Vehicle weight sensor

• US 20150053487A1
• Filed: 08/23/2013
• Published: 02/26/2015
• Est. Priority Date: 08/23/2013
• Status: Active Grant

• Current Assignee: Trimble Navigation Limited (Trimble Inc.)
• Original Assignee: Trimble Navigation Limited (Trimble Inc.)
• Inventors: Cash, Michael F.
• Granted Patent: US 9,068,878 B2
• Time in Patent Office: Days
• US Class Current: 177/1
• CPC Class Codes: G01G 19/12 having electrical weight-sensitive devices
• CPC Class Codes: G01G 23/3728 with wireless means
• CPC Class Codes: G01G 9/00 Methods of, or apparatus for, the determination of weight, not provided for in groups G01G1/00 - G01G7/00
• CPC Class Codes: G01L 1/2231 the supports being disc- or ring-shaped, adapted for measuring a force along a single direction
• CPC Class Codes: G01L 5/0019 by using strain gages, piezoelectric, piezo-resistive or other ohmic-resistance based sensors
• CPC Class Codes: G01L 5/1627 of strain gauges using piezoresistors G01L5/162
• CPC Class Codes: G07C 5/085 using electronic data carriers

Abstract

A vehicle weight sensor is based on wheel-rim stress measurement.

Claims

1. A system for measuring vehicle weight comprising:

a strain sensor including a strain gauge and a radio transmitter that transmits strain data;

a data receiver including a radio receiver that receives strain data and a processor and memory;

wherein, the processor uses the strain data to estimate weight on a wheel of the vehicle having a metal wheel rim, and the strain data represents strain in the wheel rim as measured by the strain gauge while the strain gauge is bonded to the wheel rim.

2. The system of claim 1, the strain data representing tangential strain in the wheel rim.

3. The system of claim 1, the strain data representing axial strain in the wheel rim.

4. The system of claim 1, the strain data representing a combination of tangential and axial strain in the wheel rim.

5. The system of claim 1, the strain gauge being bonded to an outside surface of a bead seat of the rim.

6. The system of claim 1, the processor estimating weight based on peak-to-peak strain amplitude as reported by the strain gauge during one or more rotations of the wheel.

7. The system of claim 1, the processor estimating weight based on integrated strain amplitude as reported by the strain gauge during one or more rotations of the wheel.

8. The system of claim 1, the processor further estimating the entire weight of the vehicle from the weight on the wheel.

9. The system of claim 1, the sensor further comprising a microelectromechanical accelerometer that detects wheel rotation angle and rotation rate.

10. The system of claim 9, the sensor turning off its strain gauge and radio transmitter whenever the accelerometer detects a wheel rotation rate greater than a predetermined value.

11. A method for measuring vehicle weight comprising:

bonding a strain gauge of a strain sensor to a metal wheel rim of a wheel of the vehicle;

obtaining strain data representing strain in the wheel rim during one or more wheel rotations;

transmitting strain data from the strain gauge to a data receiver via radio; and

,

a processor in the data receiver using the strain data to estimate weight on the wheel of the vehicle.

12. The method of claim 11, the strain data representing tangential strain in the wheel rim.

13. The method of claim 11, the strain data representing axial strain in the wheel rim.

14. The method of claim 11, the strain data representing a combination of tangential and axial strain in the wheel rim.

15. The method of claim 11 where the processor estimates weight on the wheel as a function of peak-to-peak strain amplitude.

16. The method of claim 11 where the processor estimates weight on the wheel as a function of integrated strain amplitude.

17. The method of claim 11, wherein the strain gauge is bonded to an outside surface of a bead seat of the wheel rim.

18. The method of claim 11 further comprising obtaining wheel rotation angle data using an accelerometer included in the strain sensor and the processor estimating weight on the wheel as a function of wheel strain and rotation angle while the wheel is not moving.

19. The method of claim 11 further comprising obtaining wheel rotation rate data using an accelerometer included in the strain sensor and turning off the strain gauge and the radio whenever the wheel rotation rate exceeds a predetermined value.