DE10123527A1 - Method and system for determining the angular position of a sidewall torsion sensor - Google Patents

Abstract

The invention relates to a method for determining the angular position of a sidewall torsion sensor on a tire (10), comprising the steps of measuring the phase position of the tire (10) by the sidewall torsion sensor and measuring the phase position of a rim (12) assigned to the tire (10), whereby from the measured phase position of the tire (10) and from the measured phase position of the rim (12) the absolute angular position of the tire (10) is determined. The invention further relates to a system for determining the angular position of a sidewall torsion sensor.

Description

The invention relates to a method for determining the Angular position of a sidewall torsion sensor on one Tire with the steps: measuring the phase of the Rei fens through the sidewall torsion sensor and measuring the Phase position of a rim assigned to the tire. The he The invention also relates to a system for determining the Angular position of a sidewall torsion sensor on one Tires with means for measuring the phase of the tire by the sidewall torsion sensor and means for measuring sen the phase of a rim assigned to the tire.

State of the art

Sidewall torsion sensors are particularly useful set from a wheel and a tire to the Roadway transmitted moments or the moments evaluate the frictional values of tires on the road. For this purpose it is known in the side wall of a Tires a variety of permanent magnetic areas ver evenly over the entire circumference of the tire divide. In particular, it is possible to use the permanent magnetic  Store areas in or on the tire wall to apply the tire wall. At a distance from A measuring sensor is arranged on the tire wall at least two at different radial distances measuring elements arranged from the axis of rotation of the wheel having. The changes in the magnetic fields as a result of Rotation of the tire call at the exits of the Transducer signals that indicate the rotary motion of the tire. Now there is a Verfor tire due to the attack on the tire Forces or as a result of the transferred to driving or braking torques, this causes a ver shift of the phase position between those of the Messele emitted measurement signals. Thus, this ver shift of the phase position as a measure of the transmitted Moments or for the current coefficient of friction be evaluated.

When determining the phase position of a tire, it has proved problematic in that manufacture a homogeneous sinusoidal magnetization over the entire tire circumference connected with great difficulty that is. Correction procedures are therefore needed to to compensate for these shortcomings in magnetization chen. These include, for example, that the Magnetization of the tire depending on the angular position sition and the relationship of these quantities in one Characteristic curve stored. By considering this Characteristic curve can have the disadvantages of the imperfect mag netization can be eliminated mathematically. Indeed is necessary to take this characteristic into account that the absolute angular position of the magnetized tire  is known, because this is the only way the system knows which Place the characteristic curve for determining the correction data is to be used.

Advantages of the invention

The invention is based on the generic method in that from the measured phase position of the Rei fens and from the measured phase position of the rim absolute angular position of the tire is determined. The The measured phase of the tire alone is not enough to determine the absolute angular position. By doing However, one also measures the measured phase position of the rim taken into account, the absolute angular position of the Tire can be determined. This can then be used for corrective procedures are used.

As a result, the method is particularly advantageous formed the phase of the rim by a magnet wheel is measured with N pole pairs or teeth and that the sidewall torsion sensor M magnetic phases has, where M ≠ N. Change in this way the measurement signals of the sidewall torsion sensor with a different frequency than the measurement signals of the rim ordered Polrades. Consequently, the ver equal to the two measurement signals on the absolute angular position Close the tire sition.

In this context, it is particularly useful that the pole wheel to measure the phase position of the rim to one ABS speed sensor belongs. ABS speed sensors are anyway  provided on numerous vehicles so that it is particularly economical, the signals of this speed sensor for determining the absolute angular position of the Tire to use.

In a particularly preferred embodiment, it is provided that the side wall torsion sensor M has magnetic phases, wherein | M - N | = 1. The number of magnetic phases of the sidewall torsion sensor thus differs by exactly one phase from the number of magnetic phases of the ABS speed sensor. Thus, the absolute angular position of the tire can be concluded using the principle of nius. The larger the number of pole pairs, the more precise the determination of the absolute angular position. For example, if there is a pole wheel of the ABS speed sensor with 48 pole pairs and the side wall torsion sensor has 47 magnetic phases, the angular position can be measured with an accuracy of 360 ° / 48.

The method according to the invention is advantageously further developed in that when the tire is firmly connected to the rim, the phase Ph (rim) of the rim is measured by measuring a phase Ph (ImB) of an inner magnetized area and a phase Ph (ÄmB) of an outer magnetized area Area as

Ph (rim) = k. (Ph (ÄmB) - Ph (ImB))

is determined, where k is a tire constant. at the tire firmly connected to the rim corresponds to Phase of ripening the phase of the rim. Do you now know that  Phase of the tire with respect to the rim and the Pha The position of the rim itself, which is fixed to the speed sensor ler is connected, with the help of the Noni principle determines the absolute phase position of the tire become.

The method according to the invention is particularly advantageous can be used when the measured phase of the tire taking into account the absolute angular position of the Tire is corrected. Thus, knowledge of the absolute angular position of the tire to improve determination of the phase of the tire by a Sidewall torsion sensor can be used advantageously.

It is also particularly advantageous if the measured Phase position of the tire with knowledge of a characteristic curve kor rigging the magnetization of the tire in Ab dependence of the angular position of riding. By knowledge of the absolute angular position of the tire it is possible to have a previously measured characteristic curve that the Magnetization depending on the angular position shows to use.

The invention builds on the generic system through on that means to determine the absolute win position of the tire from the measured phase of the Tires and from the measured phase of the rim hen are. In this way, according to the invention system the advantages of the method according to the invention implemented.  

The system according to the invention is particularly advantageous in that a pole wheel with N pole pairs or Teeth provided for measuring the phase position of the rim and that the sidewall torsion sensor M is magnetic Has phases, where M ≠ N. By comparing the measuring signals vibrating with different frequencies le can be based on the absolute angular position of the Rei close fens.

In the context of the system according to the invention, it is useful that the magnet wheel for measuring the phase position of the rim too belongs to an ABS speed sensor. It is about a particularly economical solution, as ABS Speed sensors already featured in numerous vehicles are seen.

In a very preferred embodiment of the inventions system according to the invention is designed so that the Sidewall torsion sensor M has magnetic phases, where | M - N | = 1. Since the number of magnetic Pha sen of the respective sensors by exactly one phase differs can with the absolute angular position closed by the nonius principle.

In the system according to the invention it is preferably provided that when the tire is firmly connected to the rim, the phase Ph (rim) of the rim is measured by measuring a phase Ph (ImB) of an inner magnetized area and a phase Ph (ÄmB) of an outer magnetized area

Ph (rim) = k. (Ph (ÄmB) - Ph (ImB))

is determined, where k is a tire constant. When the tire is firmly connected to the rim, the phase of the tire corresponds to the phase of the rim. If you now know the phase position of the tire with respect to the rim and the phase position of the rim itself, which is firmly connected to the speed sensor, the absolute phase position of the tire can be determined with the aid of the non-principle.

The measured phase position of the Rei fens taking into account the absolute angular position corrected the tire. Overall, the Bestim measurement of the phase of the tire through a sidewall torsion sensor with higher accuracy.

It has proven to be particularly advantageous that knowing the measured phase of the tire a characteristic curve that corrects the magnetization of the tire depending on the angular position of the tire fens contains. A previously measured characteristic gives the dependence of magnetization on the angular position of the tire. By this knowledge and by knowing the absolute angular position the accuracy of the determination of the Pha Improve the tire's position.

The invention is based on the finding that through the combination of a sidewall torsion sensor and egg ABS speed sensor the absolute position of the side wall torsion sensor can be determined. In particular this is possible if the number of magneti phases of the sidewall torsion sensor exactly by one  Phase differs from that of the ABS speed sensor. Under these conditions there is an exact one Determination of the absolute position using the Noniusprin zips possible.

drawings

The invention will now be described with reference to the accompanying Drawings based on preferred embodiments explained in a playful way.

It shows:

Figure 1 is a schematic representation of part of a wheel to explain the determination of the Pha senlage a tire.

Fig. 2 is a plurality of diagrams for explaining the vernier principle; and

Fig. 3 is a block diagram for explaining an inventive system.

Description of the embodiments

Fig. 1 shows a schematic representation of a part of a wheel to explain the determination of the phase position of a tire. A tire 10 is arranged on a rim 12 . This tire 10 has differently magnetized permanent magnetic areas 14 , 16 , 18 , the polarity of which is alternately arranged. For example, area 14 is the north pole of a magnet, area 16 is the south pole, area 18 is again the north pole, etc. Tire 10 is shown in a twisted state in FIG. 1, that is to say that the tire areas are essentially in The circumferential direction of the tire 10 are shifted. Radially further outward areas of the tire 10 are shifted ben more than inward lying areas, that is to say those surfaces which are closer to the rim 12 . If one now attaches to various radial positions, that is to say for example at lines a and b, one will find that when the tire 10 is deformed as a result of the forces acting on the tire 10 or as a result of the transmitted drive or braking torques there is a shift in the phase between the measurement signals emitted by the measurement elements arranged at lines a and b. When the tire is firmly connected to the rim, the phase of the rim Ph (rim) (line c) results

Ph (rim) = k. (Ph (ÄmB) - Ph (ImB)),

where Ph (ÄmB): phase of the outer magnetized area at line a in Fig. 1;
Ph (ImB): phase of the inner magnetized region at line b in Fig. 1;
Ph (rim): phase of the rim at line c in Fig. 1;
k: tire constant.

Knowing the phase of the tire 10 with respect to the rim 12 and the phase of the rim 12 itself, which is firmly connected to the speed sensor of the ABS, it can be concluded on the absolute phase of the tire 10 ge.

FIG. 2 explains how the absolute phase position of the tire can be determined from the variables mentioned. Fig. 2 shows several diagrams for explaining the vernier principle used for this. In the diagrams shown in FIG. 2, different sizes are shown depending on the angle of rotation ϕ of the wheel. FIG. 2a shows a sinusoidal or cosine-shaped function which is associated with the recording of measured values with N pole pairs. In the present case, N = 2. Fig. 2b shows corresponding sinusoidal or cosine-shaped curves which are correlated with N + 1 = 3 pole pairs. By forming the inverse function of the tangent (arctan), the functions shown in FIG. 2c or in FIG. 2d are obtained, FIG. 2c being derived from the sinusoidal or cosine-shaped courses in FIG. 2a, while FIG. 2d is derived from the sinusoidal or cosine-shaped courses according to FIG. 2b. Fig. 2e illustrates how one can determine the absolute phase position by subtracting the functions shown in Fig. 2c and Fig. 2d. If FIGS. 2a and 2c are assigned, for example, to the pole wheel of the ABS speed sensor and FIGS. 2b and 2d correspond to the sidewall torsion sensor, it can be seen from FIG. 2e that exactly after a wheel rotation of ϕ = 360 ° there is a difference between the functions present in Fig. 2c and Fig. 2d of 0 ° mod 360 °. This corresponds to a certain angular position of the side wall torsion sensor. If there is a change to this absolute angular position, the difference of 0 ° mod 360 ° is at another Radwin angle position, from which the absolute angular position of the side wall torsion sensor emerges.

Fig. 3 shows a block diagram for explaining a system of the invention. The symbols used in FIG. 3 are first explained:
101: Measuring the phase position with a sidewall torsion sensor.
102: Measuring the phase position with an ABS magnet wheel.
103: Determine the absolute phase position with a vernier method.
104: Correcting the phase position measured by the sidewall torsion sensor.
105: Result of the determination of the absolute phase position in functional element 103 .
106: Output of the improved phase position of the side wall torsion sensor.

In functional element 101 , a phase position is measured by a sidewall torsion sensor. This phase position measured by the side wall torsion sensor is to be corrected in function element 104 , for example via a characteristic curve which contains information about the magnetic field as a function of the angular position. In order to be able to reliably carry out such a correction in functional element 104 , it is necessary to know the absolute phase position. For this purpose, the phase position of an ABS magnet wheel is measured in functional element 102 . The phase positions measured in functional element 101 and in functional element 102 are combined in functional element 103 by means of a vernier method. This gives the result 105 , namely the absolute phase position. In function element 104 , a correction is now made from the measured phase position and the absolute phase position, for example via the characteristic curve, so that the improved phase position can be output in function element 106 .

The preceding description of the exemplary embodiments according to the present invention only serves to illustrate tive purposes and not for the purpose of restricting the Invention. Various are within the scope of the invention Changes and modifications possible without the scope leave the invention and its equivalents.

Claims (14)

1. A method for determining the angular position of a side wall torsion sensor on a tire ( 10 ), comprising the steps:

• - Measuring the phase position of the tire ( 10 ) by the sidewall torsion sensor and
• - Measuring the phase position of a rim ( 12 ) assigned to the tire ( 10 ),

characterized in that the absolute angular position of the tire ( 10 ) is determined from the measured phase position of the tire ( 10 ) and from the measured phase position of the rim ( 12 ). 2. The method according to claim 1, characterized in that
that the phase position of the rim ( 12 ) is measured by a pole wheel with N pole pairs or teeth and
that the side wall torsion sensor M has magnetic phases, where M ≠ N. 3. The method according to claim 1 or 2, characterized in that the magnet wheel for measuring the phase position of the rim ( 12 ) belongs to an ABS speed sensor. 4. The method according to any one of the preceding claims, characterized in that the sidewall torsion sor M has magnetic phases, where | M - N | = 1. 5. The method according to any one of the preceding claims, characterized in that in an attached to the rim (12) tire (10), the phase Ph (rim) of the rim (12) by measuring a phase Ph (IMB) of an inner magnetized region and a phase Ph (ÄmB) of an outer magnetized area as
Ph (rim) = k. (Ph (ÄmB) - Ph (ImB)),
is determined, where k is a tire constant. 6. The method according to any one of the preceding claims, characterized in that the measured phase position of the tire (10) is corrected taking into account the absolute angular position of the tire (10). 7. The method according to any one of the preceding claims, characterized in that the measured phase position of the tire ( 10 ) is corrected with knowledge of a characteristic curve which contains the magnetization of the tire ( 10 ) as a function of the angular position of the tire ( 10 ). 8. System for determining the angular position of a side wall torsion sensor on a tire ( 10 )
Means for measuring the phase of the tire ( 10 ) by the sidewall torsion sensor and
Means for measuring the phase position of a rim ( 12 ) assigned to the tire ( 10 ),
characterized in that means are provided for determining the absolute angular position of the tire ( 10 ) from the measured phase position of the tire ( 10 ) and from the measured phase position of the rim ( 12 ). 9. System according to claim 8, characterized in that
that a pole wheel with M pole pairs or teeth for measuring the phase position of the rim ( 12 ) is provided and
that the sidewall torsion sensor has M magnetic phases, where M ≠ N. 10. System according to claim 8 or 9, characterized in that the magnet wheel for measuring the phase position of the rim ( 12 ) belongs to an ABS speed sensor. 11. System according to any one of claims 8 to 10, characterized characterized that the sidewall torsion sensor M likes has netic phases, where | M - N | = 1. 12. System according to any one of claims 8 to 11, characterized in that when firmly connected to the rim ( 12 ) connected tire ( 10 ), the phase Ph (rim) of the rim ( 12 ) by measuring a phase Ph (ImB) of an inner magnetized area and a phase Ph (ÄmB) of an outer magnetized area as
Ph (rim) = k. (Ph (ÄmB) - Ph (ImB)),
is determined, where k is a tire constant. 13. System according to one of claims 8 to 12, characterized in that the measured phase position of the fens Rei (10) taking into account the absolute Winkelpo sition of the tire (10) is corrected. 14. System according to one of claims 8 to 13, characterized in that the measured phase position of the Rei is corrected having regard to a characteristic fens (10) that contains the magnetization of the tire (10) in dependence on the angular position of the tire (10).