JP2000180462A - Posture angle detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a posture angle detecting device which can be widely used by relaxing limitations on use location and use environments. SOLUTION: A posture angle detecting device is constituted of gyros 12a, 12b, and 12c to detect angular velocities about three axes which intersect one another at right angles, a motion angle computing device 18 to compute a movement angle corresponding to an angular velocity detected by each gyro, acceleration sensors 23a and 23b to detect biaxial acceleration, two geomagnetic sensors 22a and 22b, a stationary angle computing device 24 to compute a stationary angle about the three axes, a determining device 32 to determine and compute and whether the computation result of the stationary angle computing device 24 is false or not, a correction coefficient selecting device 33 to select the correction coefficient of the stationary angle computing device 24, a motion angle computing device 18 to compute a movement angle corresponding to the computation result of the determining device 32, and a posture angle computing device 42 to compute an output posture angle from the computation result of the stationary angle computing device 24 and the selection result of the correction coefficient selecting device 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head mounted display (hereinafter, referred to as HMD) used for detecting and controlling the attitude of a moving object, virtual reality, and the like.
The present invention relates to a posture angle detection device suitable for use in detecting a posture angle (a rotation angle of three axes) of an object in a three-dimensional space, such as a tracker for detecting a head posture angle, a 3D game pad, and the like.

[0002]

2. Description of the Related Art Conventionally, as a method of detecting head movement, which is used in virtual reality, a weak alternating magnetic field is generated from an externally installed alternating magnetic field source, and detected and controlled by a sensor unit arranged in an HMD. A method that uses an alternating magnetic field to detect head movement in the arithmetic unit, or an ultrasonic signal from an externally installed ultrasonic source is detected by the sensor unit located on the HMD, and the head operation is detected by the control arithmetic unit. There is a method using ultrasonic waves to be detected.

[0003]

However, in the former method using an alternating magnetic field, since the signal generating source is a weak alternating magnetic field, the responsiveness is reduced by using a large number of filters to cancel noise, and the head is reduced. Compared to the movement of
In some cases, the motion of the image of the HMD was slowed down, resulting in sickness and sickness.

In the latter method using ultrasonic waves,
Signals may not be detected due to malfunctions due to the effects of various other ultrasonic signals or obstacles between the signal source and the sensor.Received only with the arm or hair in front of the sensor There has been a problem that it becomes impossible and malfunctions.

Accordingly, the present invention has solved the above problems,
It is an object of the present invention to provide a posture angle detecting device which can relax a restriction on a place and an environment of use and can be used widely.

[0006]

According to the present invention, there are provided three gyros for detecting an X-axis and a Y-axis orthogonal to a horizontal plane and an angular velocity about a Z-axis orthogonal to each of the X-axis and the Y-axis; Based on the output corresponding to the angular velocity, the yaw angle that is the rotation angle around the Z axis, the pitch angle that is the new rotation angle around the Y axis after turning the coordinate axis around the Z axis by the yaw angle, and the Z axis A motion angle calculation device for calculating a roll angle which is a new rotation angle around the X-axis after being rotated around the yaw angle and a pitch angle around a new Y-axis, and at least XY
An acceleration sensor arranged to detect accelerations of two axes orthogonal to each other on a plane and detecting a roll angle and a pitch angle; and a geomagnetic sensor arranged to detect at least the geomagnetism of the two axes. A stationary angle computing device that computes a roll angle, a pitch angle, and a yaw angle based on the outputs of the acceleration sensor and the geomagnetic sensor; a discriminating device that determines whether the computation result by the static angle computing device is true or false; A correction coefficient selection device for selecting a correction coefficient of an attitude angle based on a calculation result by an angle calculation device; and a calculation result of the motion angle calculation device and the static angle calculation device and the correction coefficient selection device in accordance with a calculation result of the discrimination device. And a posture angle calculating device for calculating a posture angle output from the selection result of the above.

Further, according to the present invention, in the correction coefficient selection device, the static angle [temporary roll angle R (n), temporary pitch angle P (n), temporary yaw angle Φ
(N)] is divided into a plurality of areas according to the accuracy expected in advance, and the correction coefficient selection device performs correction coefficients m1 (i), m2 (i), and m3 according to the divided areas.
(I) (where i is a natural number representing the divided area of 2 or more, and the smaller i is, the higher the expected accuracy is), and a correction coefficient is selected in accordance with the area of the current stationary angle, and the attitude angle is selected. And the correction coefficients m1 (i), m2
(i) and m3 (i) are: m1 (1)> = m1 (2)>=...> = m1 (i) m2 (1)> = m2 (2)>=...> = m2 (i) m3 (1)> = m3 (2)>=...> = m3 (i)

Further, according to the present invention, the output to be obtained by the attitude angle detecting device is a roll angle α (n), a pitch angle β (n),
The yaw angle γ (n) and the motion angle obtained from the motion angle detecting means are calculated by the provisional roll angle change ΔX (n) and the provisional pitch angle change Δ
Y (n), the temporary yaw angle change ΔZ (n), and the static angle determined by the static angle detection means are converted into a temporary roll angle R (n), a temporary pitch angle P (n), and a temporary yaw angle Φ ( n), error α (n−1) + ΔX (n) −R between the output to be obtained and the static angle
(N), β (n-1) + ΔY (n) -P (n), γ (n
−1) + ΔZ (n) −Φ (n), a variable proportional to a proportional constant of 1 or less, or a constant that is not larger than the error is C1, C2, C3, and a correction coefficient selected by the correction coefficient selection device is m1. , M2, and m3, the posture angle when it is determined that the posture angle information R, P, and Φ from the stationary angle detection means are correct based on the determination result of the determination device is α (n) = α ( n-1) + [Delta] X (n) -C1 * m
1, β (n) = β (n−1) + ΔY (n) −C2 × m
2. By using γ (n) = γ (n−1) + Z (n) −C3 × m3, respective pieces of posture angle information R ·
The posture angle corresponding to the posture angle information determined as an error in P · Φ is α (n) = α (n−1) + ΔX (n), β
(N) = β (n−1) + ΔY (n), γ (n) = γ (n
−1) + ΔZ (n).

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an HMD to which an attitude angle detecting device is applied.
This HMD is provided so that the image displayed on the display in front of the HMD changes in conjunction with the movement of the user's head and allows the user to experience a virtual space. If you turn to the right while holding it, the head posture angle measured by the posture angle detection device is transmitted to the video generation device, and the video generation device transmits the video corresponding to the posture angle to the HMD, so the video developed to the right Is displayed so that a 360-degree image of the entire space can be realized by the movement of the head.

As shown in FIG. 1, reference numeral 1 denotes an HMD main body, in which an attitude angle detecting device 2 according to the present invention is arranged, and a video signal generator 7 is connected to a signal cable 4.
It is connected to the.

FIG. 2 is a block diagram showing the overall configuration of the attitude angle detecting device according to the present invention. As shown in FIG.
A motion angle detecting means 11 having a motion angle calculating device 18 for calculating a temporary attitude angle from outputs of the three gyros 12a, 12b, 12c, and two geomagnetic sensors 22a, 22
b and the stationary angle detecting means 21 provided with a stationary angle calculating device 24 for calculating a stationary angle from the two acceleration sensors 23a and 23b.
And whether or not the posture angle obtained by the stationary angle detecting means 21 includes an error (for example, when a linear acceleration is applied,
A discriminating device 32 for discriminating whether the acceleration sensor as an inclinometer includes a signal other than tilt), a correction coefficient selecting device 33 for selecting a correction coefficient based on a static angle, a motion angle calculating device 18, and a static angle calculating device 24. , And an attitude angle calculation device 42 for processing a signal from the discrimination device 32.

FIG. 3 is an explanatory view showing the arrangement of a gyro, an acceleration sensor, and a geomagnetic sensor in the attitude angle detecting device of the present invention. As shown in FIG. 3, three axes orthogonal to each other (an axis orthogonal to the horizontal plane is an X axis, a Y axis, an axis orthogonal to each of the X axis and the Y axis is a Z axis, a rotation angle around the Z axis is a yaw angle, Rotate the new Y-axis rotation angle around the Z-axis by the yaw angle coordinate axis, rotate the Y-axis rotation angle around the Z-axis by the yaw angle, and rotate the new Y-axis around the new Y-axis by the pitch angle. A first gyro 12 a for detecting an angular velocity around the X-axis (hereinafter, a rotation angle around the X axis is referred to as a roll angle);
The gyro 12b and the third gyro 12c are arranged in parallel to the sensor coordinate X, Y, and Z axes, that is, orthogonal to each other. First geomagnetic sensor 2 for detecting yaw angle
The 2a and the second geomagnetic sensor 22b are configured by two axes (here, sensor coordinate X axis and Y axis) orthogonal to each other on a horizontal plane. Similarly, the first acceleration sensor 23a
The second acceleration sensor 23b is arranged on two axes (here, sensor coordinates X axis and Y axis) orthogonal to each other on a horizontal plane. As the gyro, a vibrator made of a non-magnetic material such as piezoelectric ceramic, piezoelectric single crystal, or silicon can be used. Note that, in the present embodiment,
A piezoelectric vibrating ceramic gyro made by Tokin was used.

Next, among the attitude angle detecting devices of the present invention, a static angle calculating device will be described. From the acceleration Ax (n) in the X-axis direction and the acceleration Ay (n) in the Y-axis direction obtained from the outputs of the two-axis acceleration sensor, the roll angle R (n) and the pitch angle P (n) are expressed by the following equation (1). , (2).

R (n) = sin ⁻¹ [Ax (n) / cosP (n)] (1)

P (n) = sin ⁻¹ Ay (n) (2)

Here, the above equations (1) and (2) are arc sine functions. Therefore, R and P have high accuracy at low angles and low accuracy at high angles. For example, Ax,
Considering the case where the output resolution of Ay is 0.01 G, 0 °
The resolution in the vicinity is 0.57 °, and the resolution in the vicinity of 90 ° is 8.11 °. As for Φ, since R and P are used in the calculation process, the accuracy is low when either R or P is at a high angle. Therefore, it should be noted that when R and P are high angles, the accuracy is low even when the static angle calculation device determines that the angle is correct.

Next, among the attitude angle detecting devices of the present invention, a correction coefficient selecting device will be described. Although the accuracy of the static angle changes as described above, this is divided into several regions in advance, and appropriate correction coefficients m1, m2, m
Put 3 in. Table 1 shows one example.

(Table 1)

As shown in Table 1, as R and P become higher angles and the accuracy becomes lower, the correction coefficient becomes smaller. m1
Is affected by the precision of R, m2 is affected by the precision of P, and m
It can be seen that the accuracy of both R and P affects 3.
As described above, the correction coefficient selection device determines the correction coefficients m1, m2, and m3 based on the current attitude angle.

Next, among the attitude angle detecting devices of the present invention, an attitude angle calculating device will be described. Α (n), β (n), γ (n) are the outputs to be obtained by the attitude angle detecting device of the present invention, and X (n) is the temporary attitude angle obtained from the dynamic motion angle detecting means.
When Y (n), Z (n), and the static angles determined by the static static angle detecting means are R (n), P (n), and Φ (n),
When it is determined that the posture angle information R and P from the stationary angle detecting means are correct, α (n) = α (n−1) + ΔX (n) −k [α (n−1) + ΔX
(n) −R (n)] × m1 β (n) = β (n−1) + ΔY (n) −k [β (n−1) + ΔY
(n) −P (n)] × m2 γ (n) = γ (n−1) + ΔZ (n) −k [γ (n−1) + ΔZ
(n) −Φ (n)] × m3, and the attitude angle is calculated. Here, k is a proportional constant of 1 or less that is arbitrarily selected.

When it is determined that the attitude angle information from the stationary angle detecting means is incorrect, α (n) = α (n−1) + ΔX (n) β (n) = β (n−1) + ΔY (n The attitude angle is calculated and obtained by γ (n) = γ (n−1) + ΔZ (n).

Therefore, when the attitude angle detecting device of the present invention is applied to an HMD as in the present embodiment, it is possible to obtain high-speed response-free angle information without using an external signal without using an external signal. Performance. In the attitude angle detection device according to the present invention, since the gyro is mounted as an element, it is possible to reduce the size and weight, and since the ceramic vibrator is used, magnetic noise is not received and the device is brought close to the magnetic sensor. However, the function is not impaired.

In this embodiment, a geomagnetic sensor,
Although two acceleration sensors have been described as examples, at least one of them may be three. This embodiment is most preferable in terms of miniaturization.

[0025]

According to the present invention, it is possible to provide a posture angle detecting device that can be used widely by alleviating restrictions on the place and environment of use.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a usage state of a posture angle detection device in an HMD of the present invention.

FIG. 2 is a block diagram showing the overall configuration of the attitude angle conversion device of the present invention.

FIG. 3 is an explanatory diagram showing an arrangement of a gyro, an acceleration sensor, and a geomagnetic sensor in the attitude angle detecting device of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 HMD main body 2 Attitude angle detection device 4 Signal cable 7 Image generation device 11 Motion angle detection means 12a (First) gyro 12b (Second) gyro 12c (Third) gyro 13a (First) A / D Converter 13b (Second) A / D converter 13c (Third) A / D converter 14 (IIR) digital high-pass filter 15 Positive / negative inversion determination device 16 IIR coefficient reset device 17 Offset correction device 18 Motion angle calculation device 21 Stationary Angle detecting means 22a (first) terrestrial magnetism sensor 22b (second) terrestrial magnetism sensor 23a (first) acceleration sensor 23b (second) acceleration sensor 24 Static angle calculator 32 discriminator 33 correction coefficient selector 42 posture Angle calculation device

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G01P 9/04 G01P 9/04 G01R 33/02 G01R 33/02 Q G01V 3/04 G01V 3/04

Claims (3)

[Claims] 1. An X-axis and a Y-axis orthogonal to each other in a horizontal plane, and
Three gyros for detecting angular velocities around the Z axis orthogonal to each of the axis and the Y axis, and based on outputs corresponding to the angular velocities of the gyros, a yaw angle which is a rotation angle around the Z axis and a rotation around the Z axis. The pitch angle, which is the new rotation angle around the Y axis after turning the coordinate axis by the yaw angle, and the new X axis after turning the yaw angle around the Z axis, and the pitch angle around the new Y axis A motion angle calculating device for calculating a roll angle, which is a rotation angle of, and an acceleration for detecting a roll angle and a pitch angle, which are arranged to detect at least two-axis accelerations orthogonal to each other on an XY plane. A sensor, a geomagnetic sensor arranged to detect at least the two-axis geomagnetism, a static angle calculating device that calculates a roll angle, a pitch angle, and a yaw angle based on outputs of the acceleration sensor and the geomagnetic sensor; Static angle A discriminating device for judging whether the calculation result by the device is true or false, a correction coefficient selecting device for selecting a correction coefficient for the attitude angle based on the calculation result by the static angle calculating device, and the motion according to the calculation result of the discriminating device. An attitude angle detection device comprising: an angle calculation device; an attitude angle calculation device that calculates an attitude angle output from a calculation result of the static angle calculation device and a selection result of the correction coefficient selection device. 2. The method according to claim 1, wherein the static angle determined by the static angle detecting means is divided into a plurality of regions with a predicted accuracy. Correction coefficient m1
(I), m2 (i), and m3 (i) (where i is a natural number representing two or more of the divided areas), and a correction coefficient is selected in accordance with the current static angle area and the attitude angle is selected. , And the correction coefficients m1 (i), m2 (i), m
3 (i): m1 (1)> = m1 (2)>=...> = M1 (i) m2 (1)> = m2 (2)>=...> = M2 (i) m3 (1) > = M3 (2)>=...> = M3 (i). 3. An output to be obtained by the attitude angle detecting device is a roll angle α (n), a pitch angle β (n), and a yaw angle γ.
(N) the tentative roll angle change ΔX (n) and the tentative pitch angle change ΔY
(N), the provisional yaw angle change ΔZ (n), the provisional roll angle R (n), the provisional pitch angle P (n), and the provisional yaw angle Φ (n ), The error α (n-1) + ΔX (n) -R between the output to be obtained and the static angle
(N), β (n-1) + ΔY (n) -P (n), γ (n
−1) + ΔZ (n) −Φ (n), a variable proportional to a proportional constant of 1 or less, or a constant that is not larger than the error is C1, C2, C3, and a correction coefficient selected by the correction coefficient selection device is m1. , M2, and m3, the posture angle when it is determined that the posture angle information RP, Φ from the stationary angle detection means is correct, based on the determination result of the determination device, is α (n) = α ( n-1) + [Delta] X (n) -C1 * m
1, β (n) = β (n−1) + ΔY (n) −C2 × m
2. By using γ (n) = γ (n−1) + Z (n) −C3 × m3, respective pieces of posture angle information R ·
The posture angle corresponding to the posture angle information determined as an error in P · Φ is α (n) = α (n−1) + ΔX (n), β
(N) = β (n−1) + ΔY (n), γ (n) = γ (n
3. The attitude angle detection device according to claim 1, wherein the calculation is performed by -1) + ΔZ (n).