System and method for predicting tire forces using tire deformation sensors

a technology of deformation sensor and tire force, which is applied in the field of tire dynamics, can solve the problems of confounding the measurement of longitudinal torque using the swt sensor as originally envisioned, adversely and the force on the tire further affecting the calculation of driving torque or braking torqu

Inactive Publication Date: 2005-01-13
GIUSTINO JAMES M
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

It is therefore an advantage of the present invention to provide a system and method for determining circumferential torque using tire deformation sensors, e.g., SWT sensors.
to provide a system and method for determining circumferential torque using tire deformation sensors, e.g., SWT sensors.
It is also an advantage of the present invention to provide a system and method for determining lateral force using tire deformation sensors, e.g., SWT sensors.
It is therefore another advantage of the present invention to provide a system and method for decoupling lateral force and circumferential torque in measurements from tire deformation sensors, e.g., SWT sensors.
It is a further advantage of this invention to provide a system and method for determining vehicle yaw rate from tire deformation sensors, e.g., SWT sensors, thereby eliminating the need for a separate yaw rate sensor.
It is yet another advantage of the present invention to provide a system and method for determining vehicle speed from tire deformation sensors, e.g., SWT sensors, thereby eliminating the need for a separate speed sensor.

Problems solved by technology

However, cornering maneuvers adversely affect the calculation of driving torque or braking torque, because the presence of lateral forces on the tire confounds the measurement of longitudinal torque using the SWT sensor as originally envisioned (using phase differences between the two sensors detecting the magnetic bands in the tire sidewall to calculate torsional deformation).
Additionally, the presence of a vertical force on the tire further confounds the measurement of longitudinal torque using the SWT sensor as originally envisioned, although not as severely as lateral force does.

Method used

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  • System and method for predicting tire forces using tire deformation sensors
  • System and method for predicting tire forces using tire deformation sensors
  • System and method for predicting tire forces using tire deformation sensors

Examples

Experimental program
Comparison scheme
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example 1

Neural Network

First, a Conti Sport Contact, 245 / 40 R18 magnetic sidewall tire was prepared as generally described in U.S. Pat. No. 5,895,854 and copending U.S. patent application Ser. No. 09 / 347,757, with 200 phr (parts per hundred) of strontium ferrite powder embedded in the sidewall prior to curing. The embedded strontium ferrite was magnetized to magnetic saturation using 96 electromagnets providing 48 North poles alternating with 48 South poles.

Next, the Conti Sport Contact tire was mounted on an MTS Model 860 tread wear machine (available from MTS Systems Corporation) as follows: The magnetic sidewall tire was mounted to a precision rim. Two pairs of SWT sensors (Philips KMZ10A magneto-resistive sensors) were mounted to a strut fixed to the MTS machine, with one outer and inner pair at 180° and one outer and inner pair at 90°, with each sensor pair using the bracket shown in FIGS. 4 and 5 positioned approximately 12.5 mm from the surface of the sidewall with the tire at res...

example 2

Bilinear Equations

In this example, the data from Example 1 was used to determine a pair of bilinear equations to predict lateral force and circumferential torque.

The constants for the two equations were calculated with Matlab using the multiple linear least squares regression technique.

Using the above procedure, the following bilinear equations were determined to predict lateral force and circumferential torque:

My=−5.9835+7.4517 p−0.7741 a+0.3313 d+0.7102 p·a

Fy=−39.6433+7.7312 p+6.2483 a+9.7848 d−2.8222 p×a Where, p=SWT Phase at 180 degree position, in radians a=SWT Amplitude of outer sensor 26 at 180 degree position, in mm d=Difference between SWT outer and inner amplitudes, in mm My=Circumferential torque, kN-m Fy=Lateral Force, kN

FIGS. 16 and 17 show graphical representations of the closeness of the predictions as compared to measured data in the validation set. Using these bilinear equations, the predicted lateral force is close to the measured lateral force in th...

example 3

Neural Network

An Contitrac AW P275 / 65 R17 magnetic sidewall tire was prepared as generally described in U.S. Pat. No. 5,895,854 and copending U.S. patent application Ser. No. 09 / 347,757, with 200 phr (parts per hundred) of strontium ferrite powder embedded in the sidewall prior to curing. The embedded strontium ferrite was magnetized to magnetic saturation using 96 electromagnets providing 48 North poles alternating with 48 South poles.

Next, the Contitrac AW P275 / 65 R17 tire was mounted on an MTS Model 860 tread wear machine (available from MTS Systems Corporation) as follows: The magnetic sidewall tire was mounted to a precision rim. Two pairs of SWT sensors (Philips KMZ10A magneto-resistive sensors) were mounted to a strut fixed to the MTS machine, with one outer and inner pair at 180° and one outer and inner pair at 90°, with each sensor pair using the bracket shown in FIGS. 4 and 5 positioned approximately 12.5 mm from the surface of the sidewall with the tire at rest.

With...

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Abstract

A system and method for predicting the forces generated in the fire contact patch from measurements of tire deformations, including separating the lateral force, the vertical force, and the circumferential torque using measurements of tire deformations. A system and method for using a trained neural network or bilinear equations to determine any combination or permutation of one or more of any of the following from tire sidewall deformation sensors, e.g., magnetic tire sidewall torsion measuring (SWT) sensors: the lateral force acting on the tire, the circumferential torque acting on the tire, the longitudinal force acting on the tire, the vertical force acting on the tire, and forces and / or torques having any one or more of the foregoing as components thereof.

Description

FIELD OF THE INVENTION The present invention relates generally to the field of tire dynamics and more specifically to predicting the forces generated in the tire contact patch from measurements of tire deformations, including separating the lateral force and the circumferential torque using measurements of tire deformations. BACKGROUND OF THE INVENTION U.S. Pat. No. 5,895,854, which is incorporated herein by reference, discloses a vehicle wheel that is provided with a pneumatic (rubber) tire having at least at one predetermined location a rubber mixture that is permeated with magnetizable particles that have been magnetized. As stated in that patent, the tire disclosed therein can be used in a slip regulation system. Preferably, the magnetized locations are located in one or more annular bands in the sidewall of the tire, i.e., in the longitudinal or peripheral direction, and have successive zones of different magnetization in one or more rows disposed at different radii along the...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): B60T8/58B60R16/02B60T8/172B60T8/174B60T8/1763
CPCB60T2240/04B60T8/1725B60T8/00
Inventor GIUSTINO, JAMES M.
Owner GIUSTINO JAMES M
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