Method for facilitating the removal of objects adhering to motor vehicle tires

Abstract

Method for facilitating the removal of objects adhering to motor vehicle tires, in which - a time course of a wheel speed variable representing a wheel speed is recorded (101), - the temporal course of the wheel speed variable is monitored with regard to the occurrence of periodic disturbances correlating with a wheel revolution (102) and - when such a periodic disturbance occurs, the presence of an object adhering to a motor vehicle tyre is detected (103), characterized in that - an angular position of the object on the motor vehicle tyre is determined based on a phase position of the periodic disturbance (104) and - a direction of travel and a movement variable of a motor vehicle characterising a distance of movement in the direction of travel are determined (105), when which the object on the motor vehicle tyre assumes such a predetermined angular position that manual or automatic removal of the object is possible.

Description

State of the art

[0001] Paragraphs

[0041] -

[0042] of DE 197 35 313 ​​B4 mention a cost-effective tire pressure monitoring system that requires no additional sensors such as pressure sensors, yet still provides the required accuracy and reliability of direct pressure measurement. Even on very smooth road surfaces without any obvious bumps, the relevant resonance frequencies, influenced, for example, by tire pressure, can be determined from the ABS signals. In addition, an overview is obtained of how the speed detection deviations are distributed over one wheel revolution. These deviations can be used to evaluate or detect a change in wheel irregularity, for example, due to wheel imbalance or a stone in the tread.

[0002] The publications US 2004 / 0 168 512 A1, GB 2 356 610 A and KR 10 2013 0 051 797 A describe procedures for detecting foreign body adhesions to motor vehicle tires. Disclosure of the invention

[0003] The invention relates to a method for facilitating the removal of objects adhering to motor vehicle tires, in which - the time course of a wheel speed variable representing the wheel speed is recorded, - the temporal course of the wheel speed variable is monitored with regard to the occurrence of periodic disturbances correlating with a wheel revolution and - when such a periodic disturbance occurs, the presence of an object adhering to the tyre is detected, whereby - the angular position of the object on the tire is determined based on the phase position of the periodic disturbance and - a direction of travel and a displacement parameter of the motor vehicle characterising the distance or length of travel in the direction of travel are determined, upon compliance with which the object on the tyre assumes a predetermined angular position such that manual or automatic removal of the object is possible.

[0004] This automatically determines how far the vehicle must move forward or backward to bring the tire into a stationary position such that the attached object is in a location suitable for manual or automatic removal. This allows the driver to precisely position the tire in a position where the tire's rotational orientation is at rest, allowing easy access to the attached object and allowing manual removal of the object.

[0005] An advantageous embodiment of the invention is characterized in that such a vehicle movement with regard to the direction of travel and the width of the vehicle movement is carried out independently of the driver, that the vehicle is at a standstill after the vehicle movement has been carried out and the object on the tire assumes the predetermined angular position, so that a manual or automatic removal of the object is possible.

[0006] An advantageous embodiment of the invention is characterized in that the predetermined angular position is such that the object is located on the tire contact patch between the tire and the roadway and that an automatic attempt to remove the object is made in such a way that the tire is moved back and forth by a driver-independent steering intervention.

[0007] An advantageous embodiment of the invention is characterized in that such a predetermined angular position is such that the object is located approximately halfway between the tire contact surface and the tire top surface. In this position, the object is particularly easily accessible for manual removal. The term "top surface" refers to the upper side of the tire relative to the vehicle's vertical axis, i.e., the side of the tire opposite the tire contact patch.

[0008] An advantageous embodiment of the invention is characterized in that driver information is provided as soon as the object on the tire assumes such a predetermined angular position that manual removal of the object is possible.

[0009] An advantageous embodiment of the invention is characterized in that the method is carried out using an automatic parking system. Since the functions essential to the invention are already included in an automatic parking system, the invention can be implemented there without significant additional effort.

[0010] The invention further encompasses a device containing means designed to carry out the methods according to the invention. This is, in particular, a control unit in which the program code for carrying out the methods according to the invention is stored.

[0011] The drawing includes the Fig. 1 and Fig. 2. Fig. Figure 1 shows two snapshots of a rotating tire with an object attached to it, as well as a diagram showing the time course of the circumferential speed and the corresponding frequency spectrum. Fig. Figure 2 shows the basic sequence of the method according to the invention. Tire condition is a key component of road safety. Objects such as stones and nails have a significant impact on tire durability. Detection of these objects and automatic or semi-automatic removal can increase tire durability and road safety.

[0012] When an object sticks to a tire, a frequency change in the speed signal occurs with each wheel cycle. Frequency analysis makes it possible to detect these frequency changes in the speed signal. The phase position indicates the exact position of the object.

[0013] When an object is reliably detected, a display can appear in the vehicle's infotainment system, indicating that an object is stuck to the tire tread and graphically showing the object's position. The driver can then change the object's position by rolling the vehicle slightly back and forth. The driver can also be given a visual or acoustic indication of how far they still have to drive until the object is in a suitable position for removal. This driver information can be provided particularly during a parking maneuver. With the help of an automatic parking system, the described process can be carried out automatically. The driver is then informed again when the object is in an ideal position for removal.

[0014] In addition to the mechanisms described, an additional automatic steering system can attempt to automatically remove the object. After successfully detecting an object adhering to the tire surface, an automatic parking system can bring the tire to a standstill position during a parking maneuver so that the object is located between the tire and the road, i.e. at the lowest point of the tire. Through targeted steering movements, the automatic steering algorithm can attempt to automatically remove the object. Regardless of the success or failure of the automatic removal attempt, the position of the object is stored in the algorithm. If an object is detected again at the same tire position during the next wheel rotations, this is counted as a failure of the automatic removal attempt.The driver can then be given a visual or acoustic indication of how far he still has to drive until the object is in a suitable position for manual removal.

[0015] In Fig. 1, two positions of a tire with an object 101 adhering to it are shown at the top left. In the left tire position, the object 101 is located at the bottom left of the tire surface. In the right tire position, which the tire assumes at a later point in time, the object 101 is located at the top right of the tire surface. The tire rotates in the direction shown by the arrow. The frequency spectrum of the tire's circumferential speed v(t) over time is shown at the top right. Instead of the circumferential speed, the angular speed over time can of course also be considered. For this purpose, the frequency f is plotted in the abscissa direction and the frequency amplitude in the ordinate direction. The temporal speed curve v(t) is shown in the lower part of the figure. The frequency spectrum is processed by a suitable algorithm, e.g.A Fourier transformation or application of the Goertzel algorithm yields the velocity v(t) from the temporal velocity profile. An evaluation of the phase position makes it possible to determine the azimuthal position of the object attached to the tire. Since the object is located between the tire and the road surface at the time the disturbance occurs, the azimuthal position of the object on the tire can be determined at a later time, provided the angular velocity of the tire is known.

[0016] The basic procedure of the method according to the invention is described in Fig.2. After starting the method in block 100, the time course of a wheel speed variable representing the wheel speed is recorded in block 101. This is, in particular, the wheel speed or the wheel circumferential speed. Subsequently, a check is carried out in block 102 to determine whether the time course of the wheel speed variable contains periodic disturbances correlating with a wheel revolution. If this is not the case, the system returns to block 101 via output "n." However, if such disturbances are present, the presence of an object adhering to the tire is detected via output "y" in block 103.Subsequently, in block 104, the angular position of the object on the tire is determined based on the phase position of the periodic disturbance. Afterward, in block 105, a direction of travel and a displacement variable of the motor vehicle, which characterizes the distance of travel in the direction of travel, are determined. Following these variables, the object on the tire assumes a predetermined angular position such that manual or automatic removal of the object is possible. This displacement variable can, in particular, be a distance still to be covered or an angle still to be rolled by the tire. The method ends in block 106.

Claims

[1] A method for facilitating the removal of objects adhering to motor vehicle tyres, in which - a time course of a wheel speed variable representing a wheel speed is recorded (101), - the temporal course of the wheel speed variable is monitored with regard to the occurrence of periodic disturbances correlating with a wheel revolution (102) and - when such a periodic disturbance occurs, the presence of an object adhering to a motor vehicle tyre is detected (103), characterized by , that - an angular position of the object on the motor vehicle tyre is determined based on a phase position of the periodic disturbance (104) and - a direction of travel and a movement variable of a motor vehicle characterising a distance of movement in the direction of travel are determined (105), when which the object on the motor vehicle tyre assumes such a predetermined angular position that manual or automatic removal of the object is possible. [2] Method according to claim 1, characterized by that such a motor vehicle movement is carried out independently of the driver with regard to the direction of travel and the distance of the motor vehicle movement (105), that the motor vehicle is at a standstill after the vehicle movement has been carried out and the object on the motor vehicle tire assumes the predetermined angular position, so that a manual or automatic removal of the object is possible. [3] Method according to claim 1, characterized bythat the predetermined angular position of this kind is such that the object is located on a motor vehicle tire contact patch between the motor vehicle tire and the roadway, and that an automatic attempt to remove the object is made such that the motor vehicle tire is moved back and forth by a driver-independent steering intervention. [4] Method according to claim 1, characterized by that such predetermined angular position is such that the object is located approximately halfway between a motor vehicle tire contact surface and a motor vehicle tire top surface. [5] Method according to claim 1, characterized by that the driver is informed as soon as the object on the motor vehicle tire assumes such a predetermined angular position that manual removal of the object is possible. [6] Method according to claim 1, characterized bythat the procedure is carried out using an automatic parking system. [7] Device comprising means designed to carry out the method according to one of the preceding claims.

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