Method for torque measurement

Abstract

Method for torque detection on an adjustable roll stabilizer (1) of a vehicle having two stabilizer sections (13, 14) and an actuator (15) by means of which the stabilizer sections (13, 14) can be rotated relative to one another, wherein a torque (M) acting between the two stabilizer sections (13, 14) is detected by means of a torque sensor (23) and a torque signal (Sm) characterizing this torque (M) is provided, a temperature of the torque sensor (23) is detected, one or more variables characterizing the driving dynamics of the vehicle are determined as driving dynamics parameters (29), at least one estimated value for the torque (M) acting between the two stabilizer sections (13, 14) is determined by means of a model for determining the torque based on the driving dynamics parameters (29), and the torque signal (Sm) is corrected based on the estimated value,if the temperature of the torque sensor (23) is above an upper temperature threshold.,

Description

[0001] The invention relates to a method for detecting torque on an adjustable roll stabilizer of a vehicle, which has two stabilizer sections and an actuator by means of which the stabilizer sections can be rotated relative to one another, wherein a torque acting between the two stabilizer sections is detected by means of a torque sensor and a torque signal characterizing this torque is provided.

[0002] If the temperature of the torque sensor lies within a standard temperature range, the torque signal provided by the torque sensor is considered, at least approximately, to be temperature-independent. However, if the temperature of the torque sensor exceeds an upper temperature threshold, which in particular forms the upper limit of the standard temperature range, the relationship between the torque and the torque signal changes. Inferring the torque from the torque signal to the torque, for example, by an assembly connected downstream of the torque sensor, can therefore be inaccurate if the changed relationship between the torque and the torque signal is unknown.

[0003] Based on this, the invention is based in particular on the object of being able to compensate for a temperature dependence of the torque signal at temperatures exceeding the standard temperature range.

[0004] This object is achieved according to the invention by a method according to claim 1. Preferred developments of the invention are given in the subclaims and in the following description.

[0005] A method for torque detection on an adjustable roll stabilizer of a vehicle, which has two stabilizer sections and an actuator by means of which the stabilizer sections can be rotated relative to one another, wherein a torque acting between the two stabilizer sections is detected by means of a torque sensor and a torque signal characterizing this torque is provided, is further developed according to the invention in particular in that a temperature of the torque sensor is detected, one or more variables characterizing the driving dynamics of the vehicle are determined as driving dynamics parameters, at least one estimated value for the torque acting between the two stabilizer sections is determined by means of a model for determining the torque on the basis of the driving dynamics parameters, and the torque signal is corrected on the basis of the estimated value,if the temperature of the torque sensor is above an upper temperature threshold.

[0006] If the temperature of the torque sensor is above the upper temperature threshold, the estimated value is considered to be more meaningful than the torque signal provided by the torque sensor, especially during a standard driving maneuver of the vehicle, so that the latter is corrected depending on the estimated value, for example depending on a difference between the torque signal and the estimated value.

[0007] The vehicle is preferably a motor vehicle, for example, a car. The meaning of "at least one" also includes, in particular, the meaning of "one" or "exactly one."

[0008] The vehicle is preferably assigned a transverse direction. The vehicle is preferably assigned a longitudinal direction x, which runs in particular transversely to the transverse direction. Advantageously, the vehicle is assigned a vertical direction z, which runs in particular transversely to the transverse direction and / or in particular transversely to the longitudinal direction.

[0009] The one or more variables characterizing the vehicle's driving dynamics are preferably one or more variables characterizing the vehicle's lateral dynamics. The term "driving dynamics parameter" can thus also be replaced, for example, by the term "lateral dynamics parameter."

[0010] Even if the term "driving dynamics parameters" is used in the plural, its meaning should preferably include the singular, so that, for example, the driving dynamics parameters refer to one or more driving dynamics parameters. The same preferably also applies to the term "lateral dynamics parameters."

[0011] The driving dynamics parameters are preferably determined during or during a journey of the vehicle. The driving dynamics parameters preferably comprise at least one acceleration of the vehicle and / or a steering angle of the vehicle and / or a steering wheel angle of the vehicle and / or a driving speed of the vehicle and / or an engine speed of the vehicle and / or a speed of at least one or more vehicle wheels of the vehicle and / or at least one or more wheel strokes of the vehicle and / or at least one other driving dynamics variable. The at least one acceleration of the vehicle is or comprises, for example, at least one lateral acceleration of the vehicle.

[0012] The driving dynamics parameters are preferably detected by at least one sensor, which preferably provides at least one driving dynamics parameter signal characterizing the driving dynamics parameters. The at least one sensor comprises, for example, at least one acceleration sensor and / or a steering angle sensor and / or a steering wheel angle sensor and / or a speed sensor and / or an engine speed sensor and / or at least one or more wheel speed sensors and / or at least one or more ride height sensors. The at least one acceleration sensor is or comprises, for example, at least one lateral acceleration sensor.

[0013] In particular, the torque signal is corrected by means of a correction unit based on the estimated value if the temperature of the torque sensor is above the upper temperature threshold. Preferably, the torque signal is corrected or corrected again based on the estimated value only if the temperature of the torque sensor is above the upper temperature threshold. For example, the torque signal is corrected or corrected again based on the estimated value, in particular only if the measured torque deviates from the estimated value.

[0014] The temperature of the torque sensor is preferably detected by a temperature sensor, which preferably provides a temperature signal characterizing the temperature of the torque sensor. The temperature sensor is provided, for example, on the torque sensor or in the vicinity of the torque sensor. Advantageously, the detection of the torque and the detection of the temperature are timed to one another in such a way that the detected temperature characterizes the temperature of the torque sensor during the detection of the torque.

[0015] The vehicle is preferably moving during torque detection. Preferably, the vehicle performs a, preferably previously known, standard driving maneuver, particularly during the or a journey. The execution of the or a standard driving maneuver is advantageously detected, preferably by evaluating the vehicle dynamics parameters and / or at least one other operating parameter of the vehicle, particularly using the model. The torque signal is preferably corrected, particularly only when a standard driving maneuver is detected.

[0016] The or a preferably previously known standard driving maneuver is, for example, one of several possible, preferably previously known, standard driving maneuvers. In particular, the standard driving maneuver is cornering. Cornering can be detected, for example, based on the steering angle or steering wheel angle and the driving speed. Additionally or alternatively, the lateral acceleration of the vehicle and / or the at least one other driving dynamics variable and / or the at least one other operating parameter of the vehicle can be taken into account to detect cornering. The or a standard driving maneuver is characterized in particular in that the torque acting between the two stabilizer sections is reproducible as a function of the driving dynamics parameters and / or the at least one other operating parameter of the vehicle. The model thus gains in reliability.

[0017] Preferably, the model is capable of learning, i.e., particularly amenable to machine learning. The model is preferably trained as a function of the torque signal and the driving dynamics parameters. This training occurs, in particular, only when the temperature of the torque sensor is within a standard temperature range and / or does not exceed the upper temperature threshold and / or is less than or equal to the upper temperature threshold.

[0018] The standard temperature range has, for example, an upper limit value, which preferably corresponds to the upper temperature threshold. Furthermore, the standard temperature range has, for example, a lower limit value, which preferably forms a lower temperature threshold. The upper temperature threshold is, for example, 60 °C. The lower temperature threshold is, for example, 0 °C. The standard temperature range preferably extends from 0 °C to 60 °C.

[0019] Preferably, the vehicle executes the, preferably previously known, standard driving maneuver, particularly during the journey. The execution of the, preferably previously known, standard driving maneuver is advantageously detected, preferably by evaluating the vehicle dynamics parameters and / or at least one or at least one other operating parameter of the vehicle, particularly by means of the model. The model is preferably trained, particularly only, when a standard driving maneuver is detected. The standard driving maneuver is, for example, cornering.

[0020] The model is, for example, a simulation. In particular, the model is a numerical model. Preferably, the model comprises a computer program or is formed thereby. Preferably, the model is or is provided and / or implemented by means of a computer, which is in particular a digital computer. For example, the model is used to calculate and / or determine by calculation the at least one estimated value for the torque acting between the two stabilizer sections on the basis of the driving dynamics parameters. Advantageously, the model is based on a model with which the lateral dynamics of the or a vehicle can be and / or is described. For example, the model is based on the single-track model. In particular, the model is suitably designed for determining the or a torque acting between the two stabilizer sections.

[0021] The torque signal is preferably corrected based on a deviation of the torque signal or a value obtained from the torque signal from the estimated value. A difference value is preferably formed from the torque signal or from a value obtained from the torque signal and the estimated value, in particular by subtraction, and the torque signal is corrected, for example, on the basis of this difference value. The value obtained from the torque signal is, for example, a value of the torque signal or an average value formed from several torque signals. The torque signal is preferably corrected by adding or subtracting the difference value, in particular to or from the torque signal. In this case, the influence of temperature causes, for example, merely a shift in the torque characteristic curve.

[0022] The stabilizer sections preferably comprise a first stabilizer section and a second stabilizer section. The first stabilizer section is preferably connected to a first chassis component and / or connected and / or coupled to a first vehicle wheel. Advantageously, the second stabilizer section is connected to a second chassis component and / or connected and / or coupled to a second vehicle wheel. The stabilizer sections, in particular the first stabilizer section and the second stabilizer section, are preferably rotatable relative to one another about a stabilizer rotation axis by means of the actuator.

[0023] The chassis components and / or the vehicle wheels are preferably arranged next to one another at a distance from one another in the or a transverse direction of the vehicle. The first chassis component is, for example, a first chassis link or a first wheel carrier. The second chassis component is, for example, a second chassis link or a second wheel carrier. The or a first wheel carrier is preferably articulated to a vehicle body of the vehicle by means of the or a first chassis link. The or a second wheel carrier is preferably articulated to the or a vehicle body of the vehicle by means of the or a second chassis link. The or a first vehicle wheel is preferably mounted on the first wheel carrier so as to be rotatable, in particular about a wheel axis of rotation. The or a second vehicle wheel is preferably mounted on the second wheel carrier so as to be rotatable, in particular about a wheel axis of rotation.

[0024] The stabilizer sections are preferably connected to one another, for example by the actuator. The actuator preferably has an actuator housing, which is particularly rigidly connected to the first stabilizer section or sections and / or formed by the latter. Advantageously, the actuator has an actuator shaft, which is particularly rigidly connected to the second stabilizer section or sections and / or formed by the latter. The actuator shaft is preferably mounted on or in the actuator housing so that it can rotate, particularly about the stabilizer rotation axis.

[0025] The torque sensor is preferably based on the measuring principle of inverse magnetostriction. The torque sensor preferably has a primary sensor, which in particular comprises a sleeve made of a magnetized and / or magnetizable material and / or of magnetic material. The torque sensor advantageously also has a secondary sensor, which in particular comprises one or more magnetic field sensors and / or electrical coils. The secondary sensor is preferably arranged in close spatial proximity to the primary sensor. Advantageously, the secondary sensor is arranged in the primary sensor and / or in the sleeve. For example, the primary sensor and / or the sleeve is formed, in particular at least in regions, by the actuator housing or an actuator housing. If a torque occurs in the primary sensor, its magnetization and / or magnetic behavior changes, which can be detected by the secondary sensor.

[0026] The actuator is preferably controlled by a control device, in particular as a function of the torque signal. The control device is preferably connected to the actuator and / or to the torque sensor. The control device particularly comprises the correction unit. Advantageously, the control device comprises the or a computer, which is particularly a digital computer.

[0027] The invention is described below using a preferred embodiment with reference to the drawing. In the drawing: Fig. 1 an adjustable roll stabilizer and two vehicle wheels arranged at a distance from one another in a transverse direction of the vehicle, which are coupled to one another by the roll stabilizer, Fig. 2 an actuator of the adjustable roll stabilizer with a torque sensor and a control device, Fig. 3 a corrupted and a corrected characteristic curve of the torque sensor and Fig. 4 a flowchart illustrating the method according to the invention according to an embodiment.

[0028] Fig. 1 shows a schematic view of an adjustable roll stabilizer 1 of a vehicle and two vehicle wheels 2 and 3 arranged at a distance from one another in a vehicle transverse direction y, each of which is mounted on a wheel carrier 4 and 5, respectively, so as to be rotatable about a wheel rotation axis. The vehicle wheel 2 is mounted on the wheel carrier 4 so as to be rotatable about the wheel rotation axis 6, and the vehicle wheel 3 is mounted on the wheel carrier 5 so as to be rotatable about the wheel rotation axis 7. Each wheel carrier is articulated by a chassis link, preferably designed as a wishbone, to a vehicle body 8 (indicated only schematically), on which the roll stabilizer 1 is preferably also mounted. The wheel carrier 4 is articulated to the vehicle body 8 by the chassis link 9, and the wheel carrier 5 is articulated by the chassis link 10. Each chassis link is part of a wheel suspension, by means of which the respective vehicle wheel is connected to the vehicle body 8.The vehicle wheel 2 is connected to the vehicle body 8 by the wheel suspension 11, and the vehicle wheel 3 is connected to the vehicle body 8 by the wheel suspension 12. Each wheel suspension preferably includes additional components, such as at least one vehicle spring and / or at least one damper and / or at least one tie rod and / or at least one additional suspension link and / or at least one other wheel suspension component. Furthermore, a vehicle longitudinal direction x and a vehicle vertical direction z are shown.

[0029] The roll stabilizer 1 has two stabilizer sections 13 and 14 and an actuator 15, by means of which the stabilizer sections 13 and 14 can be rotated relative to one another about a stabilizer rotation axis 16. The stabilizer section 13 is connected to the chassis link 9 via a coupling member 17, and the stabilizer section 14 is connected to the chassis link 10 via a coupling member 18. A torque M acting between the stabilizer sections 13 and 14 about the stabilizer rotation axis 16 is indicated by an arrow.

[0030] A more detailed view of the actuator 15 is shown in Fig. 2, according to which the actuator 15 comprises an actuator housing 19, which is connected in a rotationally rigid manner to the stabilizer section 13. Furthermore, the actuator 15 comprises an actuator shaft 20, which is rotatable relative to the actuator housing 19 about the stabilizer rotation axis 16 and which is connected in a rotationally rigid manner to the stabilizer section 14 or is formed by it. For example, the actuator 15 has a motor 21 and a gear 22 driven by the motor, the output shaft of which forms, in particular, the actuator shaft 20. The motor 21 is, for example, an electric motor or a hydraulic motor. The gear 22 is, for example, a planetary gear.

[0031] A torque sensor 23 is provided on the roll stabilizer 1, by means of which the torque M acting between the two stabilizer sections 13 and 14 can be detected and a torque signal Sm characterizing this torque M can be provided. The torque sensor 23 is based in particular on the measuring principle of inverse magnetostriction and comprises a primary sensor 24 formed at least partially by the actuator housing 19 and a sensor unit 25 serving as a secondary sensor, which is arranged within the actuator housing 19.

[0032] The roll stabilizer 1 further comprises a control device 26, by means of which the actuator 15 can be controlled as a function of the torque signal Sm. The roll stabilizer 1 also comprises a temperature sensor 27, by means of which the temperature of the torque sensor 23 can be detected and a temperature signal St characterizing this temperature can be provided. The torque signal Sm and the temperature signal St are fed to the control device 26, which comprises a digital computer 28. Furthermore, one or more variables characterizing the driving dynamics of the vehicle are fed to the control device 26 as driving dynamics parameters Sf, wherein the driving dynamics parameters Sf include, for example, a driving speed and / or a steering wheel angle and / or a lateral acceleration of the vehicle.

[0033] The computer 28 provides a model which is suitably designed for determining the torque, in particular one based on the single-track model, by means of which at least one estimated value Se for the torque M acting between the two stabilizer sections 13 and 14 is determined on the basis of the driving dynamics parameters Sf.

[0034] Based on a deviation of the torque signal Sm or a value obtained therefrom from the estimated value Se, a correction value So is formed and fed to the torque sensor 23 as an offset if the temperature T of the torque sensor 23 is above a, in particular predetermined, upper temperature threshold value Tmax. The offset So is subtracted, for example, from a sensor-internal torque signal, so that the torque signal Sm results from a difference between the or a sensor-internal torque signal and the offset So. Thus, for example, the torque signal Sm is corrected based on the correction value So. Alternatively, the correction can also be carried out in the control device 26, for example if the torque sensor 23 does not have an input for taking an offset into account.

[0035] Out of Fig. 3 shows a coordinate system in which the ordinate represents the torque signal Sm and the abscissa represents a twist angle α between the stabilizer sections 13 and 14. A characteristic curve 29, which is corrupted due to an excessively high temperature of the torque sensor 23, is shifted relative to the origin of the coordinate system, so that the torque signal Sm delivers a value other than zero at a twist angle α of zero, which corresponds to a torque other than zero, even though no torque is actually acting. A characteristic curve 30, corrected using the correction value So, is shifted such that it passes through the zero point of the coordinate system, thus providing a correct torque signal Sm.

[0036] Out of Fig.4 shows a flow chart illustrating the method according to the invention in accordance with one embodiment. In a step 31, the correction value So is set equal to zero. Subsequently, in a step 32, a difference value Δ is set equal to zero. After that, in a step 33, a new correction value So is formed, namely from the sum of the current correction value So and the current difference value Δ. On the first run, the new correction value So is equal to zero, since both the current correction value and the current difference value Δ are equal to zero. Subsequently, in a step 34, the new correction value So is fed to the torque sensor 23 as an offset. As already mentioned above, the offset is subtracted in particular from a sensor-internal torque signal, so that the torque signal Sm results from the difference between the sensor-internal torque signal and the offset So.

[0037] In a step 35, the querying of measured values ​​from the torque sensor 23 and the temperature sensor 27 begins. For this purpose, in a step 36, the temperature T of the torque sensor 23 is measured using the temperature sensor 27, and a temperature signal St characterizing this temperature is provided. In a subsequent step 37, a check is made as to whether the temperature T is above the or a, in particular predetermined, upper temperature threshold value Tmax. If this is not the case, the process returns to step 31 and the correction value is set equal to zero or left at zero. If, on the other hand, the temperature T is above the upper temperature threshold value Tmax, a check is made in a subsequent step 38, for example using the control device 26 and / or the model, as to whether a standard driving maneuver is present, such as cornering. If this is not the case, the process returns to step 35.If, however, a standard driving maneuver is present, an estimated value Se for the torque acting between the two stabilizer sections 13 and 14 is determined in a step 39 using the torque determination model. For this purpose, the model uses variables characterizing the vehicle's driving dynamics, which are provided to the model as driving dynamics parameters Sf.

[0038] Now, in a step 40, the torque M acting between the two stabilizer sections 13 and 14 is detected by means of the torque sensor 23, and a torque signal Sm characterizing this torque M is provided. As already mentioned above, the offset So is taken into account.

[0039] In a subsequent step 41, the difference value Δ is calculated as the difference between the torque signal Sm and the estimated value Se, the latter being subtracted in particular from the torque signal Sm.

[0040] Next, in step 42, a check is made to determine whether the torque signal Sm differs from the estimated value Se. For this purpose, a check is made, in particular, to determine whether the magnitude of the difference value |Δ| is less than a threshold value ε. The threshold value ε is preferably greater than zero, but in particular, so small that the torque signal Sm and the estimated value Se can be considered equal. Alternatively, a check could also be made to determine whether the magnitude of the difference value |Δ| is equal to zero, although this can be numerically disadvantageous for floating-point numbers. If the magnitude of the difference value |Δ| is less than the threshold value ε, no correction is deemed necessary, and the system returns to step 32. If, on the other hand, the magnitude of the difference value |Δ| is greater than or equal to the threshold value ε, the system returns to step 33, and the correction value is corrected by the difference value, after which, in step 34, the new correction value So is supplied to the torque sensor 23 as a new offset. Reference symbol 1 roll stabilizer 2 vehicle wheel 3 vehicle wheel 4 wheel carriers 5 wheel carriers 6 Wheel rotation axis 7 Wheel rotation axis 8 Vehicle body 9 chassis links 10 chassis links 11 Wheel suspension 12 Wheel suspension 13 Stabilizer section 14 Stabilizer section 15 Actuator 16 Stabilizer rotation axis 17 coupling link 18 coupling link 19 Actuator housing 20 Actuator shaft 21 Actuator motor 22 Actuator gear 23 Torque sensor 24 Primary sensor 25 Sensor unit / secondary sensor 26 Control device 27 Temperature sensor 28 computers 29 falsified characteristic curve 30 corrected characteristic curve 31-42 procedural steps Δ difference value ε threshold M torque See estimated value Sf parameter(s) characterizing the driving dynamics of the vehicle Sm torque signal So correction value / offset St temperature signal T Temperature Tmax upper temperature threshold

Claims

[1] Method for torque detection on an adjustable roll stabilizer (1) of a vehicle, which has two stabilizer sections (13, 14) and an actuator (15) by means of which the stabilizer sections (13, 14) can be rotated relative to one another, wherein - a torque (M) acting between the two stabilizer sections (13, 14) is detected by means of a torque sensor (23) and a torque signal (Sm) characterizing this torque (M) is provided, characterized by , that - a temperature (T) of the torque sensor (23) is detected, - one or more variables characterising the driving dynamics of the vehicle are determined as driving dynamics parameters (Sf), - at least one estimated value (Se) for the torque (M) acting between the two stabilizer sections (13, 14) is determined by means of a model for determining the torque on the basis of the driving dynamics parameters (Sf), and - the torque signal (Sm) is corrected on the basis of the estimated value (Se) if the temperature (T) of the torque sensor (23) is above an upper temperature threshold value (Tmax). [2] Method according to claim 1, characterized by , that - the vehicle performs a standard driving maneuver, - the execution of the standard driving maneuver is detected by evaluating the driving dynamics parameters (Sf) and / or other operating parameters of the vehicle, - the torque signal (Sm) is corrected when a standard driving maneuver is detected. [3] Method according to claim 2, characterized by that the standard driving maneuver is cornering. [4] Method according to one of the preceding claims, characterized bythat the model is capable of learning and is trained as a function of the driving dynamics parameters (Sf) and the torque signal (Sm) when the temperature (T) of the torque sensor is within a standard temperature range whose upper limit is formed by the upper temperature threshold (Tmax). [5] Method according to claim 4, characterized by , that - the vehicle performs the or a standard driving maneuver, - the execution of the standard driving maneuver is detected by evaluating the driving dynamics parameters (Sf) and / or other operating parameters of the vehicle, - the model is only trained when a standard driving maneuver is recognized. [6] Method according to claim 5, characterized by that the standard driving maneuver is cornering. [7] Method according to one of the preceding claims, characterized by that the model is provided by means of a digital computer (28). [8] Method according to one of the preceding claims, characterized by , the model is based on the single-track model. [9] Method according to one of the preceding claims, characterized by that the driving dynamics parameters (Sf) are determined while the vehicle is driving. [10] Method according to one of the preceding claims, characterized by that the driving dynamics parameters (Sf) comprise a lateral acceleration of the vehicle and / or a steering angle of the vehicle and / or a steering wheel angle of the vehicle and / or a driving speed of the vehicle and / or at least one wheel stroke of the vehicle. [11] Method according to one of the preceding claims, characterized by that a difference value (Δ) is formed from the torque signal (Sm) and the estimated value (Se) and the torque signal (Sm) is corrected on the basis of this difference value (Δ).

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