ACCELEROMETER BASED SYSTEM FOR DETECTION OF TIRE TREAD SEPARATION AND LOOSE WHEELS

• US 20070299573A1
• Filed: 06/26/2006
• Published: 12/27/2007
• Est. Priority Date: 06/26/2006
• Status: Abandoned Application

• Current Assignee: International Truck Intellectual Property Co. LLC (Volkswagen AG)
• Original Assignee: International Truck Intellectual Property Co. LLC (Volkswagen AG)
• Inventors: Carlstrom, Kevin R.
• Application Number:
  US11/426,504
• Publication Number:
  US 20070299573A1
• Time in Patent Office: Days
• US Class Current: 701/29
• CPC Class Codes: B60T 2270/416 Wheel speed sensor failure
• CPC Class Codes: B60T 8/885 using electrical circuitry
• CPC Class Codes: B60W 2300/12 Trucks; Load vehicles
• CPC Class Codes: B60W 2300/126 Multi-axles trucks
• CPC Class Codes: B60W 2300/147 Road trains
• CPC Class Codes: B60W 2510/104 Output speed
• CPC Class Codes: B60W 2520/30 Wheel torque
• CPC Class Codes: B60W 2530/20 Tyre data
• CPC Class Codes: B60W 2720/28 Wheel speed
• CPC Class Codes: B60W 40/068 Road friction coefficient
• CPC Class Codes: B60W 40/12 related to parameters of the vehicle itself , e.g. tyre models
• CPC Class Codes: B60W 50/02 Ensuring safety in case of control system failures, e.g. by diagnosing, circumventing or fixing failures
• CPC Class Codes: B60W 50/0205 Diagnosing or detecting failures; Failure detection models

Abstract

Wheel acceleration on a vehicle is measured rotationally and laterally to isolate tire out of round and loose wheel conditions. A wheel accelerometer is mounted outwardly from the axis of rotation to provide both rolling and lateral acceleration measurements. Rotational acceleration should normally be a regular sinusoid under steady state, straight line movement of a vehicle. Lateral acceleration under the same conditions should be zero. Where a wheel is loose a sinusoidal acceleration pattern appears in the direction lateral to the vehicle'"'"'s direction of travel. Where a portion of a tire is out of round due to physical changes, such as uneven wear or tread separation, the wheel rotational acceleration will assume a spreading frequency other than a simple sinusoid. Appropriate data processing facilities, coupled with wheel rotational speed data from the anti-lock braking system, are used to detect the acceleration changes.

Claims

1. Vehicle running gear comprising:

a plurality of wheels mounted for rotation;

tires installed on the plurality of wheels;

an accelerometer installed on each of the plurality of wheels providing measurements of wheel rotational and lateral acceleration;

data processing means coupled to receive the measurements of wheel rotational and lateral acceleration when the wheels are rotating, the data processing means providing for determining non-zero lateral acceleration indicating a wheel mounting problem and for determining rotational acceleration components other than an expected sinusoidal component indicating out of round tire conditions.

2. A vehicle drive train as claimed in claim 1, further comprising:

the data processing means being programmed to determine the presence of lateral acceleration exhibiting a sinusoidal profile as indication of a loose wheel.

3. A vehicle drive train as claimed in claim 1, further comprising:

the data processing means being programmed to determine the occurrence of rhythmic changes in wheel rotational speed other than a pure sinusoid and associating such with a tire defect such as impending tread separation.

4. A vehicle drive train as claimed in claim 3, further comprising:

a vehicle anti-lock brake system providing rotational velocity measurement for each of the plurality wheels; and

the data processing means being further programmed to generate a nominal acceleration profile for each wheel in response to the rotational velocity measurement for each wheel.

5. A vehicle drive train as claimed in claim 4, further comprising:

the data processing means providing for comparing the nominal acceleration profile for a wheel with the measured rotational acceleration profile for the same wheel to determine recurring transient acceleration events indicative of a tire problem associated with the wheel.

6. A method of detecting operational faults in tires and wheels of a motor vehicle, the method comprising the steps of:

measuring the rotational acceleration of the wheels at a reference point for each wheel;

measuring the lateral acceleration of the wheels;

detecting recurring transient deviations of the measured rotational acceleration;

evaluating the deviations for amplitude and period as an indicator of a tire defect; and

evaluating the measured lateral acceleration for period and deviation from a zero value as an indicator of a non-nominal wheel condition.

7. A method of detecting operational faults in tires and wheels of a motor vehicle as set forth in claim 6, the step of detecting includes:

measuring the rotational velocity of the wheels;

responsive to the measured rotational velocity for each wheel generating a nominal acceleration profile for the wheel at the reference point; and

comparing the nominal acceleration profile with the measured rotational acceleration profile for a wheel to generate a deviance curve indicative of possible tire defects.

8. A wheel and tire monitoring system for a vehicle comprising:

rotational and lateral accelerometers mounted with respect to and spaced from the axis of rotation of each wheel to be monitored; and

data processing means coupled to receive the measurements of the rotational and lateral accelerometers, the data processing means providing for determining periodic non-zero lateral acceleration events indicating a wheel mounting problem and for determining rotational acceleration components outside an expected sinusoidal profile indicating a tire problem.

9. A wheel and tire monitoring system for a motor vehicle as set forth in claim 8, further comprising:

the data processing means being programmed to generate a nominal acceleration profile for each wheel.

10. A wheel and tire monitoring system for a motor vehicle as set forth in claim 9, further comprising:

an anti-lock brake system providing individual wheel rotational velocity measurements to the data processing means; and

the data processing means being responsive to the wheel rotational velocity measurements for generating a nominal acceleration profile for each wheel for comparison to the measurements of the rotational and lateral accelerometers.

11. A wheel and tire mounting system for a motor vehicle as set forth in claim 10, further comprising:

an anti-lock brake system for receiving measurement signals from the accelerometers and providing the measurements to the data processing means.