Method for operating an electric drive unit of a seat component in a motor vehicle, preferably in a pre-crash situation, and system for carrying out the method

Abstract

The invention relates to a method and a system for operating an electric drive unit of a seat component in a motor vehicle, preferably a method and a system for operating an electric drive unit of a seat component in a motor vehicle in the event of a detected pre-crash situation, wherein an optimal target position of the occupant for an impending crash situation is approached as a function of the occupant's current position (S1, S2), wherein for this purpose a control strategy (S3) is determined for coordinating the adjustment of the seat components in order to control at least two drive units simultaneously or directly one after the other in such a way that the power required by the drive units is minimized (S4).

Description

Technical Field

[0001] The invention relates to a method for operating an electric drive unit of a seat part in a motor vehicle, preferably in a pre-crash situation, and a system for carrying out the method according to the independent claims. Background Art

[0002] A device for rapidly adjusting a seat adjustment drive is known from DE 103 09 083 A1, which moves a backrest into a crash-optimized position by means of a rapid run when an impending crash is detected. In addition, this rapid run is used as an entry aid for adjusting an unloaded backrest.

[0003] If the flexibility of vehicle seats increases further in future vehicle designs due to automated driving, there is a risk that in the event of a crash the occupants will not be in a position optimized for the restraint system and thus their risk of injury increases. However, the seat adjustment drives known from the prior art are not suitable for moving seat parts quickly enough over large paths and angles within the short time period until an impending crash is detected. However, for reasons of weight and cost, the installation of significantly more powerful adjustment drives should be avoided. Summary of the invention

[0004] In contrast, the method according to the invention for operating a drive unit of a motor vehicle component, preferably a side window, a sliding roof or a seat part, and a drive unit for carrying out the method, having the features of the independent claims, have the following advantages: By implementing a time-sequential adjustment strategy of different drive units for different seat parts, the maximum power required by the drive can be reduced. As a result, the drive unit can be significantly smaller and lighter than if the individual drive units adjust the different seat parts completely independently of one another. The idea here is that, for the coordination of the drive units, on the one hand, the external acceleration of the vehicle can be used, and on the other hand, the dynamics of one adjustment level can be used to actuate another adjustment level. By means of this control design, the occupants in the motor vehicle can be moved from one of the resting positions into a seat position optimized for the crash situation in the shortest possible time, so that the restraint system, such as a belt tensioner or an airbag, can optimally protect the occupants in the event of a crash. As a result, due to the very fast adjustment movement of the seat parts, the occupants in the second row of seats or in an automated driving can also be adjusted from any resting position into a target position that is optimal for an impending crash.

[0005] The embodiments described in the dependent claims can be advantageously expanded and improved by the measures described in the dependent claims. Preferably, the determination of the control strategy for the different seat adjustment levels is initiated by the sensor signal of the pre-crash sensor system. The time available until the collision and also the acceleration forces acting on the vehicle during this time period are used as the basis for determining the control strategy. By using the sensors already present in the motor vehicle, no further additional sensors are required for determining the scenario up to a possible collision.

[0006] The position data of the seat component are determined continuously by detecting the position of the electric drive, preferably by means of an incrementally operating Hall sensor system or by means of a sensorless system which evaluates the current ripple of the actuating motor.

[0007] In addition to the current position data of the seat components and / or the occupant, individual characteristics of the occupant are also used to determine the control strategy. These individual characteristics of the occupant can be read into a memory beforehand, for example, or can be determined in the vehicle using sensors suitable for this purpose. It is particularly advantageous that the weight and body values, in particular the body dimensions, of the occupant can be used as a basis for developing the control strategy.

[0008] In order to achieve the best possible seat position for an impending collision within the time still available, the maximum performance of the individual drive units is also taken into account for the control strategy. In addition, the current state of available energy can also be used to determine the control strategy.

[0009] In order to save energy for the adjustment movements, the dynamics of the individual adjustment levels of the seat part are taken into account. Thus, in particular, the braking of a first adjustment movement can be used to accelerate the seat part of a second adjustment movement. Thus, for example, it is reasonable to start different adjustment movements not exactly simultaneously, but in a staggered manner one after the other.

[0010] In order to prevent the occupants from getting injured during the rapid control movements in the pre-crash period, the control strategy takes into account the maximum load of the individual body parts at the maximum acceleration. In this case, for example, it is preferably taken into account that the head or neck area is subject to lower acceleration than other parts of the body. For example, the maximum acceleration values ​​of the individual body parts are determined in the pre-crash system and stored in the control device to generate the control strategy.

[0011] The adjustment strategy preferably controls at least two different adjustment movements of different seat parts, wherein the longitudinal seat adjustment and the seat tilt adjustment and the bracket tilt adjustment are considered to be the most important in order to achieve the optimal target position in the event of a crash. At least two, preferably all three, of the adjustment levels are coordinated with one another by the adjustment strategy.

[0012] Additionally, other adjustment levels, such as seat height adjustment, headrest height adjustment, leg rest length adjustment, can also be considered in the adjustment strategy. Here, the adjustment strategy can include at least two of all seat adjustment levels, or can also include three, or four or more adjustment levels.

[0013] In order to reach the desired target position as quickly as possible, the electric drive unit is preferably operated at a significantly higher voltage than the usual 12-volt onboard electrical system. Preferably, a voltage of approximately 24, 36, 48 or 60 volts is applied to the drive motor so that, for example, all necessary seat components can be adjusted within a pre-crash time period of approximately 0.1 to 0.3 seconds. In this time period, a movement of the seat component up to a 20 cm length adjustment or a 15° inclination can then be achieved by the adjustment strategy.

[0014] A particularly efficient adjustment strategy is achieved by coordinating the longitudinal seat adjustment with the backrest inclination adjustment. In this case, the inertia moment of the longitudinal seat adjustment braking process is utilized to reduce the energy requirement when the seat backrest is raised. For this purpose, the drive of the seat backrest is activated later in time than the drive of the longitudinal seat adjustment, so that in particular the greatest possible overlap between the braking process of the longitudinal seat adjustment and the backrest adjustment is utilized.

[0015] Another advantageous adjustment strategy is the advantageous coordination of the seat tilt adjustment and the backrest tilt adjustment. Here, when the seat back is erected, the seat tilt is preferably adjusted simultaneously on the contrary.

[0016] In addition to the interaction of the various control levels, external accelerations acting on the motor vehicle can also be taken into account for determining the control strategy. In particular, in the case of an impending frontal collision, the braking of the vehicle can be used for a more effective backrest tilt adjustment, in which the occupant is raised accordingly for the collision. The pre-crash sensor system provides predictable acceleration values ​​for adopting the control strategy of the electric drive.

[0017] In order to achieve the fastest possible adjustment of the seat part in the pre-crash situation, the electric drive has in particular the highest possible efficiency. For this purpose, the transmission and bearings of the electric drive are designed so that they have the lowest possible self-locking properties. In this embodiment, it is necessary that the drive unit then has a locking ratchet which keeps the seat part in its position when the target position is reached.

[0018] The system according to the invention for determining and executing a control strategy for adjusting different seat components advantageously uses existing pre-crash sensors, which detect a possible imminent collision. In addition, existing position sensors of the drive motors of the seat components are used to detect the current position of the seat components. The system has a control device into which these existing raw data are read. In the control device, a control strategy for controlling the drive motor is determined based on the time period still available until the collision and the current position of the seat component. In addition, previously determined data, such as specific characteristic feature values ​​of the passenger, such as height or weight, can be stored in the control device. The maximum performance of the electric drive can also be stored in the control device. The control strategy is derived from all these data, with the goal of achieving the optimal position of the passenger within a preset time period with the help of a given electric drive. Attention should be paid here to: the passenger is not subjected to excessive acceleration and the vehicle's onboard power supply is loaded as little as possible. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention is explained in more detail below based on examples, but the present invention is not limited thereto.

[0020] in:

[0021] Figure 1 The method steps for operating an electric drive unit (10) for a seat component in a motor vehicle in the event of a crash are schematically shown.

[0022] Figure 2a shows the time curve of the power of the backrest adjustment, and

[0023] Figure 2b The time curve of the corresponding acceleration of the longitudinal adjustment of the seat is shown. DETAILED DESCRIPTION

[0024] exist Figure 1 2 shows a method for operating an electric drive unit for a seat component in a motor vehicle. In a first step S1, a pre-crash sensor system detects the risk of an imminent collision. The pre-crash sensor system includes an acceleration and / or rotational speed sensor, but can also be used in combination with any other environmental sensors, such as radar, ultrasound and video sensors. In order to determine a control strategy for coordinating the adjustment of the seat component, the pre-crash sensor system provides the necessary time period and the acceleration acting on the vehicle at that time.

[0025] In a further step S2 , the current position of the individual seat components is detected. Since the drive units each have a position detection in order to approach a preset position, the current values ​​of the position detection can be used to determine the control strategy.

[0026] In addition, according to step S3, passenger-specific characteristic data can optionally be recorded, which have either been stored previously or are currently detected by corresponding internal sensor devices (e.g., cameras, seat occupancy sensors). For example, the weight and physical values ​​of the passenger can be used to determine the control strategy.

[0027] Furthermore, in step S4 the current energy reserve of the electric drive unit to be activated, in particular the charge state of a battery or rechargeable battery or supercapacitor, can be detected. The design-dependent maximum performance of the individual electric drives is also stored in the system for determining the control strategy.

[0028] In step S5, taking into account all of these available input data, an optimal control strategy for the electric drive unit for operating the seat component is generated. The goal of the control strategy is to approach the optimal seat position of the passenger for a specific collision situation within the time that is still available. Due to the targeted determination of the optimal time sequence of the movements of the various adjustment levels, the maximum power required by the built-in electric drive can be reduced - thereby reducing the structural size. The control strategy also takes into account in particular that specific body parts, such as the head and neck, are not subjected to excessive acceleration loads. The control strategy is determined in the processor of the control device, preferably by means of an algorithm implemented for this purpose. The electric drive is then also controlled via the control device.

[0029] In step S6, the individual electric drives of the different adjustment levels are now controlled. According to the control strategy, the time sequence and power requirements of the drives are coordinated with each other so that the synergy effects of the different movements are fully utilized to reduce the maximum power and energy consumption of the drives. This control strategy also allows: large adjustment distances and adjustment angles of the seat parts in a short time, so that in the event of an imminent collision, the occupants can also be moved from a comfortable position - for example in automated driving - to a safe target position in time so that the restraint system can optionally work.

[0030] As an example of an adjustment strategy, the adjustment level of the backrest tilt adjustment is coordinated with the longitudinal adjustment of the seat. Figure 2a and 2b As shown in the figure. Figure 2a In FIG. 1 , the acceleration a of the adjustment movement of the longitudinal adjustment of the seat is shown over time t, which adjustment movement starts immediately after the pre-crash situation is detected at time t=0. In this case, the entire seat with the passenger moves in the direction of travel at, for example, 1.3 m / s 2 Acceleration. As a reference line, as a dotted line with a=0m / s 2 Shown is the situation without longitudinal seat adjustment.

[0031] exist Figure 2bIn the figure, the required power is plotted over time t as the required torque m at the joint for the backrest tilt adjustment. Without actuating the longitudinal adjustment of the seat, a maximum torque of approximately 1000 Nm is required for the backrest adjustment, which is shown as a dashed line. The drive for the backrest tilt adjustment is not activated until 0.06 s, before which, if the seat is not accelerated in the longitudinal direction, the drive must apply a holding torque of approximately 300 Nm to the backrest.

[0032] When adjusting the seat longitudinally, first adjust the seat longitudinally at a = 1.3 m / s 2 Accelerate and then brake ( Figure 2a In the case of the solid line in the figure, the maximum torque required for backrest tilt adjustment is reduced to about 650Nm ( Figure 2b ), since the braking of the longitudinal seat adjustment causes inertia moments of the seat back and the passenger, which significantly reduce the maximum power requirement during the braking. During the acceleration of the longitudinal seat movement, the holding torque for the backrest in Δt=0.0-0.05s (approximately 650 Nm) is significantly greater than without longitudinal seat adjustment. However, due to the control strategy, the backrest tilt adjustment is performed with a lower maximum required power by later actuation of the drive for the longitudinal seat adjustment (at the moment of braking of the longitudinal seat adjustment) than when both drives of the two adjustment levels are activated simultaneously.

[0033] It should be pointed out that with respect to the embodiments shown in the drawings and the description, various combination options of the individual features are possible. Thus, for example, individual method steps can be omitted or their order can be changed. Different sensors can be used for inputting data, or the data can be stored in advance in the control device. The coordination of the number of adjustment levels and the specific control strategy can be matched to the corresponding seats and collision events. Preferably, an electric motor with a subsequent transmission is used as an electric drive, wherein different transmission configurations, such as worm gears, eccentric gears or spur gears or bevel gears, can be used. The control unit can be configured as a central control device for multiple electric motors, or integrated into the control device of the drive - or configured as a component of a pre-crash control device. Similarly, the method can also be used for applications other than pre-crash events, for example as an entry / exit aid for quickly adjusting seat components or for other comfort applications in motor vehicles.

Claims

1. A method for operating an electric drive unit (10) of a seat component in a motor vehicle, the method operating the electric drive unit of a seat component in a motor vehicle in the event of a detected pre-crash situation, wherein an optimal target position of the occupant is approached for an impending collision situation based on the current position of the occupant, wherein a control strategy for coordinating the adjustment of the seat component is determined for this purpose so as to control at least two drive units simultaneously or directly in succession so as to minimize the power required by the drive units, wherein the control strategy for coordinating the adjustment of the seat component takes into account the estimated interaction of the movements of different seat components, wherein the control strategy for coordinating the adjustment of the seat component controls at least two adjustment levels of the seat component, the adjustment levels being selected from the group consisting of longitudinal seat adjustment, seat tilt adjustment, or backrest tilt adjustment, wherein the control strategy accelerates the vehicle seat along the longitudinal seat adjustment in the direction of travel and subsequently brakes it again, wherein the braking process for the longitudinal seat adjustment is used for the vertical raising of the seat backrest for the backrest tilt adjustment performed simultaneously with the braking process in order to reduce the maximum power required.

2. The method according to claim 1, characterized in that The operation includes accelerations of the various seat components.

3. The method according to claim 1, characterized in that A control strategy for coordinating the adjustment of the seat parts is determined based on sensor signals of a pre-crash sensor system in the motor vehicle, which estimates acceleration values ​​and times of the vehicle in all directions up to the collision.

4. The method according to any one of claims 1 to 3, characterized in that A control strategy for coordinating the adjustment of the seat parts is determined as a function of the detected position data of the seat parts and / or the detected position of the occupant.

5. The method according to any one of claims 1 to 3, characterized in that A control strategy for coordinating the adjustment of the seat parts is determined as a function of the detected characteristic values ​​of the occupant.

6. The method according to claim 5, characterized in that The characteristic values ​​include weight or physical values ​​or state of consciousness.

7. The method according to any one of claims 1 to 3, characterized in that A control strategy for coordinating the adjustment of the seat parts is determined as a function of the available maximum performance of the drive unit and / or its maximum energy reserve.

8. The method according to claim 7, characterized in that The maximum energy reserve is the maximum energy reserve of the associated battery or rechargeable battery or supercapacitor.

9. The method according to any one of claims 1 to 3, characterized in that The control strategy for coordinating the seat part adjustments takes into account the maximum permissible acceleration loads on different body parts of the occupant.

10. The method according to any one of claims 1 to 3, characterized in that In addition to at least one adjustment level consisting of seat longitudinal adjustment or seat inclination adjustment or backrest inclination adjustment, the adjustment strategy for coordinating the adjustment of the seat parts also controls at least one further adjustment level of seat height adjustment or headrest height adjustment or legrest adjustment.

11. The method according to any one of claims 1 to 3, characterized in that The electric drive unit of the seat part is operated with a 24 V or 36 V or 48 V or 60 V on-board electrical system and executes the adjustment movements required up to a crash situation in a time period of 0.1 to 0.3 seconds.

12. The method according to claim 11, characterized in that The electric drive unit of the seat part executes the adjustment movements required up to the crash situation in a period of 0.2 seconds.

13. The method according to any one of claims 1 to 3, characterized in that The adjustment strategy performs a seat tilt adjustment opposite to the backrest tilt adjustment while the backrest is being raised during the backrest tilt adjustment in order to reduce the maximum required power of the electric drive unit.

14. The method according to any one of claims 1 to 3, characterized in that The control strategy coordinates the tilting of the seat and / or the raising of the backrest to the braking of the vehicle based on a pre-crash sensor system in order to reduce the maximum required power of the electric drive unit for adjusting the backrest tilt.

15. The method according to any one of claims 1 to 3, characterized in that The electric drive unit is designed to optimize efficiency and has a self-braking transmission.

16. The method according to claim 15, characterized in that The electric drive units each have a locking ratchet for fixing the seat part in a desired position.

17. A system for performing the method according to any one of the preceding claims, characterized in that The system has a pre-crash sensor system and / or an orientation sensor for seat components and / or a sensor for detecting the position of an occupant, and the sensor data are processed in a control unit of the system in order to determine a control strategy, according to which the individual seat components are actuated in a pre-crash situation with the aid of an electric drive unit in such a way that the required power of the drive unit is minimized.

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