NZ752017B2 - Method and system utilized by multi-axle articulated vehicle tracking central lane line - Google Patents
Method and system utilized by multi-axle articulated vehicle tracking central lane line Download PDFInfo
- Publication number
- NZ752017B2 NZ752017B2 NZ752017A NZ75201717A NZ752017B2 NZ 752017 B2 NZ752017 B2 NZ 752017B2 NZ 752017 A NZ752017 A NZ 752017A NZ 75201717 A NZ75201717 A NZ 75201717A NZ 752017 B2 NZ752017 B2 NZ 752017B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- vehicle
- lane line
- front wheel
- steering
- course
- Prior art date
Links
- 230000000007 visual effect Effects 0.000 claims abstract description 46
- 238000000034 method Methods 0.000 claims abstract description 8
- 238000005070 sampling Methods 0.000 claims description 10
- 238000006073 displacement reaction Methods 0.000 claims description 3
- 230000002708 enhancing Effects 0.000 abstract 2
- 238000010586 diagram Methods 0.000 description 6
- 230000005484 gravity Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000003247 decreasing Effects 0.000 description 1
- 239000000686 essence Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006011 modification reaction Methods 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000004642 transportation engineering Methods 0.000 description 1
Abstract
method and system utilized by a multi-axle articulated vehicle tracking a central lane line. The method comprises: S1. acquiring a visual navigation deviation and a navigation estimate of a vehicle; and S2. computing, according to the visual navigation deviation and the navigation estimate of the vehicle, and using an incremental PID algorithm, an expected front wheel turning angle of the vehicle, and controlling a front wheel of the vehicle to change a direction. The system comprises: a lane line identification module, a data acquisition unit, a determination control unit, and an execution unit. The system has advantages of ensuring a vehicle to effectively track, in an automatic driving process, a central lane line, implementing automatic tracking and automatic control of the vehicle with respect to the central lane line, enhancing safe driving, and reducing labor intensity of a driver. vehicle, and using an incremental PID algorithm, an expected front wheel turning angle of the vehicle, and controlling a front wheel of the vehicle to change a direction. The system comprises: a lane line identification module, a data acquisition unit, a determination control unit, and an execution unit. The system has advantages of ensuring a vehicle to effectively track, in an automatic driving process, a central lane line, implementing automatic tracking and automatic control of the vehicle with respect to the central lane line, enhancing safe driving, and reducing labor intensity of a driver.
Description
METHOD AND SYSTEM UTILIZED BY MULTI-AXLE ARTICULATED VEHICLE
TRACKING CENTRAL LANE LINE
FIELD
[0001] The present disclosure relates to the technical field of multi-axle steering vehicle
control, and in particular to a steering control method for a multi-axle steering vehicle
tracking a central lane line, and a steering control system for a multi-axle steering vehicle
tracking a central lane line.
BACKGROUND
As a new-type urban public vehicle, the multi-axle steering rubber-tyred train has
the following features: being railless, sharing the road with conventional vehicles, and
travelling without tracking a fixed rail. The multi-axle steering rubber-tyred train not only has
the advantages of running flexibly and having low capital and maintenance cost like the bus,
but also has the large transportation capacity. Further, the multi-axle steering rubber-tyred
train does not have disadvantages of having high cost in construction of infrastructures and
vehicle purchase as that in the subway, the light railway and the tramcar, which requires a
specific power system and a specific rail.
The multi-axle steering rubber-tyred train flexibly travels along the ground mark
lines under support of rubber wheels like the cars, rather than tracking a steel rail. Since the
train does not track the fixed rail, the capital cost is decreased, and the multi-axle steering
rubber-tyred train has larger operation advantages than the tramcar. The steering of the
tramcar is not required to be controlled by a driver, while the steering of the multi-axle
steering rubber-tyred train is required to be controlled by the driver by continuously adjusting
the steering wheel to track the ground mark line (such as a central lane line, a white double
dashed line) in a real time manner. In this case, driver fatigue is inevitable due to the long
term driving. Therefore, it is desired to provide a device for automatically recognizing the
central lane line to achieve the lane keeping of the multi-axle steering vehicle, so as to reduce
the driver fatigue.
SUMMARY
In view of the technical problems existing in the conventional technology, a steering
control method for a multi-axle steering vehicle tracking a central lane line and a steering
control system for a multi-axle steering vehicle tracking a central lane line are provided in the
present disclosure, which can ensure the vehicle to effectively track the central lane line
during an automatic driving process, so that the automatic tracking and keeping of the vehicle
with respect to the central lane line can be achieved, thereby improving the driving safety and
reducing the workload of a driver.
In order to solve the above technical problems, a steering control method for a
multi-axle steering vehicle tracking a central lane line is provided according to technical
solutions of the present disclosure. The method includes:
S1, acquiring a visual course deviation and a predicted course of the vehicle; and
S2, calculating, based on the visual course deviation and the predicted course, a desired
front wheel steering angle of the vehicle by using an incremental PID algorithm to control
front wheel steering of the vehicle, wherein
the visual course deviation indicates an angle between the central line of the vehicle and
a line connecting a preview point and a center point of the vehicle, and the predicted course
indicates a predicated change amount of a course of the vehicle in a preset time period.
As a further improvement for the preset disclosure, the visual course deviation is
acquired by a lane line visual recognition system of the vehicle.
As a further improvement for the preset disclosure, the predicted course is
determined by calculating a ratio of a longitudinal displacement of the vehicle to a turning
radius of the vehicle in a preset time period.
As a further improvement for the preset disclosure, a front wheel steering angle of
the vehicle and a distance between a front axle and a rear axle of the vehicle are acquired, and
the turning radius of the vehicle is calculated from a trigonometric relationship between the
turning radius of the vehicle, the distance between the front axle and the rear axle of the
vehicle, and the front wheel steering angle of the vehicle.
As a further improvement for the preset disclosure, the incremental PID algorithm in
step S2 is expressed as the following formula (1):
u = u(k) −u(k −1) = K [e(k) −e(k −1)] + K e(k) + K [e(k) −2e(k −1) + e(k −2)]
p i d
in the formula (1), u represents an increment of the front wheel steering angle of the
uk ()
vehicle, represents a front wheel steering angle at a k-th sampling time instant, where
ek ()
k=0, 1, 2, …, represents an equivalent course deviation at the k-the sampling time
instant, ek () = − , represents the visual course deviation, and represents
the predicted course.
As a general inventive concept, a steering control system for a multi-axle steering
vehicle tracking a central lane line is further provided in the present disclosure. The steering
control system includes a lane line visual recognition module, a data acquisition unit, a
decision control unit and an execution unit. The lane line visual recognition module is
configured to recognize a lane line and provide information on a visual course deviation of
the vehicle to the decision control unit. The data acquisition unit is configured to: acquire
speed information of the vehicle and front wheel steering angle information of the vehicle,
and provide the speed information of the vehicle and the front wheel steering angle
information of the vehicle to the decision control unit. The decision control unit is configured
to: calculate a predicted course of the vehicle based on the speed information of the vehicle
and the front wheel steering angle information of the vehicle provided by the data acquisition
unit; calculate a desired front wheel steering angle of the vehicle based on the predicted
course and the visual course deviation; and provide the desired front wheel steering angle to
the execution unit. The execution unit is configured to control steering of the vehicle based on
the desired front wheel steering angle. The visual course deviation indicates an angle between
the central line of the vehicle and a line connecting a preview point and a center point of the
vehicle, and the predicted course indicates a predicated change amount of a course of the
vehicle in a preset time period.
[0011] As a further improvement for the preset disclosure, the lane line visual recognition
module includes a camera and an image processing system. The camera is configured to
acquire an image of the lane line. The image processing system is configured to perform an
analysis process on the image of the lane line to acquire the visual course deviation.
As a further improvement for the preset disclosure, the data acquisition unit includes
a front wheel steering angle sensor and a vehicle speed sensor. The front wheel steering angle
sensor is configured to acquire the front wheel steering angle information of the vehicle. The
vehicle speed sensor is configured to acquire the speed information of the vehicle.
[0013] As a further improvement for the preset disclosure, the decision control unit has a
manual driving mode in which the decision control unit does not provide the desired front
wheel steering angle to the execution unit.
As a further improvement for the preset disclosure, the data acquisition unit further
includes a torque sensor. The torque sensor is configured to acquire information on an
external force applied to a steering wheel of the vehicle, and transmit the information on the
external force to the decision control unit. The decision control unit operates in the manual
driving mode in response to the information on the external force.
Compared with the conventional technology, the present disclosure has the
following advantages. With the technical solutions of the present disclosure, the vehicle can
be ensured to effectively track the central lane line during an automatic driving process, so
that automatic tracking and keeping of the vehicle with respect to the central lane line can be
achieved, thereby improving the driving safety and reducing the workload of a driver.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 is a schematic flowchart of a steering control method according an
embodiment of the present disclosure;
Figure 2 is a schematic diagram showing an arrangement of a system for tracking a
central lane line provided in the present disclosure;
Figure 3 is a schematic diagram showing course prediction and preview provided in
the present disclosure;
Figure 4 is a schematic diagram showing a central lane line provided in the present
disclosure;
Figure 5 is a schematic diagram showing a two-degree-of-freedom course prediction
model for a vehicle provided in the present disclosure;
Figure 6 is a schematic flowchart of calculating a desired front wheel steering angle
provided in the present disclosure;
Figure 7 is a schematic diagram showing a first structure of a steering control system
for tracking a central lane line provided in the present disclosure; and
[0023] Figure 8 is a schematic diagram showing a second structure of the steering control
system for tracking a central lane line provided in the present disclosure.
DETAILED DESCRIPTION OF EMBODIMENTS
The present disclosure is further described below in combination with the drawings
and some preferred embodiments, and the protection scope of the present disclosure is not
limited hereto.
As shown in Figure 1, a steering control method for a multi-axle steering vehicle
tracking a central lane line is provided according to an embodiment of the present
embodiment. The steering control method includes the following steps S1 and S2. In S1, a
visual course deviation and a predicted course of the vehicle are acquired. In S2, a desired
front wheel steering angle of the vehicle is calculated based on the visual course deviation and
the predicted course by using an incremental PID algorithm to control front wheel steering of
the vehicle.
In this embodiment, based on vehicle road information provided by a lane line visual
recognition module, information such as a lateral distance deviation yL between a preview
point and a center of a lane line, a course angle Δψ, and a curvature of a road are acquired to
determine the desired front wheel steering angle. The determined desired front wheel steering
angle is transmitted to a steering execution unit, to control the vehicle to follow a desired
path.
[0027] In this embodiment, the visual course deviation is acquired by a lane line visual
recognition system of the vehicle. As shown in Figure 2, in the lane line visual recognition
system, a camera module is installed on the head of the vehicle to acquire image information
of the central lane line by using a monocular camera, and an image processing system
performs an analysis process on the image information to obtain the information such as a
lateral distance deviation between a center of the vehicle and the lane line, the course
deviation, and the curvature of the road. Then a course angle deviation between the preview
point and a central line of the vehicle is calculated. In this embodiment, by setting a position
in front of the vehicle as the preview point, the automatical control for the lane line tracking is
inherently consistent with the manual steering performed by a driver, so that the steering
control for the vehicle performed based on the visual course deviation acquired by the lane
line visual recognition system provided in the present disclosure just like being controlled by
the driver. As shown in Figure 3, which shows course prediction and preview in the lane line
visual recognition system, XOY represents a ground coordinate system, xoy represents a
vehicle coordinate system, p represents a preview point, d represents a preview distance, y1
represents a predicted deviation, and f(d) represents a distance deviation at a preview point.
The central lane line is indicated by a mark painted on a ground of a central lane, and is
represented as a double dashed line having a certain length and a certain width. As shown in
Figure 4, l =50cm, l =50cm, l =10cm and l =25cm. The lane may be accurately determined
1 2 3 4
by processing the image of the lane acquired by the camera.
[0028] In the conventional course control, a controller acquires a course deviation based on
a desired course and an actual course of the vehicle to calculate a control quantity, and an
executing mechanism executes the control quantity after one sampling period elapses. In this
case, the actual course of the vehicle is changed, that is, there is a delay of one sampling
period when the control quantity is executed. However, in the course prediction method
provided in the present disclosure, a change trend of the course of the vehicle is predicted in
advance, and is added in the control deviation, so that an output of the controller is affected by
the change trend of the course of the vehicle, and thus the central lane line is tracked better.
In this embodiment, the predicted course is determined by calculating a ratio of a
longitudinal displacement of the vehicle to a turning radius of the vehicle in a preset time
period. Reference is made to Figure 5, which shows a two-degree-of-freedom course
prediction model (i.e., a half model) of the vehicle. In this embodiment, a sampling period T
() rad
of the controller is taken as a preset time period, and a change quantity of the
vehicle course in a control period may be expressed as the following formula (2):
= vT / R
in the formula (2), represents a predicted course, represents a longitudinal
speed of the vehicle, T represents a sampling period of the controller, and R represents a
turning radius of the vehicle.
In this embodiment, a front wheel steering angle of the vehicle and a distance
between a front axle and a rear axle of the vehicle are acquired, and the turning radius of the
vehicle is calculated from a trigonometric relationship between the turning radius of the
vehicle, the distance between the front axle and the rear axle of the vehicle, and the front
wheel steering angle of the vehicle. As shown in Figure 5, G represents a gravity center of
the vehicle, R represents a turning radius of the vehicle, represents a distance between
the gravity center of the vehicle and the front axle of the vehicle, b represents a distance
between the gravity center of the vehicle and the rear axle of the vehicle, represents a
front wheel steering angle of the vehicle, and ab + represents a distance between the front
axle of the vehicle and the rear axle of the vehicle. Since a connection line between a center
O of a turning circle of the vehicle and the front axle of the vehicle is perpendicular to a
direction in which the front wheel of the vehicle travels, the following formula (3) is obtained
from the trigonometric relationship in a right-angled triangle shown in Figure 6.
R=+ (a b) / sin( )
The formula (3) is substituted into the formula (2) to obtain the predicted course
expressed by the following formula (4):
= vT sin( ) / (a + b)
The parameters in the formula (4) are identical to those in the formulas (2) and (3).
Reference is made to Figure 6. In this embodiment, the incremental PID algorithm
in step S2 is expressed as the following formula (1):
u = u(k) −u(k −1) = K [e(k) −e(k −1)] + K e(k) + K [e(k) −2e(k −1) + e(k −2)]
p i d
in the formula (1), u represents an increment of the front wheel steering angle of the
vehicle, uk () represents a front wheel steering angle at a k-th sampling time instant, where
k=0, 1, 2, …, ek () represents an equivalent course deviation at the k-the sampling time
ek () = −
instant, , represents the visual course deviation, and represents
the predicted course.
As shown in Figure 7 and Figure 8, a steering control system for a multi-axle
steering vehicle tracking a central lane line is provided according to an embodiment of the
present disclosure. The steering control system includes a lane line visual recognition module,
a data acquisition unit, a decision control unit and an execution unit. The lane line visual
recognition module is configured to recognize a lane line and provide information on a visual
course deviation of the vehicle to the decision control unit. The data acquisition unit is
configured to: acquire speed information of the vehicle and front wheel steering angle
information of the vehicle, and provide the speed information of the vehicle and the front
wheel steering angle information of the vehicle to the decision control unit. The decision
control unit is configured to: calculate a predicted course of the vehicle based on the speed
information of the vehicle and the front wheel steering angle information of the vehicle
provided by the data acquisition unit; calculate a desired front wheel steering angle of the
vehicle based on the predicted course and the visual course deviation; and provide the desired
front wheel steering angle to the execution unit. The execution unit is configured to control
steering of the vehicle based on the desired front wheel steering angle.
In this embodiment, the lane line visual recognition module includes a camera and
an image processing system. The camera is configured to acquire an image of the lane line.
The image processing system is configured to perform an analysis process on the image of the
lane line to acquire the visual course deviation. The data acquisition unit includes a front
wheel steering angle sensor and a vehicle speed sensor. The front wheel steering angle sensor
is configured to acquire the front wheel steering angle information of the vehicle. The vehicle
speed sensor is configured to acquire the speed information of the vehicle.
In this embodiment, the decision control unit has a manual driving mode in which
the decision control unit does not provide the desired front wheel steering angle to the
execution unit. The data acquisition unit further includes a torque sensor. The torque sensor is
configured to acquire information on an external force applied to a steering wheel of the
vehicle, and transmit the information on the external force to the decision control unit. The
decision control unit operates in the manual driving mode in response to the information on
the external force. In this embodiment, the decision control unit may acquire a signal for
switching on the manual driving mode via a human machine interface connected with the
decision control unit. The decision control unit includes a computer communication interface
via which a computer is connected to the decision control unit. In this case, control programs
are written via a CAN bus, and changes of the parameters are monitored.
The above description shows only some preferred embodiments of the present
disclosure, and is not intended to limit the present disclosure in any form. Although the
present disclosure has been disclosed as above in the preferred embodiments, the present
disclosure is not limited thereto. Therefore, simple variants, equivalent changes and
modifications made to the above embodiments from the technical essences of the present
disclosure without departing from the technical solutions of the present disclosure should fall
in the protection scope of the present disclosure.
Claims (10)
1. A steering control method for a multi-axle steering vehicle tracking a central lane line, the steering control method comprising: 5 S1, acquiring a visual course deviation and a predicted course of the vehicle; and S2, calculating, based on the visual course deviation and the predicted course, a desired front wheel steering angle of the vehicle by using an incremental PID algorithm to control front wheel steering of the vehicle, wherein the visual course deviation indicates an angle between the central line of the vehicle and 10 a line connecting a preview point and a center point of the vehicle, and the predicted course indicates a predicated change amount of a course of the vehicle in a preset time period.
2. The steering control method for a multi-axle steering vehicle tracking a central lane line according to claim 1, wherein the visual course deviation is acquired by a lane line visual recognition system of the vehicle. 15
3. The steering control method for a multi-axle steering vehicle tracking a central lane line according to claim 2, wherein the predicted course is determined by calculating a ratio of a longitudinal displacement of the vehicle to a turning radius of the vehicle in a preset time period.
4. The steering control method for a multi-axle steering vehicle tracking a central lane 20 line according to claim 3, wherein a front wheel steering angle of the vehicle and a distance between a front axle and a rear axle of the vehicle are acquired, and the turning radius of the vehicle is calculated from a trigonometric relationship between the turning radius of the vehicle, the distance between the front axle and the rear axle of the vehicle, and the front wheel steering angle of the vehicle. 25 5. The steering control method for a multi-axle steering vehicle tracking a central lane line according to any one of claims 1 to 4, wherein the incremental PID algorithm in step S2 is expressed as the following formula (1): u = u(k) −u(k −1) = K [e(k) −e(k −1)] + K e(k) + K [e(k) −2e(k −1) + e(k −2)] p i d in the formula (1), u represents an increment of the front wheel steering angle of the vehicle, uk () represents a front wheel steering angle at a k-th sampling time instant, wherein ek () k=0, 1, 2, …, represents an equivalent course deviation at the k-the sampling time ek () = − instant, , represents the visual course deviation, and represents the predicted course.
5
6. A steering control system for a multi-axle steering vehicle tracking a central lane line, the steering control system comprising: a lane line visual recognition module; a data acquisition unit; a decision control unit; and 10 an execution unit, wherein the lane line visual recognition module is configured to recognize a lane line and provide information on a visual course deviation of the vehicle to the decision control unit; the data acquisition unit is configured to: acquire speed information of the vehicle and front wheel steering angle information of the vehicle, and provide the speed information of 15 the vehicle and the front wheel steering angle information of the vehicle to the decision control unit; the decision control unit is configured to: calculate a predicted course of the vehicle based on the speed information of the vehicle and the front wheel steering angle information of the vehicle provided by the data acquisition unit; calculate a desired front wheel steering 20 angle of the vehicle based on the predicted course and the visual course deviation; and provide the desired front wheel steering angle to the execution unit; and the execution unit is configured to control steering of the vehicle based on the desired front wheel steering angle, wherein the visual course deviation indicates an angle between the central line of the vehicle and 25 a line connecting a preview point and a center point of the vehicle, and the predicted course indicates a predicated change amount of a course of the vehicle in a preset time period.
7. The steering control system for a multi-axle steering vehicle tracking a central lane line according to claim 6, wherein the lane line visual recognition module comprises: a camera configured to acquire an image of the lane line; and an image processing system configured to perform an analysis process on the image of 5 the lane line to acquire the visual course deviation.
8. The steering control system for a multi-axle steering vehicle tracking a central lane line according to claim 7, wherein the data acquisition unit comprises: a front wheel steering angle sensor configured to acquire the front wheel steering angle information of the vehicle; and 10 a vehicle speed sensor configured to acquire the speed information of the vehicle.
9. The steering control system for a multi-axle steering vehicle tracking a central lane line according to claim 8, wherein the decision control unit has a manual driving mode in which the decision control unit does not provide the desired front wheel steering angle to the execution unit. 15
10. The steering control system for a multi-axle steering vehicle tracking a central lane line according to claim 9, wherein the data acquisition unit further comprises: a torque sensor configured to: acquire information on an external force applied to a steering wheel of the vehicle, and transmit the information on the external force to the decision control unit, wherein 20 the decision control unit operates in the manual driving mode in response to the information on the external force. Acquire a visual course deviation and a predicted course of a vehicle Calculate, based on the visual course deviation and the predicted course, a desired front wheel steering angle of the vehicle by using an incremental PID algorithm to control front wheel steering of the vehicle
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
CN201610910594.9A CN107933686B (en) | 2016-10-19 | 2016-10-19 | A kind of multi-shaft steering vehicle tracking center lane line rotating direction control method and system |
CN201610910594.9 | 2016-10-19 | ||
PCT/CN2017/106045 WO2018072647A1 (en) | 2016-10-19 | 2017-10-13 | Method and system utilized by multi-axle articulated vehicle tracking central lane line |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ752017A NZ752017A (en) | 2020-10-30 |
NZ752017B2 true NZ752017B2 (en) | 2021-02-02 |
Family
ID=
Similar Documents
Publication | Publication Date | Title |
---|---|---|
WO2018072647A1 (en) | Method and system utilized by multi-axle articulated vehicle tracking central lane line | |
CN109520498B (en) | Virtual turnout system and method for virtual rail vehicle | |
CN107963126B (en) | Large-curvature automatic driving steering control method for multi-axle steering vehicle | |
CN107139917B (en) | It is a kind of based on mixing theoretical pilotless automobile crosswise joint system and method | |
CN108482370B (en) | Commercial vehicle lane keeping system and control strategy design thereof | |
US10435024B2 (en) | Driving support apparatus performing driving support based on reliability of each detection apparatus | |
US12054149B2 (en) | Vision-based follow the leader lateral controller | |
CN106740811B (en) | The self-steering method of bend automatic steering system and the bend based on the system | |
WO2020029462A1 (en) | Self-driving system for electric vehicle | |
US10994744B2 (en) | Travel control apparatus, travel control method, and non-transitory computer-readable storage medium | |
CN103223975B (en) | For make the method for Vehicular turn by means of steering assist system | |
CN108058706B (en) | Lane keeping system and method | |
CN103921788A (en) | Automobile traveling control system and automobile traveling control method | |
CN105197010A (en) | Auxiliary parking system and auxiliary parking control method | |
JP6377942B2 (en) | Driving assistance device | |
CN104691609A (en) | Algorithm for steering angle command to torque command conversion | |
CN110389589A (en) | Intelligent driving vehicle obstacle-avoidance system and method | |
US20180170429A1 (en) | Deviation avoidance apparatus | |
CN105329238A (en) | Self-driving car lane changing control method based on monocular vision | |
CN104245462A (en) | Vehicle driving support system, and road frictional condition inferring system | |
CN114084158B (en) | Automatic driving redundancy control system | |
CN105059287A (en) | Lane keeping method and device | |
US10773723B2 (en) | Method and device for adapting a vehicle velocity for a vehicle | |
US20230027357A1 (en) | Vehicle control system, vehicle control method, and storage medium | |
CN111103882A (en) | Autonomous following control method for unmanned electric vehicle |