ELECTRIC SIDE DOOR DRIVE ASSEMBLY FOR A VEHICLE

Abstract

An electric side door drive assembly for a vehicle having a length-adjustable electric actuator to bring about opening and closing of the side door, and a door movement sensor unit designed to detect stopping and a current position of the side door during opening or closing of the side door. In the event of stopping of the side door detected by the door movement sensor unit, a controller determines, on the basis of side door position data provided by the door movement sensor unit, a necessary current strength which is to be supplied to the electric motor to hold the side door in its current position, and to deliver the necessary current strength to the motor of the actuator for a holding operation.

Claims

1. Electric side door drive assembly for a vehicle, comprising: a length-adjustable electric actuator which is arranged between a vehicle body and a side door of the vehicle, and which is configured to facilitate opening and closing of the side door and which comprises a controllable electric motor; a control unit which is operationally coupled to the length-adjustable electric actuator and which is associated with a storage unit on which geometric parameters of the vehicle and operating parameters of the length-adjustable electric actuator are stored; and a door movement sensor unit which is operationally coupled to the control unit and is designed to detect stopping and a current position of the side door during opening or closing of said side door, wherein the control unit is designed, in the event of stopping of the side door detected by the door movement sensor unit: to determine, on the basis of side door position data provided by the door movement sensor unit, and the geometric parameters of the vehicle and the operating parameters of the length-adjustable electric actuator stored in the storage unit, a necessary current strength which is to be supplied to the controllable electric motor of the actuator in order to hold the side door in its current position; and to deliver a necessary current strength to the motor of the length-adjustable electric actuator for a holding operation.

2. Side door drive assembly according to claim 1, further comprising a tilt sensor unit which is operationally coupled to the control unit and is designed to detect a tilt of the vehicle relative to a horizontal plane, and/or a temperature sensor unit which is operationally coupled to the control unit and is designed for detecting a temperature of the controllable electric motor of the length-adjustable electric actuator, wherein the control unit is designed to take into account the tilt of the vehicle and/or the temperature of the controllable electric motor when determining the necessary current strength.

3. Side door drive assembly according to claim 1, wherein the length-adjustable electric actuator is designed as a spindle drive having a permanently excited brushed direct current motor or having a brushless direct current motor.

4. Side door drive assembly according to claim 1, wherein the control unit is integrated with the length-adjustable electric actuator.

5. Side door drive assembly according to claim 1, wherein the door movement sensor unit is formed by a position encoder associated with the length-adjustable electric actuator.

6. Side door drive assembly according to claim 1, wherein the control unit is designed to firstly determine, before determining the necessary current strength, whether a passive holding force of the length-adjustable electric actuator is sufficient for holding the side door at its current position.

7. Side door drive assembly according to claim 1, wherein the control unit is designed to convert the determined necessary current strength into a duty cycle for a pulse width modulation operation of the controllable electric motor of the length-adjustable electric actuator, and to deliver a corresponding, pulse width modulated necessary current to the controllable electric motor.

8. Side door drive assembly according to claim 7, wherein the control unit is designed for normal operation of the controllable electric motor, in that, when a movement of the side door during the holding operation is identified, an adjustment of the necessary current strength or of the duty cycle is performed.

9. Side door drive assembly according to claim 1, wherein the control unit is designed to temporally limit the holding operation in that the delivery of current to the controllable electric motor of the length-adjustable electric actuator is ended after a maximum holding time.

10. Side door drive assembly according to claim 9, wherein the control unit is designed, after the maximum holding time has elapsed, to transfer the side door, in the context of a protective closing movement, into a state in which a passive holding force of the length-adjustable electric actuator is sufficient for holding the side door in this state or for completely closing the side door.

11. Side door drive assembly according to claim 10, further comprising an optical or acoustic output unit which is operationally coupled to the control unit and is designed to output a signal in the event of a directly imminent protective closing movement and/or during a protective closing movement.

12. Side door drive assembly according to claim 1, wherein the control unit is designed, upon detection of a manual actuation of the side door during the holding operation, to transfer the length-adjustable electric actuator into an active supporting operation, in which a force acting in the direction of the manual actuation is exerted on the side door, in that a corresponding supporting current is delivered to the controllable electric motor of the length-adjustable electric actuator.

13. Side door drive assembly according to claim 12, wherein during the detection of the manual actuation, a speed and/or an acceleration of the side door is furthermore detected, and the corresponding supporting current is adjusted on the basis of the detected speed and/or the acceleration of the side door.

14. Side door drive assembly according to claim 1, wherein the parameters of the vehicle stored in the storage unit include a mass and/or a center of gravity of the side door, and/or the operating parameters of the length-adjustable electric actuator include a friction, an efficiency, a transmission and/or a motor constant of the length-adjustable electric actuator.

15. Vehicle comprising the vehicle body and the side door pivotably hinged thereto, wherein a side door drive assembly according to claim 1 is arranged between the vehicle body and the side door.

16. Method for operating an electric side door drive assembly according to claim 1, comprising: determining stopping of the side door during opening or closing, and the current position of the side door; determining the necessary current strength on the basis of side door position data, the geometric parameters of the vehicle and the operating parameters of the length-adjustable electric actuator; and delivering the necessary current strength to the controllable electric motor of the length-adjustable electric actuator.

Description

[0034] FIG. 1 is a schematic plan view of a side door drive assembly according to the invention; and

[0035] FIG. 2 is a flow diagram illustrating a method according to the invention for operating the side door assembly from FIG. 1.

[0036] FIG. 1 is firstly a schematic plan view of a side door drive assembly according to the invention of a vehicle 100 (not shown in greater detail), which drive assembly is denoted very generally by reference sign 10. In this case, the side door drive assembly 10 comprises a length-adjustable electric actuator 12 in the form of a spindle drive (known per se) having a housing 12a and an electric actuator motor 14, the actuator 12 being arranged between the vehicle body 102 and a side door 104 pivotably hinged thereto, and being coupled to both. It should be noted at this point that for example two or four side doors 104 can be installed in the vehicle 100, which doors can all be provided with such a side door drive assembly 10 according to the invention.

[0037] Furthermore, the side door drive assembly comprises a control unit 16 which is operationally coupled to the actuator 12 and in particular to the actuator motor 14 for actuation and energization, and which is associated with a storage unit 18 on which geometric parameters of the vehicle 100 and operating parameters of the actuator 12 are stored. The control unit 16 is also capable of monitoring the current motor speed of the actuator motor 14, for example in that a voltage induced therein during a manual operation is detected. In this case, the control unit 16 is arranged inside the actuator housing 12a, which applies in a similar manner for a door movement sensor unit 20 designed as a position encoder, which is designed to detect a pivot position or an opening angle and a pivot movement of the side door 104 relative to the vehicle 102, and in particular to detect stopping of such a pivot movement.

[0038] As further sensor units operationally coupled to the control unit 16, the side door drive assembly 10 comprises a tilt sensor unit 22 which is associated with the vehicle body 102 and is designed to detect a tilt of the vehicle body 102 relative to a horizontal plane, and a temperature sensor unit 24 which is arranged inside the actuator housing 12a, in the region of the actuator motor 14, and is designed to detect the temperature of the actuator motor 14.

[0039] Lastly, with reference to FIG. 1, the output unit 26 which is associated with the vehicle 100 and operationally coupled to the control unit 16 is also noted, which output unit, depending on the embodiment, can be designed to inform an occupant of the vehicle 100 of particular operating states of the side door drive assembly 10, in particular the protective closing movement described below.

[0040] In this case, it is noted that the side door drive assembly 10, and in particular its control unit 16, is designed to typically enable operating processes provided for such door drives, for example an active opening or closing operation of the side door 104 of the vehicle 100 and a manual opening or closing operation, in which the side door 104 can be opened, closed, or pivoted into any opening angle manually by a user. At the same time, however, the side door drive assembly 10 according to the invention also allows for what is known as active holding operation, in which the side door 104 can also be held open, by appropriate energization, for example by means of pulse width modulation, in situations having a constant opening angle in which an external force acts on said door in the direction of an opening or closing, i.e. in particular when the vehicle 100 is in a tilt position deviating from the horizontal. With reference to the flow diagram from FIG. 2, in the following a corresponding method for carrying out an active holding operation in the side door drive assembly 10 from FIG. 1 will be explained.

[0041] Firstly, in step S1, the door movement sensor unit 20 detects that the side door 104 is moving, and it is checked, in a step S2, whether in this case the door movement has fallen below a specified threshold value (yes in step S2), which is a criterion for the side door 104 having stopped its movement. At the same time, at this point the current position of the side door 104 or its opening angle is determined. As soon as it has been identified that the side door 104 has stopped, the process passes to step S3, in which a tilt of the vehicle 100 relative to the horizontal is detected by the tilt sensor unit. Should this tilt be zero or fall below a predetermined minimum tilt (no in step S3), then the process ends at this point at S4, since no active holding operation is required.

[0042] If, on the other hand, a tilt of the vehicle is not zero (yes in step S3), then in step S5 the required motor torque T.sub.actuator is calculated on the basis of the geometry data of the vehicle 100 stored in the storage unit 18, and the detected tilt of said vehicle, from the torque equilibrium during holding of the side door 104, on the basis of the formula

[00001]$\begin{array}{cc}{T}_{\mathrm{breakaway}}+T_{\mathrm{gravity}}+T_{\mathrm{cctuator}}=0.& \left(\mathrm{Equation}1\right)\end{array}$

[0043] In this case, the breakaway torque T.sub.breakaway depends, in a known manner, via the formula

[00002]$\begin{array}{cc}{T}_{\mathrm{breakaway}}=F_{\mathrm{breakaway}}?I_{\mathrm{arm}},& \left(\mathrm{Equation}2\right)\end{array}$

on the breakaway force F.sub.breakaway and the lever length l.sub.arm of the side door 104.

[0044] Furthermore, in order to calculate the torque T.sub.gravity that acts on the side door 104 and is caused by gravitational force thereof, known geometric and structural variables, as well as the determined tilt of the vehicle 100, are used, i.e. in particular the mass of the side door 104, the position of the center of gravity of the side door 104 in its closed state, the orientation of its pivot axes vector, pitch angle and roll angle of the vehicle 100, and the opening angle of the side door 104. In this connection, the opening angle constitutes a measure for the side door position within the meaning of the present invention, which can be determined by means of the door movement sensor unit 20 discussed above. In this case, it is conceivable, as soon as the pitch angle and roll angle of the vehicle 100 have been determined, to create a characteristic diagram, on the basis of the invariable properties of the side door 104 stored in the storage unit 18, in which characteristic diagram T.sub.gravity is plotted against the opening angle, such that during a movement of the side door 104 and the associated change in the opening angle the corresponding value of T.sub.gravity can be accessed quickly.

[0045] In this case, the specific calculation thereof is based on a known transformation of the pivot axis and of the center of gravity of the door by means of a reference system transformation using respective rotation matrices with respect to the roll angle and the pitch angle of the vehicle 100, which will not be discussed in detail here since it is readily derivable from mathematical principles.

[0046] The actuator torque T.sub.actuator required for achieving the torque equilibrium from Equation 1 results, in turn, as the product of the actuator force and the actuator lever arm, which depends on the connection points of the actuator 12 on the vehicle body 102 and the side door 104 in the closed state, the orientation of the pivot axis without a vehicle tilt, and the opening angle of the side door 104. Accordingly, in this way, the torque to be applied by the actuator motor 14 for a holding operation, and thus also the force that is to act, can be derived.

[0047] Since, furthermore, the passive holding force of the actuator 12 is known or can also be derived from the known properties thereof according to known principles, in the next step S6 a comparison can be made as to whether the passive holding force is already sufficient for holding the side door 104 in its current opening angle, or whether an energization of the actuator motor 14 is required for holding the side door 104. If this is not the case (no in step S6), i.e. the passive holding force alone is already sufficient, then the process ends at this point in step S4, since no holding operation of the actuator motor 14 is required. If, in contrast, it is found that energization of the actuator motor 14 is required, for holding the side door 104 in its current state (yes in step S6), then the process passes to step S7, where the current strength required for the holding operation is calculated on the basis of the remaining active holding force which is required and is to be applied by the actuator motor 14, and its known output characteristics.

[0048] Finally, for starting the active holding operation, in step S8 the corresponding current strength is delivered to the actuator motor 14, for example by means of a pulse width modulation, and feedback operation is started, in which an adjustment of the necessary current strength is performed in the event of an undesired movement of the side door 104 being identified. In this case, an undesired movement refers to a behavior of the side door 104 which does not result from a manual opening or closing actuation by a user, i.e. for example a creeping pivot movement of the side door 104 triggered by too small or too great a holding force, or a movement of said door triggered by a gust of wind. In this case, the control unit 16 is capable of distinguishing, by means of comparing an identified action of force on the side door 104 with predetermined time profiles, whether the specific action of force was performed by a human user or is undesired.

[0049] In step S9 a check is now made as to whether a predetermined maximum holding time has elapsed since the start of the active holding operation. If this is the case (yes in step S9), then in step S10 the active holding operation is ended in that a protective closing movement of the side door is performed by corresponding actuation and energization of the actuator motor 14, by means of which the side door 104 is transferred into a state in which the passive holding force, introduced above, is sufficient for holding the side door 104, or the side door 104 is fully closed. Furthermore, while carrying out the protective closing movement, a corresponding optical and/or acoustic output is performed by means of the output unit 26, in order to inform the driver and/or occupants of the vehicle 100 of the protective closing movement of the side door 104.

[0050] In contrast, if the maximum holding time has not elapsed (no in S9), then a check is made in step S11 as to whether an error state is present in the side door drive assembly 10, for example whether one of the sensor units required for carrying out the method is not delivering data or is delivering obviously incorrect data. Should this be the case (yes in step S11), then the process passes to step S10, in the same way as just described, and the protective closing movement is performed.

[0051] If, in contrast, no error state is identified (no in step S11), then a check is made in step S12 as to whether an opening or closing of the side door 104 was triggered by a user, either manually by an action of force on the side door 104 or in the context of a request of an automatic opening or closing operation. If this is not the case (no in step S12), then the process passes again to step S8 and the holding operation is continued accordingly by delivering the necessary current strength to the actuator motor 14. If, in contrast, it is found that an opening or closing of the side door 104 has been triggered (yes in step S12), then the process ends, as does the active holding operation, in that the control unit 16 transitions into another operating mode of the side door drive assembly 10, in particular an active opening or closing operation or a supporting operation in the case of a manual actuation of the side door 104.