Method for operating steering device, steering device, and motor vehicle

Abstract

To provide a method for operating a steering device of a motor vehicle according to the steer-by-wire principle.SOLUTION: A steering device (1) comprises a rotatable steering handle (2), in particular steering wheel, to provide a steering request. The steering device (1) comprises an electric machine (3) mechanically coupled to the steering handle (2). The electric machine (3) is drive-controlled in an active state of the steering device (1) to generate a reset torque counteracting a rotational movement of the steering handle (2), and the machine (3) is drive-control free in an idle state of the steering device (1). In the idle state, an electrical voltage of the electric machine (3) is detected to determine a rotational movement of the steering handle (2), and if the electrical voltage reaches a predetermined threshold value, in particular exceeds it, the active state is activated.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for operating a steering device of a motor vehicle based on the steer-by-wire principle, where the steering device has a rotatable steering handle for setting a steering requirement, in particular a steering wheel, where the steering device has an electromechanic mechanically coupled to the steering handle, and where the electromechanic is drive-controlled to generate a return torque reacting to the rotational movement of the steering handle in the active state of the steering device, and where the machine is not drive-controlled in the rest state of the steering device.

[0002] Furthermore, the present invention relates to a steering device and a motor vehicle equipped with such a steering device.

[0003] Prior Art Steering devices based on the steer-by-wire principle are known. Here, the steering handle, usually the steering wheel, is not mechanically connected to a steering adjuster assigned to at least one wheel of the motor vehicle, but is only coupled to an electromechanic for simulating a torque reacting to the rotational movement. For energy savings, this machine is shifted to a rest state without drive control when the motor vehicle is parked and the engine is switched off, for example.

[0004] For example, from German Patent Application Publication No. 102020206435, a method for operating such a steer-by-wire steering system is known, where, for example, to assist the driver when getting out of the vehicle, depending on the active conditions, the return torque at the steering handle is simulated using a simulation function in a passive operating mode different from the normal driving operation mode. These active conditions particularly include the ignition signal and / or the closed state of the vehicle door.

[0005] From U.S. Patent Application Publication No. 2012 / 0009197, a method for operating this type of steer-by-wire steering system is known, in which, in order to assist the driver when getting out of the vehicle, the steering shaft coupled to the steering wheel is rotated to a mechanical stopper in response to a set signal, thereby making further rotation in the corresponding direction impossible and enabling the driver to be held at the steering wheel when getting out of the vehicle. These signals particularly include the ignition signal.

[0006] From German Patent Application Publication No. 102017218830, conventional steering devices not configured according to the steer-by-wire principle without a mechanical fallback level are also known, where, for example, when the movement of a servo motor caused by an external force by a manually accelerated wheel is detected, the servo motor switches to a special deceleration operation mode for maintenance or anti-theft. This servo motor is arranged in a steering gear acting on the wheels of a motor vehicle. For example, a voltage, particularly an electromotive force, generated by the movement of the wheels is detected.

[0007] Disclosure of the Invention The method according to the invention having the features of claim 1 is characterized in that, in order to identify the rotational movement of the steering wheel, the voltage of the electromechanical device is detected in the rest state, and when the voltage reaches at least, especially exceeds, a set threshold value, the active state is activated. Thereby, the rotational movement of the steering wheel is guaranteed the advantage of being identified with minimal energy costs by monitoring only the voltage as the operating quantity of the electromechanical device. Compared with the known method described at the beginning, it is not assumed to monitor and evaluate complex trigger conditions. To that extent, the basic idea of the invention is to identify, in an energy-efficient manner, the case where the steering wheel is rotated by the driver in the rest state, i.e., especially when the motor vehicle is parked, and in that case, the voltage is measured and, depending on the voltage, the active state that preferably provides the same counter torque as in the normal driving operation mode period of the electromechanical device is automatically activated, or alternatively, to at least partially, especially completely, compensate for the rotational movement, or to keep the steering wheel, especially in the period of the normal driving mode where rotation is only possible against the corresponding torque, in a state different from the active state set at least in the vehicle stop state, for example, held at the current rotational position, in order to identify, in an energy-efficient manner, the case where the steering wheel is rotated by the driver. Preferably, in the active state, the rotational angle of the steering wheel is detected and / or the height adjustment of the steering wheel is made possible and / or carried out. In particular, it is assumed that the period between the arrival of the threshold value and the activation of the active state is only a part of 1 second, especially in the range of less than 100 milliseconds, for example, in the range of 200 to 300 ms. Usually, as also mentioned at the beginning, for example, the opening of the vehicle door is used as a trigger for switching on the machine. However, if the driver wishes to get out of the vehicle while remaining seated in the parked vehicle, for example, because he is waiting for something, and in that case, holds the steering wheel in order to be able to get out well, the machine will not provide reverse torque thereby. Because the machine is switched off.In this exemplary application case, if the driver does not take into account that the steering wheel has no rotational resistance or only very little rotational resistance, there is a risk of injury to some extent. According to the method of the present invention, it is guaranteed that as soon as the corresponding voltage reaches the threshold value, the machine is driven and controlled to provide a counter torque. This threshold value is set as low as possible, in particular, so as to reach before the end of the getting-off process, provided that it is set high to some extent so that the machine is not driven and controlled during the minimum movement of the steering wheel. Preferably, the threshold value is variably adjustable. For example, the threshold value is automatically determined depending on driver characteristics (weight, age, physical ability, etc.). In particular, the steering wheel is rotatable with at least substantially no resistance in the rest state.

[0008] According to a preferred development of the present invention, the electromechanical machine is configured in multiple phases, and as the voltage, at least one voltage induced in one of the multiple phases of the electromechanical machine is detected. Thereby, it is easily guaranteed, in particular advantageously, that the rotational movement is identified. In that regard, the voltage necessarily induced by the rotational movement is measured in the phase of the electromechanical machine. Because, for example, the permanent magnet induces a voltage in the stator of the machine in the rotor of the machine.

[0009] Particularly preferably, it is assumed that as the voltage, the voltage drop through the electrical resistance of the integrated circuit (ASIC) of the electromechanical machine is detected. Thereby, a particularly simple means for detecting the voltage is obtained. The measurement is carried out, in particular, in any case in the existing ASIC, and therefore no additional components or sensors are required.

[0010] According to a preferred development of the present invention, it is assumed that the control device assigned to the electromechanical machine is activated in order to activate the active state. Thereby, a particularly suitable and simple means for activating the active state is obtained. In that regard, the control device assigned to the electromechanical machine is activated to provide a counter torque.

[0011] Particularly preferably, it is assumed that the control device is activated using an active signal of an application specific integrated circuit (ASIC). Thereby, the control device itself only needs to react to the active signal, and the advantage is that it remains in a power-saving standby state otherwise. This control device is particularly configured as a control device (ECU) and / or a microcontroller.

[0012] According to a preferred development of the invention, the threshold value corresponds to the high level of the integrated circuit, and it is assumed that an active signal is generated when at least reaching the high level, particularly when exceeding it. As long as that is the case, the active signal is preferably automatically generated without requiring further method steps. Thereby, particularly reliable activation is ensured.

[0013] Particularly preferably, it is assumed that the open state of the driver's door of the motor vehicle is monitored, and when it is identified that the driver's door has been closed after being opened for the first time, the active state is set to inactive again. Thereby, the steering device has the advantage of returning to a power-saving standby state immediately when the driver's own assistance function is no longer required, particularly because the above-described getting-off process has ended.

[0014] An automotive steering device according to the steer-by-wire principle having the features of claim 8 has a rotatable steering handle for setting a steering requirement, particularly a steering wheel, and an electromechanical device mechanically coupled to the steering handle. This device is characterized in that it comprises a control device and / or an integrated circuit specially configured to implement the method according to the invention. As a result, the above-described advantages already occur.

[0015] An automotive vehicle having the features of claim 9 is characterized in that it comprises a steering device according to the invention. Also from this, the above-described advantages already occur.

[0016] Further preferred features and combinations of features will become apparent from the above description and the claims. Hereinafter, the invention will be described in detail based on the drawings.

Brief Description of the Drawings

[0017]

Figure 1

Figure 2

[0018] FIG. 1 shows the components of a steering device 1 of an automobile, which is shown only schematically and not in detail otherwise. This steering device 1 is configured according to the steer-by-wire principle and, according to the present invention, has a rotatable steering wheel 2 for setting a steering requirement, which is configured as a steering wheel, and an electromechanical device 3 mechanically coupled to the steering wheel. The electromechanical device 3 is configured in a polyphase manner and, in the present invention, has three electrical phases 4, to which an integrated circuit (ASIC) 5 is electrically connected. Finally, a control device 6 is provided, which is connected to the circuit 5 both communicatively and / or electrically, and thus to the electromechanical device 3 and the steering wheel 2.

[0019] The electromechanical device 3 is configured to be driven and controlled so as to generate a return torque reacting to the rotational movement of the steering wheel 2 in the active state of the steering device 1. In the rest state of the steering device, the machine 3 is not driven and controlled.

[0020] Hereinafter, with reference to FIG. 2, an advantageous method for operating the steering device 1 will be described. For this purpose, in FIG. 2, this method is shown based on a flowchart. In particular, according to this method, it is guaranteed that as soon as the rotational movement of the steering wheel 2 is identified, the electromechanical device 3 will surely shift to the active state.

[0021] In step S1, the method is started by the fact that the steering device 1 is in a rest state. As long as that is the case, the electromechanism 3 is not driven and controlled as described above. Here, in order to identify the rotational movement of the steering wheel 2, the voltage of the electromechanism 3 is detected. In particular, at least one voltage induced in one of the plurality of phases 4 of the electromechanism 3 is detected as the voltage. More precisely, preferably, the voltage drop through the electrical resistance of the integrated circuit 5 is detected.

[0022] When the voltage reaches at least, especially exceeds, the set threshold value, the method continues to step S2. This threshold value corresponds in particular to the high level of the integrated circuit 5.

[0023] In step S2, the active state is activated, that is, the electromechanism 3 is driven and controlled to generate a return torque reacting to the rotational movement. Thereby, for example, the driver can be held / supported on the steering wheel 2 when getting out of the vehicle. For this purpose, preferably, the control device 6 is activated, in particular using the active signal of the integrated circuit 5. In particular, the active signal is generated when it reaches at least, especially exceeds, the high level. The method ends here in step S4.

[0024] Alternatively, in an optional intermediate step S3, the open state of the driver's side door of the motor vehicle is monitored. If it is identified that the driver's side door has been closed after being opened for the first time, the getting-out process ends and the active state is deactivated again, that is, starting from the fact that the rest state is activated again. The method ends in step S4. In particular, the method is fed back to step S1 again.

Claims

1. A method for operating a steering device (1) of a motor vehicle according to the steer-by-wire principle, comprising: The steering device (1) comprises a rotatable steering handle (2), in particular a steering wheel, for setting steering requirements, The steering device (1) has an electric machine (3) mechanically coupled to the steering wheel (2), The electric machine (3) is driven and controlled to generate a return torque counteracting the rotational movement of the steering wheel (2) in an active state of the steering device (1); The electric machine (3) is not driven in the rest state of the steering device (1), the voltage of the electric machine (3) is detected in a rest state in order to identify the rotational movement of the steering wheel (2); 4. A method according to claim 3, characterized in that the active state is activated when the voltage at least reaches, in particular exceeds, a set threshold value.

2. 2. The method according to claim 1, wherein the electric machine (3) is configured as a multi-phase and the voltage detected is at least one voltage induced in one of the phases (4) of the electric machine (3).

3. 3. The method according to claim 1, wherein the voltage detected is a voltage drop across an electrical resistance of an integrated circuit (ASIC) (5) of the electric machine (3).

4. 4. The method according to claim 1, further comprising activating a control device (6) assigned to the electric machine (3) for activating the active state.

5. 5. The method according to claim 1, wherein the control device (6) is activated by means of an active signal of an integrated circuit (ASIC) (5) of the electric machine (3).

6. 6. The method according to claim 5, wherein the threshold value corresponds to a high level of the integrated circuit (5), and an active signal is generated at least when the high level is reached, in particular when it is exceeded.

7. 7. The method of claim 1, wherein the open state of a driver's door of the motor vehicle is monitored and the active state is deactivated again if it is identified that the driver's door has been closed after an initial opening.

8. A steering device (1) for an automobile based on the steer-by-wire principle, The steering device (1) comprises a rotatable steering handle (2), in particular a steering wheel, for setting steering requirements, The steering device (1) has an electric machine (3) mechanically coupled to the steering wheel (2), A steering device (1), characterised in that it comprises a control device (6) and / or an integrated circuit (5) specially adapted to carry out the method according to any one of claims 1 to 7.

9. Motor vehicle, characterized in that it is equipped with a steering device (1) according to claim 8.

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