EP4097323A1

EP4097323A1 - Method and device for determining the external force exerted on a motor vehicle flap which can be moved about an axis by a motor and in a regularly rotatory manner

Info

Publication number: EP4097323A1
Application number: EP21720392.6A
Authority: EP
Inventors: Ingo NÖVERMANN; Nils Sören GUNTRUM
Original assignee: Kiekert AG
Current assignee: Kiekert AG
Priority date: 2020-01-27
Filing date: 2021-01-27
Publication date: 2022-12-07
Also published as: JP2023511982A; WO2021151432A1; DE102020101815A1; KR20220129082A

Abstract

The subject matter of the invention is a method for determining an external force (Tz) exerted on a motor vehicle flap (1) which can be moved about an axis (2) by a motor and in a regularly rotatory manner. At least one acceleration sensor (4) is provided as a first sensor (4) in or on the motor vehicle flap (1). A second sensor (5) is also implemented. The signals of both sensors (4, 5) are evaluated by a control unit (6). According to the invention, the second sensor (5) is designed to measure the angle and/or measure the path of the motor vehicle flap (1) with respect to a motor vehicle body (3).

Description

description

Method and device for determining the external force exerted on a motor vehicle flap which can be moved by motor and regularly rotatably about an axis

The invention relates to a method for determining the external force exerted on a motor vehicle flap, which can be moved by motor and regularly rotatably about an axis, in particular for determining a manual opening or closing force on a motor vehicle side door, a motor vehicle tailgate or a motor vehicle front hood, according to which at least one acceleration sensor is provided as a first sensor on or in the motor vehicle flap, and according to which a second sensor is implemented and the signals from both sensors are evaluated by a control unit.

Motor vehicle flaps that can be moved by motor and regularly rotatively about an axis generally have an actuator or generally an electric motor drive. The motor vehicle flap in question can, for example, be opened or closed with the aid of the drive. Partial opening and closing movements are also possible, among other things in the sense of closing the relevant motor vehicle flap. In the context of the invention, a motor vehicle side door, but also a motor vehicle tailgate or a motor vehicle front hood, is understood as a motor vehicle flap. This also includes sliding doors, for example. Such sliding doors are usually also acted upon by a motor, but are predominantly linearly movable with respect to the associated motor vehicle body.

In the interest of increasing the ease of use, the electromotive drive or the actuator for the motor vehicle flap can now be controlled accordingly. Here, for example, the actuating force of the actuator is adjusted the respective operating situation of the motor vehicle flap is possible. This is the procedure for the generic prior art according to DE 10 2007 062 472 B4, for example.

In fact, at this point it is a question of a method and a device for adapting the actuating force of the actuator to support an opening and / or closing movement of a door that can be opened in a translational and / or rotational manner. For this purpose, position and acceleration values of the door are usually recorded with associated sensors and transmitted to an evaluation device or a control unit. An acceleration sensor and a camera are used as sensors. For this purpose, the camera can be mounted on the exterior mirror of the motor vehicle door. The camera can be used to detect whether there is contact between an operator and the motor vehicle door in question. In addition, an effective lever arm for a predominantly orthogonally acting force can be determined from this. This is relatively complex, especially since a camera required in this context must also be mounted. In addition, attachment to or in the exterior mirror of the motor vehicle door poses problems in the event that the camera does not supply any usable signals to the evaluation device or control unit due to soiling.

The further prior art according to DE 10 2017 011 478 A1 concerns a method for measuring the closing force of a vehicle wing element. In this case, too, an additional external force should be recorded. A combined force-displacement measuring device is provided for this purpose. This has an acceleration sensor, with the help of which a measurement closing time is determined. This corresponds to the fact that vibrations of the vehicle wing element are observed during the transition from the open position to the closed position. In addition, a microphone is implemented, with the aid of which a second measurement closing time can be recorded. This characterizes a change in the vehicle wing element from the open position to the closed position, based on sound waves. The measurement closing times determined in this way are compared and lead to an actual closing time, on the basis of which the force to be detected can be evaluated.

The additional use of the microphone as a second sensor, as it were, is associated with disadvantages comparable to those of the camera already mentioned in DE 10 2007 062 472 B4. Not only exist here

Soiling problems, but also the risk that no reliable and evaluable signal from the microphone is available at all. This applies in particular to significant outside noises, for example wind and / or rain.

The still relevant prior art according to DE 10 2006 018 031 B4 relates to a sensor arrangement and a method for triggering a restraint device. This is intended to detect a collision with the vehicle. For this purpose, a first acceleration element and a second acceleration element are implemented, which are installed inside the vehicle door or close to a hinge of the vehicle door. Modifications of the actuating force of an actuator for the motorized movement of the associated motor vehicle door are not addressed.

The prior art has basically proven itself when it comes to modifying the force of an actuator or generally an electric motor drive for the associated motor vehicle flap, depending on the external force exercised by an operator and also acting on the motor vehicle flap Power. However, the previous approaches are relatively complex and, due to the sensors used, in particular the camera and microphone, are prone to contamination of the motor vehicle, Interfering noises, etc. In connection with the relatively high price for such a sensor system, this has so far led to the fact that the known systems have practically not found widespread use or use. The invention aims to provide a remedy here overall.

The invention is based on the technical problem of specifying such a method and an associated device for determining the external force exerted on a motor vehicle flap that can be moved regularly about an axis, with the aid of which a structurally simple and functionally reliable solution is made available which is particularly robust in terms of dirt, noise, etc.

To solve this technical problem, a generic method for determining the external force exerted on a motor vehicle flap that can be moved regularly around an axis is characterized within the scope of the invention, characterized in that the second sensor is used to measure the angle and / or distance of the motor vehicle flap opposite a motor vehicle body is performed. That is to say, in the simplest case, the invention only uses the acceleration sensor as the first sensor and, in addition, the second sensor for angle measurement or distance measurement. Both sensors can advantageously be arranged in or on the motor vehicle flap and in this way are particularly well protected from any environmental influences. In addition, acceleration sensors or angle or displacement sensors have a robust, permanent and functionally reliable structure in this context, so that the signals from the two sensors can easily be evaluated safely, reliably and permanently by the control unit. This is where the main advantages can be seen.

As already explained, the second sensor is advantageously arranged on or in the motor vehicle flap. In addition, according to the invention, the control unit also generates mechanical signals in addition to the two sensor signals Property values of the motor vehicle flap are included in the calculation of the external force.

These mechanical property values of the motor vehicle flap were generally at least a matter of its moment of inertia. In other words, when evaluating the two signals from the sensors, the control unit also includes the moment of inertia or mass moment of inertia of the motor vehicle door under consideration in the evaluation. As is known, the moment of inertia expresses the inertia of the motor vehicle flap, which is regarded as a rigid body, in relation to a change in its angular velocity when it rotates about a given axis. This applies at least to a motor vehicle flap that can be rotated about the axis, for example the motor vehicle side door mentioned above, but also the motor vehicle tailgate or motor vehicle front hood. In principle and as an alternative to this, in the case of a sliding door, for example, its mass or mass inertia can also be evaluated very simply by the control unit instead of the moment of inertia.

As is known, the moment of inertia depends on the mass distribution of the motor vehicle flap under consideration in relation to its axis or axis of rotation. In this respect, data for the moment of inertia with the symbol J can easily be derived from the design data of the relevant motor vehicle flap. Alternatively, in the case of the predominantly linearly moving motor vehicle side door, instead of the moment of inertia J, the mass M can also flow into the evaluation of the control unit in addition to the two signals from the sensors.

Friction parameters of the motor vehicle flap are preferably also evaluated by the control unit as mechanical property values of the motor vehicle flap. These friction parameters of the motor vehicle flap are in the case of the motor vehicle flap that can be rotated about the axis mainly about the coefficient of friction of the hinge that is regularly implemented at this point. In the case of the linearly moving motor vehicle sliding door, frictional forces of the necessary guides are predominantly observed and taken into account. In most cases, it is possible to work with a frictional torque Tfr which, in the simplest case, is proportional to the speed of the motor vehicle flap in question, or increases and decreases. So it is typically worked with a linear sliding friction. This also results in a braking torque that is linearly dependent on the speed of the motor vehicle flap. This can be determined in particular on the basis of the signals from the second sensor for measuring the angle of the motor vehicle flap with respect to the motor vehicle body. If the control unit then acts on an actuator or an electric motor drive for the motor vehicle flap, the corresponding actuating signals of the control unit can be identified with a driving torque or motor torque Tdr.

On the basis of the basic equation of motion for the motor vehicle flap that can be rotated about the axis in the sense of

/ 'f = Tdr - Tfr - Tz can then be inferred from an additional and external external force exerted on the motor vehicle flap in question or a corresponding torque T _z , which in the specified case may work against the driving torque. In fact, the measured variable f is the angular acceleration of the motor vehicle flap in question, which is detected with the aid of the first sensor or acceleration sensor and transmitted to the control unit for evaluation.

A comparable procedure can be used for the motor vehicle sliding door that can be moved back and forth in a linear manner. In this case, the previously mentioned angular acceleration f is not measured with the aid of the first sensor or acceleration sensor. But here one is either carried out by the operator exerted external force F _z and / or a force Fdr exerted by the actuator or electromotive drive so that the associated motor vehicle flap of the inertial mass M performs an accelerated movement with the acceleration s. The associated equation of motion, evaluated by the control unit in this case, is basically as follows in this case:

M S = Fdr - Ffr - Fz

(with Ffr the frictional force and s the distance covered and s the associated acceleration). In any case, it becomes clear that and how the control unit determines the exerted external force F _z or exerted external torque Tz from the sensor values of the two sensors and the mechanical property values using equations of motion. This is done advantageously and additionally using a so-called Kalman filter, which is a mathematical process. This is used to reduce errors in the real measured values of the two sensors and to provide estimates for non-measurable system variables, in this case estimates for the exerted external force F _z or the external torque T _z . Such Kahlmann filters are generally known and reference is made to the corresponding explanations at “Wikipedia” with the references also referred to there.

The subject matter of the invention is also a device for determining the external force exerted on a motor vehicle flap which can be moved by motor and regularly rotatably about an axis. This device initially has the acceleration sensor as the first sensor on the motor vehicle flap. The acceleration sensor is advantageously a so-called three-axis acceleration sensor, i.e. one with the help of which acceleration values in the direction of all three vehicle axes, i.e. in the vehicle longitudinal (X) direction, in the vehicle transverse (Y) - Direction and finally in the vehicle vertical axis (Z) direction can be detected. Due to their widespread use, such three-axis acceleration sensors are available in an inexpensive and robust embodiment.

The device according to the invention is also equipped with an actuator or an electric motor drive. The motor vehicle flap in question can be moved with the aid of the actuator or the electric motor drive. In addition, the design is advantageously made in such a way that the control unit controls the actuator in a variable manner in accordance with determined values of the external force exerted or the external torque exerted. For example, the procedure here is such that the opening force exerted by the actuator on the motor vehicle flap is correspondingly reduced if an operator also exerts an opening force on the motor vehicle cap. In the same way, a closing force on the part of the actuator can also be reduced if an operator also exerts such a closing force on the motor vehicle flap.

Conversely, the invention also provides variants such that the force exerted by the actuator on the motor vehicle flap, for example during an opening process, is increased when an operator simultaneously acts on the motor vehicle flap in question in the closing direction. An increase in force during a closing process is also conceivable if the operator in question also acts on the motor vehicle flap in an opening direction. Either way, a method and a device are provided with the help of which the external force exerted on the motor vehicle flap in question - in addition to the actuator - by an operator is calculated using simple means and taking into account a structurally simple and robust structure on the part of the control unit can be. All of this succeeds in a particularly functionally reliable manner. This is where the main advantages can be seen. In the following, the invention is explained in more detail with reference to a drawing showing only one embodiment. The only FIG. 1 shows a device according to the invention schematically.

In Fig. 1, a device for determining an external force or an external torque T _{z is} shown very fundamentally. The force in question or the associated external torque T _z is exerted on a motor vehicle flap 1 by an operator. This is done according to the exemplary embodiment and not restrictively in the opening sense. According to the exemplary embodiment, the motor vehicle flap 1 can be moved rotationally about an axis 2 with respect to a body or motor vehicle body 3.

The basic structure includes an acceleration sensor 4, which is provided and arranged as the first sensor in or on the motor vehicle flap 1. According to the exemplary embodiment, an angular acceleration f of the motor vehicle flap 1 is measured with the aid of the acceleration sensor 4. In addition, a further second sensor 5 is also implemented, which, according to the exemplary embodiment, is a rotation angle sensor. With the aid of the rotation angle sensor or the second sensor 5, according to the exemplary embodiment, an angle f of the motor vehicle flap 1 and, as a result, a frictional torque Tfr of the motor vehicle flap 1 is determined. In contrast, the acceleration sensor 4 is equipped as a three-axis acceleration sensor.

Both sensors 4, 5 are each connected to a control unit 6 which evaluates its signals. The control unit 6 also controls an actuator 7 or an electric motor drive, with the aid of which the motor vehicle flap 1 can be moved back and forth as shown.

With the aid of the actuator 7, the motor vehicle flap 1 is actuated in the illustrated example with a motor torque or drive torque Tdr acted upon, as indicated in FIG. 1 by a corresponding arrow. In the illustration, the actuator 7 ensures a closing movement of the motor vehicle flap 1 in this context, which of course is only to be understood as an example and not restrictive. The motor vehicle flap 1 opposes this closing movement indicated in FIG. 1 with the friction torque Tfr, which mainly depicts the friction coefficients arising in a hinge in the area of the axis 2 and already described in the introduction.

The sensor values of the two sensors 4, 5 are now evaluated and processed in the control unit 6. In addition, mechanical property values of the motor vehicle flap 1 are also taken into account. This includes at least the moment of inertia J of the motor vehicle flap 1, which is also indicated in FIG Kalman filters determine the exerted external force or, according to the exemplary embodiment, the exerted external torque T _z , as already described in the introduction. In addition, the control unit 6 ensures that the actuator 7 is controlled variably in accordance with determined values of the exerted external force or the exerted external torque Tz.

There is also the possibility that the control unit 6 detects the engine torque or drive torque Tdr exerted on the motor vehicle flap 1. For this purpose, for example, current values for the control of the actuator 7 can be used to infer the force with which the motor vehicle flap 1 in question is acted upon by means of the actuator 7, for example in a closing direction. The motor torque or drive torque Tdr can be derived from this, for example, taking into account known geometric specifications stored in the control unit 6. In this context, it is conceivable that the position of the actuator in the control unit 6 7 is stored in comparison to the axis or axis of rotation of the motor vehicle flap 1 and from this, in connection with the force exerted by the actuator 7 on the motor vehicle flap 1, the drive torque Tdr in question can be inferred.

If, for example, the previously mentioned drive torque Tdr is applied to the motor vehicle flap 1 (for example in a closing direction), this results in a change in position that can be detected with the aid of the second sensor 5. If this change in position deviates from a change in position calculated with the aid of the control unit 6, for example, this allows conclusions to be drawn about the external force or the external torque Tz exerted. Transferred to the illustrated embodiment, this means that with such an external force exerted by the operator or the exerted external torque T _z in the opening sense, the control unit 6 as a whole ensures that the actuator 7 has a greater force or a greater torque Tdr is controlled than would be necessary in the event that the operator would not exert an opening force on the motor vehicle flap 1.

In the illustrated embodiment and with the external force exerted by the operator or the exerted external torque T _z in the opening sense, this means that the control unit 6 as a whole ensures that the actuator 7 is controlled with a greater force or a greater torque Tdr than would be necessary in the event that the operator did not exert an opening force on the motor vehicle flap 1. List of reference symbols

Motor vehicle flap 1 axle 2 motor vehicle body 3 acceleration sensor 4 sensor 5 control unit 6 actuator 7

Moment of inertia J Torque T _z Frictional torque Tfr Torque Tdr Angle f

Angular acceleration f

Claims

1. A method for determining the external force (Tz) exerted on a motor vehicle flap (1) movable by motor and regularly rotatory around an axis (2), in particular for determining a manual opening or closing force on a motor vehicle side door, a motor vehicle tailgate or a motor vehicle front hood, according to which at least one acceleration sensor (4) is provided as a first sensor (4) on or in the motor vehicle flap (1), and according to which a second sensor (5) is implemented and the signals from both sensors (4, 5) are evaluated by a control unit (6), characterized in that an angle measurement and / or distance measurement of the motor vehicle flap (1) with respect to a motor vehicle body (3) is carried out by means of the second sensor (5).

2. The method according to claim 1, characterized in that the second sensor (5) is arranged on and / or in the motor vehicle flap (1).

3. The method according to claim 1 or 2, characterized in that, in addition to the two sensor signals, the control unit (6) also includes mechanical property values of the motor vehicle flap (1) in the calculation of the external force (Tz).

4. The method according to any one of claims 1 to 3, characterized in that at least its moment of inertia (J) is taken into account as mechanical property values of the motor vehicle flap (1).

5. The method according to any one of claims 1 to 4, characterized in that additional friction parameters of the motor vehicle flap (1) are evaluated by the control unit (6) as mechanical property values of the motor vehicle flap (1).

6. The method according to any one of claims 1 to 5, characterized in that the control unit (6) determines the exerted external force (Tz) from the sensor values and the mechanical property values using equations of motion and advantageously a Kalman filter.

7. Device for determining the external force (Tz) exerted on a motor vehicle flap (1) movable by motor and regularly rotatory around an axis (2), in particular for determining a manual opening or closing force on a motor vehicle side door, a motor vehicle tailgate or a motor vehicle front hood, preferably for carrying out the method according to one of claims 1 to 6, with at least one acceleration sensor (4) as the first sensor (4) in or on the motor vehicle flap (1), and with a second sensor (5 ), the signals from both sensors (4, 5) being evaluated by a control unit (6), characterized in that the second sensor (5) is set up for angle measurement and / or distance measurement of the motor vehicle flap (1) with respect to a motor vehicle body (3) is.

8. The device according to claim 7, characterized in that the second sensor (5) is designed as a rotation angle sensor arranged in or on the axis (2).

9. Apparatus according to claim 7 or 8, characterized in that a Actuator (7) is provided for acting on the motor vehicle flap (1).

10. Device according to one of claims 7 to 9, characterized in that the control unit (6) controls the actuator (7) variably in accordance with determined values of the external force (Tz) exerted.