Method for detecting movement of flap of motor vehicle

Abstract

The invention relates to a method for detecting a movement of a pivotable body part, in particular a flap, of a motor vehicle, the motor vehicle comprising an electric motor having a stator and a rotor, the electric motor being configured for electrically opening and / or closing the pivotable body part, the electric motor being a BLDC motor having a three-phase stator (A, B, C), the two phases of the stators (A, B) are loaded with a pulse width modulated voltage, the third phase (C) remaining free floating, the third phase (C) being monitored as a measurement point for an inductive voltage divider formed using the other two phases (A, B), and if a signal at the measurement point or a variable derived from the signal exceeds a specified threshold value, the third phase (C) is monitored as the measurement point for the inductive voltage divider. If so, an opening movement or a closing movement of the pivotable body part is detected, and a motor vehicle wherein a control device of the motor vehicle is configured to carry out such a method.

Description

Technical Field

[0001] The present invention relates to a method for detecting the movement of pivotable body parts of a motor vehicle, particularly a hinged door, and to a motor vehicle wherein a control device of the motor vehicle is configured to perform the method in order to detect the movement of pivotable body parts of the motor vehicle. Background Technology

[0002] It is known that motor vehicles include pivotable body parts, such as doors, tailgates, and fuel doors. Nowadays, these hinged doors can sometimes be closed and / or opened electrically by means of an electric motor.

[0003] To detect a user's intention to open or close an electrically actuated flip-top door, sensors or switches are often used, which initiate the electrical opening or closing process after actuation. However, it is often desirable to open or close after a short manual movement (a so-called "tip torun"): the user initiates the opening or closing process by hand, and the electric motor mechanism (electric motor, gear unit) is subsequently activated and completes the opening or closing process. This method is known from CD drives, for example, from US8799934B2. EP3554875B1, for example, discloses that a reverse induced voltage can be measured to initiate the closing process.

[0004] The use of external sensors or switches increases the number of components in the system and thus increases the cost of the vehicle. The measurement of the reverse induced voltage is speed-dependent. Depending on the transmission ratio between the component to be moved and the electric motor, very slow movement produces an excessively low reverse induced voltage, and manual actuation is not detected. Summary of the Invention

[0005] The objective of this invention is to describe a method for detecting the movement of a pivotable vehicle body component, the method being capable of reliably detecting opening and / or closing processes and being inexpensive to implement, and to describe a motor vehicle capable of performing such a reliable and inexpensive method for detecting opening and / or closing movements.

[0006] This objective is achieved by a method for detecting the movement of pivotable body components of a motor vehicle, particularly a hinged door, wherein the motor vehicle includes an electric motor having a stator and a rotor, wherein the electric motor is configured to electrically open and / or close the pivotable body components.

[0007] The electric motor is a BLDC electric motor with a three-phase stator, wherein two phases of the stator are loaded with pulse width modulated voltages, the third phase remains free-floating, and the third phase is monitored as a measurement point for an inductive voltage divider formed using the other two phases. Movement of the pivotable body component, particularly opening or closing movement, is detected if the signal at the measurement point or a variable derived from the signal exceeds a specified threshold.

[0008] According to the present invention, a BLDC electric motor with a three-phase stator is used to monitor the opening and / or closing process of a folding door, which is typically connected to the rotor of the BLDC electric motor via a gear unit.

[0009] By using a three-phase BLDC motor and energizing appropriate coils, changes in rotor position can be reliably determined. These changes in rotor position can be quantified, compared to thresholds, and interpreted as the expected opening or closing of folding doors, handles, gates, etc.

[0010] The detection of manual component movement is carried out in this case by means of the movement of the rotor, and after that, the initiation of electric movement of the pivotable body components can be realized.

[0011] By using components that are essential for the electric actuation of the flip-door anyway, additional parts can be saved, thus reducing costs. In this case, the detection of manual movement is independent of speed, and most importantly, it is the opposite of the measurement of reverse induced voltage.

[0012] External manual movement at the folding door (e.g., a gate) achieves angular changes in the rotor within the drive unit via a non-self-locking gear unit. The motor stator is implemented with three phases, each connected in a star configuration. When the motor is stationary, two phases are loaded with pulse-width modulated voltages of different pulse widths in each case, and the third phase remains free-floating in terms of potential (so-called "tri-state"). This third phase then forms the measurement point for an inductive voltage divider, which is formed using the other two phases. If the position of the rotor's magnetic poles changes relative to the stator's magnetic poles, the inductance of the voltage divider changes, and this change can be measured in the free-floating phase. Thus, the rotor's rotation can be determined, and the rotation angle can also be determined by counting periodic fluctuations. Using corresponding logic, the obtained result can then be interpreted as the user's expectation of opening or closing the folding door, gate, etc. After this, the drive can begin electrical regulation of the pivotable components.

[0013] The improvements of the invention are described in detail in the dependent claims, the specification, and the drawings.

[0014] Preferably, the signal measured at the measurement point is continuously monitored, preferably the star point voltage. In this case, it is preferable to count the periodic fluctuations of the signal at the measurement point in order to determine the rotation angle of the rotor.

[0015] Preferably, the signal measured at the measurement point is continuously monitored, wherein the rotation direction of the rotor is determined based on the fluctuation type of the signal at the measurement point. In particular, the rotation direction of the rotor can be determined based on the direction of the star point voltage fluctuation relative to the star point voltage fluctuation at the center position of the rotor at the beginning and end of the regulating motion over time.

[0016] The motor vehicle according to the invention includes a pivotable body component, particularly a hinged door, wherein the motor vehicle includes an electric motor having a stator and a rotor, wherein the electric motor is configured to electrically move the pivotable body component. The electric motor is a BLDC motor having a three-phase stator, wherein the control device of the motor vehicle is configured to perform the methods described herein in order to detect manual external movement of the pivotable body component by a user of the motor vehicle.

[0017] Preferably, the control device is configured to, upon detecting manual movement of a pivotable body component, trigger the electric opening and / or electric closing of the pivotable body component. Attached Figure Description

[0018] The invention is described below by way of example with reference to the accompanying drawings.

[0019] Figure 1 This is a schematic diagram of the stator of a motor vehicle according to the present invention, and in particular an equivalent circuit diagram.

[0020] Figure 2 It schematically shows the following based on Figure 1 An example measurement using an oscilloscope at the stator of a motor vehicle according to the present invention: Top: PWM pulses at phases A and B; Middle: star point voltage at phase C; Bottom: current through L1 and L2.

[0021] Figure 3 The diagram schematically illustrates the change in the star point voltage at phase C when the rotor is moved away from its central position by means of an external force in one direction.

[0022] Figure 4 This schematically illustrates the situation where the rotor, by means of external force, is in contact with... Figure 3 The change in star point voltage at phase C when it moves away from its center position in the opposite direction. Detailed Implementation

[0023] Figure 1 The stator of a motor vehicle according to the invention and the three-phase stator in the method according to the invention are schematically shown.

[0024] In three-phase BLDC motor ( Figure 1 The equivalent circuit diagram of the stator shows PWM pulses with the same pulse height applied to two phases (A and B). The PWM pulses at A and B have a time offset and are never active simultaneously. The rotor is held in place by a current limited by coils L1 and L2, determined by the pulse width (the difference in pulse width between A and B). If the pulse width at A is wider than the pulse width at B, on average, current flows from A to B. Coil L3 does not carry current. At phase C, the voltage at point S can be measured. The level of the point voltage measured at C without the rotor inserted is half the pulse height at A and B – a voltage divider principle. The inductance and resistance of L1, L2, and L3 are the same. However, the measurement principle is also suitable if L1 is not equal to L2 and / or L2 is not equal to L3.

[0025] If the rotor is inserted into the stator, the inductances of L1 and L2 also change (and similarly L3, but this is not necessary for the effect of the invention). The rotor can then be positioned such that the pulse height of A or B is still measured at point S at half its original value. If no load is applied to the rotor and the rotor is free to move, it automatically occupies this position. The rotor moves to this position by the current flowing through L1 and L2 and the resulting magnetic force. Figure 2 An example measurement using an oscilloscope is shown. Here, the process of the two curves shown at the top illustrates the change of the PWM pulses applied at phases A and B over time. Figure 2 The middle illustration shows the star point voltage at phase C during the same time process, which is measured at the measurement point. Figure 2 The curve at the bottom shows the current flowing through the coils or inductors L1 and L2.

[0026] If the rotor moves away from its center position in one direction by means of an external force, the star point voltage will be as follows: Figure 3 The changes shown.

[0027] Conversely, if the rotor moves away from its center position in the opposite direction by means of an external force, the star point voltage will be as follows: Figure 4 The changes are shown.

[0028] By continuously monitoring and evaluating the star point voltage, especially at the beginning and end of the external adjustment motion, the direction of the force acting on the rotor can be detected.

[0029] If the external force is increased further, causing the rotor to perform electrical rotation ("jumping a pole pair"), then the star point voltage will change from... Figure 3 The process shown suddenly changes to, as Figure 4 The process shown or from such Figure 4The process shown suddenly changes to, as Figure 3 The process is illustrated. This depends on the rotor's rotation direction. By continuously measuring and evaluating these changes, the degree of external adjustment with "pole pair accuracy" can be calculated. Furthermore, this also allows the detection of the external adjustment's rotation direction.

[0030] When rotor movement is detected and thus manual movement of a pivotable body component is detected, the body component can be further opened or closed electrically or in an electrically assisted manner (prompt operation).

[0031] List of reference numerals

[0032] Stator A, Phase A

[0033] Stator B, Phase B

[0034] C stator, C phase

[0035] L1 Inductor 1

[0036] L2 Inductor 2

[0037] L3 Inductor 3

[0038] S Star Point

Claims

1. A method for detecting the movement of pivotable body parts of a motor vehicle, particularly a hinged door, wherein, Motor vehicles include electric motors having stators and rotors, wherein the electric motors are configured to electrically move pivotable body components. The electric motor is characterized in that it is a BLDC electric motor having a three-phase stator (A, B, C), wherein two phases of the stator (A, B) are loaded with pulse width modulated voltages, wherein the third phase (C) remains free-floating, wherein the third phase (C) is monitored as a measurement point for an inductive voltage divider formed using the other two phases (A, B), wherein movement of the pivotable body component is detected if the signal at the measurement point or a variable derived from the signal exceeds a specified threshold.

2. The method according to claim 1, Its features are, The two phases (A and B) of the stator are loaded with pulse width modulation voltage in a time-off manner, so the two phases (A and B) are not activated at the same time.

3. The method according to claim 1, Its features are, The two phases (A, B) of the stator are loaded with pulse width modulated voltages of the same amplitude.

4. The method according to claim 1, Its features are, The signal measured at the measurement point is continuously monitored, and the periodic fluctuations of the signal at the measurement point are counted in order to determine the rotation angle of the rotor.

5. The method according to claim 1, Its features are, The signal measured at the measurement point is continuously monitored, and the rotation direction of the rotor is determined based on the fluctuation type of the signal at the measurement point.

6. A motor vehicle comprising a pivotable body component, particularly a hinged door, wherein, Motor vehicles include electric motors having stators and rotors, wherein the electric motors are configured to electrically move pivotable body components. The electric motor is characterized in that it is a BLDC electric motor having a three-phase stator (A, B, C), wherein the control device of the motor vehicle is configured to perform the method according to at least one of the preceding claims in order to detect the movement of the pivotable body component.

7. The motor vehicle according to claim 6, Its features are, The control device is configured to, upon detecting movement of the pivotable body component, initiate an electric movement of the pivotable body component according to the detected direction of rotation, preferably an electric closing or electric opening.

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