Method and device for determining motor vehicle acceleration

• US 20070112495A1
• Filed: 06/03/2004
• Published: 05/17/2007
• Est. Priority Date: 07/12/2003
• Status: Active Grant

• Current Assignee: Allison Transmission Incorporated (Allison Transmission Holdings Incorporated)
• Original Assignee: Torotrak Limited (Torotrak Plc)
• Inventors: Murray, Stephen
• Granted Patent: US 8,489,299 B2
• Time in Patent Office: Days
• US Class Current: 701/70
• CPC Class Codes: F16H 59/48 Inputs being a function of acceleration
• CPC Class Codes: F16H 61/06 by controlling rate of change of fluid pressure
• CPC Class Codes: F16H 61/664 Friction gearings
• CPC Class Codes: F16H 61/6648 controlling of shifting being influenced by a signal derived from the engine and the main coupling
• CPC Class Codes: G01P 15/165 for measuring angular accelerations
• CPC Class Codes: G01P 21/00 Testing or calibrating of apparatus or devices covered by the preceding groups

Abstract

A method is disclosed for obtaining a signal representing motor vehicle acceleration. The method involves obtaining a high pass filtered vehicle acceleration signal and a low pass filtered vehicle acceleration signal. One of these signals (preferably the high pass filtered signal) is obtained based upon the net driving force applied to the vehicle, which can be used to obtain an estimate of acceleration by means of an adoptive vehicle model (28). The other signal is obtained by measurement, for example by differentiating a measured vehicle speed signal with respect to time. Adding the two filtered signals together gives a vehicle acceleration signal of potentially good quality.

Claims

1. A method of determining acceleration of a motor vehicle, comprising obtaining a high pass filtered acceleration signal and a low pass filtered acceleration signal, one of the filtered acceleration signals being obtained based upon net driving force applied to the vehicle and the other being obtained by measurement, and adding the two filtered acceleration signals to obtain an output signal representing vehicle acceleration.

2. A method as claimed in claim 1 wherein obtaining the low pass filtered acceleration signal comprises measuring vehicle speed and differentiating with respect to time.

3. A method as claimed in claim 1 wherein the high pass filtered acceleration signal is obtained based upon the net driving force applied to the vehicle and the low pass filtered acceleration signal is obtained by measurement.

4. A method as claimed in claim 3 wherein net driving force is obtained by subtracting vehicle braking force from driving force applied through driven vehicle wheels.

5. A method as claimed in claim 3 wherein net driving force is supplied to an adaptive vehicle model to obtain an estimate of vehicle acceleration.

6. A method as claimed in claim 5 wherein net driving force is high pass filtered before being supplied to the adaptive model.

7. A method as claimed in claim 1 wherein high pass filtering is carried out by low pass filtering and adding the low pass filtered and unfiltered signals together.

8. A device for determining acceleration of a motor vehicle, comprising means for obtaining a high pass filtered acceleration signal, means for obtaining a low pass filtered signal, one of the filtered acceleration signals being obtained on the basis of net driving force applied to the vehicle and the other being obtained by measurement, and adding the two filtered acceleration signals to obtain an output signal representing vehicle acceleration.

9. A device as claimed in claim 8 which comprises a microprocessor handling the signals in digital form.

10. A device as claimed in claim 8 which obtains the high pass filtered signal based upon the net driving force applied to the vehicle and the low pass filtered signal by measurement.