Recursive vehicle mass estimation apparatus and method

• US 20010001138A1
• Filed: 12/22/2000
• Published: 05/10/2001
• Est. Priority Date: 04/23/1998
• Status: Active Grant

• Current Assignee: Dennis O. Taylor, Thomas L. Bailey, Zhu G. George
• Original Assignee: Dennis O. Taylor, Thomas L. Bailey, Zhu G. George
• Inventors: Zhu, G. George, Bailey, Thomas L., Taylor, Dennis O.
• Granted Patent: US 6,438,510 B2
• Time in Patent Office: Days
• US Class Current: 702/175
• CPC Class Codes: B60T 2250/02 Vehicle mass
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence
• CPC Class Codes: G01G 19/086 wherein the vehicle mass is dynamically estimated

Abstract

A method and apparatus is disclosed for recursively estimating vehicle mass and/or aerodynamic coefficient of a moving vehicle. The vehicle speed and push force data are collected and a segment of qualified data is then selected from the collected data. Newton'"'"'s second law is integrated to express vehicle mass and/or aerodynamic coefficient in terms of vehicle push force and vehicle speed. This expression is then used in a recursive analysis of the qualified data segment to determine an estimated vehicle mass and/or aerodynamic coefficient.

Claims

1. A method of estimating the mass of a vehicle, the vehicle including an internal combustion engine, the engine producing a torque in accordance with a fueling rate provided by a fueling system thereof, the torque being applied to a drive-train coupled to the engine, the drive train including a transmission coupled to the engine having a plurality of engageable gear ratios, a drive axle and a propeller shaft coupling the drive axle to the transmission, the drive axle including at least one wheel for moving the vehicle, the method comprising:

(a) periodically determining a vehicle speed and a vehicle push force corresponding to the vehicle speed and storing corresponding vehicle speed and vehicle push force data within a memory portion of a control computer;

(b) qualifying a segment of the vehicle speed and push force data; and

(c) determining vehicle mass by a recursive least square estimation analysis of the segment of data by defining the vehicle speed as a function of the push force.

2. The method of

claim 1

, further comprising estimating a vehicle aerodynamic coefficient.

3. The method of

claim 2

further comprising correcting the vehicle mass and the aerodynamic coefficient when at least one of the vehicle mass and the aerodynamic coefficient is beyond a predetermined limit.

4. The method of

claim 1

, wherein said periodically determining the vehicle speed includes sensing the rotational speed of a vehicle component.

5. The method of

claim 1

, wherein said periodically determining the vehicle push force includes sensing engine fueling to determine an engine torque, converting the engine torque to a tire torque based on an engaged gear ratio, and converting the tire torque to the vehicle push force.

6. The method of

claim 1

, wherein said periodically determining vehicle speed and push force includes determining a shift status, the shift status corresponding to a determination of vehicle speed and push force.

7. The method of

claim 6

, wherein said qualifying includes buffering the vehicle speed, push force, and shift status data, and selecting the longest qualified segment therefrom.

8. The method of

claim 6

, wherein said qualifying includes establishing a throttle percentage exceeding a threshold amount.

9. The method of

claim 8

, wherein said threshold amount is about 30%.

10. The method of

claim 6

, wherein said qualifying includes establishing a torque percentage exceeding a threshold amount.

11. The method of

claim 6

, wherein said qualifying includes establishing a brake status.

12. The method of

claim 6

, wherein said qualifying includes establishing the transmission is in-gear.

13. The method of

claim 1

, further including adjusting a control computer parameter in accordance with the estimated vehicle mass.

14. A control system for estimating mass of a vehicle, the vehicle including an engine with a fueling system associated therewith, a transmission coupled to the engine having a plurality of engageable gear ratios, a drive axle and a propeller shaft coupling the transmission to the drive axle, the system comprising:

means for determining a vehicle speed and providing a vehicle speed signal corresponding thereto;

means for determining an engine fueling rate and providing an engine fueling rate signal corresponding thereto;

means for determining a presently engaged gear ratio of the transmission and providing a gear ratio signal corresponding thereto; and

a processor responsive to said engine fueling rate signal and said gear ratio signal to determine a vehicle push force corresponding to said vehicle speed signal, said processor being further responsive to qualify a data segment therefrom and calculate an estimated vehicle mass, said estimated vehicle mass being determined by a recursive analysis of said data segment and establishing said vehicle speed as a function of said push force.

15. The system of

claim 14

, further including means for determining a throttle percentage corresponding to said vehicle speed and vehicle push force, said data not being qualified when said throttle percentage is less than a threshold requirement.

16. The system of

claim 15

, wherein said threshold requirement is a throttle percentage of about 30%.

17. The system of

claim 15

, wherein qualification of said data segment includes establishing a torque percentage exceeding a threshold amount.

18. The system of

claim 15

, wherein qualification of said data segment includes establishing a brake status.

19. The system of

claim 14

, wherein qualification of said data segment requires the transmission to be in-gear.

20. The system of

claim 14

, wherein said processor is operable to further calculate an estimated vehicle aerodynamic coefficient from said function.

21. The system of

claim 14

, wherein said processor is further operable to correct said estimated vehicle mass and aerodynamic coefficient when either one is beyond a predetermined limit.

22. The system of

claim 14

, further including a data communications link connected to said processor, and wherein at least one of said engine fueling rate signal, said vehicle speed signal, and said gear ratio signal is provided to said processor from a remote processor with said data communications link.

23. The system of

claim 14

, wherein said processor being further operable to sense engine fueling to determine an engine torque, converting the engine torque to a tire torque based on an engaged gear ratio, and converting the tire torque to the vehicle push force.

24. A system, comprising:

a vehicle including an engine with a fueling system, a transmission coupled to said engine having a plurality of engageable gear ratios, a drive axle, and a propeller shaft coupling said transmission to said drive axle;

a vehicle speed sensor, said sensor providing a speed signal corresponding to speed of the vehicle;

a programmable processor with a memory portion operatively coupled thereto, said processor being responsive to an engine fueling rate signal and a gear ratio signal stored in said memory to determine a vehicle push force corresponding to said speed signal, said processor being programmed to qualify a data segment from vehicle speed and vehicle push force to calculate an estimated vehicle mass, said estimated vehicle mass being determined by a recursive analysis of said data segment and establishing said vehicle speed as a function of said push force.

25. The system of

claim 24

, further including a throttle percentage stored in said memory corresponding to said vehicle speed and vehicle push force, said data segment not being qualified when said throttle percentage is less than a threshold requirement.

26. The system of

claim 25

, wherein said threshold requirement is a throttle percentage of about 30%.

27. The system of

claim 24

, wherein qualification of said data segment includes establishing a torque percentage exceeding a threshold amount.

28. The system of

claim 24

, wherein qualification of said data segment includes establishing a brake status.

29. The system of

claim 24

, wherein said data is not qualified if a gear is not presently engaged.

30. The system of

claim 24

, wherein said processor is operable to further calculate an estimated vehicle aerodynamic coefficient from said function.

31. The system of

claim 24

, wherein said processor is further operable to correct said estimated vehicle mass and aerodynamic coefficient when one of said estimates is outside an upper or lower limit.

32. The system of

claim 24

, further including a data communications link connected to said processor, and any of said engine fueling rate signal, said vehicle speed signal or said gear ratio signal being provided to said processor from a remote processor via said data communications link.

33. The system of

claim 24

, wherein said processor is further operable to sense an engine fueling to determine an engine torque, convert the engine torque to a tire torque based on an engaged gear ratio, and convert the tire torque to the vehicle push force.