Patent Description:
The present disclosure is also directed to a method for starting a vehicle.

The present disclosure is additionally directed to a data processing apparatus, a computer program, and a computer-readable storage medium.

Furthermore, the present disclosure relates to a steering system for a vehicle.

In order to be able to precisely operate a steering system, a rotatory steering wheel position of a steering wheel needs to be synchronized to an angular road wheel position of a road wheel. This means that any rotatory steering wheel position needs to be associated with one angular road wheel position. This allows a user of the steering system to which the steering wheel and the at least one road wheel are coupled to precisely steer the vehicle.

In situations in which the synchronization has been lost, the rotatory steering wheel position of the steering wheel needs to be synchronized to the angular road wheel position of a road wheel before the vehicle may start. Otherwise, the vehicle may not be steered in a reliable manner.

In this context, <CIT> discloses a method for synchronizing a vehicle steering. First, a steering rack is turned from lock-to-lock to determine a steering rack midpoint. Second, a steering wheel is turned from lock-to-lock to determine a steering wheel midpoint. Third, the steering rack is synchronized with the steering wheel based on the steering rack midpoint and the steering wheel midpoint.

Further, <CIT> teaches a method for calibrating a vehicle steering. The method includes determining at least one maximum steering angle of a vehicle and identifying a midpoint of a steering mechanism of the vehicle based on the at least one maximum steering angle.

It is an objective of the present disclosure to provide a simple and reliable method for synchronizing a rotatory steering wheel position of a steering wheel to an angular road wheel position of a road wheel.

According to a first aspect, there is provided a method for synchronizing a rotatory steering wheel position of a steering wheel to an angular road wheel position of a road wheel. The steering wheel and the road wheel are coupled to a steering system for a vehicle. The method comprises:.

In the present context, the fact that the steering wheel and the road wheel are coupled to a steering system for a vehicle is to be understood in that the steering wheel and the road wheel are coupled to the same steering system. Synchronizing the rotatory steering wheel position of the steering wheel to an angular road wheel position of the road wheel means to establish a relationship between the rotatory steering wheel position and the angular road wheel position such that any rotatory steering wheel position is associated with one angular road wheel position. The neutral steering wheel position is the rotatory steering wheel position which is used to steer a corresponding vehicle straight ahead. Correspondingly, the neutral road wheel position is the angular road wheel position which makes a corresponding vehicle travel straight ahead. The present method uses the fact that a rotatory positon of a steering wheel end stop position and/or an angular position of the road wheel end stop position is known. These positions are usually known using the neutral steering wheel position and/or the neutral road wheel position as a point of reference or origin. It is understood that the steering wheel only needs to be caused to move into the steering wheel end stop position if it is not already in the steering wheel end stop position. Analogously, the road wheel only needs to be caused to move into the road wheel end stop position if it is not already in the road wheel end stop position. It is noted that in a case in which both the road wheel and the steering wheel are moved into a respective end stop position, the end stop positons need to correspond to each other, i.e. both end stop positions are left end stop positions or both end stop positions are right end stop positions. Consequently, using the present method, a rotatory steering wheel position of a steering wheel and an angular road wheel position of a road wheel can be synchronized using incremental position sensors only. This means that the present method can be used in situations in which an absolute position of the steering wheel and/or an absolute position of the road wheel is unknown. This may be the case, if one or more associated absolute position sensors are subject to an error on malfunction. The fact that only incremental sensors are necessary for executing the method has the consequence that redundant absolute position sensors are not necessary. This reduces the complexity of the steering system. Thus, the present method is comparatively simple and reliable.

In an example, the steering system is a steer-by-wire system. In such a system, the steering wheel and the road wheel may be moved independently from one another. In another example, the steering system is a mechanical steering system, i.e. a steering system comprising a mechanical coupling between the steering wheel and the road wheel.

In an example, the steering wheel is moved using a steering wheel actuator which may also be called a hand wheel actuator (HWA).

In an example, the method further comprises receiving at least one of the known rotatory position of the steering wheel end stop position and the known angular position of the road wheel end stop position from a data storage means. This is a simple and reliable manner of providing the known rotatory position of the steering wheel end stop position and/or the known angular position of the road wheel end stop position. These positions may of course be specific for each steering system and/or each vehicle. In a case in which only one of the known rotatory position of the steering wheel end stop position and the known angular position of the road wheel end stop position is received from the data storage means, the respective other one may be received from a position sensor means. The position sensor means may be an absolute position sensor. Thus, the known rotatory position of the steering wheel end stop position and/or the known angular position of the road wheel end stop position are always available.

In an example, the steering wheel end stop position is one of a left steering wheel end stop position and a right steering wheel end stop position. Additionally or alternatively, the road wheel end stop position is one of a left road wheel end stop position and a right road wheel end stop position. It is noted that when executing the method, the steering wheel end stop position and the road wheel end stop position need to correspond to each other. This means that both need to relate to a left end stop position or a right end stop position.

In an example, the method further comprises:.

causing the road wheel to move into the respective other road wheel end stop position.

An obstacle information is generated if one of the left steering wheel end stop position and the right steering wheel end stop position cannot be reached. Additionally or alternatively, an obstacle information is generated if one of the left road wheel end stop position and the right road wheel end stop position cannot be reached. In these cases it is assumed that an obstacle blocks the movement of the steering wheel and/or the road wheel. Therefore, the steering wheel and/or the road wheel are moved into the respective other end stop position. Thus, the method may be executed in cases in which an obstacle blocks the movement of the road wheel and/or steering wheel. In other words, the method may be executed in a robust manner.

In an example, causing the steering wheel to move into a neutral steering wheel position comprises causing the steering wheel to move into an intermediate steering wheel position and causing the steering wheel to temporarily stop in the intermediate steering wheel position. Additionally or alternatively, causing the road wheel to move into the neutral road wheel position comprises causing the road wheel to move into an intermediate road wheel position and causing the road wheel to temporarily stop in the intermediate road wheel position. This allows the steering wheel to be in the steering wheel end stop position for a comparatively short time only. Additionally or alternatively, the road wheel may be in a road wheel end stop position for a comparatively short time only. This reduces wear.

In an example, causing the steering wheel to move into the first end stop position comprises receiving a confirmation that the steering wheel has reached the end stop position. This enhances the reliability of the method since situations in which the steering wheel has not properly reached the end stop position can be excluded.

In an example, causing the road wheel to move into the end stop position comprises receiving an abutment force information. The abutment force information may be used as an indicator whether the road wheel has properly reached the end stop position. Consequently, the method may be executed in a reliable manner.

In an example, the method further comprises receiving a reference abutment force information and comparing the reference abutment force information to the abutment force information. The comparison between the reference abutment force information and the abutment force information is also an indicator whether the road wheel has properly reached the end stop position. Thus, the method is very reliable.

In an example, the method triggers blocking the use of the steering system and the vehicle in a case in which the steering wheel has not properly reached the end stop position and/or in which the road wheel has not properly reached the end stop position.

In an example, the method further comprises triggering a warning message for a user of the vehicle while causing the steering wheel to move and/or while causing the road wheel to move. This allows the user of the vehicle to keep away from the moving steering wheel and/or the moving road wheel. This increases the safety of the user of the vehicle.

In an example, the method further comprises triggering a confirmation message for a user of the vehicle if the steering wheel has reached the neutral steering wheel position and the road wheel has reached the neutral road wheel position. Consequently, the user of the vehicle knows when it is safe to start using the steering wheel.

According to a second aspect, there is provided a method for starting a vehicle. The method comprises:.

It is understood that in the first step, the rotatory steering wheel position and the angular road wheel position are to be understood as absolute positions. The determination may be based on an error message received from a position sensor being coupled to the steering wheel and/or a position sensor being coupled to the road wheel. The method for starting the vehicle may be executed at each vehicle start-up during a steering system check. Since the use of the steering system is only permitted after the method for synchronizing the rotatory steering wheel position of the steering wheel to the angular road wheel position of the road wheel has been performed, operational safety of the vehicle is increased. In a case in which the method for synchronizing the rotatory steering wheel position of the steering wheel to the angular road wheel position of the road wheel has not been successfully terminated, use of the steering wheel may be blocked. This additionally enhances the operational safety of the vehicle.

Both the method according to the first aspect of the present disclosure and the method of the second aspect of the present disclosure may be at least partly computer-implemented, and may be implemented in software or in hardware, or in software and hardware. Further, the methods may be carried out by computer program instructions running on means that provide data processing functions. The data processing means may be a suitable computing means, such as an electronic control module etc., which may also be a distributed computer system. The data processing means or the computer, respectively, may comprise one or more of a processor, a memory, a data interface, or the like.

According to a third aspect, there is provided a data processing apparatus comprising means for carrying out at least one of the methods of the present disclosure. Thus, the data processing apparatus may comprise means for carrying out the method according to the first aspect and/or the method according to the second aspect. Using the data processing apparatus, a rotatory steering wheel position of a steering wheel and an angular road wheel position of a road wheel can be synchronized using incremental position sensors only. This means that the data processing apparatus can be used in situations in which an absolute position of the steering wheel and/or an absolute position of the road wheel is unknown. This may be the case, if an absolute position sensor is subject to an error on malfunction. As has been mentioned before, only incremental sensors are necessary for executing the method. This has the effect that redundant absolute position sensors are not necessary. This reduces the complexity of the steering system. Moreover, operational safety of a vehicle using such a steering system is enhanced.

According to a fourth aspect, there is provided a computer program comprising instructions which, when the computer program is executed by a computer, cause the computer to carry out the method of the present disclosure. Using the computer program, a rotatory steering wheel position of a steering wheel and an angular road wheel position of a road wheel can be synchronized using incremental position sensors only. This means that the computer program can be used in situations in which an absolute position of the steering wheel and/or an absolute position of the road wheel is unknown. This may be the case, if an absolute position sensor is subject to an error on malfunction. As has been mentioned before, only incremental sensors are necessary for executing the method. This has the effect that redundant absolute position sensors are not necessary. This reduces the complexity of the steering system. Moreover, operational safety of a vehicle using such a steering system is enhanced.

According to a fifth aspect, there is provided a computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to carry out the method of the present disclosure. Using the computer-readable storage medium, a rotatory steering wheel position of a steering wheel and an angular road wheel position of a road wheel can be synchronized using incremental position sensors only. This means that the computer-readable storage medium can be used in situations in which an absolute position of the steering wheel and/or an absolute position of the road wheel is unknown. This may be the case, if an absolute position sensor is subject to an error on malfunction. As has been mentioned before, only incremental sensors are necessary for executing the method. This has the effect that redundant absolute position sensors are not necessary. This reduces the complexity of the steering system. Moreover, operational safety of a vehicle using such a steering system is enhanced.

According to a sixth aspect, there is provided a steering system for a vehicle. The vehicle has at least one road wheel and a steering wheel. The steering system is configured to adjust an angular road wheel position of the road wheel based on a rotatory steering wheel position of the steering wheel. The steering system comprises a steering wheel actuator unit comprising a singular steering wheel absolute position sensor and at least one steering wheel incremental position sensor. Additionally, the steering system comprises a road wheel actuator unit comprising a singular road wheel absolute position sensor and at least one road wheel incremental position sensor. Furthermore, the steering system comprises a data processing apparatus of the present disclosure being communicatively connected to the steering wheel actuator unit and the road wheel actuator unit. Thus, compared to known steering systems, the steering system according to the present disclosure only comprises very few absolute position sensors. More precisely, redundant absolute position sensors are not necessary. This reduces the complexity of the steering system. At the same time, a rotatory steering wheel position of a steering wheel and an angular road wheel position of a road wheel can be synchronized using the steering system. This may be the case in situations in which the absolute position of the steering wheel and/or the absolute position of the road wheel is unknown, e.g. if an absolute position sensor is subject to an error on malfunction. As has been mentioned before, only incremental sensors are necessary for executing the method. Thus, in addition to the reduced complexity, the steering system is reliable.

The vehicle <NUM> comprises front wheels <NUM> and rear wheels <NUM>.

Additionally, the vehicle comprises a steering wheel <NUM>.

The steering wheel <NUM> and the front wheels <NUM> are coupled by a steering system <NUM>.

The steering system <NUM> is configured to adjust an angular road wheel position indicated by angle α of the front wheels <NUM> based on a rotatory steering wheel position indicated by angle β of the steering wheel <NUM>.

Since in the present example, only the front wheels <NUM> are connected to the steering system <NUM>, they may be called road wheels in a more general manner. Thus, the term front wheels <NUM> and road wheels will be used as synonyms in the following.

In the present example, the steering system <NUM> is a steer-by-wire system.

The steering system <NUM> comprises a steering wheel actuator unit <NUM> which is coupled to the steering wheel <NUM>.

Moreover, the steering system <NUM> comprises a road wheel actuator unit <NUM>. The road wheel actuator unit <NUM> is coupled to the front wheels <NUM> via a rack and pinion mechanism <NUM>.

The steering wheel actuator unit <NUM> comprises a singular steering wheel absolute position sensor <NUM> being configured to generate an absolute position sensor detection result and one steering wheel incremental position sensor <NUM> being configured to generate an incremental position sensor detection result.

Moreover, the steering wheel actuator unit <NUM> comprises a steering wheel abutment force sensor <NUM>.

The steering wheel abutment force sensor <NUM> is configured to detect an abutment force by which the steering wheel <NUM> abuts against an end stop in the steering wheel end stop position. Based thereon, the steering wheel abutment force sensor <NUM> is able to create an abutment force information being representative of the abutment force.

Also the road wheel actuator unit <NUM> comprises a singular road wheel absolute position sensor <NUM> being configured to generate an absolute position sensor detection result and one road wheel incremental position sensor <NUM> being configured to generate an incremental position sensor detection result.

Moreover, the road wheel actuator unit <NUM> comprises a road wheel abutment force sensor <NUM>.

The road wheel abutment force sensor <NUM> is configured to detect an abutment force by which the road wheel <NUM> abuts against an end stop in the road wheel end stop position. Based thereon, the road wheel abutment force sensor <NUM> is able to create an abutment force information being representative of the abutment force.

The steering system <NUM> further comprises a data processing apparatus <NUM>.

The data processing apparatus <NUM> is communicatively connected to the steering wheel actuator unit <NUM> and the road wheel actuator unit <NUM>.

The data processing apparatus <NUM> comprises a data storage unit <NUM> and a data processing unit <NUM>.

The data storage unit <NUM> comprises a computer-readable storage medium <NUM>.

On the computer-readable storage medium <NUM>, there is provided a computer program <NUM>.

Both the computer-readable storage medium <NUM> and the computer program <NUM> comprise instructions which, when executed by the data processing unit <NUM> or, more generally, a computer, cause the data processing unit <NUM> or the computer to carry out a method for starting the vehicle <NUM>.

Consequently, the data storage unit <NUM> and the data processing unit <NUM> form means <NUM> for carrying out the method for starting the vehicle <NUM>.

As will be explained in more detail further below, the method for starting the vehicle <NUM> comprises executing a method for synchronizing a rotatory steering wheel position β of a steering wheel <NUM> to an angular road wheel position α of a road wheel <NUM>.

Thus, the computer-readable storage medium <NUM> and the computer program <NUM> additionally comprise instructions which, when executed by the data processing unit <NUM> or, more generally, a computer, cause the data processing unit <NUM> or the computer to carry out the method for synchronizing a rotatory steering wheel position β of a steering wheel <NUM> to an angular road wheel position α of a road wheel <NUM>.

Consequently, the data storage unit <NUM> and the data processing unit <NUM> also form means <NUM> for carrying out the method for synchronizing a rotatory steering wheel position of a steering wheel <NUM> to an angular road wheel position of a road wheel <NUM>.

In the following, the method for starting the vehicle <NUM> is explained.

This method comprises three steps S1, S2, S3.

In a first step S1, the method determines that at least one of the rotatory steering wheel position β and the angular road wheel position α is unknown. This may be the case if at least one of the steering wheel absolute position sensor <NUM> and the road wheel absolute position sensor <NUM> is subject to an error.

In the present example, it is assumed that both the steering wheel absolute position sensor <NUM> and the road wheel absolute position sensor <NUM> are subject to an error. This means that an absolute position of the steering wheel <NUM> and an absolute position of the road wheel <NUM> is unknown.

In a subsequent second step S2, the method for synchronizing a rotatory steering wheel position β of a steering wheel <NUM> to an angular road wheel position α of a road wheel <NUM> is executed.

In order to be able to better distinguish between the steps of the method for starting the vehicle and the steps of the method for synchronizing a rotatory steering wheel position β of a steering wheel <NUM> to an angular road wheel position α of a road wheel <NUM>, the steps of the method for synchronizing a rotatory steering wheel position β of the steering wheel <NUM> to an angular road wheel position α of the road wheel <NUM> will be indicated by a reference signs S2x.

In order to further facilitate the following explanations, the method for synchronizing a rotatory steering wheel position β of a steering wheel <NUM> to an angular road wheel position α of a road wheel <NUM> will be simply called a method for synchronizing.

In a first step S21 of the method for synchronizing, the steering wheel <NUM> is caused to move into a steering wheel end stop position.

Additionally, the road wheels <NUM> is caused to move into a corresponding end stop position.

In other words, both the steering wheel <NUM> and the road wheels <NUM> are moved either into a left end stop position or a right end stop position.

If the steering wheel <NUM> reaches the end stop position, an abutment force information is generated by the steering wheel abutment force sensor <NUM> and is received at the data processing apparatus <NUM>.

This abutment force information is compared to a reference abutment force information which is stored on the data storage unit <NUM>.

Based on this comparison, a confirmation that the steering wheel <NUM> has reached the end stop position is generated if the received abutment force information and the reference abutment force information differ by a predefined difference threshold or less.

In the same manner, if the road wheels <NUM> reach the end stop position, an abutment force information being generated by the road wheel abutment force sensor <NUM> is received at the data processing apparatus <NUM>.

Based on this comparison, a confirmation that the road wheels <NUM> have reached the end stop position is generated if the received abutment force information and the reference abutment force information differ by a predefined difference threshold or less.

A second step S22 of the method for synchronizing is executed in parallel to the first step S21. The second step S22 triggers a warning message for a user of the vehicle <NUM>. In the present example, the warning message is an acoustic message which is delivered to a passenger compartment of the vehicle <NUM> by a loudspeaker <NUM>. The loudspeaker <NUM> is communicatively connected to the data processing apparatus <NUM>.

It is understood that in other examples, the warning message may be of any other appropriate type.

In a third step S23 of the method for synchronizing, the steering wheel <NUM> is caused to move into a neutral steering wheel position.

Moreover, the road wheels <NUM> are caused to move into the neutral road wheel position.

In order to do so, the fact that a rotatory position β of the steering wheel end stop position is known and the fact that an angular position α of the road wheel end stop position is known are used.

Both the known rotatory position β of the steering wheel end stop position and the known angular position α of the road wheel end stop position are stored on the data storage unit <NUM>.

Additionally, the steering wheel incremental position sensor <NUM> and the road wheel incremental position sensor <NUM> are used. The sensors are not subject to an error.

In other words, the steering wheel <NUM> is caused to move into a neutral steering wheel position wherein an incremental position sensor detection result of the steering wheel incremental position sensor <NUM> is used. The road wheels <NUM> are caused to move into a neutral road wheel position wherein an incremental position sensor detection result of the road wheel incremental position sensor <NUM> is used.

Again a warning message may be issued while the road wheels <NUM> and the steering wheel <NUM> are moving, i.e. the execution of step S22 is continued.

In other words, now a rotatory steering wheel position β of the steering wheel <NUM> and an angular road wheel position α of the road wheels <NUM> is known.

Thereafter, in a fourth step S24 of the method for synchronizing, a confirmation message for the user of the vehicle <NUM> may be triggered if the steering wheel <NUM> has reached the neutral steering wheel position and the road wheels <NUM> have reached the neutral road wheel position. In the present example, the confirmation message is an acoustic message which is provided to the user of the vehicle <NUM> by the loudspeaker <NUM>.

Thereafter, in a third step S3 of the method for starting the vehicle, a use of the steering system <NUM> is permitted.

In the above explanation of the method for synchronizing, both the steering wheel <NUM> and the road wheels <NUM> could be moved into the corresponding end stop positions without any problem.

In order to be able to react to situations in which at least one of the road wheels <NUM> and the steering wheel <NUM> cannot be moved into the desired end stop position, the method may comprise the following optional steps.

The fact that at least one of the steering wheel <NUM> and the road wheels <NUM> may not be moved into the corresponding end stop position may cause the generation of an obstacle information.

This obstacle information obviously relates to one of the left steering wheel end stop position and the right steering wheel end stop position, if the steering wheel <NUM> is blocked from reaching the corresponding end stop position.

In a case in which the road wheels <NUM> are blocked from reaching the corresponding end stop position, the obstacle information relates to one of the left road wheel end stop position at the right road wheel end stop position.

The obstacle information is received at the data processing apparatus <NUM>.

Following the obstacle information, the steering wheel <NUM> and the road wheel <NUM> are caused to move into the respective other steering wheel end stop position and the respective other road wheel end stop position.

This means that the method for synchronizing can also be executed in a case in which moving at least one of the steering wheel <NUM> and the road wheels <NUM> into one of the corresponding end stop positions is blocked.

Additionally or alternatively, the method may comprise the following optional steps which limit wear occurring in the end stop positions of the steering wheel <NUM> and/or the road wheel <NUM>.

According to this option, causing the steering wheel <NUM> to move into a neutral steering wheel position comprises causing the steering wheel <NUM> to move into an intermediate steering wheel position and causing the steering wheel <NUM> to temporarily stop in the intermediate steering wheel position.

This means that the steering wheel <NUM> only needs to stay in its end stop position for a comparatively short time.

In the same manner, causing the road wheels <NUM> to move into the neutral road wheel position comprises causing the road wheels <NUM> to move into an intermediate road wheel position and causing the road wheels <NUM> to temporarily stop in the intermediate road wheel position. Also in this case, the road wheels <NUM> only need to stay in the corresponding end stop position for a comparatively short time.

Claim 1:
A method for synchronizing a rotatory steering wheel position (β) of a steering wheel (<NUM>) to an angular road wheel position (α) of a road wheel (<NUM>), the steering wheel (<NUM>) and the road wheel (<NUM>) being coupled to a steering system (<NUM>) for a vehicle (<NUM>), the method comprising:
- causing the steering wheel (<NUM>) to move into a steering wheel end stop position, wherein a rotatory position (β) of the steering wheel end stop position is known (S21), and/or
causing the road wheel (<NUM>) to move into a road wheel end stop position, wherein an angular position (α) of the road wheel end stop position is known (S21),
- causing the steering wheel (<NUM>) to move into a neutral steering wheel position based on the known rotatory position (β) of the steering wheel end stop position using an incremental position sensor detection result (S23), and
- causing the road wheel (<NUM>) to move into the neutral road wheel position based on the known angular position (α) of the road wheel end stop position using an incremental position sensor detection result (S23).