System and method for calibrating an instrument kit for detecting the dynamic characteristics of a motor vehicle

Abstract

An instrument kit for detecting the dynamic characteristics of a motor vehicle in test on a road or on a test track comprises a dynamometer steering wheel (1), comprising a first sensor (20) and a second sensor (21), respectively for detecting the rotation angle of the dynamometer steering wheel (1), and the torque applied to the steering column, and an inertial measurement unit (3), for measuring the accelerations and angular speeds of rotation to which the motor vehicle is subjected as a result of the inputs provided by the driver via the steering wheel (1). An electronic control and processing unit (E) receives the output signals from the first sensor (20) and the second sensor (21) of the dynamometer steering wheel (1) and the inertial measurement unit (3) and processes these signals in such a way as to provide an assessment of the dynamic characteristics of the motor vehicle. Prior to performing the road or track test of the motor vehicle, a measurement of the delay times with which the first sensor (20), the second sensor (21) and the inertial measurement unit (3) provide an output signal is carried out using a calibration bench (4). The calibration bench (4) includes a first auxiliary sensor (7) and a second auxiliary sensor (9), whose signals are compared with those of the first auxiliary sensor (7), the second auxiliary sensor (9) and the inertial measurement unit (3), in such a way as to obtain data related to said delay times.

Description

[0001] “System and method for calibrating an instrument kit for detecting the dynamic characteristics of a motor vehicle”,

[0002] ****

[0003] TEXT OF THE DESCRIPTION

[0004] Field of the invention

[0005] This invention concerns a system and a method for calibrating an instrument kit that can be used for detecting the dynamic characteristics, in particular the handling characteristics, of a motor vehicle in tests on a road or on a test track.

[0006] The invention relates in particular to a system and a method for calibrating an instrument kit of the type comprising:

[0007] - a dynamometer steering wheel, configured to be attached to the steering column of the motor vehicle, in lieu of the steering wheel originally provided for the motor vehicle, and comprising:

[0008] - a first sensor configured to detect the rotation angle of the dynamometer steering wheel, and

[0009] - a second sensor configured to detect the torque applied to the steering column by the dynamometer steering wheel,

[0010] - an inertial measurement unit, configured to be mounted on the structure of the motor vehicle and to measure the accelerations in three orthogonal directions and / or the angular speeds of rotation about the three orthogonal axes, to which the motor vehicle is subjected as a result of the inputs provided by the driver via the steering wheel, and

[0011] - an electronic control and processing unit configured to be arranged in the motor vehicle and to receive output signals from the first sensor and the second sensor of the dynamometer steering wheel and the inertial measurement unit, and to process these signals in such a way as to provide an assessment of the handling characteristics of the motor vehicle.

[0012] Prior art

[0013] In known systems of the type indicated above, the sensors integrated in the dynamometer steering wheel and in the inertial measurement unit are usually characterized by their respective manufacturers by indicating the gain and passband. Often, however, manufacturers do not characterize (or do so in an imprecise way) the sensors from the point of view of the detection delay (i.e. the delay that occurs between the occurrence of a certain physical phenomenon and the corresponding change of the sensor output signal). Since said sensors are relatively complex components, with their own processing capacity, said delay times, although in the order of milliseconds, are not negligible

[0014] Since in the assessment of the dynamic qualities of the vehicle it is necessary to establish a correlation between the driver's action on the steering wheel of the vehicle and the dynamic behavior of the vehicle itself, the presence of any delays of a non-negligible entity and not precisely quantified in the signals provided by the sensors used can reduce the reliability of the results of the tests carried out on the vehicle, especially with reference to a situation in which multiple sensors send multiple signals to the electronic unit at the same time.

[0015] Object of the invention

[0016] The object of this invention is therefore to overcome said problem.

[0017] Summary of the invention

[0018] In order to achieve this aim, the invention has as its object a system for calibrating an instrument kit of the type indicated at the beginning of this disclosure, which is characterized in that it includes a calibration bench for carrying out, prior to performing the test on the motor vehicle, a measurement of the delay times with which said first sensor and said second sensor of the dynamometer steering wheel and said inertial measurement unit provide an output signal, with respect to the time in which a phenomenon generating said output signal occurred, said calibration bench including:

[0019] - a support structure, configured to rotatably support a steering column on which said dynamometer steering wheel, including said first sensor and said second sensor, is temporarily mounted prior to being installed on the motor vehicle, with said inertial measurement unit secured to a peripheral portion of the dynamometer steering wheel, so that the centrifugal acceleration of the dynamometer steering wheel can be detected in a test on said calibration bench, - a first sensor auxiliary sensor, separate from the dynamometer steering wheel, and configured to detect, directly or indirectly, the rotation angle, the angular speed of rotation and the centrifugal acceleration of the dynamometer steering wheel, with a delay time which is substantially zero or has a relatively small known value,

[0020] - a second auxiliary sensor, separate from the dynamometer steering wheel, and configured to detect, directly or indirectly, the torque applied to the dynamometer steering wheel, with a delay time which is substantially zero or has a relatively small known value,

[0021] - an electronic control and processing unit, which is the same electronic unit that is set up in the motor vehicle for the motor vehicle test, or which is a separate electronic unit, configured to receive the output signals from the first sensor and the second sensor of the dynamometer steering wheel, from the inertial measurement unit, as well as from the first auxiliary sensor and the second auxiliary sensor of the calibration bench,

[0022] - wherein the electronic control and processing unit of the calibration bench is configured for:

[0023] - receiving, during a calibration bench test, as a result of oscillations with increasing frequenze imparted to the dynamometer steering wheel on the calibration bench, the output signal from the first sensor and the second sensor of the dynamometer steering wheel and the inertial measurement unit mounted on the dynamometer steering wheel, as well as from the first auxiliary sensor and the second auxiliary sensor of the calibration bench, and for:

[0024] - processing the signals from the first sensor of the dynamometer steering wheel and the first auxiliary sensor to obtain data related to the delay time associated with the first sensor of the dynamometer steering wheel,

[0025] - processing the signals from the second sensor of the dynamometer steering wheel and the second auxiliary sensor to obtain data related to the delay time associated with the second sensor of the dynamometer steering wheel,

[0026] - processing the signals from the first sensor of the dynamometer steering wheel and the inertial measurement unit mounted on the dynamometer steering wheel to obtain data related to the delay time associated with the inertial measurement unit, so that the electronic control and processing unit that is set up in the motor vehicle to perform the road or track test of the motor vehicle can be programmed taking into account the delay times associated with the first sensor and second sensor of the dynamometer steering wheel and the inertial measurement unit, as detected in the calibration bench test.

[0027] In one embodiment, said first auxiliary sensor is a potentiometer associated with a telescopic arm operatively interposed between a peripheral part of the dynamometer steering wheel and a fixed support of the calibration bench. The potentiometer is configured for detecting the change in length of the telescopic arm and the data related to such change in length are processed to obtain the rotation angle and the rotation speed and the centrifugal acceleration of the dynamometer steering wheel.

[0028] Again in the case of an exemplary embodiment, the second auxiliary sensor is a load cell interposed along a tangential direction with respect to the dynamometer steering wheel, between a fixed support of the calibration bench and the free end of an auxiliary arm, rigidly connected to the steering column and projecting from it in a substantially radial direction, the load cell being configured to detect the tangential force applied to the cell by the free end of the auxiliary arm, following the application of a torque on the dynamometer steering wheel, so that the data related to said tangential force can be processed to obtain the torque applied to the dynamometer steering wheel.

[0029] In a preferred embodiment, during the calibration bench test, the electronic unit of the calibration bench is programmed to determine the delay times associated with the first sensor and the second sensor of the dynamometer steering wheel and the inertial measurement unit based on comparisons with the signals of the first auxiliary sensor and the second auxiliary sensor, by means of the cross-correlation technique, as described in detail hereinafter.

[0030] The invention also relates to the calibration method that can be implemented by means of the system described above.

[0031] Detailed description of the invention

[0032] Further features and advantages of the invention will be apparent from the following description with reference to the attached drawings, provided purely by way of non-limiting example, in which:

[0033] - figure 1 is a perspective view illustrating the interior of a motor vehicle during the execution of a test on a road or on a test track for detecting the dynamic characteristics of the vehicle, using a dynamometric steering wheel and an inertial measurement unit,

[0034] - figure 2 is a block diagram of the detection system set up on the motor vehicle for the execution of the test,

[0035] - figure 3 illustrates an example of the calibration bench forming part of the calibration system according to the invention, in a first phase of the calibration process,

[0036] - figure 4 is a further perspective view of the calibration bench in a second phase of the calibration process,

[0037] - figures 5, 6 are diagrams illustrating the way in which the data obtained in the calibration process are processed, in order to obtain information on the time of delay associated with the first sensor of the dynamometer steering wheel, configured to detect the rotation angle of the steering wheel, and

[0038] - figures 7, 8 are diagrams that illustrate how the data obtained in the calibration method are processed to determine the delay time associated with the torque sensor that is part of the dynamometer steering wheel.

[0039] With reference to figures 1 and 2, to perform a road test of a motor vehicle aimed at obtaining data related to the handling characteristics of the motor vehicle, it is provided the use a dynamometer steering wheel 1 , which is mounted on the steering column in lieu of the steering wheel originally provided on the motor vehicle and which includes a module 2, comprising a first sensor 20 (figure 2) capable of detecting the rotation angle of the steering wheel and a second sensor 21 capable of detecting the torque applied to the steering column by the steering wheel.

[0040] The devices identified with the trade names “FEL20” and “FEL30”, produced by the company RMS Dynamic Systems, are examples of known dynamometer steering wheels. Said sensors are typically arranged in the module 2, operatively interposed between the dynamometer steering wheel 1 and the steering column. Further details regarding the configuration and arrangement of the sensors form ing part of the dynamometer steering wheel are not indicated here, since they can be of any known type and do not fall, taken individually, within the scope of this invention.

[0041] With reference again to figures 1 , 2, the instrument kit arranged in the motor vehicle for performing the road or track test includes an electronic control and processing unit E, configured to receive the output signals from the sensors 20, 21 of the dynamometer steering wheel 1 , in particular from the first sensor 20 designed to detect the rotation angle and from the second sensor 21 designed to detect the torque. The unit E is also programmed to process these signals in such a way as to provide an assessment of the handling characteristics of the motor vehicle and / or any other characteristic of interest for the assessment of the performance of the motor vehicle.

[0042] An example of a test consists in making the motor vehicle proceed at a constant speed and imparting oscillations with increasing frequency to the dynamometer steering wheel 1 , rotating it alternately in opposite directions for a relatively small angle.

[0043] Still with reference to figures 1 , 2, during the execution of the test, the dynamic behavior of the vehicle is also detected with the use of an inertial measurement unit 3, which is anchored to the bearing structure of the motor vehicle and which is configured for measuring the accelerations in three orthogonal directions and / or the angular speed of rotation about the three orthogonal axes, to which the motor vehicle is subjected as a result of the inputs provided by the driver via the steering wheel 1 .

[0044] The devices identified with the trade name “MRM10”, produced by the company Gladiator Technologies, are examples of known inertial measurement units. Again, the construction details of the inertial measurement unit, or “IMU” (Inertial Measurement Unit), are not indicated, since they can be of any known type and also since they, taken individually, do not fall within the scope of this invention.

[0045] During the execution of the road or track test, the electronic unit E simultaneously receives the output signals from the sensors 20, 21 of the dynamometer steering wheel 1 and the inertial measurement unit 3. Both the sensors 20, 21 of the dynamometer steering wheel 1 and the inertial measurement unit 3 are characterized by a certain delay time, i.e. they provide the unit E with the signal indicating the change of a certain parameter with a delay time with respect to the occurrence of the change itself. The processing of the data output from the sensors, in order to obtain an assessment of the vehicle handling characteristics and any other characteristics of interest of the motor vehicle, cannot be carried out with precision due to the fact that said delay times are not known.

[0046] According to the invention, a calibration phase is therefore provided in order to determine the delay times associated with the different sensors. To this end, a calibration bench is set up to perform a calibration test of the instruments, preliminary to the execution of the vehicle test on the road or on the track.

[0047] Figure 3 shows an example of a calibration bench. The calibration bench, indicated as a whole with the reference number 4, includes a support structure 5, which rotatably supports a steering column (not visible in the drawing) on which the dynamometric steering wheel 1 is mounted, including the module 2 with the first sensor 20 for detecting the rotation angle of the steering wheel and the second sensor 21 for detecting the torque applied to the steering wheel. To perform the calibration test, the inertial measurement unit 3 is temporarily mounted on a peripheral portion of the dynamometer steering wheel 1 , in the example on a spoke 6 of the dynamometer steering wheel.

[0048] An electronic control and processing unit E1 is also set up on the calibration bench 4, which may be the same control and processing unit E that is then used on board the motor vehicle or may also be a separate and autonomous unit.

[0049] The calibration bench 4 is set up with auxiliary sensors capable of detecting the rotation angle of the dynamometer steering wheel and the torque applied to the steering wheel, in parallel with the detection performed by the sensors 20, 21 integrated into the module 2 of the dynamometer steering wheel 1 .

[0050] In the example illustrated in figure 3, a phase is provided in which the calibration bench 4 is equipped with a first auxiliary sensor comprising a potentiometer 70 associated with a telescopic arm 7 which is operatively interposed between a peripheral part of the dynamometric steering wheel 1 and a fixed support 8 of the calibration bench 4. In the example illustrated in figure 2, the telescopic arm 7 has a stem whose end is articulatedly connected to a spoke 6 of the dynamometric steering wheel 1 . Due to said arrangement, the changed in length of the telescopic arm 7 are directly related to the rotation angle of the steering wheel. The data related to the change in length of the telescopic arm 7 can therefore be processed by the electronic unit E1 to obtain the rotation angle of the dynamometric steering wheel 1 , as well as the rotation speed and centrifugal acceleration of the dynamometric steering wheel. Given the extremely simple configuration of the first auxiliary sensor (a simple potentiometer), this sensor is able to provide its output signal with a delay time that is essentially zero. In general, the first auxiliary sensor can also be of a type that presents a delay time, provided that this delay time is relatively small and is known.

[0051] The data related to the rotation angle of the steering wheel, detected by the auxiliary sensor 7, can then be compared with the data related to the rotation angle of the steering wheel detected by the first sensor 20 integrated in the module 2 of the dynamometer steering wheel 1 , which allows the delay time associated with the sensor 20 to be determined.

[0052] Similarly, the data related to the centrifugal acceleration of the steering wheel 1 determined by the electronic unit E1 on the basis of the detection carried out by the first auxiliary sensor 7 can be compared with the data provided by the inertial measurement unit 3, in order to determine the delay time associated with the inertial measurement unit 3.

[0053] Figure 4 illustrates the setup of the calibration bench 4 in a further phase of the calibration process, in which the telescopic arm 7 constituting the first auxiliary sensor has been removed, the inertial measurement unit 3 has been removed from the dynamometer steering wheel 1 , while a second auxiliary sensor 9 has been set up on the calibration bench, configured to detect the torque applied to the steering column via the steering wheel, in parallel with the detection carried out by sensor 21 of module 2 of the dynamometric steering wheel 1 .

[0054] In the example illustrated here, the second auxiliary sensor 9 consists of a load cell interposed along the tangential direction T (parallel to the plane of the bench 4) with respect to the dynamometric steering wheel 1 , between a fixed support 10 and the free end of an auxiliary arm 11 rigidly connected to the steering column and projecting from it in a substantially radial direction. As a result of the arrangement described above, the application of a torque to the steering column, via the dynamometric steering wheel 1 , determines the application on the load cell 9 of a force F, the value of which, multiplied by the distance between the direction T and the axis of the steering wheel, corresponds to the torque.

[0055] Therefore, during the calibration method, the torque applied to the steering column via the steering wheel 1 is measured in parallel by the torque sensor integrated in module 2 of the dynamometer steering wheel 1 and by the load cell 10, whose signal is received by the electronic unit E1.

[0056] Also in this case, the data related to the applied torque, obtained via the load cell 10, can be compared with the data related to the applied torque obtained via the torque sensor 21 integrated in module 2 of the dynamometer steering wheel 1. Since the load cell 9 has by its nature a delay time which is substantially zero, the comparison allows obtaining information on the delay time associated with the torque sensor 21 integrated in the dynamometer steering wheel 1 .

[0057] In the preferred embodiment, the comparisons between the output signals from sensors 20, 21 of the dynamometer steering wheel and the inertial measurement unit 3 and the signals from the auxiliary sensors 7 and 9 are processed by means of a cross-correlation technique. Essentially, this method involves superimposing the graphs of the functions detected by the two sensors and sliding one of the two graphs horizontally until it superimposes the other, thus determining the shift in the time required to obtain the superposition.

[0058] Figures 5, 6 illustrate this operation with reference to the detection of the rotation angle of the steering wheel.

[0059] During the calibration phase, continuous oscillations with increasing frequency are imparted to the steering wheel, rotating it by a relatively small angle in one direction and the other.

[0060] Figure 5 illustrates the diagrams of the change of the rotation angle of the steering wheel as a function of time, determined respectively by the sensor 20 integrated into the dynamometer steering wheel (diagram A) and by the first auxiliary sensor 7 set up on the calibration bench (diagram B).

[0061] Figure 6 shows a diagram of the product of the two signals A and B in Figure 5, as a function of the time shift assigned to signal A to superimpose it on signal B (i.e. to ensure that the two diagrams intersect the time axis at the same points). The value of this product becomes maximum when the cycles of the two signals perfectly superimpose each other. The delay time associated with sensor 20 integrated into the dynamometer steering wheel therefore corresponds to the maximum of the graph in Figure 6. In the example, this delay time is 2.3 milliseconds.

[0062] Figures 7, 8 are the corresponding graphs relating to the measurement of the torque applied to the steering column via the steering wheel. In Figure 7, diagram A indicates the change in torque detected by sensor 21 integrated into the dynamometer steering wheel, while diagram B indicates the change in torque detected by load cell 9.

[0063] Figure 8 illustrates the change of the product of the two signals A and B as the shift time varies. The maximum of the diagram corresponds to the delay time associated with sensor 21 (which in the example is equal to 10.4 milliseconds).

[0064] Thanks to the determination of the delay times associated with the sensors that are used for the road test of the motor vehicle, the processing unit E used in the road test can be programmed taking into account such delays in order to process said signals to obtain a reliable and precise assessment of the different characteristics of the motor vehicle that are to be assessed.

[0065] As is evident from the preceding description, the process systems according to the invention are characterized in that they are extremely simple and at the same time reliable.

[0066] Of course, notwithstanding the principle of the invention, the construction details and embodiments may vary widely with respect to what is described and illustrated purely by way of example, without thereby departing from the scope of this invention, as defined by the attached claims.

Claims

CLAIMS1. A system for calibrating an instrument kit that can be used for detecting the dynamic characteristics of a motor vehicle in tests on a road or on a test track, wherein said instrument kit comprises:- a dynamometer steering wheel (1 ), configured to be attached to the steering column of the motor vehicle, in lieu of the steering wheel originally provided for the motor vehicle, said dynamometer steering wheel (1 ) comprising:- a first sensor (20) configured to detect the rotation angle of the dynamometer steering wheel (1 ), and- a second sensor (21 ) configured to detect the torque applied to the steering column by the dynamometer steering wheel (1 ),- an inertial measurement unit (3), configured to be mounted on the structure of the motor vehicle and to measure the accelerations in three orthogonal directions and / or the angular speeds of rotation about the three orthogonal axes, to which the motor vehicle is subjected as a result of the inputs provided by the driver via the steering wheel (1 ),- an electronic control and processing unit (E) configured to be arranged in the motor vehicle and to receive output signals from the first sensor (20) and the second sensor (21 ) of the dynamometer steering wheel (1 ) and the inertial measurement unit (3) and to process these signals in such a way as to provide an assessment of the dynamic characteristics of the motor vehicle, said system being characterized in that it includes a calibration bench (4) for performing, prior to the performance of the road or track test of the motor vehicle, a measurement of the delay time with which said first sensor (20) and said second sensor (21 ) of the dynamometer steering wheel (1 ) and said inertial measurement unit (3) provide an output signal, with respect to the time in which a phenomenon generating said output signal has occurred, said calibration bench (4) including:- a support structure (5) configured to rotatably support a steering column on which said dynamometer steering wheel (1 ), including said firstsensor (20) and said second sensor (21 ), is temporarily mounted prior to being installed on the motor vehicle, with said inertial measurement unit (3) secured to a peripheral portion (6) of the dynamometer steering wheel (1 ), so that centrifugal acceleration of the dynamometer steering wheel can be detected in a test on said calibration bench (4),- a first auxiliary sensor (7), separate from the dynamometer steering wheel (1 ), and configured to detect, directly or indirectly, the rotation angle and centrifugal acceleration of the dynamometer steering wheel (1 ), with a delay time which is substantially zero or which has a relatively small known value,- a second auxiliary sensor (9), separate from the dynamometer steering wheel (1 ), and configured to detect, directly or indirectly, the torque applied to the dynamometer steering wheel (1 ) with a delay time which is substantially zero or which has a relatively small known value,- an electronic control and processing unit (E1 ), which is the same electronic unit (E) that is set up in the motor vehicle for the road or track test of the motor vehicle, or which is a separate electronic unit, configured to receive the output signals from the first sensor (20) and the second sensor (21 ) of the dynamometer steering wheel (1 ), from the inertial measurement unit (3) as well as from the first auxiliary sensor (7) and the second auxiliary sensor (9) of the calibration bench (4),- wherein the electronic control and processing unit (E1 ) of the calibration bench (4) is configured for:- receiving, during a calibration bench test (4), as a result of oscillations with increasing frequency imparted to the dynamometer steering wheel (1 ) on the calibration bench (4), the output signals from the first sensor (20) and the second sensor (21 ) of the dynamometer steering wheel (1 ) and the inertial measurement unit (3) mounted on the dynamometer steering wheel (1 ), as well as from the first auxiliary sensor (7) and the second auxiliary sensor (9) of the calibration bench (4), and for- processing the signals from the first sensor (20) of the dynamometer steering wheel (1 ) and from the first auxiliary sensor (7) to obtain data related to the delay time associated with the first sensor (20) of the dynamometer steering wheel (1 ),- processing the signals from the second sensor (21 ) of thedynamometer steering wheel (1 ) and the second auxiliary sensor (9) to obtain data related to the delay time associated with the second sensor (21 ) of the dynamometer steering wheel,- processing the signals from the first sensor (7) of the dynamometer steering wheel and the inertial measurement unit (3) to obtain data related to the delay time associated with the inertial measurement unit (3), so that the electronic control and processing unit (E) that is set up in the motor vehicle to perform the road or track test of the motor vehicle can be programmed taking into account the delay times associated with the first sensor (20) and the second sensor (21 ) of the dynamometer steering wheel, and the inertial measurement unit (3), as detected in the calibration bench test (4).

2. The system according to claim 1 , characterized in that said first auxiliary sensor comprises a potentiometer (70) associated with a telescopic arm (7) operatively interposed between a peripheral part (6) of the dynamometric steering wheel (1 ) and a support (8) of the calibration bench (4), said potentiometer (70) being configured to detect the change in length of the telescopic arm (7), the data related to said change in length being adapted to be processed to obtain the rotation angle and / or the rotation speed and / or the centrifugal acceleration of the dynamometric steering wheel (1 ).

3. The system according to claim 1 , characterized in that said second auxiliary sensor (9) is a load cell interposed along a tangential direction (T) with respect to the dynamometer steering wheel (1 ), between a fixed support (10) of the calibration bench (4) and the free end of an auxiliary arm (11 ) rigidly connected to the steering column and projecting from it in a substantially radial direction, said load cell (9) being configured to detect the tangential force (F) applied to the cell (9) by the free end of the auxiliary arm (11 ), following the application of a torque on the dynamometer steering wheel (1 ), the data related to said tangential force being adapted to be processed to obtain the torque applied to the dynamometer steering wheel (1 ).

4. The system according to claim 1 , characterized in that during the calibration bench test (4), said electronic unit (E1 ) of the calibration bench (4) is programmed to determine the delay time associated with the firstsensor (20), the second sensor (21 ) and the inertial measurement unit (3), based on comparisons with the signals of the first auxiliary sensor (7) and the second auxiliary sensor (9), by means of a cross-correlation technique.

5. A method for calibrating an instrument kit that can be used for detecting the dynamic characteristics of a motor vehicle in tests on a road or on a test track, wherein said instrument kit comprises:- a dynamometer steering wheel (1 ), configured to be attached to the steering column of the motor vehicle, in lieu of the steering wheel originally provided for the motor vehicle, said dynamometer steering wheel (1 ) comprising:- a first sensor (20) configured to detect the rotation angle of the dynamometer steering wheel (1 ), and- a second sensor (21 ) configured to detect the torque applied to the steering column by the dynamometer steering wheel (1 ),- an inertial measurement unit (3), configured to be mounted on the structure of the motor vehicle and to measure the accelerations in three orthogonal directions and / or the angular speeds of rotation about the three orthogonal axes, to which the motor vehicle is subjected as a result of the inputs provided by the driver via the steering wheel (1 ), and- an electronic control and processing system (E) configured to be arranged in the motor vehicle and to receive output signals from the first sensor (20) and the second sensor (21 ) of the dynamometer steering wheel and the inertial measurement unit (3) and to process these signals in such a way as to provide an assessment of the dynamic characteristics of the motor vehicle, said method being characterized in that it includes:- performing, on a calibration bench (4), prior to performing the road or track test of the motor vehicle, a measurement of the delay time with which said first sensor (20) and said second sensor (21 ) of the dynamometer steering wheel and said inertial measurement unit (3) provide an output signal, with respect to the time in which a phenomenon generating said output signal occurred,- said calibration bench (4) including:- a support structure (5) configured to rotatably support a steeringcolumn on which said dynamometer steering wheel (1 ), including said first sensor (20) and said second sensor (21 ), is temporarily mounted before being installed on the motor vehicle, with said inertial measurement unit (3) secured to a peripheral portion (6) of the dynamometer steering wheel (1 ), so that the centrifugal acceleration of the dynamometer steering wheel (1 ) can be detected in a test on said calibration bench (4),- a first auxiliary sensor (7), separate from the dynamometer steering wheel (1 ), and configured to detect, directly or indirectly, the rotation angle and the centrifugal acceleration of the dynamometer steering wheel (1 ), with a delay time which is substantially zero or has a relatively small know value,- a second auxiliary sensor (9), separate from the dynamometer steering wheel (1 ), and configured to detect, directly or indirectly, the torque applied to the dynamometer steering wheel (1 ), with a delay time which is substantially zero or has a relatively small know value,- an electronic control and processing unit (E1 ), which is the same electronic unit (E) that is set up in the motor vehicle for the road or track test of the motor vehicle, or which is a separate electronic unit, configured to receive the output signals from the first sensor (20) and the second sensor (21 ) of the dynamometer steering wheel (1 ), from the inertial measurement unit (3) as well as from the first auxiliary sensor (7) and the second auxiliary sensor (9) of the calibration bench (4),- wherein, through the electronic control and processing unit (E1 ) of the calibration bench (4), the following operations are performed:- receiving, during a calibration bench test (4), as a result of oscillations with increasing frequency imparted to the dynamometer steering wheel (1 ) on the calibration bench (4), the output signals from the first sensor (20) and the second sensor (21 ) of the dynamometer steering wheel (1 ) and the inertial measurement unit (3) mounted on the dynamometer steering wheel (1 ), as well as from the first auxiliary sensor (7) and the second auxiliary sensor (9) of the calibration bench (4),- processing the signals from the first sensor (20) of the dynamometer steering wheel and the first auxiliary sensor (7) to obtain data related to the delay time associated with the first sensor (20) of the dynamometer steering wheel,- processing the signals from the second sensor (21 ) of thedynamometer steering wheel (1 ) and the second auxiliary sensor (9) to obtain data related to the delay time associated with the second sensor (21 ) of the dynamometer steering wheel (1 ),- processing the signals from the first sensor (7) of the dynamometer steering wheel (1 ) and the inertial measurement unit (3) to obtain data related to the delay time associated with the inertial measurement unit (3), so that the electronic control and processing unit (E) that is set up in the motor vehicle to perform the road or track test of the motor vehicle can be programmed taking into account the delay times associated with the first sensor (20) and the second sensor (21 ) of the dynamometer steering wheel (1 ), and the inertial measurement unit (3), as detected in the calibration bench test (4).

6. The method according to claim 5, characterized in that said first auxiliary sensor comprises a potentiometer (70) associated with a telescopic arm (7) operatively interposed between a peripheral part (6) of the dynamometric steering wheel (1 ) and a fixed support (8) of the calibration bench (4), said method comprising detecting, by means of said potentiometer (70), data related to the change in length of the telescopic arm (7) during a calibration bench test (4), and processing the data related to the change in length of the telescopic arm (7) to obtain data related to the rotation angle and / or angular speed of rotation and / or centrifugal acceleration of the dynamometric steering wheel(I ).

7. The method according to claim 5, characterized in that said second auxiliary sensor is a load cell (9) interposed along a tangential direction (T) with respect to the dynamometer steering wheel (1 ), between a fixed support (10) of the calibration bench (4) and the free end of an auxiliary arm(I I ) rigidly connected to the steering column and projecting from it in a substantially radial direction, said load cell (9) being configured to detect the tangential force (T) applied to the cell (9) by the free end of the auxiliary arm (11 ), following the application of a torque on the dynamometer steering wheel (1 ), the data related to said tangential force (F) being processed to obtain the torque applied to the dynamometer steering wheel (1 ).

8. The method according to claim 1 , characterized in that during the calibration bench test (4), said electronic unit (E1 ) of the calibration bench (4) is programmed to determine the delay time associated with the first sensor (20), the second sensor (21 ) and the inertial measurement unit (3), based on comparisons with data based on the signals of the first auxiliary sensor (7) and the second auxiliary sensor (9), through the cross-correlation technique.

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