that the control units 120A, 120B communicate directly with one another (with one or both then including, for example, a quartz clock generator), which can reduce communication latency. Several, e.g., two parallel bus systems 13 can also be provided.

[0073] To synchronize the movements of the two adjustment elements 11A, 11B with each other, a master-slave principle is provided, according to which one of the control units 120A, 120B (namely, the control unit 120A of the first drive device 12A) specifies an adjustment, and the other of the two control units 120A, 120B (namely, the control unit 120B of the second drive device 12B) follows this adjustment. The control unit 120B of the second drive device 12B is therefore configured to synchronize a movement of the second adjustment element 11B with a movement of the first adjustment element 11A by means of the communicative connection via the bus system 13.

[0074] One of the control units 120A, 120B, namely the first control unit 120A here, can thus be referred to as the primary control unit 120A. The primary control unit 120A is configured to communicate control commands (via the bus system 13) to the other, secondary control unit 120B.

[0075] For this purpose, the control unit 120A of the first drive device 12A is configured to determine a position of the first adjustment element 11A along the first rail 10A and to communicate this position to the control unit 120B of the second drive device 12B using a data frame. To ensure the most uniform movement possible, the control unit 120A of the first drive device 12A is configured to communicate several consecutive data frames, each with an updated position, to the control unit 120B of the second drive device 12B, for example, in a periodic sequence.

[0076] Since the control unit 120B of the second drive device 12B reacts to the position of the first adjustment element 11A, the second adjustment element 11B follows the first adjustment element 11A, while the first adjustment element 11A (slightly) leads. Due to the fast communication via the bus system 13, communication takes place with low latency. Thus, the communication of a data packet from the control unit 120A of the first drive device 12A to the control unit 120B of the second drive device 12B takes place within less than 100 ms, in particular within less than 40 ms, typically within 20 ms. The position difference is therefore generally not or only barely perceptible by a seat occupant and can be compensated for by the elasticity of the seat part 20 of the vehicle seat 2 without the need for special measures.However, if an alternative communication system with a comparatively high latency were to be used, the use of one or more elastic compensation elements would be conceivable, which could be mounted, for example, between one of the adjustment elements 11A, 11B and the seat part 20. Several options for further reducing the latency are described below.

[0077] The described communication of the two control units 120A, 120B is illustrated in Fig. 3, to which reference is now made.

[0078] First, a control command B is sent to the control unit 120A of the first drive device 12A. This can be done particularly simply by actuating a switch, which is actuated, for example, for as long as an adjustment is desired. The control unit 120A then controls the drive motor 121 of the first drive device 12A to effect an adjustment in the direction corresponding to the switch.

[0079] As an alternative (or in addition) to a control command B via a switch, it can be provided that a control command with a data frame 400 can be transmitted to the control unit 120A via the bus system 13. For example, an external control unit and / or the seat control unit 130 can be used to communicate that a specific, e.g., preset, position is to be moved to. The control unit 120A of the first drive device 12A then causes the first adjustment element 11A to move to this position. The data frame 400 is transmitted, e.g., via the seat control unit 130 (alternatively, via another route).

[0080] In order to synchronize the movements of the two adjustment elements 11A, 11B with each other, the control unit 120A of the first drive device 12A sends data frames 401 with control commands to the control unit 120B of the second drive device 12B (via the seat control unit 130) at regular time intervals (at the beginning and / or during a movement of the first adjustment part 11A). The data frames comprise digital data. The control units 120A, 120B communicate with each other digitally. A data frame 401 comprises a predetermined number of bits. In the present example, the data frames 401 each have (but not necessarily) a header and a data part. The data part has a size of 8 bytes (or up to 8 bytes), for example.

[0081] The data frames 401 each comprise an actual position of the first adjustment part 11A and / or a desired adjustment speed of the first adjustment part 11A (e.g., in the form of a current rotational speed) and / or a control mode and / or a possible error state. In particular, the data frames 401 can each comprise all of these data or at least the actual position of the first adjustment part 11A and the desired rotational speed of the first adjustment part 11A. The values ​​then serve as desired values ​​for the second control unit 120B. The control commands, here in the form of the data frames 401, thus each comprise, for example, a desired speed and / or a desired position for the second control unit 120B.By communicating the current target adjustment speed of the first adjustment part 11A (instead of the actual adjustment speed, which can also be used alternatively), it is possible to prevent noise from the corresponding controllers from being transmitted to the second control unit 120B.

[0082] The control unit 120A of the first drive device 12A detects the actual position of the first adjustment part 11A, e.g. by counting revolutions of a moving part (e.g. a rotor of the drive motor 121) of the first drive device 12A, optionally using a provided position sensor, and / or an actual adjustment speed of the first adjustment part 11A (e.g. in the form of a currently set rotational speed of the drive motor 121) and / or a currently set control mode and / or a possible error state and writes this data or a part thereof, here for example the actual position and the actual rotational speed of the first adjustment part 11A, into a data frame 401, which it sends to the control unit 120B of the second drive device 12B. The control mode can indicate, for example, a standstill, a speed-controlled adjustment or a position-controlled adjustment.Furthermore, the control mode can display a standardization run, in which the drive is carried out up to a stop.

[0083] The control unit 120B of the second drive device 12B receives the data frames 401 and processes them, as will be explained in more detail below with reference to Fig. 4. After receiving and processing a respective data frame 401, the control unit 120B of the second drive device 12B sends a data frame 402 to the control unit 120A of the first drive device 12A. The data frames 402 each comprise an actual position of the second adjusting part 11B and / or an actual adjusting speed of the second adjusting part 11B (e.g. in the form of a current rotational speed) and / or a set control mode and / or a possible error state. In particular, the data frames 402 can each comprise all of this data. The data frames 402 serve in particular as feedback.Based on the feedback, the control unit 120A of the first drive device 12A can detect whether the movement of the two adjustment elements 11A, 11B is synchronous (within the scope of the communication latency of the control units 120A, 120B). Thus, the control unit 120A of the first drive device 12A can detect an error and react accordingly, e.g., stop. Such feedback is optional, however, and it could also be provided that the communication is unidirectional, directed only from the control unit 120A of the first drive device 12A to the control unit 120B of the second drive device 12B.

[0084] Specifically, it can also be provided that only errors or stop requests are transmitted as feedback from the control unit 120B of the second drive device 12B to the control unit 120A of the first drive device 12A, and that the communication for synchronizing the movements is unidirectional. The position of the first adjustment part 11A is then controlled, while the second adjustment part 11B simply follows the first. This allows for a particularly simple communication structure.

[0085] Fig. 4 shows the exemplary control for synchronizing the movement by the control unit 120B of the second drive device 12B. Part of the control is implemented here by software SW, but this is only an example. The control unit 120B comprises a memory on which the software SW is stored and a processor that executes the software SW.

[0086] As soon as a data frame 401 is received, the control unit 120B reads the current position of the first adjusting element 11A POS_1 stored therein. This is fed into a position controller 500, which also receives the current position of the second adjusting element 11B POS_2. The control unit 120B measures the current position of the second adjusting element 11B POS_2, for example, in the same way that the control unit 120A of the first drive device 12A measures the current position of the first adjusting element 11A (see above, e.g. by counting revolutions or degrees of rotation starting from a zero point position). Based on these two positions POS_1 and POS_2, the position controller 500 calculates a correction value for a target speed. If the two positions POS_1 and POS_2 are identical, the correction value for the target speed is, for example, zero. The greater the difference between the two positions POS_1 and POS_2, the greater the correction value for the target speed.

[0087] The position controller 500 provides the correction value for the target speed to a speed controller 501. This also receives a current (actual) speed DZ of the second drive device 12B. Based on the correction value for the target speed and the current speed DZ, the speed controller 501 calculates a target current and provides it to a current controller 502. This also receives a current (actual) current I of the second drive device 12B. Based on the target current and the current current, the current controller 502 calculates a pulse width modulation signal PWM, which is transmitted to the hardware HW of the second drive device 12B in order to set the drive motor 121 in a corresponding movement. In an intermediate step, a voltage can also be calculated from the current values.

[0088] Furthermore, it can also be provided that the position controller 500 calculates a corrected target speed based on the two positions POS_1 and POS_2 and a target speed received from the control unit 120A of the first drive device 12A and provides it to the speed controller 501, which then calculates the target current strength based on the corrected target speed and the actual speed DZ.

[0089] In this case, the drive motors 121 are brushless direct current motors (BLDC motors). However, it should be noted that other types of motors can also be used; the control downstream of the position controller 500 can then be configured accordingly. Furthermore, it should be noted that position control is not necessarily required; rather, direct synchronization of the speeds could also be performed. However, position control allows for particularly precise synchronization with only a negligible latency-related offset of the adjustment elements 11A, 11B.

[0090] In one embodiment, it is provided that the control units 120A, 120B are each configured to control the respective drive motor 121 using a torque-generating voltage. Such Uq control (open loop) of BLDC motors is possible instead of closed-loop control. The respective control unit 120A, 120B outputs a virtual DC voltage to a commutator. This makes it possible to achieve behavior similar to that of DC motors, with synchronization taking place via a motor characteristic curve. Apart from a start command, no further synchronization or communication is required. Fig. 5 illustrates a possible communication flow during adjustment. First, the data frame 400 with a control command is transmitted from the seat control unit 130 to the control unit 120A of the first drive device 12A.It then starts the adjustment of the first adjustment part 11A and sends the data frame 401 with the current status of the first adjustment part 11A via the seat control unit 130 to the control unit 120B of the second drive device 12B. Optionally, the seat control unit 130 processes the content of the data frame 401 and creates a new data frame for transmission to the control unit 120B of the second drive device 12B. The control unit 120B of the second drive device 12B then regulates the operation of the drive motor 121 of the second drive device 12B according to the data contained in the data frame 401. Finally, the control unit 120B of the second drive device 12B sends the data frame 402 with the current status of the second adjustment part 11B via the seat control unit 130 to the control unit 120A of the first drive device 12A.This (or at least the transmission of the data frame 401 ) occurs periodically, at least until the end of the adjustment.

[0091] The control unit 120B of the second drive device 12B is configured to interpolate between the control data contained therein for a period between two consecutive data frames 401.

[0092] By implementing direction-dependent and / or load-dependent situations, conscious position adjustments can also be achieved via position control. A number of respective controls in a specific direction can be taken into account.

[0093] As already mentioned, a standardization run of the adjustment elements 11A, 11B can be performed to store a respective zero-point position. The movements subsequently performed are referenced to this zero-point position. For this purpose, the control units 120A, 120B of the drive devices 12A, 12B are configured to adjust the adjustment elements 11A, 11B according to the standardization run in order to store a respective zero-point position and then to relate actual and / or target positions to the stored zero-point position.

[0094] The control units 120A, 120B of the drive devices 12A, 12B are configured here, for example, to move all adjustment elements 11A, 11B in the standardization travel against the respective stop 14 into a corresponding stop position, wherein the control units 120A, 120B are configured to store their respective stop position as a zero point position.

[0095] Alternatively or additionally, it can be provided that the stop 14 of a predetermined one of the adjustment elements 11A, 11B is configured such that the predetermined adjustment element 11A, 11B moves into its stop 14 before the other adjustment element 11A, 11B (or, in the case of more than two drive devices 12A, 12B, see e.g. Fig. 6, before the other adjustment elements) during the standardization travel. The control units 120A, 120B are then set up, for example, to store the respective zero point position in the stop position of the one predetermined adjustment element 11A, 11B, i.e. even if the other adjustment element (or the other adjustment elements) has not yet moved into the respective stop. For this purpose, the stop 14 of the one predetermined adjustment element 11A is arranged offset from the other stop 14 (or the other stops 14) and / or is designed differently.

[0096] In one example, the control units 120A, 120B are configured to store the respective zero-point position of the corresponding adjustment element 11A, 11B as soon as any of the adjustment elements 11A, 11B first reaches its stop position. For this purpose, the control unit 120A, 120B, which registers a stop, can send a message to the other control units 120A, 120B, which then stop the movement in response.

[0097] Fig. 6 shows a longitudinal adjustment device 1 ' for one or more vehicle seats, e.g. two individual seats or a bench seat.

[0098] The longitudinal adjustment device 1' comprises more than two, namely, for example, four, drive devices 12A-12D, each with a control unit 120A-120D. By means of the drive devices 12A-12D, an adjustment element 11A-11D can be adjusted, wherein the control units 120A-120D of the drive devices 12A-12D are in communicative connection with one another and / or with the seat control unit 130.

[0099] A first and a second of the drive devices 12A, 12B are designed analogously to the longitudinal adjustment device 1 explained above with reference to Fig. 2 and are communicatively connected to one another via a bus system 13. Accordingly, a third and a fourth of the drive devices 12C, 12D are also provided, which are also connected to the bus system 13. In the present case, the third and fourth drive devices 12C, 12D are designed analogously to the first and second drive devices 12A, 12B, but a different configuration would also be possible. The corresponding first, second, third, and fourth rails 10A, 10B, 10C, 10D run parallel to one another.

[0100] A first adjustment element 11A is guided and adjustable along the first rail 10A. A second adjustment element 11B is guided and adjustable along the second rail 10B. A third adjustment element 11C is guided and adjustable along the third rail 10C. A fourth adjustment element 11D is guided and adjustable along the fourth rail 10D.

[0101] One of the control units 120A-120D, here the control unit 120A of the first drive device 12A, serves as the primary control unit 120A, while the remaining control units 120B-120D serve as secondary control units 120B-120D.

[0102] Before the communication of the primary control unit 120A with the secondary control units 120B-120D is explained further below in connection with Fig. 9-11, the latencies already mentioned above will first be discussed again below.

[0103] For faster communication, two bus systems 13 can also be provided. For example, the seat control unit 130 is then connected to both bus systems 13, and the control units 120A-120D are each connected to one of the two bus systems 13, or some or all of them are connected to both bus systems 13.

[0104] Fig. 7 shows a position plotted against time using the longitudinal adjustment device 1 according to Fig. 2 as an example. The position is represented in accumulated degrees (°) of rotation, here, for example, the rotation of a motor shaft of the respective drive motor 121 starting from a zero-point position. A position of, for example, 3600° thus corresponds to ten full revolutions of the motor shaft starting from the zero-point position.

[0105] The upper line P illustrates the actual position of the first adjusting element 11A controlled by the primary control unit 120A. Since communication between the primary control unit 120A and the secondary control unit 120B takes place via periodically transmitted data frames, the secondary control unit 120B does not receive a data frame with the most recent actual position of the first adjusting element 11A controlled by the primary control unit 120A continuously, but rather at periodic time intervals. The lower line S in Fig. 7 illustrates the position received by the secondary control unit 120B. The steps each mark the receipt of a new position (here, for example, with a new data frame each time). The period has a length of 40 ms (illustrated in Fig. 7 with a long horizontal arrow), so that the position is updated every 40 ms.

[0106] The actual position of the primary control unit 120A is used by the secondary control unit 120B as the target position of the second adjustment element 11B. The secondary control unit 120B thus operates its drive motor 121 such that the second adjustment element 11B is controlled to this target position. In order to achieve the most uniform movement of the second adjustment element 11B, it can be provided that the secondary control unit 120B extrapolates from the already obtained positions (marked with markers in Fig. 7), e.g., linearly, using a polynomial or a spline.

[0107] Furthermore, Fig. 7 shows that the secondary control unit 120B receives the positions with a delay (illustrated by the short horizontal arrow). This is a communication latency for communication via the bus system 13. In the present example, this communication latency is 20 ms. At an exemplary speed of 5000 revolutions per minute (RPM), this results in a difference of 600° in 20 ms.

[0108] In order to compensate for this communication latency, the primary control unit 120A can be configured (e.g., by means of a corresponding program code) to calculate which future actual position the adjustment element (11A) of the primary control unit 120A will have after the communication latency, and then to communicate a control command (in the present example in the form of the data frame 401 already described) with the future actual position as the target position for the secondary control unit 120B to the secondary control unit 120B.

[0109] Thus, in the example of Fig. 7, the primary control unit 120A could calculate at a transmission time (at 0.54 s) which actual position its adjustment element 11A will have 20 ms in the future (i.e., at time 0.56 s) and communicate this more advanced position to the secondary control unit 120B at an earlier time. This would shift the lower line of Fig. 7 upwards so that the markers lie on the upper line. The additional extrapolation described above can ensure that both lines lie on top of each other, so that both adjustment elements 11A, 11B can be adjusted with particularly high synchronicity.

[0110] Alternatively or additionally, it can be provided that the primary control unit 120A is configured to communicate a control command (in the present example in the form of the data frame 401 already described) to the secondary control unit 120B not with a future, but with the current actual position of the adjustment element 11A of the primary control unit 120A as the target position for the secondary control unit 120B. In this case, the secondary control unit 120B can be configured to operate its drive motor 121 based on the received target position, which has become outdated due to the communication latency, and the communication latency. The secondary control unit 120B can thus calculate which additional path the drive motor 121 of the primary control unit 120A has described at the current speed during the duration of the communication (here 20 ms) and correct the target position accordingly.For example, the secondary control unit 120B adds the calculated additional travel to the obtained target position to calculate the corrected target position. The secondary control unit 120B can then control or regulate its drive motor 121 using the corrected target position.

[0111] To initiate a movement from a standstill of all adjustment elements 11A-11D, the primary control unit 120A is configured in one example to first communicate a control command to the secondary control unit(s) 120B-120D before controlling its own drive motor 121 after a predetermined delay following this communication. This also allows for latency (e.g., due to a diagnosis) to be compensated.

[0112] Fig. 8 illustrates, on the left side, data packets 401 periodically sent via bus system 13. In the present example, these are transmitted every 10 ms via bus system 13. This clock rate is determined by a clock generator in bus system 13, which can be, for example, the primary control unit 120A, the seat control unit 130, or another control unit.

[0113] The right side shows samples from the secondary control unit 120B. The sampling rate is 4 ms, for example. In this cycle, buffers for data exchange via bus system 13 are filled, or received data packets 401 are read out.

[0114] The secondary control unit 120B thus operates with a different clock than the bus system 13. Furthermore, the clock of the secondary control unit 120B may exhibit greater inaccuracies than the clock of the bus system 13 and, for this reason, may also deviate from it. However, this results in variations in the exact time at which the secondary control unit 120B processes and implements the received control commands. In Fig. 8, data packets intended for the secondary control unit 120B are marked with horizontal lines, and it can be seen that different delays result from the different scheduling. This causes jitter in the operation of the second adjustment element 11B.

[0115] To counteract this, the control commands can each include a parameter, e.g., a timestamp indicating the time of the transmitted actual position. This allows the secondary control unit 120B to correct the delay.

[0116] Furthermore, the primary control unit 120A can be configured to store an actual position of its adjustment part 11A at the moment a control command is sent to the secondary control unit 120B. Alternatively or additionally, the secondary control unit 120B can be configured to store an actual position of its drive device 12B at the moment a control command is received from the primary control unit 120A. These stored positions can then be used for a comparison in order to correct a target position.

[0117] The secondary control unit 120B can also be configured to pause the execution of a program code by means of an interrupt at the moment of receiving a control command from the primary control unit 120A in order to save the actual position of its adjustment part 11B. This can prevent the deviation illustrated in Fig. 8 due to the different scheduling.

[0118] Fig. 9 illustrates, based on a communication sequence via the bus system 13, a possible embodiment of the control units 120A-120D with more than two drive devices 12A-12D, here, for example, four drive devices 12A-12D according to Fig. 6. P denotes the primary control unit 120A, and S1 - S3 denote the individual secondary control units 120B-120D.

[0119] First, the primary control unit 120A receives a first message with a control command P.CTRL1, for example the command to move to a specific position. The primary control unit 120A implements this control command and generates a message with status values ​​of the assigned first drive device 12A, here, for example, the actual position and actual speed, P.STAT1. These status values ​​are transmitted as target values ​​via control command to the second, third, and fourth control units 120B-120D, S1.CTRL1, S2.CTRL1, S3.CTRL1, which then implement these target values. Subsequently, one of the secondary control units, namely the second control unit 120B, sends its status values ​​to the primary control unit 120A, which can indicate the actual position, actual speed, and / or an error status or the like, S1.STAT1.

[0120] This process takes a total of 60 ms over the LIN bus. The process then starts again, with another of the secondary control units, namely the third control unit 120C, sending its status values ​​to the primary control unit 120A, S2.STAT1, in the second pass.

[0121] In a third sequence, the fourth control unit 120D sends its status values ​​to the primary control unit 120A, S3.STAT1. Thus, the secondary control units 120B-120D do not send their feedback information to the primary control unit 120A after each receipt of a control command. Rather, only one of the secondary control units 120B-120D sends its feedback information per sequence, as a longer time interval is possible for this. This allows the control commands to be sent particularly quickly to the individual secondary control units 120B-120D.

[0122] The delay to the individual secondary control units 120B-120D in this communication system is 20 ms, 30 ms, and 40 ms. The total cycle length is 180 ms.

[0123] The primary control unit 120A is thus bidirectionally communicatively connected to the secondary control units 120B-120D, wherein the primary control unit 120A is configured to send control commands to each of the secondary control units 120B-120D more frequently than to receive feedback information from the respective secondary control unit 120B.

[0124] It can be provided that the primary control unit 120A only effects an adjustment if all drive units 12A-12D are normalized (logical AND) and / or if none of the drive units 12A-12D reports an error (logical NOR). It can be provided that the primary control unit 120A prevents an adjustment if at least one of the drive units 12A-12D reports an error (logical OR). Fig. 10 illustrates an example in which the primary control unit 120A is configured to communicate via more than one connection via the LIN bus system 13, namely, for example, via two connections. The primary control unit 120A can therefore simultaneously send control commands to two secondary control units 120B-120D and / or receive feedback information.

[0125] The primary control unit 120A receives a first message with a control command P1.CTRL1 on one channel, for example the command to move to a specific position, and feedback information from one of the secondary control units 120B-120D, S2.STAT1, on another channel. The primary control unit 120A then sends its message with the status values ​​of the assigned first drive device 12A, P1.STAT1, on one channel and simultaneously receives feedback information from another of the secondary control units 120B-120D, S3.STAT1, on another channel. The primary control unit 120A then sends control commands on two channels in parallel to two of the secondary control units 120B-120D, S1.CTRL1, S2.CTRL1. Thereafter, the primary control unit 120A receives feedback information from the remaining secondary control units 120B-120D, S1, on one channel.STAT1 , and in parallel sends a control command to the third of the secondary control units 120B-120D, S3.CTRL1.

[0126] This means that a cycle can be shortened to a total of 40 ms.

[0127] Fig. 11 illustrates that it can be provided, e.g. by means of the control unit 130 or the control unit 120A-120D of one of the drive devices 12A-12D, e.g. the primary control unit 120A, to send control commands via broadcast in parallel to the control units 120B-120D (e.g. of the remaining drive devices 12B-12D). It can be provided that the primary control unit 120A sends its state values ​​to the control unit 130, which then sends the broadcast message based thereon. Communication takes place, e.g., as described above in connection with Fig. 9, except that all secondary control units 120B-120D are addressed simultaneously with a broadcast message Broadcast.CTRL1 (S1-S3). In this example, this is a function of the LIN bus system 13. In this way, the cycle length can be shortened to 120 ms with only one channel.

[0128] In the manner described, a delay can be reduced particularly effectively. It should be noted that, instead of communication between the control units 120A-120D via another control unit, e.g., the seat control unit 130, it can also be provided that the control units 120A-120D communicate directly with each other.

[0129] Fig. 12 shows the speed RPM against time t, wherein two different speed ramps, namely a first speed ramp R1 and a second speed ramp R2, are illustrated, according to which the speed of the respective drive motor 121 can be increased by the control units 120A-120D.

[0130] It is provided that the control units 120A-120D are configured to increase a speed of the respective drive device 12A-12D according to a respective speed ramp R1, R2 upon the start of movement, wherein the speed ramps R1, R2 are different from one another. For example, the primary control unit 120A increases its drive motor 121 according to the first speed ramp R1. The (or, in the case of several, one) secondary control unit 120B only receives its control command to start up after a time delay. The secondary control unit 120B compensates for this by increasing its drive motor 121 according to the second speed ramp R2, which is steeper, i.e., has a greater gradient, i.e., the first speed ramp R1.As a result, the adjustment part 11 B of the secondary control unit 120B starts later, but catches up with the adjustment part 11 A of the primary control unit 120A because it reaches the same target speed more quickly for both.

[0131] One or both of the speed ramps R1 , R2 can be linear as shown.

[0132] A speed change during start-up according to the respective speed ramp R1, R2 of the primary control unit 120A and / or the secondary control unit 120B-120D can be used by the primary control unit 120A and / or the secondary control unit 120B-120D in the control of its own drive motor 121, in particular for delay compensation.

[0133] It is also possible for the primary control unit 120A and / or the secondary control unit 120B-120D to extrapolate the speed ramps, e.g., for a target speed specification. The primary control unit 120A can transmit the speed it will have after the delay compensation period. Electronic synchronization (with flexibility provided by a software-based implementation) can influence the position of the mechanical components. This ensures symmetrical wear and improves service life.

[0134] The described communication and control allow the use of a bus system 13 with a relatively low bandwidth and thus a relatively low resolution of the position of the first adjustment part 11A and the speed of the first drive device 12A.

[0135] The described longitudinal adjustment device 1 allows a particularly high degree of flexibility in implementation and also a reduction of mechanical tensions and thus in turn an improvement in service life.

[0136] Several examples are described below:

[0137] Example 1: Longitudinal adjustment device (1) for a vehicle seat (2), comprising: a first adjustment element (11 A) guided on a first rail (10A), a second adjustment element (11 B) guided on a second rail (10B), a first drive device (12A) by means of which the first adjustment element (11 A) can be adjusted along the first rail (10A), and a second drive device (12B) by means of which the second adjustment element (11 B) can be adjusted along the second rail (10B), wherein a control unit (120A) of the first drive device (12A) is in communicative connection with a control unit (120B) of the second drive device (12B).

[0138] Example 2: Longitudinal adjustment device (1) according to example 1, wherein the control unit (120B) of the second drive device (12B) is configured to synchronize a movement of the second adjustment element (11B) with a movement of the first adjustment element (11A) by means of the communicative connection.

[0139] Example 3: Longitudinal adjustment device (1) according to example 1 or 2, wherein the control unit (120A) of the first drive device (12A) is configured to determine a position of the first adjustment element (11A) along the first rail (10A) and to communicate the position to the control unit (120B) of the second drive device (12B).

[0140] Example 4: Longitudinal adjustment device (1) according to example 3, wherein the control unit (120B) of the second drive device (12B) is configured to control a drive motor (121) of the second drive device (12B) based on the position communicated by the control unit (120A) of the first drive device (12A). Example 5: Longitudinal adjustment device (1) according to example 4, wherein the control unit (120B) of the second drive device (12B) is configured to calculate a target rotational speed for the drive motor (121) of the second drive device (12B) based on the position communicated by the control unit (120A) of the first drive device (12A).

[0141] Example 6: Longitudinal adjustment device (1) according to example 4 or 5, wherein the control unit (120B) of the second drive device (12B) is configured to use the position communicated by the control unit (120A) of the first drive device (12A) as the target position for the second adjustment element (11B) along the second rail (10B).

[0142] Example 7: Longitudinal adjustment device (1) according to one of the preceding examples, wherein the control unit (120B) of the second drive device (12B) is configured to calculate a pulse width modulation signal (PWM) based on the calculated target rotational speed.

[0143] Example 8: Longitudinal adjustment device (1) according to one of the preceding examples, characterized in that the control unit (120A) of the first drive device (12A) is communicatively connected to the control unit (120B) of the second drive device (12B) by means of a bus system (13).

[0144] Example 9: Longitudinal adjustment device (1) according to Example 8, characterized in that the bus system is designed in the form of a LIN, CAN, CAN FD, FlexRay, Ethernet, K-line or MOST bus system.

[0145] Example 10: Longitudinal adjustment device (1) according to one of the preceding examples, characterized in that the control unit (120A) of the first drive device (12A) is communicatively connected to the control unit (120B) of the second drive device (12B) via a gateway (130).

[0146] Example 11: Longitudinal adjustment device (1) according to one of the preceding examples, characterized in that the control unit (120A) of the first drive device (12A) is bidirectionally communicatively connected to the control unit (120B) of the second drive device (12B). Example 12: Longitudinal adjustment device (1) according to one of the preceding examples, characterized in that the control unit (120A) of the first drive device (12A) is configured to communicate data frames (401) containing control data to the control unit (120B) of the second drive device (12B) at time intervals.

[0147] Example 13: Longitudinal adjustment device (1) according to Example 12, characterized in that the control unit (120B) of the second drive device (12B) is configured to interpolate between the control data contained therein for a period of time between two consecutive data frames (401).

[0148] Example 14: Longitudinal adjustment device (1) according to one of the preceding examples, characterized in that the control unit (120B) of the second drive device (12B) is designed to detect a fault and to communicate with the control unit (120A) of the first drive device (12A).

[0149] Example 15: Vehicle seat (2) with a seat part (20), a backrest (21) and the longitudinal adjustment device (1) according to one of the preceding examples, wherein at least the seat part (20) is mounted on the adjustment elements (11A, 11B) of the longitudinal adjustment device (1).

[0150] List of reference symbols

[0151] 1 , 1 ' (longitudinal) adjustment device

[0152] 10A-10D first, second, third, fourth rail

[0153] 11 A-11 D first, second, third, fourth adjustment element

[0154] 12A-12D first, second, third, fourth drive device

[0155] 120A-120D control unit

[0156] 121 drive motor

[0157] 122 Wave

[0158] 123 Snail

[0159] 124 spindle nut

[0160] 125 spindle

[0161] 13 Bus system

[0162] 130 Seat control unit

[0163] 14 stop

[0164] 2 vehicle seats

[0165] 20 Seat part

[0166] 21 Backrest

[0167] 22 Fitting arrangement

[0168] 3 vehicles

[0169] 30 Vehicle floor

[0170] 31 Substructure

[0171] 400-402 data frames

[0172] 500 position controllers

[0173] 501 speed controller

[0174] 502 current regulator

[0175] 6A-6C adjustment device

[0176] B control command

[0177] DZ speed

[0178] H Obstacle

[0179] HW Hardware

[0180] current

[0181] POS_1 , POS 2 Position first, second adjustment element

[0182] PWM pulse width modulation signal

[0183] SW Software

Claims

Claims 1 . Longitudinal adjustment device (1 , 1 ') for a vehicle seat (2), comprising: a first adjustment element (1 1 A) guided on a rail (10A), a second adjustment element (1 1 B) guided on a rail (10B), a first drive device (12A) by means of which the first adjustment element (I 1A) is adjustable along the rail (10A) on which the first adjusting element (11A) is guided, and a second drive device (12B) by means of which the second adjusting element (IIB) is adjustable along the rail (10B) on which the second adjusting element (11B) is guided, characterized in that a control unit (120A) of the first drive device (12A) is in communicative connection with a control unit (120B) of the second drive device (12B).

2. Longitudinal adjustment device (1, 1') according to claim 1, characterized in that the control unit (120A) of the first drive device (12A) is communicatively connected to the control unit (120B) of the second drive device (12B) via a seat control unit (130).

3. Longitudinal adjustment device (1, 1') according to claim 1 or 2, characterized in that the control units (120A, 120B) of the drive devices (12A, 12B) are designed to adjust the adjustment elements (11A, 11B) in a standardization run in order to store a respective zero point position and then to relate actual and / or desired positions to the stored zero point position.

4. Longitudinal adjustment device (1, 1') according to claim 3, characterized in that the control units (120A, 120B) of the drive devices (12A, 12B) are designed to move all adjustment elements (11A, 11B) in the standardization travel against a respective stop (14) into a stop position, wherein the control units (120A, 120B) are designed to store their respective stop position as a zero point position.

5. Longitudinal adjustment device (1, 1') according to claim 3, characterized in that the stop (14) of a predetermined one of the adjustment elements (11A, 11B) is configured such that the predetermined adjustment element (11A, 11B) moves into its stop (14) before the other adjustment element (11A, 11B) in the standardization travel, wherein all control units (120A, 120B) are set up to store the respective zero point position in the stop position of the predetermined adjustment element (11A, 11B).

6. Longitudinal adjustment device (1, 1') according to claim 3, characterized in that the Control units (120A, 120B) are adapted to control the respective Zero point position to be saved as soon as any of the adjustment elements (11 A, 11 B) first reaches its stop position.

7. Longitudinal adjustment device (1, 1') according to one of the preceding claims, characterized in that one of the control units (120A, 120B) as the primary control unit (120A) is configured to communicate control commands to the other, secondary control unit (120B).

8. Longitudinal adjustment device (1, 1') according to claim 7, characterized in that the control commands each comprise a speed and / or a position.

9. Longitudinal adjustment device (1, 1') according to claim 7 or 8, characterized in that the primary control unit (120A) is designed to first communicate a control command to the secondary control unit (120B) for a start of movement before it controls a drive motor (121) after a predetermined delay after this communication.

10. Longitudinal adjustment device (1, 1') according to one of claims 7 to 9, characterized in that the communication of a control command has a communication latency, wherein the primary control unit (120A) is configured to calculate which future actual position the adjustment element of the primary control unit (120A) will have after the communication latency, and is further configured to communicate a control command with the future actual position as the target position for the secondary control unit (120B) to the secondary control unit (120B). 1 1. Longitudinal adjustment device (1 , 1 ') according to one of claims 7 to 9, characterized in that the communication of a control command is a communication latency, wherein the primary control unit (120A) is configured to communicate a control command with the current actual position of the adjustment element of the primary control unit (120A) as a target position for the secondary control unit (120B) to the secondary control unit (120B), wherein the secondary control unit (120B) is configured to operate its drive motor (121) based on that target position and the communication latency.

12. Longitudinal adjustment device (1, 1') according to one of claims 7 to 11, characterized in that the control units (120A, 120B) are designed to increase a speed of the respective drive device (12A, 12B) according to a respective speed ramp (R1, R2) when a movement starts.

13. Longitudinal adjustment device (1, 1') according to one of claims 7 to 12, characterized in that the control commands each comprise a time stamp.

14. Longitudinal adjustment device (1, 1') according to one of claims 7 to 13, characterized in that the primary control unit (120A) is set up to store an actual position of its drive device (12A) at the moment of sending a control command to the secondary control unit (120B) and / or that the secondary control unit (120B) is set up to store an actual position of its drive device (12B) at the moment of receiving a control command from the primary control unit (120A).

15. Longitudinal adjustment device (1, 1') according to claim 14, characterized in that the secondary control unit (120B) is configured to pause the execution of a program code by means of an interrupt at the moment of receiving a control command from the primary control unit (120A) in order to store the actual position of its drive device (12B).

16. Longitudinal adjustment device (1, 1') according to one of claims 7 to 15, characterized in that the primary control unit (120A) is bidirectionally communicatively connected to the secondary control unit (120B), wherein the primary control unit (120A) is configured to send control commands to the secondary control unit (120B) more frequently than to receive feedback information from the secondary control unit (120B).

17. Longitudinal adjustment device (1, 1') according to one of the preceding claims, characterized in that the control units (120A, 120B) are each designed to control a respective drive motor (121) by means of a torque-generating voltage.

18. Longitudinal adjustment device (1') according to one of the preceding claims, characterized by more than two, in particular four, drive devices (12A-12D), each with a control unit (120A-120D), by means of which a respective adjustment element (11A-11D) can be adjusted, wherein the control units (120A-120D) of the drive devices (12A-12D) are in communicative connection with one another and / or with a control unit (130).

19. Longitudinal adjustment device (1, 1') according to one of the preceding claims, characterized in that the control unit (120A) of the first drive device (12A) is communicatively connected to the control unit (120B) of the second drive device (12B) by means of a bus system (13) in the form of a LIN bus system.

20. Longitudinal adjustment device (1, 1') according to claim 19, characterized in that the longitudinal adjustment device (1, 1') has several parallel bus systems (13).

21. Longitudinal adjustment device (1, 1') according to claim 18 and according to claim 19 or 20, characterized in that the control unit (130) is designed to send control commands by broadcast in parallel to the control units (120B-120D) of the other drive devices (12B-12D).

22. Adjusting device (1, 1', 6A-6C), in particular for a vehicle seat (2), in particular according to one of the preceding claims, comprising: a first adjusting element (11 A), a second adjusting element (11 B), a first drive device (12A), by means of which the first adjusting element (IIA) is adjustable, and a second drive device (12B), by means of which the second adjusting element (IIB) is adjustable, characterized in that a control unit (120A) of the first drive device (12A) and a control unit (120B) of the second drive device (12B) are communicatively connected to one another and / or to a further control device (130) via a bus system (13).

23. Adjusting device (1, 1', 6A-6C) according to claim 22, characterized in that the adjusting device (1, 1') is designed in the form of a longitudinal adjusting device for adjusting a longitudinal position of the vehicle seat (2), in the form of a seat height adjusting device for adjusting a seat height of the vehicle seat (2), in the form of a seat inclination adjusting device for adjusting an inclination of a seat part (20) of the vehicle seat (2) or in the form of a backrest inclination adjusting device for adjusting an inclination of a backrest (21) of the vehicle seat (2) relative to the seat part (20).

24. Vehicle seat (2) with a seat part (20), a backrest (21) and the longitudinal adjustment device (1, 1') according to one of claims 1 to 21 or the adjustment device according to claim 22 or 23 in the form of a longitudinal adjustment device, wherein at least the seat part (20) is mounted on the adjustment elements (11A, 11B) of the longitudinal adjustment device (1, 1').

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