# US 12,594,945 B2 · Detection and remediation of an instability condition in a vehicle-trailer system

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- Number: US 12,594,945 B2
- Document ID: US12594945B2
- Status: Granted
- Kind: B2
- Application number: 18/456,811
- Filed: 2023-08-28
- Published: 2025-03-06
- Granted: 2026-04-07
- Earliest claimed: 2023-08-28
- Assignees: Toyota Motor Engineering & Manufacturing North America, Inc.; Toyota Jidosha Kabushiki Kaisha
- Applicants: Toyota Motor Engineering & Manufacturing North America, Inc.
- Inventors: Christopher James Smalley; Patrick David Jordan; Nicholas Earl Merkel; Brian James Haugen; Steven William Marion
- Web page: https://patentgrep.com/patent/US12594945B2

## CPC

- B60W 30/02: Control of vehicle driving stability
- B60W 50/082: {Selecting or switching between different modes of propelling}
- B60W 30/12: Lane keeping
- B60W 50/14: Means for informing the driver, warning the driver or prompting a driver intervention
- B60W 2040/1307: {Load distribution on each wheel suspension}
- B60W 2040/1315: {Location of the centre of gravity}
- B60W 2300/14: Tractor-trailers, i.e. combinations of a towing vehicle and one or more towed vehicles, e.g. caravans; Road trains
- B60W 2520/125: Lateral acceleration
- B60W 2520/14: Yaw
- B60W 2552/30: Road curve radius
- B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT

## Abstract

A stability monitoring system for detecting an instability condition in a moving vehicle-trailer system includes a processor and a memory communicably coupled to the processor. The memory may store a stability evaluation module configured to determine if a measured value of at least one stability evaluation parameter satisfies an associated predetermined condition. The stability evaluation module may be configured to, if the measured value of the stability evaluation parameter satisfies the associated predetermined condition, determine a total amount of time within a predetermined time period that the measured value of the stability evaluation parameter satisfied the associated predetermined condition. The stability evaluation module may be configured to, if the total amount of time that the measured value of the stability evaluation parameter satisfied the associated predetermined condition exceeds a significant proportion of the predetermined time period, control operation of the vehicle to generate a stability alert.

## Claims

### Claim 1

A stability monitoring system for detecting an instability condition in a moving vehicle-trailer system, the stability monitoring system comprising:
a processor; and
a memory communicably coupled to the processor and storing a stability evaluation module including computer-readable instructions that when executed by the processor cause the processor to:
determine a total amount of time within a predetermined time period that a measured value of at least one stability evaluation parameter satisfied an associated predetermined condition; and
when the total amount of time that the measured value satisfied the predetermined condition exceeds a significant proportion of the time period, control operation of the vehicle to deactivate or prevent activation of a lane tracing assist system of the vehicle.

### Claim 2 (depends on 1)

The stability monitoring system of claim 1, wherein the at least one stability evaluation parameter comprises a yaw rate of the vehicle, and wherein the associated predetermined condition comprises a condition wherein:
(ωM−ωE)/ωE>T1Y)
where ωM=a measured yaw rate, ωE=an expected yaw rate, T1Y=an associated predetermined yaw rate threshold, and wherein the expected yaw rate is determined by the relationship:
ωE=ν/Rp
where ν=a velocity of the vehicle and RP=a perceived curve radius of the vehicle.

### Claim 3 (depends on 1)

The stability monitoring system of claim 1, wherein the at least one stability evaluation parameter comprises a lateral acceleration of the vehicle, and wherein the associated predetermined condition comprises a condition wherein:
(aM−aE)/aE>T2A
where aM=a measured lateral acceleration, aE=an expected lateral acceleration, T2A=an associated predetermined lateral acceleration threshold, and wherein the expected lateral acceleration is determined by the relationship:
aE=ν2/Rp
where ν=a velocity of the vehicle and RP=a perceived curve radius of the vehicle.

### Claim 4 (depends on 1)

The stability monitoring system of claim 1, wherein the at least one stability evaluation parameter comprises a lateral acceleration of the vehicle, and wherein the associated predetermined condition comprises a condition wherein a measured lateral acceleration exceeds an associated predetermined lateral acceleration threshold.

### Claim 5 (depends on 1)

The stability monitoring system of claim 1, wherein the at least one stability evaluation parameter comprises a yaw rate of the vehicle, and wherein the associated predetermined condition comprises a condition wherein a measured yaw rate exceeds an associated predetermined yaw rate threshold.

### Claim 6 (depends on 1)

The stability monitoring system of claim 1, wherein the at least one stability evaluation parameter comprises a yaw rate of the vehicle, and wherein the associated predetermined condition comprises a condition wherein;
(
∫
0
tM
(
ω
M
-
ω
E
)
⁢
d
⁢
ω
)
>
T
⁢
5
⁢
Y
where ωM=a measured yaw rate, and ωE=an expected yaw rate, tM=a most recent previous predetermined time period, T5Y=an associated predetermined threshold value, and wherein the expected yaw rate is determined by the relationship:
ω
E
=
v
R
p
where ν=a velocity of the vehicle and RP=a perceived curve radius of the vehicle.

### Claim 7 (depends on 1)

The stability monitoring system of claim 1, wherein the at least one stability evaluation parameter comprises a lateral acceleration of the vehicle, and wherein the associated predetermined condition comprises a condition wherein:
(
∫
0
tM
(
a
M
-
a
E
)
⁢
d
⁢
ω
)
>
T
⁢
8
⁢
A
where aM=a measured lateral acceleration, aE=an expected lateral acceleration, tM=a most recent previous predetermined time period, and T8A=an associated predetermined threshold value, and wherein the expected lateral acceleration is determined by the relationship:
aE=ν2/Rp
where ν=a velocity of the vehicle and RP=a perceived curve radius of the vehicle.

### Claim 8

A stability monitoring system for detecting an instability condition in a moving vehicle-trailer system, the stability monitoring system comprising:
a processor; and
a memory communicably coupled to the processor and storing a stability evaluation module including computer-readable instructions that when executed by the processor cause the processor to:
if a measured value of at least one stability evaluation parameter satisfies an associated predetermined evaluation parameter condition, determine an accumulation value of the at least one stability evaluation parameter;
if the accumulation value satisfies a first predetermined accumulation condition, set the accumulation value equal to a first limit value; and
if the accumulation value satisfies a second predetermined accumulation condition after being set to the first limit value, control operation of the vehicle to deactivate or prevent activation of a lane tracing assist system of the vehicle.

### Claim 9 (depends on 8)

The stability monitoring system of claim 8, wherein the at least one stability evaluation parameter comprises a yaw rate of the vehicle, wherein the accumulation value of the at least one stability evaluation parameter comprises a delta yaw accumulation based on a difference between a measured yaw rate and an expected yaw rate, and wherein the second predetermined accumulation condition comprises a condition wherein the delta yaw accumulation exceeds an associated predetermined threshold value, and wherein the expected yaw rate is determined by the relationship:
ωE=ν/Rp
where ν=a velocity of the vehicle and RP=a perceived curve radius of the vehicle.

### Claim 10 (depends on 8)

The stability monitoring system of claim 8, wherein the at least one stability evaluation parameter comprises a lateral acceleration of the vehicle, wherein the accumulation value of the at least one stability evaluation parameter comprises a delta lateral acceleration accumulation based on a difference between a measured lateral acceleration and an expected lateral acceleration, and wherein the second predetermined accumulation condition comprises a condition wherein the delta lateral acceleration accumulation exceeds an associated predetermined threshold value, and wherein the expected lateral acceleration is determined by the relationship:
aΣ=ν2/Rp
where ν=a velocity of the vehicle and RP=a perceived curve radius of the vehicle.

### Claim 11 (depends on 8)

The stability monitoring system of claim 8, wherein the stability evaluation module includes computer-readable instructions that when executed by the processor cause the processor to:
if the accumulation value does not satisfy the first predetermined accumulation condition, determine if the accumulation value satisfies a third predetermined accumulation condition;
if the accumulation value satisfies the third predetermined accumulation condition, set the accumulation value equal to a second limit value different from the first limit value; and
if the accumulation value satisfies the second predetermined accumulation condition after being set to the second limit value, deactivate a lane tracing assist system of the vehicle.

### Claim 12

A computer-implemented method for detecting an instability condition in a moving vehicle-trailer system, the method comprising steps of:
determining a total amount of time over a predetermined time period that a measured value of at least one stability evaluation parameter satisfied an associated predetermined condition;
determining if the total amount of time exceeds a significant proportion of the predetermined time period, within a range of 10%-30% (inclusive) of the predetermined time period;
if the total amount of time exceeds the significant proportion of the predetermined time period, controlling operation of the vehicle to deactivate a lane tracing assist system of the vehicle; and
if the total amount of time does not exceed the significant proportion of the predetermined time period, controlling operation of the vehicle to activate the lane tracing assist system.

### Claim 13 (depends on 12)

The method of claim 12, wherein the at least one stability evaluation parameter comprises a yaw rate of the vehicle, and wherein the associated predetermined condition comprises a condition wherein:
(ωM−ωE)/ωE>T1Y)
where ωM=a measured yaw rate, ωE=an expected yaw rate, T1Y=an associated predetermined yaw rate threshold, and wherein the expected yaw rate is determined by the relationship:
ωE=ν/Rp
where ν=a velocity of the vehicle and RP=a perceived curve radius of the vehicle.

### Claim 14 (depends on 12)

The method of claim 12, wherein the at least one stability evaluation parameter comprises a lateral acceleration of the vehicle, and wherein the associated predetermined condition comprises a condition wherein:
(aM−aE)/aE>T2A
where aM=a measured lateral acceleration, aE=an expected lateral acceleration, T2A=an associated predetermined lateral acceleration threshold, and wherein the expected lateral acceleration is determined by the relationship:
aE=ν2/Rp
where ν=a velocity of the vehicle and RP=a perceived curve radius of the vehicle.

### Claim 15 (depends on 12)

The method of claim 12, wherein the at least one stability evaluation parameter comprises a lateral acceleration of the vehicle, and wherein the associated predetermined condition comprises a condition wherein a measured lateral acceleration exceeds an associated predetermined lateral acceleration threshold.

### Claim 16 (depends on 12)

The method of claim 12, wherein the at least one stability evaluation parameter comprises a yaw rate of the vehicle, and wherein the associated predetermined condition comprises a condition wherein a measured yaw rate exceeds an associated predetermined yaw rate threshold.

### Claim 17 (depends on 12)

The method of claim 12, wherein the at least one stability evaluation parameter comprises a yaw rate of the vehicle, and wherein the associated predetermined condition comprises a condition wherein:
(
∫
0
tM
(
ω
M
-
ω
E
)
⁢
d
⁢
ω
)
>
T
⁢
5
⁢
Y
where ωM=a measured yaw rate, ωE=an expected yaw rate, tM=a most recent previous predetermined time period, T5Y=an associated, predetermined threshold value, and wherein the expected yaw rate is determined by the relationship:
ω
E
=
v
R
p
where ν=a velocity of the vehicle and RP=a perceived curve radius of the vehicle.

### Claim 18 (depends on 12)

The method of claim 12, wherein the at least one stability evaluation parameter comprises a lateral acceleration of the vehicle, and wherein the associated predetermined condition comprises a condition wherein:
(
∫
0
tM
(
a
M
-
a
E
)
⁢
d
⁢
ω
)
>
T
⁢
8
⁢
A
where aM=a measured lateral acceleration, aE=an expected lateral acceleration, tM=a most recent previous predetermined time period, and T8A=an associated predetermined threshold value, and wherein the expected lateral acceleration is determined by the relationship:
a
E
=
v
2
/
R
v
where ν=a velocity of the vehicle and RP=a perceived curve radius of the vehicle.

### Claim 19 (depends on 12)

The method of claim 12, further comprising a step of controlling operation of the vehicle to deactivate or prevent activation of a lane tracing assist system of the vehicle if the total amount of time that the measured value of the stability evaluation parameter satisfied the predetermined condition exceeds the significant proportion of the predetermined time period.