METHOD OF SENSING MOTION IN THREE-DIMENSIONAL SPACE

• US 20110181505A1
• Filed: 03/29/2010
• Published: 07/28/2011
• Est. Priority Date: 01/26/2010
• Status: Active Grant

• Current Assignee: Prolific Technology Inc.
• Original Assignee: Prolific Technology Inc.
• Inventors: Yu, Ren-Yuan, Tseng, Kui-Chang, Yeh, Hao-Chieh, Hsieh, Yi-Hsun
• Granted Patent: US 8,797,262 B2
• Time in Patent Office: Days
• US Class Current: 345/157
• CPC Class Codes: G06F 3/0346 with detection of the device orientation or free movement in a 3D space, e.g. 3D mice, 6-DOF [six degrees of freedom] pointers using gyroscopes, accelerometers or tilt-sensors

Abstract

An accelerometer and a gyroscope are disposed in a device. When the device rotates in a 3D space, angle of the device relative to gravity is calculated, movement of the device relative to gravity is calculated during the rotation process, and a real trace of the device is obtained in the 3D space.

Claims

1. A method of sensing motion in a three-dimensional (3D) space, the method comprising:

reading a plurality of values in three axes gotten from at least one accelerometer contained in a device;

reading a plurality of values in two axes of at least one gyroscope of the device;

using the plurality of values in the three axes of the accelerometer and the plurality of values in the two axes of the gyroscope to generate a rotation radius of the device;

using the rotation radius of the device and the plurality of values in the two axes of the gyroscope to generate tangential accelerations in the two axes of the device; and

using the plurality of values in the two axes of the accelerometer, the tangential accelerations in the two axes of the device, the plurality of values in the two axes of the gyroscope, and the rotation radius of the device to generate a motion output of the device.

2. The method of claim 1, wherein using the plurality of values in the two axes of the accelerometer, the tangential accelerations in the two axes of the device, the plurality of values in the two axes of the gyroscope, and the rotating radius of the device to generate the motion output of the device comprises:

using the plurality of values in the two axes of the accelerometer and the tangential accelerations in the two axes of the device to generate gravity components in the two axes of the device;

using the gravity components in the two axes of the device to obtain an angle between a composite vector composed of the gravity components in the two axes and one axis of the two axes; and

using the plurality of values in the two axes of the gyroscope, the rotation radius of the device, and the angle to generate a horizontal motion output and a vertical motion output of the device.

3. The method of claim 2, wherein using the plurality of values in the three axes of the accelerometer and the plurality of values in the two axes of the gyroscope to generate the rotation radius of the device is performed according to the following equation:

4. The method of claim 3, wherein using the rotation radius of the device and the plurality of values in the two axes of the gyroscope to generate the tangential accelerations in the two axes of the device is performed according to:

5. The method of claim 4, wherein using the plurality of values in the two axes of the accelerometer and the tangential accelerations in the two axes of the device to generate the gravity components in the two axes of the device is performed according to:

G_x=A_x−

A_rx; and

G_z=A_z−

A_rz;

wherein

G_x is a gravity component along the x axis; and

G_z is a gravity component along the z axis.

6. The method of claim 5, wherein using the gravity components in the two axes of the device to obtain the angle between the composite vector composed of the gravity components in the two axes and the axis of the two axes, the angle is performed according to:

7. The method of claim 6, wherein using the plurality of values in the two axes of the gyroscope, the rotation radius of the device, and the angle to generate the horizontal motion output and the vertical motion output of the device are comprised of:

obtaining the horizontal motion output as ω

_z×

r×

Δ

t×

sin θ

+ω

_x×

r×

Δ

t×

cos θ

; and

obtaining the vertical motion output as ω

_z×

r×

Δ

t×

cos θ

+ω

_x×

r×

Δ

t×

sin θ

.

8. The method of claim 6, wherein using the plurality of values in the two axes of the gyroscope, the rotation radius of the device, and the angle to generate the horizontal motion output and the vertical motion output of the device are comprised of:

obtaining the horizontal motion output as ω

_z×

r×

sin θ

+ω

_x×

r×

cos θ

; and

obtaining the vertical motion output as ω

_z×

r×

cos θ

+ω

_x×

r×

sin θ

.