JP2000266546A - Attitude detecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the attitude easily and accurately. SOLUTION: The attitude detecting method comprises an arrangement where a reference angle sensor 1 and an attitude sensor 2 for measuring the angles around three axes of an absolute coordinate with reference to the globe are fixed, respectively, to one and the other objects, a difference operating section 14 determines a correction angle data (Ar, Ap, Ay) based on the angle detection results from the angle sensors 1, 2 and an attitude data (Br, Bp, By) is determined by difference operation using the correction angle data. Since only a simple data processing, e.g. difference operation, is required and the angle sensors 1, 2 can detect the attitude with high accuracy with no restriction on the installation thereof, attitude of one object with respect to the other object can be detected easily and accurately.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an HMD, for example.
The present invention relates to an attitude detection method used for detecting the attitude of the pilot's head (the other object) with respect to the body (one reference object) of an aircraft pilot equipped with a (head-mounted display). The present invention relates to a technique for easily and accurately detecting a posture of another object with respect to an object.

[0002]

2. Description of the Related Art An HMD worn by an aircraft pilot is:
A necessary image such as a horizontal line is projected on a visor on the front of the helmet, and a display image of the visor is adjusted according to a change in the attitude of the pilot so that the relationship between the pilot and the image is always appropriately maintained. In the case of the HMD, it is necessary to detect the attitude of the pilot's head with respect to the reference aircraft in order to adjust the display image of the visor according to the attitude change of the pilot.
Conventionally, there are an optical system, a mechanical system, an ultrasonic system, and a magnetic system as methods for detecting the attitude of the pilot's head.

[0003]

However, the above-mentioned conventional attitude detection method has a problem that it is difficult to accurately and easily detect the attitude of the pilot's head.

That is, the optical method utilizes the fact that the phase of the measurement light applied to the pilot's head corresponds to the posture of the head. In the case of this optical method, noise light is used. It is not easy to detect the attitude of the pilot's head because it is necessary to secure the light path for shielding and measurement, and the installation location is strongly restricted.

[0005] The mechanical method is a method utilizing the fact that the angle of an articulated link attached to a pilot corresponds to the attitude of the pilot head. It is still not easy to detect the attitude of the pilot head due to insufficient durability of the detection potentiometer and restrictions on the mounting position. Further, according to this method, there is a problem that the movement of the pilot is hindered.

[0006] The ultrasonic method is a method of detecting a three-dimensional position change of a measurement point on the pilot side with respect to a reference point on the fuselage side using an ultrasonic receiving / transmitting element. However, there are problems such as low sensitivity and low resolution, which are fundamental weak points of ultrasonic measurement, and a remarkable error caused by disturbance ultrasonic waves, so that the attitude of the pilot head cannot be accurately detected.

The magnetic method is a method of detecting a three-dimensional change in the position of a measurement point on the pilot side with respect to a reference point on the fuselage side using a transmitting / receiving coil. It is difficult to detect the pilot's attitude because it is difficult to correct the error caused by the surroundings and the surrounding metal body. That is, errors are suppressed by a mapping method of creating a correction data table for each installation environment including surrounding metal bodies, but it takes a lot of labor and cost to create an appropriate correction data table.

In view of the above circumstances, an object of the present invention is to provide a posture detection method capable of easily and accurately detecting the posture of another object with respect to one object.

[0009]

In order to solve the above-mentioned problems, a posture detecting method according to the present invention is a method for detecting the posture of another object with respect to one reference object. And the absolute coordinate 3
An angle measurement sensor (reference angle sensor) for measuring an angle around each axis, and an angle measurement for measuring the angle around each of the three axes in absolute coordinates with respect to the earth on the other object. A sensor (posture angle sensor) is attached, and a difference calculation is performed based on the angle detection result obtained by the reference angle sensor and the angle detection result obtained by the posture angle sensor, thereby detecting the posture of the other object. .

[Operation] Next, the operation when the posture of an object is detected by the posture detection method of the present invention will be described.
When posture detection is performed by the method of the present invention, an angle measurement sensor (reference angle sensor) for measuring angles around each of three axes of absolute coordinates with respect to the earth is attached to one of the reference objects in advance. An angle measuring sensor (posture angle sensor) for measuring angles around each of the three axes of absolute coordinates with respect to the earth is also attached to the other object to be subjected to posture detection. Then, along with the start of the posture detection, the reference angle data is obtained by the reference angle sensor, and in parallel with the obtaining of the posture angle data by the posture angle sensor, the difference calculation between these two angle data and the posture angle data is performed. Done.

In the method of the present invention, the result of angle detection by the reference angle sensor is attitude data of one object with respect to three axes of absolute coordinates with respect to the earth, and the result of angle detection by the attitude angle sensor is based on the earth. The orientation data of the other object with respect to the three axes of the absolute coordinates. Therefore, by performing a difference operation based on the results of the two angle detections, the angle difference between one object and the other object is obtained for each of the three axes of absolute coordinates with respect to the earth, and As a result of determining the difference in the posture data between the other objects, the other posture of one object can be detected.

[0012]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an overall configuration of a posture detection system in which a posture detection method as an example of the present invention is implemented, and FIG. 2 is a schematic diagram for explaining a measurement principle of an angle measurement sensor used in the embodiment. .

The attitude detection system shown in FIG. 1 includes a reference angle sensor (angle measurement sensor) 1 attached to one reference object, and an orientation detection sensor attached to the other object which is an object of orientation detection with respect to one reference object. And a posture angle sensor (angle measurement sensor) 2 provided. Hereinafter, for the sake of convenience, one of the reference objects is an aircraft (not shown), and the object whose posture is to be detected is the head of a pilot (not shown) on board (the head is directly and integrally covered with the head). Helmet). Therefore, the reference angle sensor 1 is mounted at an appropriate position in the aircraft, and the attitude angle sensor 2 is mounted at an appropriate position on the helmet. Each of the reference angle sensor 1 and the attitude angle sensor 2 is an angle measurement sensor that measures an angle around each of three axes of absolute coordinates with respect to the earth. The measurement principle of these angle measurement sensors is as follows.

As shown in FIG. 2, the angle measuring sensor used in the embodiment has a substantially U-shaped vibration tuning fork type fork 3, and the vibration speed V is kept constant at the tip end of the fork 3 by a piezoelectric element or the like. When the periodic vibration is applied and the rotation of the rotation angular velocity Ω is applied to the root side of the fork 3, the Coriolis force (Coriolis force) perpendicular to the vibration surface of the fork 3 is applied.
iolis force). The Coriolis force F is the product of the vibration velocity V and the rotational angular velocity Ω (F = V
· Ω). That is, if the vibration velocity V is constant, the Coriolis force F is proportional to the rotational angular velocity Ω, and the rotational angular velocity Ω corresponds to the attitude (the amount of angular displacement) of the fork 3 with respect to the absolute coordinates with respect to the earth. are doing. As a result, by measuring the Coriolis force F,
It is possible to measure the angles around each of the three axes of absolute coordinates with respect to the earth. Usually, the angle measuring sensor is provided with as many (for example, three) forks 3 as necessary.

Therefore, in the angle measuring sensor used as the reference angle sensor 1 and the attitude angle sensor 2, a transmitting unit and a receiving unit using light, ultrasonic waves, or electromagnetic induction are installed separately for one object and the other object. Or a self-closing type with a non-split installation structure in which an articulated link is installed as a whole on an object whose angle is to be detected, instead of a split-installation type sensor where an articulated link is installed between one object and the other Since the angle sensor can avoid an error caused by a disturbance ultrasonic wave or a disturbance induction magnetic field, there is an advantage that the position can be detected with high accuracy without being restricted by sensor installation.

An angle measuring sensor of this kind is disclosed, for example, in the references: Eric Foxlin, Michael Harrington and Yury Altshul
er Miniature 6-DOF inertial system for tracking
HMDs "Proc. SPIE, 3362, PP. 214-228 (1998). As a specific product, for example, I-Cube I
It is sold by the company InterSence, INC.USA under the product name S-300.

The output signal Xe from each of the angle sensors 1 and 2
As shown by the following equation (1), Roll, PiTC, which is customary when indicating the attitude of an object in the aviation industry field,
It is sent out in the form of three components, h and Yaw.

[0018]

(Equation 1)

The roll, pitch, and yaw components of equation (1) will be described with reference to FIG. 3 while taking the case of the pilot's head posture as an example. Roll indicates the front of the pilot when facing the front, as shown in FIG.
This is the rotation angle (rotation angle generated on the YZ plane) when the screw is rotated clockwise in the positive direction of the X axis, and the angle of rotation when the pilot tilts the head to the left and right. It is the angle of inclination of the head, and the case where the head is tilted to the right is the forward direction.

The pitch is such that the right side when the pilot faces the front is the positive direction of the Y axis of the XYZ three-axis orthogonal coordinates as shown in FIG. 3, and the screw is screwed clockwise in the positive direction of the Y axis. Rotation angle when rotated (angle of rotation generated on XZ plane)
This is the inclination angle of the head when the pilot shakes the head up and down, and the case where the head is swung upward is the forward direction.

As shown in FIG. 3, Yaw sets the downward direction when the pilot faces the front as the positive direction of the Z-axis of the XYZ three-axis orthogonal coordinates, and turns the screw clockwise in the positive direction of the Z-axis. This is the rotation angle when rotated (rotation angle generated on the XY plane), which is the rotation angle of the head when the pilot turns his / her head to the left and right, and is correct when the head is turned to the right. Direction.

As shown in FIG. 3, the output signals Xe from the angle sensors 1 and 2 indicate the attitude of each of the three-axis orthogonal coordinates sharing the origin O of the absolute coordinates with respect to the earth, as shown in FIG. Become. That is, the rotation coordinate system OX
In the embodiment in which the reference angle sensor 1 is attached to a point K (Xr, Yr, Zr) on the plane k of YZ, the output signal Xe from the reference angle sensor 1 is three signals for the earth of the vector OK. Shows the angle component (direction component). Also,
A point H (X on the plane h of the rotating coordinate system O-Xa-Ya-Za
m, Ym, Zm), the output signal Xe from the attitude angle sensor 2 indicates three angle components (directional components) of the vector OH with respect to the earth.

The system shown in FIG.
Are provided downstream of the sensors 1 and 2 for performing processing (normal data conversion processing) for converting the output signal Xe from the data into Euler angle data according to the following equations (2) to (4). That is, the output signal Xe of the reference angle sensor 1 is output from the conversion unit 4 to the temporary memory 6 as Euler angle data (Rr, Pr, Yr) and is sequentially rewritten.
The output signal Xe of the attitude angle sensor 2 is also output from the conversion unit 5 to the temporary memory 7 as Euler angle data (Rm, Pm, Ym) and is sequentially rewritten. Where R
r and Rm are angles around the X axis or Xa axis, and Pr and P
m is the angle around the Y axis or Ya axis, and Yr and Ym are Z
Axis or the angle around the Za axis.

[0024]

(Equation 2)

The origin memories 8, 9 fetch and store the Euler angle data held in the temporary memories 6, 7 when receiving the origin fetch command. The origin memory 8 stores the origin Euler angle data (Rro, Pro, Yro), and the origin memory 9 stores the origin Euler angle data (Rmo, Pmo, Ym).
o) Remember. The origin take-in command is issued when the aircraft and the pilot are in arbitrary postures. Usually, the pilot's posture is issued when the pilot's head is facing straight ahead, which is the standard posture.

Temporary memories 6, 7 and origin memories 8, 9
Subtraction units 10 and 11 at the subsequent stage subtract the respective data in the temporary memories 6 and 7 and the origin memories 8 and 9 and send the results to the angle difference data memories 12 and 13 for storage. The angle difference data memory 12 stores the angle difference data (Δ
Rr = Rr-Rro, .DELTA.Pr = Pr-Pro, .DELTA.Yr = Yr
−Yro), and the angle difference data memory 13 stores the angle difference data (ΔRm = Rm−Rmo, ΔPm = Pm−Pm).
o, ΔYm = Ym-Ymo) is stored. Subtraction unit 1
In addition to the case where the operation is performed only when a command is received, the operations 0 and 11 may be performed every time data is updated.
The angle difference data (ΔRr, ΔPr, ΔYr) corresponds to the angle difference between the origin angle of the aircraft and the current angle, and the angle difference data (ΔRm, ΔPm, ΔYm) corresponds to the pilot's head (helmet). It will correspond to the angle difference between the origin angle and the current angle.

Further, the difference calculation unit 14 of the system shown in FIG.
Calculates the angle indicating the attitude of the pilot's head with respect to the aircraft based on the data in the angle difference data memories 12 and 13 as follows. First, correction angle data Ay is obtained by performing a difference operation according to the following equation (5). Ay = ΔYm−ΔYr (5) Subsequently, the correction angle data A is calculated according to the following equation (6).
Find r. Ar = COS (Ay) × ΔRr + SIN (Ay) × ΔPr (6) Further, according to the following equation (7), the correction angle data A
Find p. Ap = −SIN (Ay) × ΔRr + COS (Ay) × ΔPr (7)

The difference calculator 14 calculates the correction angle data (A
After calculating r, Ap, Ay), a difference operation according to the following equations (8) and (9) is performed to obtain final attitude angle data (Br, Bp, By). It is held in the memory 14a. Br is Roll
And Bp is the attitude angle data corresponding to Ptich. By is attitude angle data corresponding to Yaw, and is the same angle as the correction angle data Ay obtained by Expression (5). Br = ΔRm−Ar (8) Bp = ΔPm−Ap (9) By = Ay (= ΔYm−ΔYr) (5)

That is, as shown in equations (8) and (9),
For the two attitude angle data Bp corresponding to Roll and the attitude angle data Bp corresponding to Ptich, the correction angle data Ar and Ap according to the equations (6) and (7) are used without using the angle difference data ΔRr and ΔPr as they are. By obtaining and using it, accurate attitude angle data is obtained.

In the case of the system of the embodiment, the difference calculation unit 14
In the subsequent stage, when a polling command is received, the posture angle data (Br, B) held in the posture angle data memory 14a is read.
Also, an interface 15 for transmitting the data (p, By) to the attitude display unit 16 is provided. The posture display unit 16 adjusts the image being displayed on the visor (not shown) based on the posture angle data (Br, Bp, By). For example,
When the horizontal line is displayed, the vertical position and inclination of the horizontal line are corrected according to the current posture of the pilot's head.

The obtained attitude angle data (Br,
Bp, By) is not limited to being used for image adjustment, but can also be used to display attitude angle data (Br, Bp, By) itself or to be used for attitude adjustment of an infrared camera mounted on an airframe. . The conversion units 4 and 5 and the subtraction units 10 and 11 or the difference calculation unit 14 in the system shown in FIG.
Is mainly composed of a computer and its operation program (software).

Next, the operation of the apparatus when the attitude detection is performed by the attitude detection system described in detail above will be described with reference to FIG. FIG. 4 is a flowchart showing a process of collecting angle data for executing posture detection in the system of FIG.

[Step S1] When the execution of the posture detection is started, the output signals Xe are sequentially sent from the angle sensors 1 and 2 to the conversion units 4 and 5, respectively.

[Step S2] Each of the converters 4 and 5 converts each output signal Xe to Euler angle data (Rr, Pr) for the reference angle.
, Yr) or Euler angle data (Rm
, Pm, Ym).

[Step S3] The temporary memory 6 stores (updates) the Euler angle data (Rr, Pr, Yr), and the temporary memory 7 stores (updates) the Euler angle data (Rm, Pm, Ym).

[Step S4] If there is a command to take in the origin, the stored data in the temporary memories 6 and 7 at the time of the command are taken as the origin Euler angle data (Rro, Pro, Yro) and the origin Euler angle data (Rmo, Pmo, Ymo). Origin memory 8,
Then, the process proceeds to step S5.

[Step S5] If there is an interrupt command to start the attitude finding process, the attitude finding subroutine is started, and the process returns to step S1. If there is no interrupt command, the process immediately returns to step S1 without starting the posture finding subroutine.

Next, the execution status of the attitude finding subroutine started by the interrupt command in step S5 will be described with reference to FIG. FIG.
4 is a flowchart showing a calculation process for posture detection in the system of FIG. [Step F1] Each of the subtraction units 10 and 11 subtracts the data in the temporary memories 6 and 7 and the data in the origin memories 8 and 9 to calculate angle difference data.

[Step F2] Each angle difference data memory 1
2 and 13 are obtained angle difference data (ΔRr, ΔPr, ΔY
r) and (ΔRm, ΔPm, ΔYm) are stored, respectively.

[Step F3] The difference calculator 14 first obtains correction angle data Ay by a difference calculation of Ay = ΔYm−ΔYr.

[Step F4] The difference calculation section 14 further calculates the correction angle data Ar and the correction angle data Ap according to the above-mentioned equation (6) or (7).

[Step F5] The difference calculation unit 14 determines that the Br
= ΔRm−Ar or Bp = ΔPm−Ap, and the attitude angle data (Br, Bp, By) is determined according to the relationship By = Ay.

[Step F6] When the determined attitude angle data (Br, Bp, By) is stored in the attitude angle data memory 14a, the attitude finding subroutine ends. When a polling command is issued, the posture / angle data memory 1
The data (Br, Bp, By) held in 4a is transmitted from the interface 15 to the attitude display unit 16.

As described above, in the case of the posture detection method of the present invention, accurate posture angle data can be obtained by simple data processing such that difference calculation of angle data is executed based on the output signals Xe of the angle sensors 1 and 2. (Br, Bp, By) can be detected.

The present invention is not limited to the above embodiment, but can be modified as follows. (1) In the embodiment, only one angle measurement sensor is installed on one reference object and the other object of the posture detection target. However, the angle measurement sensor is installed on one or both objects. As a modified example, a configuration in which a plurality of angle measurement sensors are attached and used extra as a spare sensor, or an average of output signals of the plurality of angle measurement sensors is sent to the conversion unit is mentioned.

(2) In the embodiment, the data (Br, Bp, By) held in the attitude angle data memory 14a is sent to the attitude display unit 16 only when the polling command is issued. As a modified example, a configuration in which the angle data (Br, Bp, By) is automatically transmitted to the attitude display unit 16 as soon as it is determined is given.

(3) In the embodiment, the detection of the attitude of the pilot's head with respect to the airframe has been described as an example, but the object of the attitude detection by the method of the present invention is not limited to any particular object.

[0048]

As described above in detail, according to the posture detection method of the present invention, one of the reference object and the other object of which the posture is to be detected have three axes of absolute coordinates with respect to the earth. A simple data processing that only requires a reference angle sensor and an attitude angle sensor to measure the angle around each axis, and performs a difference calculation based on the angle detection results obtained by both angle sensors. Sensor and attitude angle sensor,
Uses a non-optical angle measurement sensor with a non-divided installation type (self-closing type) that does not cause errors due to disturbance ultrasonic waves or disturbance induction magnetic fields, so that posture detection can be performed with high accuracy without restrictions on sensor installation. . Therefore, in the case of the method of the present invention, it is possible to easily and accurately detect the posture of the other object whose posture is to be detected.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of a posture detection system according to an embodiment.

FIG. 2 is a schematic diagram for explaining a measurement principle of the angle measurement sensor according to the embodiment.

FIG. 3 is a schematic diagram showing an angle setting situation with respect to a reference angle sensor and a posture angle sensor.

FIG. 4 is a flowchart illustrating a process of collecting angle data for executing posture detection in the system according to the embodiment.

FIG. 5 is a flowchart illustrating an arithmetic processing process for posture detection in the system according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Reference angle sensor 2 ... Attitude angle sensor 4,5 ... Transformation part 6,7 ... Temporary memory 8,9 ... Origin memory 10,11 ... Subtraction part 12,13 ... Angle difference data memory 14 ... Difference calculation part 14a ... Attitude Angle data memory

Claims (1)

[Claims] 1. A method for detecting the orientation of another object with respect to one reference object, wherein the one object measures angles around each of three absolute coordinate axes with respect to the earth. In addition to attaching an angle measurement sensor (reference angle sensor), the other object is also equipped with an angle measurement sensor (posture angle sensor) that measures the angle around each of the three absolute coordinate axes with respect to the earth. And performing a difference calculation based on an angle detection result obtained by the reference angle sensor and an angle detection result obtained by the posture angle sensor to detect the posture of the other object.