METHOD FOR OPERATING ELECTRICAL DRIVE UNITS OF SEAT COMPONENTS IN A MOTOR VEHICLE, PREFERABLY IN A PRE-CRASH CASE, AND SYSTEM FOR PERFORMING THE METHOD

Abstract

The invention relates to methods and a system for operating electrical drive units of seat components in a motor vehicle, preferably in the case of a detected pre-crash situation, wherein an optimum target position of a passenger for an imminent crash case is moved to (S1, S2) depending on a current position of the passenger, wherein, for this purpose, a rule strategy for coordinating the adjustment of the seat components is determined (S3) in order to actuate at least two of the drive units at the same time or directly in succession such that the required power of the drive units is minimized (S4).

Claims

1. A method for operating electrical drive units (10) of seat components in a motor vehicle during a detected pre-crash situation, the method comprising: depending on an actual position of a passenger, moving the passenger to an optimum target position for the impending crash case, determining a control strategy for coordinating the adjustment of the seat components in order to actuate at least two of the drive units simultaneously or immediately successively such that the required power of the drive units is minimized.

2. The method as claimed in claim 1, wherein the control strategy for coordinating the adjustment of the seat components is determined as a function of sensor signals from pre-crash sensors in the motor vehicle which estimate the time and acceleration values of the vehicle in all directions until the crash.

3. The method as claimed in claim 1, wherein the control strategy for coordinating the adjustment of the seat components is determined as a function of detected positional data of the seat components and/or a detected position of the passenger, or both.

4. The method as claimed in claim 1, wherein the control strategy for coordinating the adjustment of the seat components is determined as a function of detected key values of the passenger selected from the group consisting of weight, body mass, and consciousness state.

5. The method as claimed in claim 1, wherein the control strategy for coordinating the adjustment of the seat components is determined as a function of the available maximum performance capacity of an assigned battery, an accumulator, or a supercapacitor.

6. The method as claimed in claim 1, wherein the control strategy for coordinating the adjustment of the seat components takes into account the estimated interaction of the movements of the various seat components.

7. The method as claimed in claim 1, wherein the control strategy for coordinating the adjustment of the seat components takes into account a maximum permitted acceleration load on the different body parts of the passenger.

8. The method as claimed in claim 1, wherein the control strategy for coordinating the adjustment of the seat components actuates at least two adjustment levels of the seat components, selected from the group consisting of a seat length setting, a seat slope setting, and a backrest slope setting.

9. The method as claimed in claim 1, wherein the control strategy for coordinating the adjustment of the seat components actuates at least one adjustment level of selected from the group consisting of a seat height setting, a headrest height setting, a leg support setting.

10. The method as claimed in claim 1, wherein the electrical drive units seat components are operated with a 24V or 36V or 48V or 60V vehicle network, and execute the necessary adjustment movements until to the crash event in a time period from 0.1 to 0.3 seconds.

11. The method as claimed in claim 1, wherein the control strategy accelerates the vehicle seat along the seat length adjustment in the direction of travel and then decelerates it again, wherein the process of decelerating the seat length adjustment is used to reduce the maximum necessary power for the erection of the seat backrest via the backrest slope adjustment, which is performed simultaneously with the deceleration process.

12. The method as claimed in claim 1, wherein the control strategy, simultaneously with the erection of the backrest via the backrest slope adjustment, performs the seat slope adjustment in the opposite direction to the backrest slope adjustment in order to reduce the maximum necessary power of the electrical drives.

13. The method as claimed in claim 1, wherein the control strategy matches the erection of the backrest and/or the seat slope to the deceleration of the vehicle on the basis of the pre-crash sensors, in order to reduce the maximum necessary power of the electrical drive of the backrest slope adjustment.

14. The method as claimed in claim 1, wherein the electrical drive units are configured for optimized efficiency and comprise self-braking gear mechanisms, and each comprise a clamping lock for fixing the seat components in a desired position.

15. A system for performing the method as claimed in claim 1, wherein the system comprises pre-crash sensors, position sensors for the seat components, sensors for detecting the passenger position, or a combination of the foregoing 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 by means of electrical drive units in a pre-crash case such that the required power of the drive units is minimized.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings show:

[0021] FIG. 1 schematically, the method steps for operating electrical drive units (10) of seat components in a motor vehicle in the case of a crash,

[0022] FIG. 2a the temporal development of the power of the backrest adjustment, and

[0023] FIG. 2b the temporal development of the acceleration of the corresponding seat length adjustment.

DETAILED DESCRIPTION

[0024] FIG. 1 depicts schematically for example a method for operating electrical drive units of seat components in a motor vehicle. In a first step S1, the pre-crash sensors detect the danger of an impending crash. The pre-crash sensors comprise acceleration and/or rotation rate sensors, but may also be combined with any other environmental sensors such as radar, ultrasound and video sensors. The pre-crash sensors supply the time period necessary for determining the control strategy for coordinating the adjustment of the seat components, and the accelerations acting on the vehicle during that time.

[0025] In a further step S2, the current position of the individual seat components is detected. Since the drive units each comprise a position detection for reaching predefined positions, their current values may be used for determining a control strategy.

[0026] In addition, according to a step S3, optional passenger-specific key data may be included which was either previously stored or is detected currently by corresponding interior sensors (e.g. camera, seat occupation sensor). For example, the weight and body mass of the passenger are made available for determining the control strategy.

[0027] Furthermore, in a step S4, the current energy reserves of the electrical drive units to be actuated, in particular the charge state of the battery or accumulator or supercapacitor, are detected. The structurally imposed maximum performance capacity of the individual electrical drives is also stored in the system for determination of the control strategy.

[0028] In a step S5, taking into account all these available input data, the optimum control strategy for actuating the electrical drive units of the seat components is generated. The aim of the control strategy is to reach an optimum seat position of the passenger for the specific crash case in the time still available. Because of the achieved determination of the optimum temporal sequence of the movements of the individual adjustment levels, the necessary maximum power and hence the installation size of the fitted electrical drives may be reduced. The control strategy in particular also takes into account the need to ensure that certain body parts, such as head and neck, are not exposed to excessive acceleration loads. The control strategy is determined in a processor of a control unit, preferably by means of implemented algorithms. The electrical drives are then actuated via the control unit.

[0029] In step S6, now the individual electrical drives of the different adjustment levels are actuated. According to the control strategy, the temporal sequence and power requirement of the drives are matched to one another such that a synergy effect of the various movements is utilized in order to lower the maximum power of the drives and the energy consumption. This control strategy also allows large adjustment travels and adjustment angles of the seat components within a short time, so that in the case of an impending crash, passengers can be moved in good time out of a comfort position, for example for autonomous driving, into a safe target position so that the restraint systems function optimally.

[0030] As an example of a control strategy, the coordination of the adjustment levels of the backrest slope setting with the seat length setting is shown in the diagrams of FIGS. 2a and 2b. FIG. 2a shows the acceleration a of the adjustment movement of the seat length setting over the time t which begins immediately after detection of a pre-crash case at time t=0. The entire seat with passenger is accelerated in the direction of travel at for example 1.3 m/s.sup.2. As a reference line, a dotted line at a=0 m/s.sup.2 indicates the case without seat length adjustment.

[0031] FIG. 2b shows the necessary power as the necessary torque m in the hinge joint of the backrest setting over the time t. In the case that the seat length adjustment is not actuated, a maximum torque for backrest adjustment of around 1000 Nm is required, which is shown as a dotted line. The drive of the backrest setting begins only at 0.06 s, therefore the drive must apply a retaining moment of approximately 300 Nm for the backrest if the seat is not accelerated in the longitudinal direction.

[0032] In the case that the seat length setting is first accelerated with a=1.3 m/s.sup.2 and then decelerated (solid line in FIG. 2a), the maximum necessary torque for the backrest adjustment is reduced to approximately 650 Nm (solid line in FIG. 2b), since the deceleration of the seat length adjustment achieves an inertia moment of the seat backrest and passenger which significantly reduces the maximum power requirement during this deceleration. The retaining moment for the backrest at Δt=0.0-0.5 s is significantly greater (approximately 650 Nm) during the acceleration of the seat length movement than without the seat length adjustment. However, because of the control strategy, due to later actuation of the drive of the backrest slope adjustment (at the time of deceleration of the seat length adjustment), the latter may be executed with a lower maximum necessary power than if both drives for both adjustment levels were started simultaneously.

[0033] It is pointed out that with respect to the exemplary embodiments shown in the figures and in the description, many possible combinations of individual features are possible. Thus for example, individual method steps may be omitted or their sequence modified. For input data, different sensors may be used or data may be previously stored in the control unit. The matching of the number of adjustment levels and the concrete actuation strategy may be adapted to the respective seat and crash event. As electrical drives, preferably electric motors with a following gear mechanism are used, wherein different gear designs such as worm gears, eccentric gears, or cylindrical or bevel gears may be used. The control unit may be configured as a central control unit for several electric motors, or be integrated in a control unit of a drive, or be configured as a component of the pre-crash controller. Also, the method may be used for applications outside a pre-crash case, for example for rapid adjustment of the seat components as an entry/exit aid or for other comfort uses in the motor vehicle.