KR101235692B1 - Geo-pointing Apparatus and Method using Inertial Navigation System - Google Patents

Abstract

The present invention relates to a gimbal coordinate directing device using an inertial navigation apparatus capable of preventing saturation of the position controller of the gimbal, and in particular, a gimbal for coordinate orientation and mounted in the gimbal to be coordinate-oriented A sensor, an inertial navigation apparatus mounted on the sensor, a coordinate director for generating azimuth and elevation driving commands of the gimbal using a target coordinate and the inertial navigation apparatus, and the load according to the command output from the coordinate director. A gimbal position controller for controlling the position of the foot, an inertial measurement unit (IMU) for measuring the attitude of the sensor in the inertial space, and a driving speed of the gimbal according to the signals provided from the gimbal position controller and the inertial measurement unit. A speed controller for outputting a signal for controlling the controller, and a sphere for driving the gimbal according to the control signal of the speed controller Circuit includes a motor, and the coordinate-oriented group without using the actual target when a large driving load foot angle for aiming the actual target is driven by the coordinate-oriented method of using a target point of the virtual.
By using the coordinate directing device of the gimbal using the inertial navigation apparatus according to the present invention, it is possible to prevent the controller from saturation, implement smooth position control, and to drive quickly and smoothly to the target coordinates without lowering the gain of the gimbal controller. Can be.

Description

 Coordinate pointing device of gimbal using inertial navigation system and coordinate pointing method using same {Geo-pointing Apparatus and Method using Inertial Navigation System}

The present invention relates to a coordinate orientation device and a coordinate orientation method of the gimbal, the coordinate orientation device in which the inertial navigation device is mounted on the sensor to coordinate the coordinates using the same, within the driving ability of the gimbal An apparatus and a coordinate orientation method using the same.

There have been many studies for obtaining information of targets by driving gimbals equipped with sensors such as video / thermal cameras and lasers to direct the targets. Coordinate-oriented technology is one of them, and its purpose is to control the position of the gimbal line of sight quickly and accurately using the coordinates of the target. Until now, most devices have been installed in equipment equipped with sensors such as aircraft, ships, vehicles, etc. due to technical problems such as size and performance of the inertial navigation system. Therefore, for the coordinate orientation, the angle that the gimbal should be driven relative to the position and attitude of the payload (aircraft, ship, vehicle, etc.) was calculated, and the resolver, encoder, etc. to detect the relative angle between the payload and the payload. The relative position detection element of was used. However, in this case, not only static errors such as gimbal mounting error and alignment error, but also dynamic influences such as vibration, disturbance, and bending transmitted during driving have a problem of precise and fast position control.

Recently, the technology has been developed to mount the inertial navigation device on the gimbal to independently obtain the position and posture of the gimbal in the inertial space regardless of the position and posture of the payload. In this case, the effects of the static, dynamic errors, and disturbances described above can be eliminated, so that precise eye position control is possible. However, the method of obtaining the driving angle command of the motor for coordinate orientation can be complicated.

If the driving angle for coordinate orientation is calculated and used as a command of the gimbal controller as it is, a large value is initially applied so that the controller saturates, causing a large overshoot and it takes a lot of time to aim at the target point. Therefore, when the initial driving angle is large, the gain of the controller is lowered or the trajectory of the driving angle is modified in a controllable range and trimmed to a smooth curve. In this case, the driving angle is a relative angle between the payload and the gimbal, and the path can be easily planned when the relative position detecting element is used, but in the case of the coordinate orientation of the gimbal equipped with the inertial navigation system, the inertia is independent of the payload. Since the angle relative to the coordinate system is measured, it is difficult to generate a driving angle path. In reality, there is a problem that only the method of lowering the gain of the controller can be selected for the coordinate orientation of the gimbal equipped with the inertial navigation system.

An object of the present invention is to provide a coordinate orientation device and a coordinate orientation method of a gimbal using an inertial navigation apparatus capable of preventing saturation of the position controller of the gimbal.

Another object of the present invention is to provide a gimbal coordinate directing device and a coordinate directing method using an inertial navigation apparatus capable of smoothly directing coordinates.

It is still another object of the present invention to provide a gimbal coordinate orientation device and a coordinate orientation method using an inertial navigation device that enables fast and accurate coordinate orientation.

The coordinate pointing device of the gimbal using the inertial navigation apparatus according to the present invention to achieve these objects is initially coincided with the gaze of the gimbal, and finally the coordinate pointing device operates using a virtual target point that moves to the target coordinate at the required time. It is characterized by that.

Gimbal coordinate orientation device using the inertial navigation apparatus according to the present invention gimbal (gimbal) for coordinate orientation; A sensor mounted in the gimbal and oriented in coordinates; An inertial navigation device mounted on the sensor; A coordinate director for generating azimuth and elevation driving commands of the gimbal using a target coordinate and the inertial navigation device; A gimbal position controller for controlling the position of the gimbal according to a command output from the coordinate director; An inertial measurement unit (IMU) for measuring the attitude of the sensor in the inertial space; A speed controller for outputting a signal for controlling a driving speed of the gimbal according to signals provided from the gimbal position controller and an inertial measurement device; And a driving circuit motor for driving the gimbal according to a control signal of the speed controller, wherein the coordinate director uses a virtual target point without using an actual target when the driving angle for the gimbal is directed to an actual target is large. It is driven by the coordinate orientation method.

The coordinate orientation method of the gimbal using the inertial navigation apparatus according to the present invention comprises the steps of setting a virtual target point on the X axis of the current sensor coordinate axis so that the current gaze position and the direction vector can match; And continuously moving the virtual target point to the actual target point using the driving angle path planning method.

Another feature of the coordinate directing method of the gimbal using the inertial navigation apparatus according to the present invention comprises the steps of: generating the azimuth, elevation driving command of the gimbal using the inertial navigation apparatus; Transmitting a command generated by the coordinate pointing machine to the gimbal position controller; Driving the gimbal according to a control signal of the gimbal position controller; Outputting the position / posture of the sensor as a result of the position of the gimbal driven by the inertial navigation system and the position / posture of the aircraft; The coordinate aligner compares the position / posture of the sensor with the target coordinates to generate a next drive angle command.

Gimbal coordinate orientation device and coordinate orientation method using the inertial navigation apparatus according to the present invention has the following effects.

First, saturation of the controller can be prevented.

Second, smooth position control can be realized.

Third, it is possible to drive quickly and smoothly to the target coordinates without lowering the gain of the gimbal controller.

1 is an exemplary view showing a configuration of a gimbal for driving a sensor.
Figure 2 is a block diagram showing the configuration of the coordinate orientation device of the gimbal using the inertial navigation apparatus according to the present invention.
Figure 3 is a flow chart showing the progress of the coordinate orientation method of gimbal using the inertial navigation apparatus according to the present invention.
4 is an exemplary view showing the coordinates of the gimbal and the target viewed from the geocentric coordinate system and the direction vector from the gimbal to the target.
5 is an explanatory diagram of a coordinate directing device using the inertial navigation apparatus according to the present invention.
6 is an exemplary view illustrating a description of a moving virtual target point based on the initial sensor coordinate system.
7 is a graph illustrating an embodiment of generating a path on one axis of the generated virtual target point.

Hereinafter, with reference to the accompanying drawings it will be described the configuration and operation according to the coordinate orientation of the gimbal using the inertial navigation apparatus according to the present invention.

1 is an exemplary view showing the configuration of a gimbal for driving a sensor, Figure 2 is a block diagram showing the configuration of the coordinate orientation device of the gimbal using the inertial navigation apparatus according to the present invention.

 The structure of the coordinate orientation device for controlling the gimbal 10 to direct the coordinates by calculating the driving angle from the coordinates of the target point includes: a gimbal 10 for coordinate orientation; A sensor (11) mounted in the gimbal (10) to be coordinate-oriented; An inertial navigation device (26) mounted on the sensor (11); A coordinate director 21 for generating azimuth and elevation driving commands of the gimbal 10 using a target coordinate and the inertial navigation device 26; A gimbal position controller 22 for controlling the position of the gimbal according to a command outputted from the coordinate director 21; An inertial measurement unit (IMU) 25 for measuring the attitude of the sensor in the inertial space; A speed controller 23 for outputting a signal for controlling a driving speed of the gimbal 10 according to signals provided from the gimbal position controller 22 and an inertial measurement device 25; And a driving circuit motor 24 for driving the gimbal according to the control signal of the speed controller 23. Here, referring to FIG. 1, the gimbal 10 for coordinate orientation may include a sensor 11 mounted in the gimbal 10 such as a video camera, a thermal camera, a laser director, and the like. The gimbal 10 generally consists of two drive shafts, azimuth 13 and elevation 14.

Figure 3 is a flow chart showing the progress of the coordinate orientation method of gimbal using the inertial navigation apparatus according to the present invention. Looking at the process, step of generating the azimuth, elevation driving command of the gimbal using the coordinate steering apparatus using the inertial navigation (S1); Transmitting a command generated by the coordinate pointing device to the gimbal position controller (S2); Driving the gimbal according to the control signal of the gimbal position controller (S3); Outputting the position / posture of the sensor as a result from the posture of the gimbal driven by the inertial navigation device and the position / posture of the aircraft (S4); The coordinate aligner compares the position / posture of the sensor with the target coordinates (S5), and generates a next driving angle command (S6).

The coordinate directing unit 21 generates the azimuth and elevation driving commands of the gimbal 10 using the target coordinates and the inertial navigation apparatus 26 mounted on the sensor 11. This drive command is applied to the position controller 22, and then to the speed control loop composed of the speed controller 23, the motor drive circuit 24, the gimbal 10, and the IMU 25, and the gimbal 10 Is driven. The inertial navigation device 23 outputs the position / posture of the sensor 11 from the position of the driven gimbal 10 and the position / posture 21 of the aircraft. The coordinate director 21 subsequently compares the position / posture of the sensor 11 with the target coordinates to generate the next drive angle command. The target coordinates of the target are planned in advance or calculated in real time, and the coordinates of the gimbal 10 are also obtained in real time from the inertial navigation apparatus 26.

  The contents of calculating the angle at which the coordinate locator should be driven from the target coordinates and the attitude of the sensor 11 are shown through FIGS. 4 and 5. FIG. 4 is a description of coordinate transformation, and FIG. 5 is a content of calculating driving angles of azimuth and elevation using a result of coordinate transformation.

4 is an exemplary view showing the coordinates of the gimbal and the target viewed from the geocentric coordinate system and the direction vector from the gimbal to the target. Gimbal coordinates (31) and target coordinates (20) as seen from the Earth Centered Earth Fixed coordinate (ECEF).

In general, the geocentric coordinate system 30 defines a position having a longitude of 0 ° on the equator plane of the earth ellipsoid as a right hand coordinate system having an axis and a true north direction axis. In general, input values for coordinate orientation are input as longitude, latitude, and altitude (LLA) values as coordinates of the sensor 10 and the target 20, respectively. Based on these coordinates, the driving angle in the direction of the azimuth 41 and the elevation 42 of the gimbal is calculated to send a control output to the gimbal position controller 22. To this end, coordinates expressed in latitude, longitude, and altitude are first converted into the geocentric coordinate system 30 and then calculated as a direction vector 34 from the sensor 11 to the target 20. This is calculated as shown in Equation 1 below.

는 지구중심좌표계에서 표현된 목표점의 변위 벡터(32),

는 지구중심좌표계에서 표현된 센서 위치의 변위 벡터(33), 그리고

는 센서에서 목표점의 방향 벡터(34)이다. 이 방향 벡터의 단위 벡터(35)와 그 크기는 아래의 [수학식 2]와 같이 표현된다.here,

Is the displacement vector (32) of the target point expressed in the geocentric coordinate system,

Is a displacement vector 33 of the sensor position expressed in the geocentric coordinate system, and

Is the direction vector 34 of the target point in the sensor. The unit vector 35 and its magnitude of this direction vector are expressed as shown in Equation 2 below.

R _LOS is the magnitude of the direction vector of Equation 1, and n ^E is the unit vector 35 of the direction vector. Each of these thus represents the direction and distance from the sensor to the target. Coordinates and vectors expressed in the geocentric coordinate system 30 may be converted into a sensor coordinate system through a coordinate transformation matrix.

라고 하면 센서좌표계에서 표현된 센서(11)에서 목표(20)까지의 단위방향벡터 (35)는 [수학식 3]과 같다.5 shows a sensor 11 mounted on the gimbal 10 and an inertial navigation device 26 mounted thereon. The sensor coordinate system 40 can be defined as shown in FIG. 5 with the direction of the eye of the sensor 11 as the axis. Coordinate transformation matrix from the geocentric coordinate system (30) to the sensor coordinate system (40)

In this case, the unit direction vector 35 from the sensor 11 to the target 20 expressed in the sensor coordinate system is expressed by Equation 3 below.

Therefore, the angles between the azimuth angle 41 and the elevation angle 42 necessary for directing from the current line of sight position to the target direction are expressed as Equation 4 from the relational expression of the trigonometric function.

Where x , y , and z are the three elements of the unit direction vector 35 of Equation 3, and AZ and EL are the azimuth angle 41 and the elevation angle 42 commands necessary for coordinate orientation, respectively. This command is applied to the position controller 22 of FIG. 2 shown above to drive the gimbal 10, thus directing the desired coordinates.

In this case, when the calculated values of the azimuth angle 41 and the elevation 42 driving commands AZ and EL are large, if they are directly applied to the gimbal position controller 22, problems may occur in driving the gimbal 10. There is a limit to driving the gimbal 10 due to the limitation of the driving ability of the driving amplifier, the maximum driving angular velocity of the motor, the angular acceleration, and when the driving command exceeding this is applied, the gimbal 10 becomes large due to the saturation of the controller. You may experience churning or instability.

Therefore, in the present invention, a technique of manipulating the direction vector 35 from the gimbal 10 to the target 20 is used. That is, when the angle for driving to the actual target point 20 is large, a coordinate orientation method using a virtual target point that changes gradually from a small driving angle to a real driving angle is used without using the actual target 20.

6A and 6B are exemplary views illustrating a description of a moving virtual target point based on an initial gimbal coordinate system. 6A, the virtual target point is first set on the X axis 52 of the current sensor coordinate axis so that the current line of sight position and the direction vector coincide. Since the sensor coordinate axis 40 is a value that continuously changes as the gimbal 10 is driven, the direction 52 of the initial line of sight is based on the sensor coordinate system 50 at the moment when the virtual target point 53 is set.

When the driving azimuth and elevation commands of the motor are calculated in this state, the driving angles of the azimuth angle 41 and the elevation angle 42 will be "0" because the current line of sight and the virtual target direction vector 52 coincide. Thereafter, the virtual target point 53 is continuously moved to the actual target point 54 using a general driving angle path planning method.

As a result, as shown in FIG. 6B, the target direction vector 55 also changes continuously, and the azimuth angle 41 and elevation driving 42 commands of the motor calculated based on this change continuously. In this case, the change trajectory of the virtual target point 54 may be calculated to go to a desired angle at a desired time in consideration of the gimbal 10 driving ability in the azimuth 41 and elevation 42 directions.

7A and 7B show an embodiment of driving angle command generation in the azimuth 41 or elevation 42 direction. 7A is a graph showing the relationship between time and angle, and FIG. 7B is a graph showing the relationship between time and angular velocity.

The driving angle and angular velocity commands generated using the general minimum time trajectory generation method are shown in Equation 5 below. When the gimbal 10 is moved from the initial angle q ₀ to the desired angle q _f for the maximum acceleration a _M for a time t _f , the driving angle is as follows.

Here, t _s is an angular velocity switching time, which accelerates to an acceleration a _M until this time, and after this time, it decelerates to -a _M and moves to a desired angle q _f at a minimum time. When the target point is moved by using the virtual target point 54 moving trajectory in the direction of the azimuth angle 41 and the elevation angle 42 in consideration of the driving acceleration and the driving angular acceleration limit of the motor, the gimbal is AZ 41, The target point can be directed by driving the target driving angle for the desired time t _f with the EL 42 axis. Therefore, unstable phenomena such as vibration and oscillation of the gimbal 10 due to saturation of the controller can be prevented.

The coordinate director using the virtual coordinate point described above may be utilized as follows. In general, when performing a coordinate orientation with a small driving range, the actual coordinate point is coordinate-oriented using Equation 4 above. However, when target coordinates requiring a coordinate orientation having a large driving range are set, a virtual coordinate point according to the present invention is assigned in place of an actual coordinate point, and coordinate-oriented by using the replaced virtual coordinate point. Since the virtual coordinate point is a trajectory generated by considering driving angular velocity / angular acceleration with respect to each axis as in Equation 5, stable coordinate orientation is possible without saturation of the controller to a desired target point at a desired time.

In the case where the coordinate oriented device coordinates a plurality of coordinates, the virtual coordinate point is set back to the current sensor coordinate system reference gaze position to replace the actual coordinate point and used for coordinate orientation. It is the moment when it enters the director. In addition, even when the driving angle is out of the driveable range, the virtual coordinate point is set back to the current sensor coordinate system reference gaze position to replace the actual coordinate point and used for coordinate orientation.

10: gimbal 11: sensor
12: LOS 13: Azimuth
14: elevation 20: target
21: coordinate director 22: position controller
23: speed controller 24: drive circuit motor
25: IMU 26: Inertial Navigation System
31: coordinate of gimbal 32: displacement vector of target point
33: displacement vector of sensor position 34: direction vector of target point
35: unit vector of the direction vector 40: sensor coordinate system
41: azimuth 42: elevation
51: virtual target
50: Sensor coordinate system at the moment the virtual target point is set
52: Initial eye direction 53: X axis of the sensor coordinate axis
54: actual target point 55: target direction vector

Claims (10)

Gimbal for coordinate orientation;
A sensor mounted in the gimbal and oriented in coordinates;
An inertial navigation device mounted on the sensor;
A coordinate director for generating azimuth and elevation driving commands of the gimbal using a target coordinate and the inertial navigation device;
A gimbal position controller for controlling the position of the gimbal according to a command output from the coordinate director;
An inertial measurement unit (IMU) for measuring the attitude of the sensor in the inertial space;
A speed controller for outputting a signal for controlling a driving speed of the gimbal according to signals provided from the gimbal position controller and an inertial measurement device; And
A driving circuit motor for driving the gimbal according to a control signal of the speed controller,
The coordinate director is driven by a coordinate-oriented method using a virtual target point without using the actual target when the driving angle for the gimbal to direct the actual target is larger than the driveable range. A coordinate orientation device of gimbals using an inertial navigation system, characterized by converting highly expressed coordinate values into a geocentric coordinate system and calculating a direction vector from a sensor to a target. The method of claim 1,
And the sensor comprises at least one of a video camera, a thermal camera, and a laser directivity device. The method of claim 1,
The inertial navigation device is a coordinate orientation device of the gimbal using the inertial navigation system, characterized in that for outputting the position / attitude of the sensor from the position of the driven gimbal and the position / attitude of the aircraft. The method of claim 1,
The coordinates of the gimbal using the inertial navigation system, characterized in that the coordinates of the gimbal is provided in real time from the inertial navigation system. delete The method of claim 1,
When the coordinate director directs a plurality of coordinates, the point of time when the virtual target point is reset to the current sensor coordinate system reference gaze position and used for coordinate orientation instead of the actual target is a moment when the target coordinates are input to the coordinate director. Gimbal coordinate orientation device using an inertial navigation system characterized in that. The method of claim 1,
When the coordinate director directs a plurality of coordinates, the point of time when the virtual target point is set to the current sensor coordinate system reference gaze position and used for coordinate orientation instead of the actual target is the moment when the driving angle is out of the driveable range. Gimbal coordinate orientation device using an inertial navigation system characterized in that. delete delete Generating an azimuth, elevation driving command of the gimbal using the inertial navigation apparatus;
Transmitting a command generated by the coordinate pointing machine to the gimbal position controller;
Driving the gimbal according to a control signal of the gimbal position controller;
Outputting the position / posture of the sensor as a result of the position of the gimbal driven by the inertial navigation system and the position / posture of the aircraft;
Wherein the coordinate locator compares the position / posture of the sensor with the target coordinates to generate a next drive angle command,
In generating the azimuth, elevation driving command of the gimbal, and generating the next driving angle command, the coordinate pointing device sets the actual target when the driving angle for the gimbal to aim at the actual target is larger than the driveable range. It is driven by the coordinate-oriented method using virtual target points without using them, and converts coordinates expressed by longitude, latitude, and altitude of the sensor and target into a geocentric coordinate system and then calculates the direction vectors from the sensor to the target. Coordinate orientation method of gimbal using inertial navigation system.

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