Ascertaining an offset of an inertial sensor

Patent metadata

Field	Value
Publication number	US-10766468-B2
Application number	US-201615379640-A
Country	US
Kind code	B2
Filing date	Dec 15, 2016
Priority date	Apr 23, 2014
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

A method of providing an additive offset of a longitudinal acceleration signal of a traveling motor vehicle. The signal being measured by an inertial sensor is ascertained. At least the longitudinal acceleration signal, a braking signal, and a drive signal are detected. A force balance of the longitudinal dynamic of the motor vehicle is analyzed. The signals are detected both during at least one acceleration process as well as during at least one braking process. The signals during the acceleration processes are detected and/or analyzed separately from the signals during the braking processes, and the additive offset is ascertained by comparing the signals detected during the acceleration processes or the values calculated therefrom with the signals detected during the braking processes or the values calculated therefrom. The invention further relates to an electronic controller.

First claim

What is claimed is:

1. A method for measuring an additive displacement of a longitudinal acceleration signal of a traveling motor vehicle with an inertial sensor comprising:
detecting at least the longitudinal acceleration signal, a brake signal and a drive signal;
analyzing a balance of forces of longitudinal dynamics of the motor vehicle;
detecting the signals for at least one acceleration process and for at least one braking process, wherein the signals for acceleration processes are detected separately from the signals for braking processes;
determining the additive displacement from a comparison of
the signals detected during acceleration processes or values calculated from the signals detected during acceleration process,
with the signals detected during braking processes or values calculated from the signals detected during braking processes, wherein analysis of the balance of forces of longitudinal dynamics includes a determination of a longitudinal force acting on the vehicle using at least one of the drive and brake signal;
determining a first longitudinal acceleration a acc during an acceleration process using the longitudinal acceleration signal;
determining a first longitudinal force F acc at least using the drive signal;
determining a second longitudinal acceleration a dec during a braking process using the longitudinal acceleration signal;
determining a second longitudinal force F dec at least using the brake signal; and
determining an additive displacement a x drift of the longitudinal acceleration according to:

a
x
drift

=

a
acc

⁢

F
dec

-

a
dec

⁢

F
acc

F
dec

-

F
acc

.

2. The method of claim 1 , wherein analysis of the balance of forces of the longitudinal dynamics is only carried out if a stable driving state.

3. The method of claim 2 , wherein the stable driving state is traveling straight ahead.

4. The method of claim 2 , wherein the stable driving state is detected if at least one of the following conditions are met:
a magnitude of an acceleration demand by a driver lies within a predetermined acceleration interval;
a gas pedal operation by the driver exceeds a predetermined threshold value;
a brake pedal operation by the driver exceeds a predetermined threshold value;
a speed of travel of the traveling motor vehicle lies within a predetermined speed interval;
a magnitude of a steering angle set by the driver;
a measured yaw rate below a predetermined steering angle threshold value;
a predetermined yaw rate threshold value;
a magnitude of a change with time of the drive signal lies below a predetermined fluctuation threshold value;
a magnitude of a change with time of the brake signal lies below a predetermined fluctuation threshold value;
the magnitude of the longitudinal acceleration signal exceeds a predetermined minimum threshold value;
magnitude of a measured lateral acceleration lies below a predetermined turn threshold value; and
none of drive dynamics control, brake slip control nor drive slip control is active.

5. The method of claim 1 , wherein a wind resistance force is determined and taken into account using a speed of travel of the vehicle.

6. The method of claim 1 , wherein detecting of the sensor signals is carried out continuously at fixed time intervals.

7. The method of claim 6 , further comprising
determining a first mass using the signals measured during acceleration processes;
determining a second mass using the signals measured during braking processes; and
wherein determining the additive displacement of the longitudinal acceleration signal is carried out if a difference between the first mass and the second mass exceeds a predetermined tolerance threshold value.

8. The method of claim 7 , wherein determining the additive displacement is carried out recursively further comprising:
determining a plurality of the first mass values and the second mass values;
calculating an expected value for the first mass and an expected value for the second mass;
minimizing a difference between the first expected value for the first mass and the expected value for the second mass; and
maintaining the determined additive displacement when a difference between the expected values lies below a termination threshold.

9. The method of claim 8 , wherein the additive displacement is predetermined when the expected value at least one of meets and exceeds the termination threshold.

10. The method of claim 1 , further comprising determining a speed signal using at least one wheel revolution rate sensor.

11. The method of claim 1 , further comprising determining the brake signal is determined using one of a brake pressure sensor and a pedal travel sensor on a brake pedal.

12. The method of claim 1 , further comprising determining the drive signal from at least one of: a drive torque signaled by an engine control unit of an internal combustion engine, by a motor control unit of an electrical drive, and a revolution rate measured on a motor shaft.

13. An electronic control unit for a brake system of a motor vehicle, comprising:
interfaces for connection of at least one wheel revolution rate sensor and at least one brake operation sensor;
at least one inertial sensor disposed in a longitudinal direction and an interface to a vehicle data bus; and
a computing unit with instructions for:
detecting at least a longitudinal acceleration signal, a brake signal and a drive signal;
analyzing a balance of forces of longitudinal dynamics of the motor vehicle;
detecting the signals for at least one acceleration process and for at least one braking process, wherein the signals for acceleration processes are detected separately from the signals for braking processes;
determining an additive displacement from a comparison of the signals detected during acceleration processes or values calculated from the signals detected during acceleration process with the signals detected during braking processes or values calculated from the signals detected during braking processes, wherein analysis of the balance of forces of the longitudinal dynamics is only carried out if a stable driving state, wherein the stable driving state is traveling straight ahead;
determining a first longitudinal acceleration a acc during an acceleration process using the longitudinal acceleration signal,
determining a first longitudinal force F acc at least using the drive signal;
determining a second longitudinal acceleration a dec during a braking process using the longitudinal acceleration signal;
determining a second longitudina

Assignees

• Continental Teves Ag & Co Ohg

Inventors

• Zhang Chen
• Levrier Julien

Classifications

• B60T2250/02

  Vehicle mass · CPC title

• B60T8/17551 Primary

  determining control parameters related to vehicle stability used in the regulation, e.g. by calculations involving measured or detected parameters · CPC title

• B60W2510/182

  Brake pressure, e.g. of fluid or between pad and disc · CPC title

• B60T2250/06

  Sensor zero-point adjustment; Offset compensation · CPC title

• B60W40/105 Primary

  Speed · CPC title