Hand off / hand on detection sensor in a vehicle

Abstract

A hand-off / hand-on detection sensor of a steering wheel assembly can be operated. The steering wheel assembly comprises at least a steering column, a steering wheel coupled to the steering column, a steering torque sensor, a steering wheel angle sensor, and an evaluation device. The steering torque sensor and the steering wheel angle sensor are coupled at least to the steering column. The evaluation device is coupled at least to the steering torque sensor and the steering wheel angle sensor. A steering angle of the steering column is detected using the steering wheel angle sensor. A maximum hysteresis angle threshold value and a minimum hysteresis angle threshold value are determined by the evaluation device based on an initial steering angle.

Description

Technical Field

[0001] This disclosure generally relates to a method for operating a steering wheel assembly with a hand off / hand on detection sensor, a steering wheel assembly with a hand off / hand on detection sensor, and a vehicle including a steering wheel assembly having a hand off / hand on detection sensor. Background Technology

[0002] During semi-autonomous driving, such as when operating an advanced driver assistance system at a higher level, the driver may be required to keep their hands on the steering wheel. In this case, the driving system must actively check whether the driver actually has their hands on the steering wheel during operation. This is typically achieved through hands-off / hand-on detection sensors. If the system detects that the driver has taken their hands off the steering wheel while driving, it outputs a notification reminding the driver to put their hands back on the steering wheel.

[0003] According to some methods, hand-off / hand-on detection sensors rely on readings of a conductive mesh structure included within the steering wheel. When the driver grips the steering wheel, a change in relative capacitance allows for the detection of manual contact. However, this method relies on the complex structure of the steering wheel, resulting in high manufacturing costs.

[0004] According to a different approach, hand-off / hand-on detection can be based on a steering torque sensor coupled to the steering column where the steering wheel is mounted. Whether the driver is holding the steering wheel can be assessed based on the steering torque detected by the steering torque sensor. Essentially, the steering torque applied to the steering wheel by the driver's hands is estimated based on the detected steering torque. The detected steering torque value is compared to a predefined column torque threshold. If the detected steering torque value applied to the steering column is higher than the threshold, the hand-off / hand-on detection sensor considers the driver's hands to be in contact with the steering wheel. If the detected steering torque value is lower than the threshold, the hand-off / hand-on detection sensor considers no contact.

[0005] Typically, the steering wheel assembly is affected by friction. Friction generates drag torque as the steering pinion moves. Friction is included in the measurement of steering torque. Therefore, friction also affects proper hand-off / hand-on detection. To prevent unintended hand-on detection, the torque threshold used to properly confirm hand-on detection must be set to a value greater than the steering torque caused by the potential maximum friction. Therefore, the torque threshold used for hand-on detection is calculated through the so-called cumulative friction torque of all upstream steering components.

[0006] In other words, this method is very conservative, resulting in a relatively high torque threshold for hand grip detection. The problem with this high torque threshold is that if the driver is indeed only lightly gripping the steering wheel, thus only causing a small steering torque below the threshold, the "hand grip" scenario may not be properly detected in many situations. Therefore, driver comfort is lower because the driver is still being signaled to make contact with the steering wheel even though they have already gripped it.

[0007] CN115593511A discloses a method for determining the frictional torque applied inside the steering column of an electric power steering system. The steering column is provided with a torsion bar that withstands instantaneous torsional torque. The instantaneous torsional torque is measured using a torsion bar sensor. At least one value of the frictional torque is measured using the torsion bar sensor.

[0008] JP2019189180A discloses a steering mechanism for a vehicle. A torque sensor detects the torque applied to a first position of the steering shaft. The upper friction torque is the absolute value of the torque detected by the sensor, caused by the frictional force acting between the steering shaft and the steering wheel at the first position when the steering shaft rotates. The vehicle control system repeatedly estimates the upper friction torque and variably sets a determination threshold to the estimated upper friction torque or a greater value. The vehicle control system determines whether the driver's hands are in a gripping or ungripped state based on a comparison between the absolute value of the torque detected by the sensor and the threshold level.

[0009] JP2020117025A discloses a driver assistance device that controls the drive of a steering actuator that applies steering torque to a steering mechanism to assist the driver's steering operation. A release threshold is considered and set to a value greater than the frictional torque, making it possible to determine whether the driver is holding the steering wheel. Summary of the Invention

[0010] According to one aspect, a method is provided for operating a hand-off / hand-on (HOOD) sensor of a steering wheel assembly. The steering wheel assembly includes at least a steering column, a steering wheel coupled to the steering column, a steering torque sensor, a steering wheel angle sensor, and an evaluation device. The steering torque sensor and the steering wheel angle sensor are coupled to at least the steering column. The evaluation device is coupled to at least the steering torque sensor and the steering wheel angle sensor and can be configured to perform the steps of the method. The method includes at least the following steps: a) Use a steering wheel angle sensor to detect the steering column angle.

[0011] b) Determine the maximum hysteresis angle threshold and the minimum hysteresis angle threshold based on the initial steering angle. The initial steering angle corresponds to the steering angle detected when the method is started in one loop (i.e., iteration).

[0012] c) Use a steering torque sensor to detect the steering torque of the steering column until the detected steering angle reaches both the maximum hysteresis angle threshold and the minimum hysteresis angle threshold.

[0013] d) Based on the detected steering torque, determine the maximum and minimum torque values ​​of the steering column for a specific cycle of the method.

[0014] e) Repeat steps a) through d) to determine multiple maximum torque values ​​and multiple minimum torque values ​​for different cycles of the method.

[0015] f) Determine the mean and standard deviation for multiple maximum torque values ​​and multiple minimum torque values ​​for different cycles of the method.

[0016] g) By adding the determined average value to n times the determined standard deviation, at least one suitable torque threshold is determined for the HOOD sensor, where n is a non-zero natural number.

[0017] This disclosure is based on the finding that conservative, constant friction-related torque thresholds are chosen too broadly for many applications. By actively measuring friction drag torque while the vehicle is in motion, a context-dependent, situation-specific torque threshold can be determined, tailored to the context-dependent characteristics of a particular steering assembly. Therefore, the situation-specific torque threshold is more precisely adapted to the specific operating scenario. For example, upstream steering friction of a particular steering wheel assembly can be more accurately accounted for within the situation-specific torque threshold. In turn, this method produces a situation-specific torque threshold that does not need to include a conservative, constant, wide tolerance region, i.e., a dispersion range, whereas in prior art methods, all steering wheel assemblies (e.g., assemblies throughout the entire production cycle) are considered within a single tolerance region.

[0018] Because the appropriate torque threshold is tailored to the specific steering wheel assembly, the HOOD sensor can properly detect whether the driver is holding the steering wheel. This reduces the error rate of detecting driver non-contact with the steering wheel. Consequently, fewer inappropriate notifications are output to remind the driver to hold the steering wheel, thus enhancing driver comfort. Furthermore, this method does not rely on a mesh structure integrated into the steering wheel, resulting in lower production costs for the steering wheel assembly.

[0019] The minimum hysteresis angle does not refer to the absolute value of the hysteresis angle, but rather to a value that depends on the direction. Therefore, the maximum hysteresis angle relates to the hysteresis angle along the first rotation direction, while the minimum hysteresis angle relates to the hysteresis angle along the second rotation direction opposite to the first rotation direction.

[0020] The minimum torque value does not refer to the absolute value of the detected steering torque, but rather to a value that depends on the direction. Therefore, the maximum torque value relates to the torque value along the first direction of rotation, while the minimum torque value relates to the torque value along a second direction of rotation opposite to the first direction of rotation.

[0021] The steering wheel angle sensor can transmit the detected steering column steering angle to the evaluation equipment.

[0022] In some examples, the steering torque sensor transmits the steering torque detected by the steering column to the evaluation device.

[0023] The adapted torque threshold can be a combination of the average and standard deviation of multiple maximum torque values ​​and multiple minimum torque values. This means that the adapted torque threshold can be direction-independent. However, in an alternative approach, the adapted torque threshold can include two direction-dependent components, each relating to rotation in opposite directions.

[0024] According to one aspect, the maximum and minimum torque can be determined based on at least one drag pointer logic of the evaluation device. The drag pointer logic can be configured to maintain the maximum and / or minimum torque values ​​during variations in the steering angle between a maximum hysteresis angle threshold and a minimum hysteresis angle threshold. If an even larger and / or smaller torque value is detected during a single specific cycle or iteration, the maximum and / or minimum torque values ​​maintained by the drag pointer logic are replaced with the updated maximum and / or minimum torque values. Essentially, the drag pointer logic is configured to determine extreme values ​​within the detected torque values ​​for each specific cycle. Therefore, a very convenient and efficient procedure for determining extreme values ​​is implemented, resulting in high operational efficiency.

[0025] The evaluation equipment can include separate drag pointer logic for both the maximum and minimum torque values. In other words, one drag pointer logic is assigned to determine the maximum torque value, and another different drag pointer logic is assigned to determine the minimum torque value.

[0026] In one example, an online least squares filter with limited field of view and outlier detection is applied to determine the average and standard deviation of multiple maximum and minimum torque values ​​for different iterations (or cycles) of the method. Therefore, the average can be determined efficiently in real time. For example, the online least squares filter could be an incremental online least squares filter based on a linear regression process. Outlier detection advantageously allows for continuously improving the accuracy of the friction-related precision of the fitted torque threshold. Therefore, based on a customized, fitted torque threshold, torques less than the steering wheel assembly friction caused by driver input can be more appropriately rejected.

[0027] According to one aspect, once the online least squares filter has processed the mean and standard deviation for a predetermined number of iterations of the method, the evaluation device can apply only outlier detection to the online least squares filter. The predetermined number of iterations of the method can be selected such that initial convergence of outlier detection is guaranteed before any outliers are removed. Therefore, inappropriate outlier removal can be prevented.

[0028] If the time interval between different operating cycles of the steering wheel assembly is less than a predetermined time threshold, the evaluation device can apply outlier detection using an online least-squares filter immediately after the steering wheel assembly is started. The predetermined time threshold can be selected such that the steering wheel assembly or its components are unlikely to have been modified, maintained, or replaced during the intermediate time interval between subsequent operating cycles. Here, the term "operating cycle" does not refer to the cycle of this method, but rather to the cycle of use of the steering wheel assembly. In simpler terms, different operating cycles occur after the vehicle has stopped, been deactivated, and restarted (also known as an ignition cycle). Since the steering wheel assembly (presumably) has not been modified if this time interval is less than the predetermined time threshold, outlier detection can be applied immediately without considering influencing factors. In this case, for example, a previously determined difference can be used for outlier detection (explained in more detail later).

[0029] In some examples, the evaluation device can determine the maximum and minimum hysteresis thresholds by taking into account the hysteresis angle. The hysteresis angle is determined by dividing a predetermined friction value of the upstream portion of the steering wheel assembly by the stiffness of the upstream portion of the steering wheel assembly.

[0030] The upstream portion of the steering wheel assembly may include at least one of the following: steering gear, steering column, instrument panel seal, upper I-shaft, lower I-shaft, shaft bearing, shaft seal, and disc spring. Essentially, the upper portion of the steering wheel assembly can be considered to involve all components affecting the torque sensed by the steering torque sensor. For the upstream portion of the steering wheel assembly, a predetermined friction value can be obtained based on calibration measurements during the manufacturing process. For example, the predetermined friction value for the upstream portion could be 0.7 Nm. In this respect, the stiffness of the upstream portion of the steering wheel assembly could, exemplarily, be 0.6 Nm / degree. Therefore, the hysteresis angle can be determined as 1.17 degrees. The hysteresis angle precisely specifies how much movement of the steering column needs to be monitored in order to reliably determine the maximum and minimum (friction-related) torque values.

[0031] According to one aspect, if the detected steering torque of the steering column exceeds at least one predefined torque threshold of the upstream portion of the steering wheel assembly, a loop of the method can be canceled. In this case, it can be inferred that the driver is influencing the method by applying torque to the steering wheel. Therefore, this loop of the method will result in an incorrect value. Therefore, canceling this loop of the method makes the result of the method unaffected by the external torque applied by the driver.

[0032] Optionally, one cycle of this method can only be initiated when the steering wheel assembly is operated according to autonomous or semi-autonomous driving modes. Thus, the steering wheel assembly is operated without driver input. Specifically, when the steering wheel assembly is operated according to autonomous or semi-autonomous driving modes, the friction-related characteristics of the steering wheel assembly can be determined, which is at least more complex, if not impossible, if the driver applies additional torque.

[0033] Steering torque detection is initiated only when the detected steering torque of the steering column, measured by the steering torque sensor, is less than a predetermined trigger threshold—for example, when the measured steering torque is zero. Therefore, a defined reference point is established at the start of one cycle of this method. This ensures that the steering torque is between the maximum and minimum torque values ​​to be determined during the cycle of this method. Thus, situations where the steering wheel assembly's initial characteristics prevent the attainment of one of these extreme torque values ​​can be prevented.

[0034] According to some examples, the method may also include the following steps: h) The HOOD sensor is operated based on an adapted torque threshold such that if the torque of the steering column is detected to exceed the adapted torque threshold, it is determined that there is hand-to-steering wheel contact.

[0035] Because the adapted target threshold is tailored to the specific steering wheel assembly and its contextual attributes, it more appropriately reflects the boundary between internal friction within the steering wheel assembly and the configuration of torque applied to the steering wheel assembly by external factors (such as the driver). Therefore, with the adapted torque threshold, the false detection rate of misinterpreting a lack of contact between the driver's hands and the steering wheel can be reduced. Consequently, the rate of false notifications to the driver is reduced, thereby improving driver comfort.

[0036] Optionally, upon startup of the steering wheel assembly, the evaluation device uses the average and standard deviation determined by the method during the most recent use of the steering wheel assembly as initial values ​​in step f) of the method, until multiple maximum torque values ​​and multiple minimum torque values ​​are determined according to step e) of the method. This ensures rapid convergence of the method. By using the previously determined differences, outlier detection is also appropriate if the steering wheel assembly has not been modified during this period. Therefore, inappropriate values ​​can be immediately excluded.

[0037] According to another aspect, this disclosure also relates to a data processing apparatus comprising means for performing the methods described above. The advantages achieved by the methods described above are also realized by this data processing apparatus.

[0038] According to another aspect, this disclosure also relates to a computer program product including instructions that, when executed by a computer, cause the computer to perform the methods described above. The advantages achieved by the methods described above are also realized accordingly through this computer program product.

[0039] According to another aspect, this disclosure also relates to a computer-readable storage medium including instructions that, when executed by a computer, cause the computer to perform the methods described above. The advantages achieved by the methods described above are also realized accordingly through this computer-readable storage medium.

[0040] According to another aspect, a HOOD sensor for a steering wheel assembly is provided. The steering wheel assembly includes at least a steering column, a steering wheel coupled to the steering column, a steering torque sensor, a steering wheel angle sensor, and an evaluation device. The steering torque sensor and the steering wheel angle sensor are coupled to at least the steering column. The evaluation device is coupled to at least the steering torque sensor and the steering wheel angle sensor. The steering wheel angle sensor is configured to detect the steering angle of the steering column. The steering torque sensor is configured to detect the steering torque of the steering column until the detected steering angle reaches both a maximum hysteresis angle threshold and a minimum hysteresis angle threshold. The evaluation device is configured to: - The maximum and minimum hysteresis angle thresholds are determined based on the initial steering angle. The initial steering angle corresponds to the steering angle detected during the control interval when the evaluation device is started.

[0041] - Based on the detected steering torque, determine the maximum and minimum torque values ​​of the steering column for each control interval.

[0042] - Determine the average value and standard deviation for multiple maximum torque values ​​and multiple minimum torque values ​​for different control intervals.

[0043] - By adding the determined average value to n times the determined standard deviation, an appropriate torque threshold is determined for the hand off / hand on detection sensor, where n is a non-zero natural number.

[0044] The advantages achieved by the method described in this paper are also realized in a corresponding manner by the HOOD sensor of the steering wheel assembly. In particular, a customized, adapted torque threshold is implemented, which more appropriately reflects the contextual attributes of a particular steering wheel assembly.

[0045] In some examples, the steering wheel assembly can be part of a steer-by-wire system. However, in other examples, other types of steering systems, such as electric power steering, can be applied.

[0046] According to another aspect, a vehicle is provided. This vehicle includes a steering wheel assembly having the HOOD sensor described above. The advantages achieved by the HOOD sensor in the steering wheel assembly are also achieved by the vehicle in a corresponding manner. Attached Figure Description

[0047] The foregoing aspects and further advantages of the claimed subject matter will be better understood with reference to the following detailed description taken in conjunction with the accompanying drawings. In the drawings: Figure 1 A schematic diagram of an exemplary vehicle with a hand off / hand on sensor for the steering wheel assembly; Figure 2 An exemplary method for operating the steering wheel assembly by removing / holding the sensor is shown; Figure 3 This is a schematic diagram of the steering torque hysteresis detected during the process of this method. Detailed Implementation

[0048] All features disclosed below with respect to exemplary embodiments and / or the accompanying drawings may be combined individually or in any sub-combination with features of various aspects of this disclosure (including features of preferred embodiments thereof), provided that the resulting combination of features is reasonable to those skilled in the art.

[0049] Figure 1 A schematic diagram of an exemplary vehicle 10 having a steering wheel assembly 14 and a hand off / hand on sensor 12.

[0050] The steering wheel assembly 14 is part of the steering system 16, which in this example is configured as a steer-by-wire system 18 (hereinafter referred to as the SBW system). However, the steering wheel assembly 14 is not limited to a steering system 16 with this topology. Other topologies can also be implemented for the steering system 16.

[0051] In this example, the SBW system 18 includes a road wheel actuator 20 (hereinafter referred to as RWA). The SBW system 18 also includes a feedback actuator 22 (hereinafter referred to as FBA). Furthermore, the SBW system 18 includes an evaluation device 24, which in this example includes a HOOD sensor 12. The evaluation device 24 is coupled to the RWA 20 and the FBA 22. Additionally, in this example, the evaluation device 24 is part of the control device 26 of the SBW system 18. Alternatively, the evaluation device 24 may also be part of the steering wheel assembly 14 and separate from the RWA 20.

[0052] The evaluation device 24 includes a complex evaluation topology, such as drag-point logic and an online least-squares filter with limited field of view and outlier detection. The drag-point logic is suitable for identifying extreme values ​​in the received measurement data. The online least-squares filter with limited field of view and outlier detection is suitable for efficiently determining the mean and standard deviation of the received set of measurements.

[0053] RWA 20 and FBA 22 are connected to each other and to control device 26.

[0054] In this example, RWA 20 is indirectly connected to the steerable road wheel 28 of vehicle 10. Therefore, according to this example, RWA 20 has an electric motor connected to rack 30. RWA 20 can use this electric motor to output torque to change the position of rack 30 along the rack path.

[0055] The rack 30 is connected to the steerable road wheels 28 of the vehicle 10. Displacement of the rack 30 relative to a reference position (e.g., a neutral position) causes a change in the orientation of the steerable road wheels 28 about their respective steering axes.

[0056] The operation of the steerable wheel 28 is controlled by the wheel angle sensed by a wheel angle sensor 32 assigned to at least one steerable wheel. The wheel angle sensor 32 is coupled to the control device 26. Alternatively, the wheel angle sensor 32 may sense the position of the rack 30 or at least the angle of the pinion gear indirectly coupled to the RWA 20 and transmit it to the control device 26.

[0057] The SBW system 18 also has a steering wheel 34. The steering wheel 34 is connected to the steering column 36, and the FBA 22 is also connected to the steering column 36 at least indirectly. The FBA 22 is configured to apply torque to the steering column 36, which, in the absence of other torque, in turn causes the steering wheel 34 to rotate.

[0058] In this way, the driver of vehicle 10 is given a sense of lateral guidance of vehicle 10.

[0059] The driver of vehicle 10 can typically execute steering commands for vehicle 10 via steering wheel 34.

[0060] The SBW system 18 also includes at least one steering wheel angle sensor 38, which is configured to detect the steering wheel angle, i.e., the steering wheel position, of the steering wheel 34 via the steering column 36. This means that the steering wheel angle sensor 38 is at least indirectly connected to the steering column 36 and is also configured to transmit the detected steering angle to the evaluation device 24.

[0061] Furthermore, the SBW system 18 includes at least one steering torque sensor 40. In this case, the steering torque sensor 40 is also coupled to the steering column 36. The steering torque sensor 40 is configured to detect torque with respect to the steering column 36 and transmit the detected torque to the evaluation device 24.

[0062] If the driver grips the steering wheel 34 and applies torque, the torque sensed by the steering torque sensor 40 can be at least partially caused by the driver's input. Furthermore, the torque detected by the steering torque sensor 40 can be at least partially caused by friction generated between the structural connections between the internal components of the steering wheel assembly 14. Specifically, the steering wheel assembly 14 includes a so-called upstream portion 42, the components of which may generate friction that can be detected by the steering torque sensor 40.

[0063] According to this example, the upstream portion 42 of the steering wheel assembly 14 includes at least one of a steering gear, a steering column, an instrument panel seal, an upper I-shaft, a lower I-shaft, a shaft bearing, a shaft seal, and a disc spring. Additionally, the upstream portion 42 may include additional components.

[0064] FBA 22 also includes an electric motor. With the help of the electric motor, FBA 22 can apply torque to steering column 36, thereby affecting steering wheel angle and / or steering wheel speed, for example based on control signals from control device 26.

[0065] The current steering configuration (including the current steering wheel angle) typically corresponds to a specific target angle for the current road wheels, and the steerable road wheels 28 should be aligned according to this target angle. Since the road wheels 28 are at least indirectly connected to the rack 30, the steering command is equivalent to a specific steering rack position of the rack 30. In other words, the steering wheel angle corresponds to the position to which the rack 30 must be moved to achieve the desired orientation of the road wheels 28.

[0066] The driver can dynamically change the current steering command by changing the steering wheel position, thereby dynamically changing the wheel angle. Furthermore, based on the orientation of the steerable wheel 28, or based on the rack position of the rack 30, or based on the angle / position of the pinion gear connected to the RWA 20, the control device 26 determines the feedback torque to be applied to the steering column 36 by the FBA 22. Based on the feedback torque, the driver should be given a sense of lateral control of the vehicle 10.

[0067] According to this example, vehicle 10 includes a driving control device 44. The driving control device 44 is configured to perform autonomous or semi-autonomous driving modes, such as according to a higher ADAS level. For example, the driving control device 44 can autonomously influence the lateral control of vehicle 10 in this manner. To this end, the driving control device 44 can, for example, set default values ​​for steering wheel angle, steering wheel travel, or corresponding parameters, which are then set accordingly by the control device 26 and / or FBA 22 of the SBW system 18. The subsequently set steering wheel angle is detected by the steering wheel angle sensor 38 and transmitted to the evaluation device 24 and / or control device 26 and / or RWA 20, or directly from the driving control device 44 to the control device 26 and / or RWA 20. The driving control device 44 can also receive measurement data from various sensors, such as the wheel angle sensor 32, the steering wheel angle sensor 38, the HOOD sensor 12, and / or optional environmental sensors for detecting the environment surrounding vehicle 10 to adapt to the autonomous or semi-autonomous driving mode.

[0068] Here, the SBW system 18 is shown as front axle steering. The vehicle 10 and the SBW system 18 may also optionally have other steerable road wheels 28, such as rear wheels, which are coupled to an additional public or separate RWA 20.

[0069] Figure 2 This is a schematic diagram of a method for operating the HOOD sensor 12 of a steering wheel assembly 34 according to an example. Optional steps are shown in dashed lines.

[0070] In step S2, the steering angle of the steering column 36 is detected using the steering wheel angle sensor 38. The detected value is transmitted to the evaluation device 24.

[0071] Step S4 is performed simultaneously with step S2. In step S2, the steering torque of the steering column 36 is detected using the steering torque sensor 40. The detected steering torque value is transmitted to the evaluation device 24.

[0072] Once the steering system 16 is activated, the steering angle and steering torque are typically always monitored.

[0073] In optional step S6, a loop of the method can be started, which, according to this example, depends on specific conditions.

[0074] Optional step S6 can be modified by optional step S8. In optional step S8, it is evaluated whether the steering wheel assembly 14 is operated according to an autonomous or semi-autonomous driving mode. For this purpose, the evaluation device 24 can communicate with the driving control device 44. If the driving control device 44 is responsible for steering the vehicle 10, the steering wheel assembly 14 is operated according to the desired driving mode. In autonomous or semi-autonomous driving mode, there is no driver input, so the driver does not apply torque to the steering wheel 34. In this case, the friction-related characteristics of the steering wheel assembly 14 can be evaluated to determine the appropriate torque threshold.

[0075] Optional step S6 can also be modified by optional step S10. In optional step S10, the evaluation device 24 evaluates whether the torque sensed by the steering torque sensor 40 is less than a predetermined activation threshold. Furthermore, it can evaluate whether the detected steering torque is essentially zero, i.e., whether it is small enough to be negligible. This condition ensures that the detected torque with respect to the steering column 36 can be used as a reference for subsequent steps of the method.

[0076] After one cycle of the method is started, the method includes step S12, in which the evaluation device 24 determines a maximum hysteresis angle threshold and a minimum hysteresis angle threshold based on an initial steering angle. The initial steering angle corresponds to the steering angle detected at the start of one cycle of the method. This means that the initial steering angle detected by the steering angle sensor 38 is used as a reference for determining the minimum hysteresis angle threshold and the maximum hysteresis angle threshold.

[0077] Step S12 can be modified by an optional step S14. In this case, the evaluation device 24 considers the hysteresis angle to determine the maximum / minimum hysteresis angle threshold. Therefore, if the initial steering angle is denoted as α_initial, the maximum / minimum hysteresis angle threshold α_hys_max / α_hys_min can be determined by the evaluation device 24 as: α_hys_max / α_hys_min = α_initial ± α_hys. The hysteresis angle α_hys is determined by the evaluation device 24 by dividing a predetermined friction value of the upstream portion 42 of the steering wheel assembly 14 by the stiffness of the upstream portion 42 of the steering wheel assembly 14. Both the predetermined friction value and the stiffness of the upstream portion 42 can be determined during the manufacturing process and / or the design phase. Thus, a threshold is obtained that specifies how much the steering column 36 needs to be rotated to determine the frictional characteristics of the upstream portion 42 of the steering wheel assembly 14.

[0078] In a subsequent step S16 of the method, the evaluation device 24 determines the maximum and minimum torque values ​​of the steering column 36 for a specific cycle of the method. For this purpose, the steering torque applied to the steering column 36 is detected by the steering torque sensor 40 until the detected steering angle (measured by the steering wheel angle sensor 38) reaches both the maximum and minimum hysteresis angle thresholds. In this respect, according to this example, the drag pointer logic of the evaluation device 24 is applied to evaluate the value of the detected steering torque received for that corresponding cycle. The drag pointer logic identifies the maximum and minimum torque values ​​within a group of detected steering torques for the method cycle.

[0079] Steps S2, S4, S12, and S16 are repeated at least multiple times to obtain a set of maximum and minimum torque values ​​for multiple different cycles. Optionally, each individual cycle may depend on specific starting conditions, as explained with reference to optional step S6.

[0080] Subsequently, in step S18 of the method, the evaluation device 24 determines the average and standard deviation for multiple maximum torque values ​​and multiple minimum torque values ​​for different cycles of the method. In this regard, the evaluation device 24 can apply an online least-squares filter with limited field of view and outlier detection. For outlier detection, the average and standard deviation can be reduced after outlier exclusion, enabling continuous improvement in the accuracy of friction-related precision.

[0081] Optionally, once the online least squares filter has processed the mean and standard deviation for a predetermined number of cycles for the method, the evaluation device 24 applies only outlier detection of the online least squares filter in step S18.

[0082] Step S18 can also be modified to: if the time interval between different operation cycles of the steering wheel assembly 14 is less than a predetermined time threshold, then the evaluation device 24 applies anomaly detection of the online least squares filter immediately after the steering wheel assembly 14 is started.

[0083] If the steering wheel assembly 14 has just been started, step S18 may further include: the evaluation device 24 using the average value and standard deviation determined by the method during the most recent use of the steering wheel assembly 14 as initial values ​​in step S18 of the method until a plurality of maximum torque values ​​50 and a plurality of minimum torque values ​​52 are determined according to repeated step S16 of the method.

[0084] In the next step S20, the evaluation device 24 determines the torque threshold for the adaptation of the HOOD sensor 12 by adding the determined average value to n times the determined standard deviation. n is a non-zero natural number.

[0085] Therefore, the torque threshold used for adapting the HOOD sensor 12 is no longer a constant value independent of the situational properties of the steering system 16. Instead, this method makes it possible to determine the situational torque threshold. Thus, the adapted torque threshold also appropriately takes into account operational effects such as wear or reduced smearing. Essentially, the adapted torque threshold is tailored to the current properties of the steering wheel assembly 14, allowing for a narrower tolerance range. In effect, the hand off / hand on detection of the HOOD sensor 12 is enhanced, becoming more adaptive and reliable.

[0086] The method may include an optional step S22, according to which, if the evaluation device 24 determines that the detected steering torque of the steering column 36 exceeds at least one predefined torque threshold of the upstream portion 42 of the steering wheel assembly 14, one cycle of the method is canceled. The predefined torque threshold is selected based on the characteristics of the upstream portion 42 of the steering wheel assembly 14. In this case, the evaluation device 24 considers that the driver of the vehicle 10 has applied torque to the steering wheel 34, thereby affecting the method.

[0087] Furthermore, the method may include an optional step S24, in which an appropriate torque threshold is applied to the HOOD sensor 12. Thus, if the detected torque of the steering column 36 exceeds the appropriate torque threshold, hand contact with the steering wheel 34 is determined. The appropriate torque threshold makes the detection by the HOOD sensor 12 more reliable and appropriate, taking into account the characteristics of the specific steering wheel assembly 14.

[0088] Figure 3 This is a schematic diagram of the steering torque hysteresis detected by performing this method.

[0089] Steering torque is plotted on the y-axis and steering angle on the x-axis. The steering torque of the steering column 36 must be monitored until the steering angle reaches both the maximum hysteresis angle threshold 46 and the minimum hysteresis angle threshold 48.

[0090] During the movement of the steering angle between the maximum hysteresis angle threshold 46 and the minimum hysteresis angle threshold 48, the maximum torque value 50 and the minimum torque value 52 are determined using the single or multiple drag pointer logic of the evaluation device 24 until the steering angle reaches both the maximum hysteresis angle threshold 46 and the minimum hysteresis angle threshold 48. This provides a suitable basis for determining the average and standard deviation of the multiple maximum torque values ​​50 and multiple minimum torque values ​​52. This, in turn, enables the accurate determination of the appropriate torque threshold.

[0091] The systems and methods described herein may be modified and / or omitted depending on the context, situation, and applicable laws, rules, and regulations. Furthermore, regardless of the actions a vehicle, such as a computer controlling the vehicle, may take, users should exercise good judgment and common sense when operating the vehicle. The operations described herein should always be performed and / or executed in accordance with the user manual and safety guidelines.

[0092] The computing devices discussed herein, including the ECM 110, include a processor and memory. Memory typically includes instructions executable by the processor of one or more computing devices, such as the instructions disclosed above, as well as instructions for performing the aforementioned processes or steps. Computer-executable instructions can be compiled or interpreted from computer programs created using various programming languages ​​and / or technologies, including but not limited to Java. TM Languages ​​such as C, C++, Visual Basic, JavaScript, Python, Perl, and HTML can be used individually or in combination. Typically, a processor (e.g., a microprocessor) receives instructions from, for example, memory, computer-readable media, and executes those instructions to cause one or more actions and / or processes to occur, including one or more processes described herein. Such instructions and other data can be stored and transferred using various computer-readable media. Files in ECM 110 are typically collections of data stored on computer-readable media (e.g., storage media, random access memory, etc.).

[0093] Computer-readable media include any medium that contributes to providing data (such as instructions) that can be read by a computer. Such media can take many forms, including but not limited to non-volatile media, volatile media, etc. Non-volatile media include, for example, optical discs or magnetic disks, and other persistent storage devices. Volatile media include dynamic random access memory, which typically constitutes main memory. Common forms of computer-readable media include, for example, floppy disks, flexible disks, hard disks, magnetic tape, any other magnetic media, CD-ROMs, DVDs, any other optical media, punched cards, paper tape, any other physical media with a perforated pattern (such as clay tablets), RAM, PROM, EPROM, FLASH EEPROM, any other memory chip or cartridge memory, or any other medium from which a computer can read.

[0094] Regarding the media, processes, systems, methods, etc., described herein, it should be understood that although the steps of these processes, etc., are described as occurring in a certain specific order, such processes can also be practiced by performing the described steps in a different order than that described herein. It should also be understood that some steps can be performed simultaneously, other steps can be added, or some steps described herein can be omitted. For example, in process 400, one or more steps can be omitted, or steps can be performed in a different order than those described herein. Figure 2 The steps are performed in the order shown. In other words, the description of the system and / or process herein is for illustrative purposes and should in no way be construed as limiting the subject matter disclosed.

[0095] "Based on" means at least partially based, unless otherwise explicitly stated. Therefore, if A is "based on" B, it means that A can be determined entirely based on B, or it can be determined based on B and one or more other factors. The article "one" modifying a noun should be understood to mean one or more, unless otherwise stated or required by the context.

[0096] Therefore, it should be understood that this disclosure (including the foregoing description, the accompanying drawings, and the following claims) is intended to be illustrative and not limiting. Many other embodiments and applications will be apparent to those skilled in the art upon reading the foregoing description, in addition to the examples provided. The scope of the invention should not be determined by reference to the foregoing description, but rather by reference to the full scope of the claims appended to and / or included in non-provisional patent applications and their equivalents. It is anticipated and envisioned that the field discussed herein will undergo future developments, and the disclosed systems and methods will be incorporated into such future embodiments. In conclusion, it should be understood that the disclosed subject matter is capable of modifications and variations.

Claims

1. A method comprising: a) The steering angle of the steering column is detected by the steering wheel angle sensor; b) Determine the maximum hysteresis angle threshold and the minimum hysteresis angle threshold based on the initial steering angle, wherein the initial steering angle corresponds to the initially detected steering angle; c) The steering torque of the steering column is detected by the steering torque sensor until the detected steering angle reaches both the maximum hysteresis angle threshold and the minimum hysteresis angle threshold; d) Determine the maximum and minimum torque values ​​of the steering column based on the detected steering torque; e) Repeat steps a) to d) to determine multiple maximum torque values ​​and multiple minimum torque values ​​for different cycles of the method; f) The evaluation equipment determines the average and standard deviation of the plurality of maximum torque values ​​and the plurality of minimum torque values ​​for different cycles of the method, respectively; and g) Determine the torque threshold for at least one adapter of the hand-off / hand-hold detection sensor by adding the determined average value to n times the determined standard deviation, where n is a non-zero natural number.

2. The method according to claim 1, wherein, The maximum torque and the minimum torque are determined based on the drag pointer logic.

3. The method according to claim 1, wherein, The average and standard deviation of the plurality of maximum torque values ​​and the plurality of minimum torque values ​​for different cycles of the method are determined by applying an online least squares filter with limited field of view and outlier detection.

4. The method according to claim 3, further comprising: After the online least squares filter has processed the average value and the standard deviation for a predetermined number of iterations, only the outlier detection of the online least squares filter is applied.

5. The method according to claim 3, further comprising: When the time interval between different operating cycles of the steering wheel assembly is less than a predetermined time threshold, the outlier detection of the online least squares filter is applied immediately after the steering wheel assembly is started.

6. The method according to claim 5, further comprising: The maximum hysteresis angle threshold and the minimum hysteresis angle threshold are determined by considering the hysteresis angle, wherein the hysteresis angle is determined by dividing a predetermined friction value of the upstream portion of the steering wheel assembly by the stiffness of the upstream portion of the steering wheel assembly.

7. The method according to claim 1, further comprising: The iteration of the method is canceled when the steering torque of the steering column is detected to exceed at least one predefined torque threshold of the upstream portion of the steering wheel assembly.

8. The method according to claim 1, further comprising: The steering torque is detected only when the steering torque of the steering column, as measured by the steering torque sensor, is less than a predetermined start-up threshold.

9. The method according to claim 8, further comprising: The hand off / hand on detection sensor is operated based on the adapted torque threshold, such that if the torque of the steering column is detected to exceed the adapted torque threshold, it is determined that there is contact between the hand and the steering wheel.

10. The method according to claim 9, wherein, When the steering wheel assembly is started, the evaluation device uses the average value and standard deviation determined by the method during the most recent use of the steering wheel assembly as the initial values ​​in step f) until multiple maximum torque values ​​and multiple minimum torque values ​​are determined according to step e).

11. A method for removing / holding an evaluation device, configured to execute program instructions, said instructions including instructions for performing the following operations: a) The steering angle of the steering column is detected by the steering wheel angle sensor; b) Determine the maximum lag angle threshold and the minimum lag angle threshold based on the initial steering angle, where, The initial steering angle corresponds to the initially detected steering angle; c) The steering torque of the steering column is detected by the steering torque sensor until the detected steering angle reaches both the maximum hysteresis angle threshold and the minimum hysteresis angle threshold; d) Determine the maximum and minimum torque values ​​of the steering column based on the detected steering torque; e) Repeat steps a) to d) to determine multiple maximum torque values ​​and multiple minimum torque values ​​for different cycles of the method; f) The evaluation device determines the average and standard deviation of the plurality of maximum torque values ​​and the plurality of minimum torque values ​​for different cycles of the method, respectively; as well as g) Determine the torque threshold for at least one adapter of the hand-off / hand-hold detection sensor by adding the determined average value to n times the determined standard deviation, where n is a non-zero natural number.

12. The device according to claim 11, wherein, The maximum torque and the minimum torque are determined based on the drag pointer logic.

13. The device according to claim 11, wherein, The average and standard deviation of the plurality of maximum torque values ​​and the plurality of minimum torque values ​​for different cycles of the method are determined by applying an online least squares filter with limited field of view and outlier detection.

14. The apparatus of claim 13, further comprising instructions for applying only the outlier detection of the online least squares filter after the online least squares filter has processed the average value and the standard deviation for a predetermined number of iterations.

15. The device of claim 13, further comprising instructions for applying the outlier detection of the online least squares filter immediately after the steering wheel assembly is started when the time interval between different operating cycles of the steering wheel assembly is less than a predetermined time threshold.

16. The device of claim 15, further comprising instructions for determining the maximum hysteresis angle threshold and the minimum hysteresis angle threshold by taking into account the hysteresis angle, wherein, The hysteresis angle is determined by dividing a predetermined friction value of the upstream portion of the steering wheel assembly by the stiffness of the upstream portion of the steering wheel assembly.

17. The device of claim 11, wherein the instructions further include instructions for canceling the iteration of the method when it is detected that the steering torque of the steering column exceeds at least one predefined torque threshold of the upstream portion of the steering wheel assembly.

18. The device of claim 11, wherein the instructions further include instructions for detecting the steering torque only when the determined steering torque of the steering column, as measured by the steering torque sensor, is less than a predetermined start-up threshold.

19. The device of claim 18, the instructions further comprising instructions for operating the hand off / hand on detection sensor based on the adapted torque threshold, such that if the torque of the steering column is detected to exceed the adapted torque threshold, then a hand-to-steering wheel contact is determined.

20. The device according to claim 19, wherein, When the steering wheel assembly is started, the evaluation device uses the average value and standard deviation determined by the method during the most recent use of the steering wheel assembly as the initial values ​​in step f) until multiple maximum torque values ​​and multiple minimum torque values ​​are determined according to step e).

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