EP1347901A1

EP1347901A1 - System and method for monitoring an automotive subsystem

Info

Publication number: EP1347901A1
Application number: EP01985794A
Authority: EP
Inventors: Werner Hess; Klaus Ries-Mueller
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2000-12-30
Filing date: 2001-12-21
Publication date: 2003-10-01
Also published as: DE10160051A1; KR20020081365A; US20030139855A1; WO2002053431A1; JP2004516982A

Abstract

The invention relates to a system for monitoring an automotive subsystem (42) by which the vehicle speed can be influenced. Said system comprises an assessment device (14) which, according to at least one operative parameter of the vehicle (36), detects an actual operational variable of the subsystem (42) and assesses the functionality of the subsystem (42) to be monitored according to the actual operational variable detected. The inventive system further comprises at least one wheel force sensor (10) associated with one wheel (12) of a motor vehicle (36) and detecting at least one wheel force component of the corresponding wheel (12) that is substantially effective between the ground and the wheel contact surface as the at least one operational parameter, and outputs a signal (Si, Sa) representing said wheel force component. The assessment device (14) detects the actual operation variable from the processing of the signal (Si, Sa) representing the wheel force component. The invention further relates to a corresponding monitoring method.

Description

System and method for monitoring a motor vehicle subsystem

The present invention relates to a system for monitoring a motor vehicle subsystem, by means of which the vehicle speed can be influenced, the system comprising an assessment device which determines an actual operating variable of the subsystem in accordance with at least one operating parameter of the vehicle and uses the ascertained actual Company size, the functionality of the subsystem to be monitored is assessed.

The present invention also relates to a method for monitoring a motor vehicle subsystem, by means of which the vehicle speed can be influenced, preferably for execution by a system according to the invention, the method comprising the following steps: detecting at least one operating parameter of the vehicle, determining an actual value - Operating size of the subsystem in accordance with the recorded operating parameter of the vehicle, and assessing the functionality of the subsystem based on the determined actual operating size. State of the art

It is known to monitor the correct functioning of the drive system of a motor vehicle during its operation. For this purpose, for example, in an engine control unit (for example ME7) the drive torque delivered by the engine is calculated from engine parameters (such as for example from the cylinder charge). Monitoring systems, such as the EGAS system, compare the engine torque thus calculated with the torque requested by the driver. If the monitoring system detects discrepancies between the engine torque actually delivered and the driver requesting it, a corresponding measure is taken as part of a safety concept, for example the throttle valve is closed.

A disadvantage of this monitoring system or monitoring method is that the engine torque output can often only be determined very inaccurately on the basis of the available engine parameters. As a result, the functionality of the drive system can only be assessed inadequately.

In connection with the sensors provided in this category, it is also known that various tire manufacturers are planning the future use of so-called intelligent tires. New sensors and evaluation circuits can be attached directly to the tire. The use of such tires allows additional functions, such as measuring the torque occurring on the tire transversely and longitudinally to the direction of travel, tire pressure or temperature. In this context, for example, tires can be provided in which magnetized surfaces or strips are incorporated into each tire, preferably with field lines running in the circumferential direction. For example, the magnetization always takes place in sections in the same direction, but with the opposite orientation, that is to say with alternating polarity. The magnetized stripes preferably run near the rim flange and near the mountain. The sensors therefore rotate at wheel speed. Corresponding transducers are preferably attached to the body at two or more points that are different in the direction of rotation and also have a different radial distance from the axis of rotation. As a result, an inner measurement signal and an outer measurement signal can be obtained. A rotation of the tire can then be recognized in the circumferential direction via the changing polarity of the measurement signal or the measurement signals. The wheel speed can be calculated, for example, from the rolling range and the change over time of the inner measurement signal and the outer measurement signal.

It has also already been proposed to arrange sensors in the wheel bearing, this arrangement being able to take place both in the rotating and in the static part of the wheel bearing. For example, the sensors can be implemented as micro sensors in the form of micro switch arrays. For example, forces and accelerations and the speed of a wheel are measured by the sensors arranged on the movable part of the wheel bearing. This data is stored electronically Basic patterns or compared with data from a similar or similar microsensor attached to the fixed part of the wheel bearing.

Advantages of the invention

The invention is based on the generic system in that it comprises at least one wheel force sensor device which is assigned to a wheel of the motor vehicle and which detects at least one wheel force component of the respective wheel acting essentially between the driving surface and the wheel contact area as the at least one operating parameter and one the wheel force component outputs signal, and in that the evaluation device determines the actual operating variable from the processing of the signal representing the wheel force component.

By determining a wheel force component, which essentially acts between the driving surface and the wheel contact area, as operating parameters, certain actual operating variables, which depend in particular on the respective subsystems of the motor vehicle, can be determined very precisely. It is therefore possible with the system according to the invention to monitor subsystems of the motor vehicle more precisely than before with regard to their correct function. The drive and braking systems are mainly considered as such subsystems.

The assessment device advantageously determines from the one detected by the wheel force sensor device at least one wheel force component a wheel torque acting on the respective wheel. With the help of the wheel torque, among other things, the functionality of the drive system and the brake system can be monitored with high accuracy and without great processing effort, since the performance of these subsystems has a direct effect on the torque exerted on the wheel.

The system according to the invention can advantageously be simplified in that the at least one detected wheel force component is already a wheel circumferential force and / or a wheel torque that decelerates or accelerates the respective wheel. As a result of this direct detection, the previously mentioned step of determining a wheel torque can be omitted.

For example, the use of a tire sensor device is conceivable for detecting the wheel force component that is important for determining the actual operating variable. Here the wheel sizes are recorded very close to where they actually occur, so that disturbing influences from downstream components are largely excluded.

Alternatively, however, a wheel bearing sensor device can also be used. This also enables an exact detection of the wheel sizes without further falsification by components present between the detection location and the place of action of the wheel sizes. Another advantage of the two sensors mentioned is that they also allow wheel speeds to be determined and thus taken into account enable the vehicle speed when determining the actual operating variable.

As already indicated, the monitoring of the drive system of the motor vehicle is of particular interest. This includes, for example, the motor and, if present, the devices that control or regulate the motor. An engine torque output by the engine is advantageously used as the actual operating variable, which can be determined particularly easily from a wheel force, in particular from a wheel circumferential force or the wheel torque.

The accuracy of the calculation of the actual engine torque from the detected wheel force component or from the detected wheel torque can be improved by the assessment device, when determining an actual engine torque as the actual operating variable, transmitting losses of at least one torque transmission device arranged in the torque transmission path from the engine to the wheel considered.

To determine the actual engine torque, predetermined characteristic curves can be stored in the system which indicate a corresponding actual engine torque as a function of a detected wheel force component or a detected wheel torque, possibly taking into account further vehicle parameters such as the speed. This type of theoretical determination of the current actual engine torque from the wheel force component or the wheel torque has the advantage that an actual engine torque can be determined very quickly. To take into account the vehicle speed, the system according to the invention can be expanded by a speed sensor.

If, on the other hand, value is placed on a calculation of the actual engine torque that is as accurate as possible, the system according to the invention can, according to an advantageous further development, comprise a further sensor device which detects the above-mentioned transmission losses on the at least one device. Such devices include clutch and gearbox (including transfer case).

The above-mentioned determination methods, i.e. characteristic curve or transmission loss sensor device, can also be used in combination in order to carry out a mutual plausibility check of the determined actual engine torques on the one hand and / or to enable an adaptive characteristic curve adaptation which generates characteristic curves in the course of the operating time changes that correlations between the detected wheel force component and the actual engine torque can be extracted more and more precisely from these.

Another subsystem that is of fundamental importance for the operation of a motor vehicle is the braking system. A braking torque exerted on the wheel by a brake interacting with this wheel can thus easily be determined from the detected wheel force component or the detected wheel torque. In this case, a detected wheel torque already serves as the actual operating variable. The functionality of a motor vehicle subsystem can be assessed in a particularly simple manner by the assessment device comparing the determined actual operating variable with a target operating variable. The accuracy of this assessment can be increased further in that the assessment device determines a target-actual deviation value from the comparison of the target and actual operating variable and compares this target-actual deviation value with a predetermined threshold value. This is because it is easier to define in advance a critical target / actual deviation value as a threshold value, which should be used to assess a malfunction of the system in question. In addition, a tolerance of deviation between the target and the actual operating variable can thereby be permitted.

For the most reliable monitoring possible, not only precise knowledge of the actual operating variable, but also precise knowledge of the target operating variable is of great importance. Therefore, according to an advantageous development, the system can furthermore have a driver intervention means sensor. The assessment device can then determine the target operating variable from an output signal of the driver intervention means sensor. Such a driver intervention means sensor can be, for example, a pedal travel sensor that detects a depression amount of an accelerator or brake pedal, or can be a steering angle sensor that detects a rotation of the steering wheel or the steering column. If monitoring of the subsystem of the motor vehicle by the system according to the invention reveals that the subsystem to be monitored is functioning incorrectly, then the driver can be informed of this by means of an optical and / or acoustic and / or haptic and / or other warning signal , To ensure the greatest possible traffic safety, however, it is advantageous that the assessment device outputs an actuating signal in accordance with the assessment result and that the system further comprises an actuating device that influences an operating state of the motor vehicle in accordance with the actuation signal.

Since such an influencing of the operating state of the motor vehicle usually represents braking and / or engine intervention, as can be carried out, for example, by ESP, anti-lock braking and ASR systems, the design effort for realizing the system according to the invention can be reduced if the Actuating device, and possibly also the assessment device, is assigned to a device for controlling and / or regulating the driving behavior of a motor vehicle, such as an ESP, anti-lock braking system and / or an ASR system. In this case, “to be assigned” should include the possibility that the actuating device and, if appropriate, the assessment device, is or are part of an ESP, ASR or anti-blocking system.

The advantages mentioned above can also be achieved by a system for fault detection in a motor vehicle with less At least one tire and / or one wheel are obtained in which a force sensor is attached to the tire and / or the wheel, in particular on the wheel bearing, and depending on the output signals of the force sensor, a wheel torque quantity representing the wheel torque is determined and this wheel torque quantity is also determined a torque variable derived from the engine output torque and / or with a brake variable representing the wheel braking torque is compared and the comparison result is used for fault detection.

The invention is based on the generic method in that a wheel force component acting at least between the driving surface and the wheel contact surface is recorded as the at least one operating parameter of at least one wheel of the motor vehicle. In this way, the advantages of the system according to the invention are implemented in the method. This method is therefore particularly suitable for use in one of the aforementioned embodiments of the system according to the invention. The advantages and special features of the corresponding system designs are also obtained in the embodiments of the method specified below. For a supplementary explanation of the method according to the invention, reference is therefore made to the description of the system according to the invention.

The method according to the invention can advantageously be further developed in that the assessment step comprises determining the wheel torque acting on the respective wheel on the basis of the at least one wheel force component detected by the wheel force sensor device. It is particularly advantageous if a wheel circumferential force and / or a wheel torque that retards or accelerates the respective wheel is detected directly in the detection step.

For reasons of a simple calculation, when monitoring a drive system, an engine torque output by the engine is preferably determined as the actual operating variable. To further increase the accuracy of the determination, transmission losses of at least one torque transmission device arranged in the torque transmission path from the engine to the wheel can be taken into account.

Furthermore, if the subsystem to be monitored is a brake system of the motor vehicle, a braking torque exerted by the brake on the wheel can be determined as an actual operating variable from the detected wheel force component with little computing effort.

A simple variant of an assessment of the functionality of the subsystem from an actual operating variable is the comparison of the determined actual operating variable with a target operating variable.

It is particularly advantageous if the comparison is independent of the respective actual and target operating variable values, so that the method advantageously determines a target / actual deviation value from processing the target and actual operating variables and includes a comparison of this target / actual deviation value with a predetermined threshold value.

In principle, the target operating variable can be predetermined by a predetermined value or a predetermined characteristic curve. In addition, an actuation of a driver intervention means, for example a pedal, can also be detected by the driver. The target operating variable can then be determined precisely from the detected actuation of the driver intervention means.

To increase traffic safety, the method can include a further step, namely influencing an operating state of the motor vehicle in accordance with the result of the assessment.

The operating state of the motor vehicle can be influenced in a particularly simple manner on the basis of the evaluation result if the influencing of an operating state of the motor vehicle is influenced by a device for controlling and / or regulating the driving behavior of a motor vehicle, such as an ESP or an anti-lock braking system. and / or an ASR system.

drawings

The invention is explained in more detail below with reference to the accompanying drawings. Show it:

Figure 1 is a block diagram of a system according to the invention;

FIG. 2 shows a flow diagram of a method according to the invention;

FIG. 3 shows part of a tire equipped with a tire sidewall sensor;

FIG. 4 shows exemplary signal profiles of the tire side wall sensor shown in FIG. 3;

FIG. 5 shows an alternative embodiment of a system according to the invention;

FIG. 6 shows a basic circuit diagram for assessing the functionality of the engine of the motor vehicle.

Description of the execution examples

Figure 1 shows a block diagram of a system according to the invention. A sensor device 10 is assigned to a wheel 12, the wheel 12 shown being shown as representative of the wheels of a vehicle. The sensor device 10 is connected to an assessment device 14 for processing signals from the sensor device 10. The evaluation device 14 comprises a storage device 15 for storing recorded values. The assessment device 14 is also connected to an actuator 16. This actuating device 16 is in turn assigned to the wheel 12.

In the example shown here, the sensor device 10 detects the wheel contact force of the wheel 12. Likewise, the sensor device 10 could detect the wheel side force of the wheel 12. The resulting detection results are transmitted to the assessment device 14 for further processing. For example, the wheel contact force is determined in the assessment device 14 from a detected deformation of the tire. This can be done by using a characteristic curve stored in the storage unit 15. In the assessment device 14, a drive torque of the motor or a braking torque of a brake can then be determined from the wheel contact force. This signal can be transmitted to the actuating device 16 so that, depending on the signal, the operating state of the vehicle, in particular the wheel 12, can be influenced. Such an influence can take place via a motor intervention and / or a brake intervention. According to one aspect of the invention, the engine output can take place by adjusting the ignition timing and / or by changing the throttle valve position and / or by deliberate injection suppression.

FIG. 2 shows a flowchart of an embodiment of the method according to the invention within the scope of the present invention, an assessment of the functionality of the drive system of the motor vehicle being shown. First, the meaning of the individual steps is given: SOI: Detection of a deformation in the radial or circumferential direction of a tire.

S02: Determining a peripheral force of the tire on the driving surface from the detected deformation.

S03: Determining an actual engine torque as the actual operating variable of the engine from the determined circumferential force.

S04: detection of a position of the accelerator pedal of the vehicle. S05: Determination of a target engine torque from the detected accelerator pedal position.

S06: Compare the determined actual engine torque with the determined target engine torque.

S07: Assess the drive system as working correctly.

S08: Assess drive system as faulty.

The method sequence shown in FIG. 2 can be carried out in this or a similar manner in the case of a rear-wheel drive or a front-wheel drive vehicle. In step SOI, for example, a tire deformation in the radial or circumferential direction is measured.

A wheel circumferential force is determined from this deformation in step S02. This can be done by a characteristic curve stored in a storage unit, which indicates the relationship between the deformation in the radial or circumferential direction and the wheel circumferential force.

In step S03, the actual engine torque currently output by the engine is determined from the wheel circumferential force. For this purpose, the losses are advantageously taken into account. tigt that occur when the engine torque is transmitted from the engine to the driven wheels.

In step S04, the depression angle of the accelerator pedal is detected. In step S05, a target engine torque required by the driver is determined from the detected depression angle.

In step S06, the determined actual engine torque and the determined target engine torque are compared with one another. If the actual engine torque does not exceed the target engine torque, the drive system is judged to be working correctly in step S07. If, on the other hand, the actual engine torque exceeds the target engine torque, the drive system is assessed as faulty in step S08. If an error in the drive system is found in the assessment, the driver can be informed by a warning signal and the vehicle can be slowed down to a standstill for safety reasons. Furthermore, an analysis process can follow that searches for the source of the error in the drive system.

The brake system can be monitored analogously to the above method illustration.

FIG. 3 shows a section of a tire 32 mounted on the wheel 12 with a so-called tire / side wall sensor device 20, 22, 24, 26, 28, 30 when viewed in the direction of the axis of rotation D of the tire 32. The tire / side wail sensor device comprises two sensor devices 20, 22 which are fixed to the body at two different points in the direction of rotation are attached. Furthermore, the sensor devices 20, 22 each have different radial distances from the axis of rotation D of the wheel 32. In the example shown, the sensor device 20 is arranged closer to the axis of rotation of the wheel 12 than the sensor device 22. The side wall of the tire 32 is provided with a plurality of magnetized surfaces, which run essentially in the radial direction with respect to the wheel axis of rotation, as measuring sensors 24, 26, 28, 30 (Stripes) with field lines running preferably in the circumferential direction. The magnetized surfaces have alternating magnetic polarity.

FIG. 4 shows the courses of the signal Si of the sensor device 20 according to FIG. 3 arranged on the inside, ie closer to the axis of rotation of the wheel 12, and of the signal Sa of the sensor device 22 arranged outside, ie further away from the axis of rotation D of the wheel 12 according to FIG FIG. 3. A rotation of the tire 32 is recognized via the changing polarity of the measurement signals Si and Sa. The wheel speed can be calculated, for example, from the rolling range and the temporal change in the signals Si and Sa. Deformations of the tire 32 can be determined by means of phase shifts T between the signals and thus, for example, wheel forces can be recorded directly. In the context of the present invention, it is particularly advantageous if forces acting in the circumferential direction of the tire 32 or a wheel torque that decelerates or accelerates the wheel 12 can be determined. From this wheel torque, it is possible to deduce the currently acting engine or braking torque, which is a check or monitoring the correct drive or brake operation.

FIG. 5 shows an alternative embodiment of the system shown in FIG. 1. A vehicle 36 with wheels 12 includes a tire control unit 38. This tire control unit communicates with an engine management system 40 (for example ME7 or Cartronic) via an interface (for example CAN). An interface is again provided between this engine management system 40 and a unit 42, which for example represents the engine, transmission and brakes of the vehicle 36. A tire / side wall sensor device of FIG. 3 is arranged in or on the tires 32 of the wheels 12, which detects on each tire a force acting in the circumferential direction of the wheel 12 or a wheel torque accelerating or decelerating the wheel 12. There is also an interface between this tire / side wall sensor device and the tire control unit 38.

FIG. 6 shows a system circuit diagram for assessing an error reaction on the basis of a detected wheel torque. A desired engine torque determined via an accelerator pedal sensor is transmitted to a subtractor 52 via the signal path 50. The accelerator pedal sensor detects the angular position or the depressed position of the accelerator pedal by the driver, from which the target engine torque is determined. Coupling and transmission losses are transmitted to the subtractor 52 via the signal path 54. The subtractor 52 delivers as the output signal of the signal path 56 a desired engine torque reduced by clutch and transmission losses, which in this case is essentially a desired wheel torque equivalent. This target wheel torque is transmitted to a subtractor 58, which receives the wheel torque detected by the wheel force sensor device via signal path 60. The subtractor 58 forms a target-actual difference from the subtraction of the target wheel torque and the detected actual wheel torque and transmits this along a signal path 62 to a comparison circuit 64. The comparison circuit 64 receives a predetermined threshold value via the signal path 66, which it uses for evaluation compares the functionality of the drive system with the target-actual difference of the signal path 62. If the target-actual difference exceeds the predetermined threshold value, then the comparison circuit 64 outputs an error signal on the signal path 68; if the target-actual difference does not exceed the predetermined threshold value, the comparison circuit 64 does not output an error signal.

The brake system can be monitored similarly. Since, as a rule, no further transmission losses occur between the brake disc and the wheel or are negligible, the signal paths 50, 54 and the subtractor 52 are unnecessary. In this case, a target braking torque is transmitted as a target wheel torque to the subtractor 58 along the signal line 56. The subtractor 58 forms a target-actual difference from the target wheel torque and the actual wheel torque of the signal path 60 and outputs this via the signal path 62 to the comparison circuit 64, which compares it with a possibly different, predetermined threshold value of the signal path 66 , Again, the comparison circuit 64 outputs an error signal on the signal path 68 depending on the comparison result. It should be a matter of course for experts that instead of reducing the engine torque and comparing the target wheel torque and the actual wheel torque on the subtractor 58, the detected wheel torque of the signal path 60 is first increased at an adder by clutch and transmission losses and then as Actual engine torque can be compared with a target engine torque.

The preceding description of the exemplary embodiments according to the present invention is only for illustrative purposes and not for the purpose of restricting the invention. Various changes and modifications are possible within the scope of the invention without leaving the scope of the invention and its equivalents.

Claims

Expectations

1. System for monitoring a motor vehicle subsystem (42), by means of which the vehicle speed can be influenced, the system comprising an assessment device (14) which, according to at least one operating parameter of the vehicle (36), is an actual operating variable of the subsystem ( 42) is determined and the functionality of the subsystem (42) to be monitored is assessed on the basis of the determined actual operating variable,

characterized,

that it comprises at least one wheel force sensor device (10) which is assigned to a wheel (12) of the motor vehicle (36) and which detects at least one wheel force component of the respective wheel (12) which acts essentially between the driving surface and the wheel contact area as the at least one operating parameter outputs the signal representing the wheel force component (Si, Sa), and

that the assessment device (14) determines the actual operating variable from the processing of the signal (Si, Sa) representing the wheel force component.

2. System according to claim 1, characterized in that the evaluation device (14) uses the at least one wheel force component (10) detected by the wheel force sensor device to determine a wheel torque acting on the respective wheel (12).

3. System according to claim 1 or 2, characterized in that the at least one detected wheel force component is a wheel circumferential force and / or a wheel torque which retards or accelerates the respective wheel (12).

4. System according to any one of the preceding claims, characterized in that the wheel force sensor device (10) is a tire sensor device (20, 22, 24, 26, 28, 30).

5. System according to any one of the preceding claims, characterized in that the wheel force sensor device (10) is a wheel bearing sensor device.

6. System according to one of the preceding claims, characterized in that the subsystem to be monitored (42) is a drive system (42) of the motor vehicle (36) and the actual operating variable is an engine torque output by the engine.

7. System according to any one of the preceding claims, characterized in that the assessment device (14) takes into account transmission losses of at least one torque transmission device arranged in the torque transmission path from the engine to the wheel (12) when determining an actual engine torque as the actual operating variable.

8. System according to one of the preceding claims, characterized in that the subsystem to be monitored (42) is a braking system (42) of the motor vehicle (36) and the actual operating variable determined by the assessment device (14) is one from the brake to the wheel (12) braking torque is exerted.

9. System according to any one of the preceding claims, characterized in that the assessment device

(14) compares the determined actual farm size with a target farm size.

10. System according to any one of the preceding claims, characterized in that the assessment device

(14) a target-actual deviation value is determined from the comparison of the target and actual operating variable and compares this target-actual deviation value with a predetermined threshold value.

11. System according to any one of the preceding claims, characterized in that

that it still has a driver intervention sensor and

that the assessment device (14) determines the target operating variable from an output signal of the driver intervention means sensor.

12. System according to one of the preceding claims, characterized in that that the assessment device (14) outputs an actuating signal in accordance with the assessment result and

that the system further comprises an actuating device (16) which influences an operating state of the motor vehicle (36) in accordance with the actuating signal.

13. System according to any one of the preceding claims, characterized in that the actuating device (16), and optionally also the assessment device

(14), a device (40) for controlling and / or regulating the driving behavior of a motor vehicle, such as an ESP, an anti-lock braking system and / or an ASR system, is or are assigned.

14. System for fault detection in a motor vehicle with at least one tire (32) and / or a wheel

(12), a force sensor (20, 22, 24, 26, 28, 30) being attached in the tire (32) and / or on the wheel (12), in particular on the wheel bearing, and depending on the output signals (Si , Sa) of the force sensor (20, 22, 24, 26, 28, 30) a wheel torque quantity representing the wheel torque is determined and this wheel torque quantity

with a torque quantity derived from the engine output torque and / or is compared with a brake variable representing the wheel braking torque and the comparison result is used for error detection.

15. A method for monitoring a motor vehicle subsystem, by means of which the vehicle speed can be influenced, preferably for execution by a system according to one of claims 1 to 14, the method comprising the following steps:

Detection (SOI) of at least one operating parameter of the vehicle,

Determining (S03) an actual operating variable of the subsystem (42) in accordance with the recorded operating parameter of the vehicle (36), and

Assessing (S02, S07, S08) the functionality of the subsystem (42) on the basis of the determined actual operating variable,

characterized,

that at least one wheel (12) of the motor vehicle (36) detects a wheel force component acting essentially between the driving surface and the wheel contact area as the at least one operating parameter.

16. The method according to claim 15, characterized in that the assessment step (S02, S07, S08) a determination (S02) of the acting on the respective wheel (12) Comprises wheel torque on the basis of the at least one wheel force component detected by the wheel force sensor device (10).

17. The method according to claim 15 or 16, characterized in that in the detection step (SOI) a wheel circumferential force and / or a wheel torque retarding or accelerating the respective wheel (12) is detected.

18. The method according to any one of claims 15 to 17, characterized in that the subsystem to be monitored (42) is a drive system (42) of the motor vehicle (36) and an engine torque output by the engine is determined as the actual operating variable (S03).

19. The method according to any one of claims 15 to 18, characterized in that transmission losses of at least one torque transmission device arranged in the torque transmission path from the engine to the wheel (12) are taken into account when determining (S03) an actual engine torque as the actual operating variable.

20. The method according to any one of claims 15 to 19, characterized in that the subsystem to be monitored (42) is a braking system (42) of the motor vehicle (36) and as an actual operating variable one from the brake to the wheel (12) exerted braking torque is determined.

21. The method according to any one of claims 15 to 20, characterized in that it comprises a comparison (S06) of the determined actual operating variable with a target operating variable.

22. The method according to any one of claims 15 to 21, characterized in that it comprises a determination of a target-actual deviation value from a processing of the target and actual operating variable and a comparison of this target-actual deviation value with a predetermined threshold value.

23. The method according to any one of claims 15 to 22, characterized in that

that further actuation of a driver intervention means is detected by the driver (S04) and

that the target operating variable is determined from the detected actuation of the driver intervention means (S05).

24. The method according to any one of claims 15 to 23, characterized in that it further comprises the following step:

Influencing an operating state of the motor vehicle in accordance with the result of the assessment.

25. The method according to any one of claims 15 to 24, characterized in that influencing an operating state of the motor vehicle by a device (40) for controlling and / or regulating the driving behavior of a motor vehicle, such as an ESP, a Anti-lock and / or an ASR system is carried out.