KR100915121B1 - Unmanned vehicle using dgnss and guiding method - Google Patents

Abstract

An unmanned vehicle and a guiding method thereof are provided to move based on the non-visual information by obtaining the directive angle and the azimuth etc. A guiding method of unmanned vehicle includes the configuration step of the reference point, the calculation step of the directivity angle, and the calculation step of the azimuth and the steering angle. The configuration step of the reference point is performed to set up the reference points(100 through 600) on the travel tract of the unmanned vehicle. The location information of the reference points is stored in the storage unit of the unmanned vehicle. The calculate step of the directivity angle is performed to calculate the directivity angle(Psi). The calculate step of azimuth is performed to calculate the azimuth based on the current and previous location information of unmanned vehicle. The calculate step of the steering angle is performed to calculate the steering angle using the directivity angle and the azimuth.

Description

Unmanned Vehicle and Guiding Method Using Satellite Navigation Compensation System {UNMANNED VEHICLE USING DGNSS AND GUIDING METHOD}

The present invention relates to an unmanned vehicle and a method for deriving a predetermined path by itself using accurate position information obtained by using a satellite navigation correction system (DGNSS).

In order to induce an unmanned vehicle (AGV, Automatic Guided Vehicle) or a golf cart to move along a given route, the unmanned vehicle itself recognizes its own path. A device capable of doing so should be provided on the unmanned vehicle.

Accordingly, a conventional unmanned moving body such as a golf cart or an unmanned transport vehicle such as Patent Publication No. 10-2003-97194 (Unmanned golf cart) is a device for recognizing a driving path. Guide lines such as cables are embedded in the lower ground, and sensors are attached to the unmanned vehicle to guide the unmanned driving by detecting the guide lines embedded in the ground.

However, it is not only expensive to bury the guide line in the lower part of the road, but also when the path of the unmanned vehicle is changed and needs to travel on another path such as when the golf course is changed, There is a inconvenience to bury or change again.

Recently, as the use of the Global Positioning System (GPS) has become popular, GPS receivers are mounted on unmanned vehicles such as golf carts to acquire their location information from multiple satellites, and then determine their own driving routes based on the location information. Many methods have been proposed.

For example, Japanese Patent Laid-Open No. 2003-71520 et al. Proposes a method of guiding autonomous driving of an unmanned vehicle by combining location information obtained using GPS and map information on a pre-entered driving route.

The invention proposed in the above document calculates how far the driving route is from a previously input driving route based on the position information received from the satellite using only GPS and determines the driving direction according to the calculation result. to be.

GPS is a system that provides a service for measuring the position, velocity, and time of an object using satellites. The position measurement is performed using a triangulation method by measuring accurate time and distance from four or more satellites using a GPS receiver as shown in FIG. Calculate your location. However, in the signals received from satellites, satellite orbit information errors, satellite time information errors, errors due to propagation time delays and receiver errors when GPS signals pass through the ionosphere and troposphere are inherent, resulting in measurement errors of around 10m. This is not suitable for guiding a path of an unmanned vehicle moving a small path of a driving path such as a golf course having a width of about 3m. In addition, the unmanned moving body sets the direction in which it should travel based only on GPS information and information obtained from its current position.

However, the present invention does not consider at all, although the unmanned vehicle may continue to move and thus may not be able to travel in the driving direction in which it is to travel due to its dynamic characteristics, and thus may actually deviate from the target driving direction. There are many problems in applying to.

In order to solve the problems of GPS, various methods for obtaining accurate location information have been proposed, one of which is a differential GPS (DGPS) or a differential global navigation satellite system (DGNSS). (Hereinafter referred to as DGNSS).

Satellite Navigation Correction System (DGNSS) is a relative positioning method of GPS surveying. A GPS receiver is installed at a reference point that already knows its position. The new value is provided to a mobile or user through a terrestrial wireless communication network.

In order to use the satellite navigation correction system (DGNSS) to guide the autonomous driving of the unmanned vehicle, the golf navigation system of Patent Publication No. 2000-29750 has been proposed, and the present invention uses a Kalman filter to obtain information obtained using the DGNSS. As a method of calculating the exact position and driving information of a golf cart by calibrating, this patent document describes only the method of obtaining the accurate position information, and does not suggest how to obtain the azimuth information which is being driven. However, in order to know its azimuth information, there is a disadvantage in that an additional sensor such as a gyroscope is required, and the present invention also has many problems in practical application since the dynamic characteristics are not considered.

It is an object of the present invention to provide an unmanned vehicle capable of unmanned driving and a method of deriving the unmanned vehicle using only position information obtained by using a satellite navigation correction system (DGNSS).

The object of the present invention as described above is to determine a plurality of reference points on the reference trajectory that the unmanned vehicle is to travel, and receives the position information about these reference points to the DGNSS receiver mounted on the unmanned vehicle, and the results are stored in the storage device in the unmanned vehicle. A reference point setting step of storing; A direction angle calculation step of calculating a direction angle based on the current position information of the unmanned vehicle and the position information of the future direction point received in real time by the DGNSS receiver while the unmanned vehicle moves along the reference point stored in the storage device; An azimuth calculation step of calculating an azimuth angle based on current position information and previous position information of the unmanned vehicle; It is achieved by a method of deriving an unmanned moving object consisting of a steering angle calculation step of calculating a steering angle by using the orientation angle obtained in the orientation angle calculation step and the azimuth angle obtained in the azimuth calculation step.

The present invention uses the precise position information provided by the satellite navigation correction system (DGNSS) to obtain the direct angle, azimuth and steering angle of the point to which the unmanned vehicle itself should move, so that the guide line is buried under the driving route, Alternatively, precision driving is possible without installing an additional sensor such as a gyroscope, and since the camera does not rely on visual information obtained by mounting a camera, it is possible to drive even in a situation where a field of view is not secured.

1 is a configuration diagram showing an example of acquiring current location information using GPS;

Figure 2 is a perspective view showing an example of setting the reference points on the reference trajectory of the unmanned vehicle guide method using the satellite navigation correction system (DGNSS) according to the present invention,

3 is a configuration diagram showing an example of obtaining a direction angle of the unmanned vehicle guide method using a satellite navigation correction system (DGNSS) according to the present invention,

Figure 4 is a configuration diagram showing an example of obtaining the azimuth angle of the unmanned vehicle in the unmanned vehicle guide method using the satellite navigation correction system (DGNSS) according to the present invention.

5 is a view showing a reference trajectory of the unmanned vehicle used to test the unmanned vehicle guide method of the present invention.

6 is a view for explaining a method for giving a direction to the orientation angle, azimuth and steering angle of the present invention.

7 and 8 are graphs showing the results of driving tests applied to the unmanned moving body guide method according to the present invention to the golf cart, respectively.

[Description of Symbols for Main Parts of Drawing]

100, 200, 300, 400, 500, 600: reference point

d: Close distance to current position P: Current position information

P _o : Previous position information P _f : Forward reference point

S: Future Direction v: Speed of Unmanned Vehicles

t: Receiving period of position information Ψ: Direction angle

θ: azimuth angle Φ: steering angle

Hereinafter, a description will be given in detail of a method of inducing an unmanned vehicle to enable the unmanned vehicle to travel by itself along a driving path.

The method for inducing driving of the unmanned moving object of the present invention comprises a reference point setting step, a direction angle calculation step, an azimuth calculation step and a steering angle calculation step.

(1) reference point setting step (S10)

In this step, first, a plurality of points (reference points) are designated on a path (hereinafter, referred to as "reference trajectory") on which the unmanned vehicle 10 should travel, and the positions of the designated reference points are obtained and stored in a storage device provided in the system. Normally this step is already performed before the unmanned vehicle 10 travels.

To set the reference point on the reference trajectory, first, as shown in FIG. 2, a plurality of points (reference points, 100, 200, 300. In order to move the unmanned moving body 10 equipped with the DGNSS receiver to these reference points, the DGNSS receiver acquires its precise position information through the DGNSS.

In order to obtain accurate location information for each reference point, the present invention uses DGNSS. At this time, if the reception time for receiving the location information from the satellite is sufficiently long, much more accurate location information can be obtained. Is obtained from a value after a predetermined time (typically 3 to 5 seconds) after the first reception by the DGNSS receiver, the position information is stabilized, or the unmanned vehicle 10 is driven several times along the reference trajectory, The location information is averaged.

In order to accurately match the reference trajectory with the actual driving route, the reference points must be continuous, but it is not only physically difficult to continuously perform the reference points, but even if the autonomous vehicle 10 can acquire the information in real time, In addition, since it is not necessary to do so on a straight driving path, the unmanned moving body 10 selects points that can well represent the characteristics of the trajectory to travel as a reference point. At this time, since the unmanned moving body 10 may be separated from the reference trajectory in the place where the path is bent or the radius of rotation is small, the reference point is divided into small intervals that the unmanned moving body 10 can follow properly. Specify.

After the position information ((x, y) coordinates) of the reference point on the reference trajectory is obtained, the result is stored in the system memory.

(2) direction angle calculation step (S100)

In this step, the unmanned vehicle 10 moves the reference trajectory based on the current position P of the unmanned vehicle 10 received in real time by the DGNSS receiver while the unmanned vehicle 10 travels along the reference points on the stored reference trajectory. It is a step of calculating a direction angle Ψ that should be aimed to drive along.

As shown in FIG. 3, the direction angle Ψ of the unmanned vehicle 10 is determined by finding a specific reference point on the reference trajectory located in front of the unmanned vehicle (hereinafter referred to as “future direction point S”). Refers to the angle formed by the line connecting the position (P) of the unmanned moving body (10).

In order to determine the future direction point (S), first obtain information (P) of the position where the current unmanned vehicle (10) is located, and the forward reference point (P _f ) at the closest distance (d) to the current position (P) Next, it is set in consideration of the speed of the unmanned moving object 10 among the reference points located in front of the front reference point (P _f ).

Since the information on the current position of the unmanned vehicle 10 is received from the satellite every predetermined time (generally 2 Hz), when the future direction point S is designated, the reception period of the position information as well as the speed of the unmanned vehicle 10 is determined. Also consider t).

However, the above calculation method of determining the angle obtained on the basis of the position of the future direction point S located in front of the unmanned vehicle 10 and the current position P of the unmanned vehicle as the orientation angle Ψ of the unmanned vehicle. Is calculated when the absolute reference point such as true north is calculated. Since the position information of the absolute reference point is continuously received from the DGNSS, the above method can be used as it is.

However, since some errors may be involved in receiving location information about the absolute reference point or converting the location information into usable data, as shown in FIG. First, the degree of inclination of the reference trajectory (hereinafter referred to as "reference trajectory direction angle (Ψ ₀ )") is the forward reference point P _f and the future direction point S closest to the current position P of the unmanned vehicle 10. It is preferable to obtain from this angle, and then to obtain a direction of inclination (Ψ) relative to the reference trajectory direction of motion (Ψ ₀ ).

In this case, when the reference trajectory direction angle Ψ ₀ and the direction angle Ψ are displayed, it is preferable to describe in which direction, that is, the quadrant of the four quadrants.

When the above process is expressed by an equation, the future directing point S may be expressed by Equation 1, the reference trajectory directing angle Ψ _{0 as} Equation 2, and the directing angle Ψ as Equation 3.

Where S : Position of future point, P: Current position of unmanned vehicle, v: Speed of unmanned vehicle, t: Period of receiving location information.

Where Ψ ₀ : reference trajectory direction angle, P _f : position of forward reference point, S : Location of future direction

Where Ψ: orientation angle, P: current unmanned vehicle, S : Position of future direction point, Ψ ₀ : Reference trajectory direction angle.

(3) azimuth calculation step (S200)

This step is to calculate the azimuth angle [theta] information of the moving object.

As described above, when the unmanned movable body 10 is induced using only the direction angle Ψ, the driver may be steered out of the reference trajectory by the dynamic characteristics of the unmanned movable body 10.

In order to solve this problem, the present invention considers the azimuth angle θ as well as the orientation angle Ψ of the unmanned moving body 10.

The azimuth angle θ of the unmanned mobile body 10 is an angle to which the unmanned mobile body is currently directed, and its value indicates the previous position (P ₀ ) information and the current position (P) information of the unmanned mobile body 10 as shown in FIG. 4. Obtain by using

At this time, it is preferable to obtain the azimuth angle θ relative to the reference trajectory in order to reduce the error even when calculating the azimuth angle θ of the unmanned vehicle 10 as in the case of obtaining the orientation angle Ψ. Obtain the angle for the line connecting the previous position (P ₀ ) and the current position (P), and subtract the reference trajectory direction angle (Ψ ₀ ) from this angle to determine the relative azimuth angle relative to the reference trajectory of the unmanned vehicle 10 ( θ) is obtained and summarized by Equation 4 below.

In this case, when displaying the azimuth angle θ, it is preferable to display the azimuth angle θ in a direction similar to the reference trajectory direction angle Ψ ₀ and the direction angle Ψ.

Where θ: azimuth, P: current location information, P: previous location information, Ψ ₀ : reference trajectory direction angle.

(4) steering angle calculation step (S300)

This step calculates the steering angle Φ for controlling the steering system of the unmanned vehicle. The steering angle Φ is obtained by using the above-mentioned direction angle (Ψ) and azimuth angle (θ). Equation 5

Where Φ: steering angle, Ψ: direction angle, θ: azimuth angle.

Hereinafter, the present invention having the configuration as described above is applied to the actual golf cart equipped with a DC motor and a DGNSS receiver produced in Korea as it is, by checking whether the unmanned vehicle 10 travels well along a given driving path. saw.

(1) setting of reference point

FIG. 5 is a reference trajectory set arbitrarily for testing the unmanned moving object of the present invention. In order to set the reference trajectory, as shown in FIG. After selecting a number of reference points, move the golf cart (unmanned moving object) equipped with DGNSS receiver to these reference points, and when the signal received from the DGNSS is stabilized and the value of the position information becomes a constant value, the value is taken to the position coordinate of the reference point. After deciding, these values are stored in memory.

(2) Calculation of the direction angle (Ψ)

In order to calculate the orientation angle (Ψ) of the unmanned vehicle, it is necessary to know the present position (P) and the future orientation point (S) of the unmanned vehicle. If the current position P (x, y) of the unmanned vehicle (where x means East and y means North) is P (6.0471, 25.2803), then the current position as shown in FIG. The forward reference point (P _f ) at the closest distance (d) to position (P) was searched for P _f (5.7875, 22.3474), and the speed of the vehicle among the various reference points in front of this forward reference point (P _f ) One point S (1.8083, 22.7539) on the trajectory of about 4 m was selected considering 5.6 km / hr and 2 Hz reception period.

to be.

At this time, a direction is given to the direction angle Ψ so that it is possible to know which quadrant of the four quadrants the direction to which the calculated direction angle Ψ is directed. That is, if Δx is less than zero (-) and Δy is also less than zero (-), the orientation angle is located in three quadrants, and thus the orientation angle is directed toward the southwest. As shown on the y axis (North), + in the clockwise direction,-in the counterclockwise direction,-is given, and if the direction is one quadrant, the calculated value is used as it is; in the case of two quadrants Add -180 ° to the third quadrant, add -180 ° to the calculated value, and add + 180 ° to the calculated quadrant.

For example, in the above orientation angle calculation, Δx is -4.2388 (= 1.8083-6.0471) less than 0 and Δy is also less than 0 with -2.5264 (= 22.7539-25.2803), so it is located in the third quadrant, and thus the calculated Adding -180 ° to the calculated direction angle to indicate that the direction angle (Ψ) is in the third quadrant results in -120.8 °. That is, the direction angle (Ψ) = 59.2 ° -180 ° = -120.8 °.

The value calculated above is based on the north-north direction, and to find the relative direction angle with respect to the reference trajectory, first, the direction angle of the reference trajectory (Ψ ₀ ) is obtained.

to be.

In the same manner as in the orientation angle (Ψ) of the above calculated reference trajectory orientation for each of (Ψ ₀₎ reference trajectory directed at a value calculated to know the direction in which the orientation of each (Ψ ₀₎ given the direction, from the above computation Δx is smaller than 0, Δy is located in the second quadrant is larger than zero, so that the calculated reference trajectory directed above each (Ψ ₀₎ to indicate that that is located in the second quadrant - attaching a signed reference trajectory orientation angles (Ψ ₀ ) Is -84.2 °, so that the orientation angle Ψ of the unmanned vehicle 10 becomes -120.8 °-(-84.2 °) =-36.55 ° from which the orientation angle of the unmanned vehicle 10 is It can be seen that the direction toward northwest (the direction inclined counterclockwise by -36.55 ° with respect to the y-axis) with respect to the reference trajectory.

(3) azimuth calculation

After the orientation angle Ψ is calculated in this step, the azimuth angle θ of the unmanned vehicle is calculated to consider the dynamic characteristics of the unmanned vehicle 10.

The azimuth angle θ is an angle formed by a line connecting the current position P of the unmanned vehicle 10 and the previous position P ₀ , and the previous position P ₀ of the unmanned vehicle is (6.1943, 25.3139), The azimuth angle θ is

to be.

As in the calculation of the direction angle, the direction is given to the direction of the azimuth angle θ. In the above calculation, Δx is smaller than 0 and Δy is smaller than 0, so it is located in the third quadrant. If -180 ° is added to the calculated reference trajectory direction angle Ψ ₀ , the above azimuth angle θ becomes -102.9 °.

The above values are based on the north-north direction. Subtract the direction angle (-84.2 °) of the reference trajectory from the value (-102.9 °) obtained above to find the relative azimuth angle (θ) to the reference trajectory. -18.7 ° (= -102.9 °-(-84.2 °)), and the direction that the unmanned vehicle is currently oriented is tilted by -18.7 ° counterclockwise relative to the northwest (y-north) with respect to the reference trajectory. Direction).

(4) steering angle calculation

To obtain the steering angle Φ to be added to the steering apparatus of the unmanned moving object 10 by using the above-mentioned direction angle Ψ and azimuth angle θ, the azimuth angle θ of the vehicle can be subtracted from the direction angle Ψ. Steering angle (Φ) = steering angle (Ψ)-azimuth angle (θ) = -36.55 °-(-18.7 °) = -17.8 °, from which the unmanned vehicle is steered in a direction tilted approximately 17.8 ° from north to west The reference trajectory is reached.

The unmanned moving object (golf cart) was placed at a position about 3 m away from the driving trajectory, and then the unmanned moving object guidance method of the present invention was applied as it was. As a result, it can be seen from FIGS. 7 and 8. When the moving object 10 received the 25th signal (12.5 seconds) after starting to travel, the reference trajectory was reached, and it was found that the vehicle was traveling along the reference trajectory within a range of about ± 0.2 m from the reference trajectory. .

The reason that the distance from the reference trajectory is ± 0.2m (see Fig. 8) is somewhat large because the response speed of the controller and driving motor of the golf cart used in the test is slow and the direction angle error of the steering system is relatively large (± 1.5 °). In case that the response speed is satisfactory and there is no direction angle error of the steering system, the reference trajectory can be followed within the range of ± 0.06m (± 6cm).

Claims (10)

The GPS receiver station located on the ground receives satellite signals, corrects the elements causing errors, and induces driving of the unmanned vehicle 10 using a satellite navigation correction system (DGNSS) that provides the corrected values through a wireless communication network. In the unmanned vehicle traveling induction method, A plurality of reference points are determined on a reference trajectory on which the unmanned vehicle 10 is to be driven, and position information about these reference points is received from a DGNSS receiver mounted on the unmanned vehicle 10 and the result is stored in the unmanned vehicle 10. A reference point setting step (S100) to store in the; While the unmanned vehicle 10 travels along the reference point stored in the storage device, a specific reference point on the reference trajectory located in front of the unmanned vehicle 10 is set as a future point S, and the unmanned vehicle received by the DGNSS receiver ( A direction angle calculation step S200 of calculating a direction angle Ψ based on the current position information P of 10) and the position information of the future direction point S; An azimuth angle calculation step (S300) of calculating an azimuth angle θ based on the current position information P of the unmanned moving object 10 and the previous position information P ₀ ; A steering angle calculation step (S400) for calculating a steering angle Φ using the direction angle Ψ obtained in the direction angle calculation step S200 and the azimuth angle θ obtained in the azimuth angle calculation step S300; When designating the future direction point (S), the unmanned vehicle driving guidance using the satellite navigation correction system (DGNSS), characterized in that the designation in consideration of the speed (v) of the unmanned vehicle (10) and the reception period (t) of the position information. Way. The method according to claim 1, When the direction angle Ψ is calculated in the direction angle calculation step S200 and when the azimuth angle θ is calculated in the azimuth angle calculation step S300, the direction angle Ψ and the azimuth angle θ are respectively directed to the reference trajectory. Unmanned vehicle driving guidance method using a satellite navigation correction system, characterized in that the calculation based on the angle (Ψ ₀ ). The method according to claim 1, When calculating the orientation angle Ψ in the orientation angle calculation step S200 and when calculating the azimuth angle θ in the azimuth angle calculation step S300, the orientation angle Ψ and the azimuth angle θ are calculated based on true north, respectively. Unmanned vehicle driving guidance method using a satellite navigation correction system, characterized in that. The method according to claim 1, The reference trajectory direction angle (Ψ ₀ ), the direction angle (Ψ) and the azimuth angle (θ) are respectively displayed so as to know the direction of the direction of the unmanned vehicle moving guidance using a satellite navigation correction system. The method according to any one of claims 1 to 4, In the reference point setting step (S100), the position information for the reference point is received from the DGNSS receiver after a predetermined time has elapsed from the value after the position information is stabilized, characterized in that the vehicle navigation guidance method using a satellite navigation correction system. The method according to any one of claims 1 to 4, In the reference point position setting step (S100), the positional information on the reference point is obtained by averaging the satellite navigation correction system characterized in that the unmanned moving body (10) equipped with the DGNSS receiver travels along the reference trajectory several times. Unmanned vehicle driving guidance method using. It uses satellite navigation correction system (DGNSS) which receives satellite signals from GPS receiver located on the ground and corrects the elements that cause errors, and provides the corrected values through wireless communication network on the ground. In the unmanned moving body (10) that travels according to its own driving route using location information received from the DGNSS receiver, Determining a plurality of reference points on the reference trajectory that the unmanned vehicle 10 must travel, receiving position information about these reference points from the DGNSS receiver mounted on the unmanned vehicle 10 and storing the result in the unmanned vehicle 10 Store on the device; While the unmanned vehicle 10 travels along the reference point stored in the storage device, a specific reference point on the reference trajectory located in front of the unmanned vehicle 10 is set as a future point S, and the unmanned vehicle received by the DGNSS receiver ( A direction angle Ψ is calculated based on the current positional information P of 10) and the positional information of the future direction point S; Calculates an azimuth angle θ based on the current position P ₁ and the previous position P ₀ of the unmanned vehicle 10; Calculating a steering angle Φ of the steering apparatus using the direction angle Ψ and the azimuth angle θ; The future point (S) is an unmanned mobile vehicle using a satellite navigation correction system (DGNSS), characterized in that it is specified in consideration of the speed (v) and the reception period (t) of the position information of the unmanned vehicle (10). The method according to claim 7, And the direction angle (Ψ) and azimuth angle (θ) are respectively calculated based on the direction angle (Ψ ₀ ) of the reference trajectory. The method according to claim 7, And the heading angle (Ψ) and azimuth angle (θ) are calculated based on true north, respectively. The method according to any one of claims 7 to 9, The reference trajectory direction angle (Ψ ₀ ), the direction angle (Ψ) and the azimuth angle (θ) are respectively displayed to know the direction of the direction of the unmanned moving body using a satellite navigation correction system.