WO2011046403A2

WO2011046403A2 - Autonomous driving apparatus and method of on-line electric vehicle

Info

Publication number: WO2011046403A2
Application number: PCT/KR2010/007106
Authority: WO
Inventors: Dongho Cho; Youjun Choi; Sunjong Lee; Jin Kyu Kim
Original assignee: Korea Advanced Institute Of Science And Technology
Priority date: 2009-10-16
Filing date: 2010-10-15
Publication date: 2011-04-21
Also published as: KR101204504B1; KR20110041948A; WO2011046403A3

Abstract

An autonomous driving apparatus mounted on an on-line electric vehicle having a power collection device supplied with power from a power supply device includes a plurality of lateral magnetic sensors installed in the on-line electric vehicle to sense lateral magnetic field values generated from the power supply device with respect to a driving direction of the on-line electric vehicle, a longitudinal magnetic sensor installed in the on-line electric vehicle to sense a longitudinal magnetic value generated from the power supply device with respect to the driving direction of the on-line electric vehicle, and a microprocessor for calculating a tilt angle between the driving direction of the on-line electric vehicle and the longitudinal direction of the power supply road by using the lateral magnetic field values and the longitudinal magnetic field value and determining a lateral position of the on-line electric vehicle by using the calculated tilt angle.

Description

AUTONOMOUS DRIVING APPARATUS AND METHOD OF ON-LINE ELECTRIC VEHICLE

The present invention relates to autonomous driving apparatus and method of an on-line electric vehicle, and more particularly, to autonomous driving apparatus and method of an on-line electric vehicle for controlling the position of the on-line electric vehicle based on estimated values by using sensors mounted thereon.

As is well known, the existing battery-powered electric vehicle have caused problems such as an excessive battery capacity, an increase in weight, a volume and price of a vehicle, a long charging time, a large-capacity charging facility, a low charging efficiency, and a battery life reduction. To solve these problems, a contactless power delivery method using magnetic induction has been proposed. In particular, an on-line electric vehicle has been developed to get the power from the road having power lines during his travel and charge a battery of a vehicle, which is disclosed in WO 2010/098547.

Meanwhile, in order to drive an unmanned electric or engine vehicle, the method using magnet markers, vision sensors or laser sensors has been proposed.

As for the method using magnet markers, magnet markers are installed at regular intervals in a longitudinal direction of a road, and a magnetic sensor is mounted on an unmanned vehicle to measure the intensity of a magnetic field generated from the magnet markers. Then, a distance between the magnet markers adjacent in the longitudinal direction of the road is calculated based on the measured intensity of the magnetic field. In this manner, an autonomous driving of the vehicle can be achieved.

As for the method using the vision sensors, information on a road shape is acquired through lane recognition and an autonomous driving of the vehicle is achieved along the recognized lane.

Also, as for the method using the laser sensors, road information can be acquired by using reflected lasers and an autonomous driving of the vehicle is achieved along a lane by using the acquired road information.

However, the method using the magnet marker has a problem that a lateral position may not be recognized. Further, the method using the vision sensor has a problem that the lane may not be recognized when a state of a lane is poor. Furthermore, the method using the laser sensor has a problem that it is not practical because the laser sensor mounted on a vehicle is expensive, and it is difficult to acquire information on a road shape even though information on obstacles placed in front of the vehicle can be acquired.

It is, therefore, an object of the present invention to provide autonomous driving method and apparatus of an on-line electric vehicle for controlling the position of the on-line electric vehicle based on a tilt angle and a lateral position estimated from the plurality of lateral magnetic sensors and one or more longitudinal magnetic sensors.

In accordance with an embodiment of the present invention, there is provided an autonomous driving apparatus mounted on an on-line electric vehicle including a power collection device supplied with power from a power supply device through a magnetic induction, the power supply device being installed on a power supply road in a longitudinal direction, the apparatus comprising: a plurality of lateral magnetic sensors installed in the on-line electric vehicle to sense lateral magnetic field values generated from the power supply device with respect to a driving direction of the on-line electric vehicle; a longitudinal magnetic sensor installed in the on-line electric vehicle to sense a longitudinal magnetic value generated from the power supply device with respect to the driving direction of the on-line electric vehicle; a microprocessor for calculating a tilt angle between the driving direction of the on-line electric vehicle and the longitudinal direction of the power supply road by using the lateral magnetic field values and the longitudinal magnetic field value, which are inputted from the lateral magnetic sensors and the longitudinal magnetic sensor, and determining a lateral position of the on-line electric vehicle by using the calculated tilt angle; and a vehicle control module for determining the driving direction of the on-line electric vehicle by using the calculated tilt angle and the determined lateral position information which are provided from the microprocessor, and controlling the position of the on-line electric vehicle through a steering and acceleration/deceleration control of the on-line electric vehicle based on the determined driving direction.

In accordance with another embodiment of the present invention, there is provided An autonomous driving method of an on-line electric vehicle having the autonomous driving apparatus including a plurality of lateral magnetic sensors, a longitudinal magnetic sensor, a microprocessor and a vehicle control module, the method comprising: receiving lateral magnetic field values and the longitudinal magnetic field value estimated from the lateral magnetic sensors and the longitudinal magnetic sensors, and operating the microprocessor to calculate a tilt angle between a driving direction of the on-line electric vehicle and a longitudinal direction of the power supply road; operating the microprocessor to adjust a scale of the lateral magnetic value based on the tilt angle; operating the microprocessor to estimate a lateral position of the on-line electric vehicle by matching a pattern of the scale-adjusted lateral magnetic field values which is outputted from the microprocessor, with a reference lateral magnetic field pattern, which is previously stored or is transmitted in real time; and estimating the driving direction of the on-line electric vehicle based on the estimated angle and the estimated lateral position, which are provided from the microprocessor.

The above and other objects and features of the present invention will become apparent from the following description of embodiments given in conjunction with the accompanying drawings, in which:

Fig. 1 is a diagram explaining an on-line electric vehicle with an autonomous driving apparatus and a power supply device embedded in parallel to a power supply road in accordance with an embodiment of the present invention.

Fig. 2 is a block diagram illustrating the structure of the autonomous driving apparatus of the on-line electric vehicle in accordance with an embodiment of the present invention.

Fig. 3 is a flowchart explaining an autonomous driving method of an on-line electric vehicle in accordance with an embodiment of the present invention.

Fig. 4 is a diagram explaining angle estimation in the autonomous driving method of the on-line electric vehicle in accordance with the embodiment of the present invention.

Figs. 5 and 6 are diagrams explaining a method for representing a matched pattern between a reference lateral magnetic field pattern (P_ref) and sensed lateral magnetic field values in the autonomous driving method of the on-line electric vehicle in accordance with the embodiment of the present invention

Fig. 7 is a graph showing the transformation of the magnetic field sensed on the power supply road, based on a predetermined equation.

Hereinafter, certain preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a diagram explaining an on-line electric vehicle with an autonomous driving apparatus and a power supply device embedded in parallel to a power supply road in accordance with an embodiment of the present invention. Fig. 2 is a block diagram illustrating the structure of the autonomous driving apparatus of the on-line electric vehicle in accordance with an embodiment of the present invention. In particular, a front view of the on-line electric vehicle and a top view of the power supply device are illustrated in Fig. 1.

Referring to Figs. 1 and 2, the autonomous driving apparatus 100 of the on-line electric vehicle 101 in accordance with the embodiment of the present invention includes lateral magnetic sensors 110, a longitudinal magnetic sensor 120, analog-to-digital (A/D)

converters

130 and 140, a microprocessor 150, a vehicle control module 160, and a monitoring module 170.

The lateral magnetic sensors 110 are installed on the bottom of the on-line electric vehicle 101 and sense a lateral magnetic field values with respect to a driving direction of the on-line electric vehicle 101, which is generated from a power supply device 3, which is embedded in parallel to a power supply road 1. In this case, the lateral magnetic sensors 110 may be implemented with a coil, and the on-line electric vehicle 101 may include N lateral magnetic sensors arranged in a row in a width direction of the power supply road 1. The number of the lateral magnetic sensors may be odd. The total width of the lateral magnetic sensors 110 may be equal to the width of a unit 4 having the power supply devices 3 installed in the power supply road 1. In some cases, the total width of the lateral magnetic sensors 110 may be smaller or larger than the width of the unit 4. Specifically, a graph showing a magnitude of a magnetic field of the power supply road 1 in accordance with a lateral position of the power supply road 1 is illustrated in Fig. 1. In the graph, a horizontal axis represents the lateral position, and a vertical axis represents the magnitude of the magnetic field of the power supply road. The magnitude of the magnetic field in accordance with the lateral position shown in the graph can be sensed through the lateral magnetic sensors 110.

The longitudinal magnetic sensor 120 is installed on the on-line electric vehicle 101 and senses a longitudinal magnetic field value with respect to the driving direction of the on-line electric vehicle 101, which is generated from the power supply device 3. The longitudinal magnetic sensor 120 may be disposed on the top surface of the lateral magnetic sensor located in the center. The longitudinal magnetic sensor 120 is generally provided to obtain a heading angle of the vehicle. Thus, only one longitudinal magnetic sensor 120 is required. However, in order to obtain a more precise heading angle, a plurality of longitudinal magnetic sensors 120 may be installed. In a case in which the longitudinal magnetic sensor 120 is installed on the front of the vehicle, the magnitude of the heading angle can be known, but it is difficult to know whether a direction of the heading angle is a plus or minus direction with respect to the center of the road. This is because the sensed values of the magnetic field acquired from the longitudinal magnetic sensors 120 are always plus. Information necessary for the autonomous driving of the real vehicle is information on an angle at which the driving vehicle is rotated from the center of the road in a plus or minus direction. Therefore, in order to solve the above problem, the respective magnetic sensor modules consisting of N lateral magnetic sensors and one longitudinal magnetic sensor may be installed on the front and rear of the vehicle. Accordingly, information on the center position of the vehicle can be acquired from the longitudinal magnetic sensors of the magnetic sensor modules disposed in the front and rear of the vehicle. For example, in a case in which the sensor position recognition result of the magnetic sensor module disposed in the front of the vehicle is located more left than the sensor position recognition result of the magnetic sensor module disposed in the rear of the vehicle, the sign of the heading angle may be determined as a minus. In the opposite case, the sign of the heading angle may be determined as a plus.

Also, the A/

D converters

130 and 140 convert analog sensing values inputted from the lateral magnetic sensors 110 and the longitudinal magnetic sensor 120 into digital sensing values. In some cases, the lateral magnetic sensors 110 are divided into a plurality of groups, and the respective A/D converters are connected to the respective divided groups. Referring to Fig. 2, the A/

D converts

130 and 140 simultaneously convert the values inputted from the sensors belonging to the groups, thereby reducing the entire converting time.

Also, the microprocessor 150 calculates a tilt angle between the driving direction of the on-line electric vehicle 101 and the longitudinal direction of the power supply road 1 by using the lateral magnetic field values and the longitudinal magnetic field value which are outputted from the lateral magnetic sensors 110 and the longitudinal magnetic sensor 120, respective and then converted by the A/

D converters

130 and 140. Then, the microprocessor 150 adjusts the scale of the lateral magnetic field values based on the tilt angle. Then, as illustrated in Figs. 5 and 6, the microprocessor 150 estimates the lateral position of the on-line electric vehicle 101 by matching the scale-adjusted lateral magnetic field values with a reference lateral magnetic field pattern (P_ref) which is previously stored or is transmitted in real time. The lateral magnetic sensors 110 implemented with coils may be disposed in parallel to the power supply road 1. That is, the reference lateral magnetic field pattern (P_ref) is the magnetic field values sensed in such a state that the normal line of the power supply device 3 embedded in parallel to the power supply road is vertically crossed with the center line of the lateral magnetic sensors disposed in the center among the plurality of lateral magnetic sensors 110. It may be useful as a matching matter because the case in which the reference lateral magnetic field pattern (P_ref) is sensed in the vertically crossed state has a larger magnetic field value than that of the case in which the reference lateral magnetic field pattern (P_ref) is disposed at a different angle. Alternatively, the coils of the plurality of lateral magnetic sensors 110 may be installed in a direction vertical to the, that is to say, the normal line of the power supply device 3 is parallel to the center line of the lateral magnetic sensors disposed in the center among the plurality of lateral magnetic sensors 110. In this case, the intensity of the magnetic field induced to the coil is always constant, regardless of the heading angle of the vehicle, and it is unnecessary to adjust the scale of the lateral magnetic field values.

Meanwhile, the vehicle control module 160 estimates the driving direction of the on-line electric vehicle 101 by using the tilt angle information and the lateral position estimation information provided from the microprocessor 150, and controls the position through the steering and acceleration/deceleration control of the on-line electric vehicle 101. Specifically, in case in which the tilt angle information and the information on the left or right position of the vehicle with respect to the center of the power supply road 1 is founded, the vehicle may be controlled to move along the center of the road by moving the vehicle in its opposite direction and angle. For example, the handle of the vehicle may be rotated at 720 degree in left and right directions, and the rotational axes of the front wheels of the vehicle may be rotated about 45 degrees left and right in proportion to the rotation degree of the handle (i.e., 720 degree). When the heading angle of the vehicle is found by using this information, it means that the vehicle is moved in that direction. Therefore, the vehicle is repetitively moved in a direction opposite to the heading angle until the heading angle becomes 0 degree. Also, since the information on the position and speed of the vehicle on the power supply road (for example, the information on the speed of the vehicle can be acquired using by CAN(controller area network) data communication from a motor driving unit (MCU) mounted on the vehicle) can be known, it is possible to acquire information on a virtual position located in the front of the vehicle in proportion to the information on the speed of the vehicle. In this case, the virtual position information is variable data and can be calculated in proportion to the speed of the vehicle. For example, when the speed of the vehicle is 10 km/h, the vehicle moves about 3-4 m per second. Therefore, the distance (about 6 m) which is about 1.5 times the moving distance may be determined as the virtual position. When the acceleration/deceleration control and the steering control of the vehicle is performed using such information, the vehicle can drive along the center of the power supply road. Since the center of the power supply road 1 is a position at which the greatest magnetic field is generated, that the vehicle drives along the center of the power supply road 1 means that the on-line electric vehicle drives along the position at which the greatest magnetic field is generated. Hence, the power supply efficiency can be maximized. Furthermore, the vehicle control module 160 can perform a wireless communication with an external control center, and the remote control can be achieved under the control of the control center.

The monitoring module 170 visually displays the tilt angle information and the lateral position estimation information provided from the microprocessor 150.

The monitoring module 170 interworks with a navigation device (not shown) to display the driving information of the on-line electric vehicle 101 travelling on the power supply road 1. In this case, the monitoring module 170 performs a wireless communication with the external control center and can allow the control center to display the tilt angle information and the lateral position estimation information in a display device included therein.

Hereinafter, an autonomous driving method of an on-line electric vehicle in accordance with an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 3 is a flowchart explaining an autonomous driving method of an on-line electric vehicle in accordance with an embodiment of the present invention. Fig. 4 is a diagram explaining angle estimation in the autonomous driving method of the on-line electric vehicle in accordance with the embodiment of the present invention. Figs. 5 and 6 are diagrams explaining a method for representing a matched pattern between a reference lateral magnetic field pattern (P_ref) and sensed lateral magnetic field values in the autonomous driving method of the on-line electric vehicle in accordance with the embodiment of the present invention. In particular, a front view of the on-line electric vehicle and a top view of the power supply device are illustrated in Figs. 5 and 6.

First, at step S100, the microprocessor 150 calculates the tilt angle between the driving direction of the on-line electric vehicle 101 and the longitudinal direction of the power supply road 1 by using the lateral magnetic field values and the longitudinal magnetic field value which are outputted from the lateral magnetic sensors 110 and the longitudinal magnetic sensor 120 and then converted by the A/

D converters

130 and 140.

The angle calculating method will be described below in detail with reference to Fig. 4. If a pattern of the lateral magnetic field values “a” are detected and an extension line C2 is drawn vertically from the center of the pattern “a”, the tilt angle θ of the on-line electric vehicle 101 with respect to the center line of the power supply device 3 (i.e. the center line C1 of the power supply road 1) is detected. At this time, the tilt angle θ is equal to θ1, as shown in Fig. 4, and θ1 can be calculated using a trigonometrical function expressed as Equation 1 below.

MathFigure 1

where h represents the sensing values of the longitudinal magnetic sensor 120, v represents the sensing values of the lateral magnetic sensors 110.

At step S110, the microprocessor 150 adjusted a scale of the lateral magnetic field values based on the tilt angle. Specifically, a lateral magnetic field sensed when the on-line electric vehicle travels in parallel to the power supply road 1 is calculated by multiplying the the sensing values of the longitudinal magnetic sensor 120 by 1/cos θ1.

At step S120, in such a state, the microprocessor 150 estimates the lateral position of the on-line electric vehicle 101 by matching the pattern “a” with the reference lateral magnetic field pattern (P_ref) which is previously stored or is transmitted in real time.

At step S130, the vehicle control module 160 estimates the driving direction of the on-line electric vehicle 101 by using the tilt angle information and the lateral position estimation information provided from the microprocessor 150.

At step S140, when the driving direction of the on-line electric vehicle 101 is estimated, the vehicle control module 150 controls the position of the on-line electric vehicle 101 through the steering and acceleration/ deceleration control of the on-line electric vehicle 101.

At step S150, the monitoring module 160 displays the tilt angle information and the lateral position estimation information provided from the microprocessor 150.

When the vehicle is rotated left or right with respect to the center of the road, the values of the sensor are reduced. Thus, the heading angle of the vehicle must be acquired and the sensing information must be compensated by using the acquired heading angle of the vehicle. Also, the data acquired from the magnetic sensor must be matched with the previous sensing data, thus increasing the execution time as much. Furthermore, when the matching fails at a specific position, the position of the vehicle on the power supply road may not be acquired. To solve these problems, the following method is used.

As illustrated in Fig. 7, if the magnetic field on the power supply road is sensed by using the magnetic sensor and transformed using Equation 2 below, a transformation graph which is sharp in the center is obtained.

MathFigure 2

In Equation 2 above, the denominator represents the absolute value of the difference between the values of the two adjacent magnetic sensors, and the numerator represents the sum of the adjacent magnetic sensors. That is to say, since the plurality of lateral sensors exist, if the absolute value of the difference between the values of the two adjacent lateral sensors is small, the values of the two sensors are almost equal to each other, and the sensor values measured at that position are symmetrical. If the absolute value of the difference between the values of the two adjacent lateral sensors is large, it means the position at which the values of the two adjacent sensors are asymmetric, that is, the sensor value increases or decreases.

Also, if the sum of the adjacent sensor values is large, the value of the sensor sensed at a specific position is large and the position means the center of the power supply road at which the greatest magnetic field is generated.

Therefore, when a plurality of magnetic sensors are installed to have a length similar to the length of the power supply road and the acquired total sensor value is transformed by using this equation, a transformation graph at which the center of the power supply road having the greatest magnetic field is obtained. Therefore, the position information of the vehicle on the power supply road can be found more quickly and robustly, without using the above-described method for the matching.

In the autonomous driving apparatus and method of the on-line electric vehicle in accordance with the embodiment of the present invention, the plurality of lateral magnetic sensors are arranged in the on-line electric vehicle in the width direction of the road, and the longitudinal magnetic sensor is installed in the center of the lateral magnetic sensors. The tilt angle and the lateral position of the on-line electric vehicle are estimated by using the sensed values inputted from these sensors, and the on-line electric vehicle is controlled based on these values, thereby achieving a stable driving without departing from the lane.

Furthermore, the on-line electric vehicle can be travelling on the area of the power supply road at which the greatest magnetic field is generated based on the current lateral position estimation result, thereby maximizing the efficiency of the power collection.

While the invention has been shown and described with respect to some of the preferred embodiments only, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the scope of the invention as defined in the following claims.

Claims

An autonomous driving apparatus mounted on an on-line electric vehicle including a power collection device supplied with power from a power supply device through a magnetic induction, the power supply device being installed on a power supply road in a longitudinal direction, the apparatus comprising:

a plurality of lateral magnetic sensors installed in the on-line electric vehicle to sense lateral magnetic field values generated from the power supply device with respect to a driving direction of the on-line electric vehicle;

a longitudinal magnetic sensor installed in the on-line electric vehicle to sense a longitudinal magnetic value generated from the power supply device with respect to the driving direction of the on-line electric vehicle;

a microprocessor for calculating a tilt angle between the driving direction of the on-line electric vehicle and the longitudinal direction of the power supply road by using the lateral magnetic field values and the longitudinal magnetic field value, which are inputted from the lateral magnetic sensors and the longitudinal magnetic sensor, and determining a lateral position of the on-line electric vehicle by using the calculated tilt angle; and

a vehicle control module for determining the driving direction of the on-line electric vehicle by using the calculated tilt angle and the determined lateral position information which are provided from the microprocessor, and controlling the position of the on-line electric vehicle through a steering and acceleration/deceleration control of the on-line electric vehicle based on the determined driving direction.
The autonomous driving apparatus of claim 1, further comprising an analog-to-digital (A/D) converter for converting analog sensing values, which are inputted from the lateral magnetic sensor and the longitudinal magnetic sensor, into digital sensing values and outputting the digital sensing values to the microprocessor.
The autonomous driving apparatus of claim 1, further comprising a monitoring module for visually displaying the calculated tilt angle and the determined lateral position, which are provided from the microprocessor.
The autonomous driving apparatus of claim 3, wherein the monitoring module interworks with a navigation device to display information on a driving of the on-line electric vehicle travelling on the power supply road.
The autonomous driving apparatus of claim 1, wherein the plurality of lateral magnetic sensors are arranged in a row in a width direction of the power supply road.
The autonomous driving apparatus of claim 5, wherein the number of the lateral magnetic sensors is odd.
The autonomous driving apparatus of claim 6, wherein the longitudinal magnetic sensor is disposed on the top surface of a longitudinal magnetic sensor located in a center among the plurality of lateral direction magnetic sensors.
The autonomous driving apparatus of claim 6, wherein the microprocessor adjusted a scale of the lateral magnetic field values based on the tilt angle, and determines the lateral position of the on-line electric vehicle by matching the scale-adjusted lateral magnetic field values with a reference lateral magnetic field pattern which is previously stored or is transmitted in real time.
The autonomous driving apparatus of claim 8, wherein the reference lateral magnetic field pattern is a magnetic field values sensed in such a state that a normal line of the power supply device is vertically crossed with or parallel to a center line of the lateral magnetic sensor disposed in the center among the plurality of lateral magnetic sensors, the plurality of lateral magnetic sensors being implemented with coils.
An autonomous driving method of an on-line electric vehicle having the autonomous driving apparatus including a plurality of lateral magnetic sensors, a longitudinal magnetic sensor, a microprocessor and a vehicle control module, the method comprising:

receiving lateral magnetic field values and the longitudinal magnetic field value estimated from the lateral magnetic sensors and the longitudinal magnetic sensors, and operating the microprocessor to calculate a tilt angle between a driving direction of the on-line electric vehicle and a longitudinal direction of the power supply road;

operating the microprocessor to adjust a scale of the lateral magnetic value based on the tilt angle;

operating the microprocessor to estimate a lateral position of the on-line electric vehicle by matching a pattern of the scale-adjusted lateral magnetic field values which is outputted from the microprocessor, with a reference lateral magnetic field pattern, which is previously stored or is transmitted in real time; and

estimating the driving direction of the on-line electric vehicle based on the estimated angle and the estimated lateral position, which are provided from the microprocessor.
The autonomous driving method of claim 10, further comprising:

converting analog sensing values, which are inputted from the lateral magnetic sensor and the longitudinal magnetic sensor, into digital sensing values and outputting the digital sensing values to the microprocessor.
The autonomous driving method of claim 10, further comprising:

visually displaying the tile angle and the lateral position, which are provided from the microprocessor.