Integrated bank and roll estimation using a three-axis inertial-measuring device

Patent metadata

Field	Value
Publication number	US-9616900-B2
Application number	US-201414888630-A
Country	US
Kind code	B2
Filing date	May 2, 2014
Priority date	May 2, 2013
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

A system, for use at a vehicle to estimate vehicle roll angle and road bank angle, in real time and generally simultaneously. The system includes a sensor configured to measure vehicle roll rate, a processor; and a computer-readable medium. The medium includes instructions that, when executed by the processor, cause the processor to perform operations comprising estimating, using an observer and the vehicle roll rate measured by the sensor, a vehicle roll rate. The operations also include estimating, using an observer and a measured vehicle roll rate, the vehicle roll angle, and estimating, based on the vehicle roll rate estimated and the vehicle roll angle estimated, the road bank angle.

First claim

What is claimed:

1. A system, for use at a vehicle to estimate vehicle roll angle and a road bank angle, comprising:
a sensor configured to measure vehicle roll rate;
a processor; and
a non-transitory computer-readable medium comprising computer-executable instructions that, when executed by the processor, cause the processor to perform operations comprising:
estimating, using a virtual observer and the vehicle roll rate measured by the sensor, a vehicle roll rate, yielding an estimated vehicle roll rate;
estimating, using the virtual observer and the vehicle roll rate measured by the sensor, the vehicle roll angle, yielding an estimated vehicle roll angle; and
estimating, based on the estimated vehicle roll rate and the estimated vehicle roll angle, the road bank angle;

wherein:
the instructions include the virtual observer, including an observer gain; and
the estimated vehicle roll rate is more accurate than the vehicle roll rate measured due at least in part to use of the virtual observer and the observer gain.

2. The system of claim 1 , wherein the sensor is, or is part of a three-axis inertial-measurement unit.

3. The system of claim 1 , wherein the vehicle roll rate measured differs from the estimated vehicle roll rate.

4. The system of claim 1 , wherein:
the operation of estimating the estimated vehicle roll rate comprises estimating the estimated vehicle roll rate using the vehicle roll rate measured and the virtual observer including a Luenberger observer, and a one-degree-of-freedom model; and
the operation of estimating the vehicle roll angle comprises estimating the vehicle roll angle using the vehicle roll rate measured and the virtual observer being the Luenberger observer, and the one-degree-of-freedom model.

5. The system of claim 1 , wherein the operations further include tuning at least one observer gain of the virtual observer.

6. The system of claim 5 , wherein the tuning includes using an optimization tool toward achieving optimal gains for multiple scenarios.

7. The system of claim 5 , wherein results from the tuning are incorporated into an organizing structure relating each of multiple observer gains with a distinct vehicle-related condition.

8. The system of claim 7 , wherein the organizing structure includes a table.

9. The system of claim 5 , wherein:
the operations are part of a process;
the tuning is performed in a tuning sub-routine; and
a first input to the tuning sub-routine is the vehicle roll rate measured, and a second input to the tuning sub-routine is the estimated vehicle roll rate from a last iteration of the process.

10. The system of claim 9 , wherein:
an output of the virtual observer is provided to an estimator sub-routine, which estimates the vehicle roll angle, vehicle roll rate, and road bank angle, and an input to the estimator sub-routine is a lateral acceleration; and
the lateral acceleration is a measured value.

11. The system of claim 1 , wherein an observer gain of the virtual observer is pre-determined, including by tuning before the system is used by a customer.

12. The system of claim 1 , wherein the vehicle roll rate measured is measured by a three-axis inertial-measuring device.

13. A system, for use at a vehicle to estimate vehicle roll angle and a road bank angle, comprising:
a sensor configured to measure vehicle roll rate;
a processor; and
a non-transitory computer-readable medium comprising computer-executable instructions that, when executed by the processor, cause the processor to perform operations comprising:
estimating, using a virtual observer and the vehicle roll rate measured by the sensor, a vehicle roll rate, yielding an estimated vehicle roll rate;
estimating, using the virtual observer and the vehicle roll rate measured, the vehicle roll angle, yielding an estimated vehicle roll angle; and
estimating, based on the estimated vehicle roll rate and the estimated vehicle roll angle, the road bank angle; and
wherein:
the operation of estimating the estimated vehicle roll rate comprises estimating the estimated vehicle roll rate using the vehicle roll rate measured and the virtual observer including a Luenberger observer, and a one-degree-of-freedom model; and
the operation of estimating the vehicle roll angle comprises estimating the vehicle roll angle using the vehicle roll rate measured and the virtual observer being the Luenberger observer, and the one-degree-of-freedom model.

14. The system of claim 13 , wherein the virtual observer and model can be represented by relationships including:
( J xx +M s h 2 ){umlaut over (θ)}+ C θθ {dot over (θ)}+K θθ θ=M s ha y   (eqn. 1);

wherein:
J xx is a roll moment of inertia of the vehicle;
M s is a sprung mass;
h is a height of the center of gravity of the sprung portion of the vehicle measured from a roll center;
ë (or, second derivative of theta, or theta^dot-dot) represents a roll acceleration;
C θθ represents a vehicle damping coefficient;
{dot over (θ)} (or, first derivative of theta, or, θ^dot) represents a roll velocity;
K θθ represents a vehicle roll stiffness coefficient;
θ represents the roll angle being estimated;
a y represents linear lateral acceleration;
{dot over (θ)}= q+L 1 ( q meas −q )  (eqn. 2);

q is the roll rate being estimated;
L 1 represents a first observer gain;
q meas represents measured roll rate;
{dot over (q)}={−C θθ [q+L 2 ( q meas −q )]− K θθ θ+M s ha y }J xx −1   (eqn. 3);

{dot over (q)} (or, first derivative of q, or, q^dot) represents the first derivative of the roll rate being estimated; and
L 2 is a second observer gain.

15. The system of claim 14 , wherein the operation of estimating the road bank angle (β), comprises:
a y,s =a y cos(φ−β)+ g sin(φ−β)  (eqn. 4);

wherein:
a y,s represents a mass-sprung lateral acceleration; and
a y represents the lateral acceleration;
θ represents the roll angle being estimated;
β represents the road bank angle;
g represents gravity;
− a y ={dot over (v)} y +rv x +O (β 2 )  (eqn. 5);

wherein:
{dot over (v)} y (V y ^dot) represents a first derivative of lateral velocity of the vehicle 100 ;
r represents a yaw rate ({dot over (ψ)}, or, first derivative of Roman numeral psi, ψ^dot);
v x is longitudinal, or forward, x-direction, velocity;
O represents a high-order function; and

ϕ
-
β

=

arcsin
⁢

a

y
,
s

a
y
2

+

g
2

Assignees

• Gm Global Tech Operations Llc

Inventors

• Chen Shih-Ken
• Sidlosky David M
• Chen Jin-Jae
• Moshchuk Nikolai K

Classifications

• B60W40/06

  Road conditions · CPC title

• B60W2420/905

  the sensor being an xyz axis sensor · CPC title

• B60W2400/00

  Indexing codes relating to detected, measured or calculated conditions or factors · CPC title

• B60W30/04

  related to roll-over prevention · CPC title

• B60W40/112 Primary

  Roll movement · CPC title