Method of sensing motion in three-dimensional space

• US 8,797,262 B2
• Filed: 03/29/2010
• Issued: 08/05/2014
• Est. Priority Date: 01/26/2010
• Status: Active Grant

• Current Assignee: Prolific Technology Inc.
• Original Assignee: Prolific Technology Inc.
• Inventors: Hsieh, Yi-Hsun, Yu, Ren-Yuan, Yeh, Hao-Chieh, Tseng, Kui-Chang
• Primary Examiner(s): Hicks, Charles V
• Application Number:
  US12/748,461
• Publication Number:
  US 20110181505A1
• Time in Patent Office: 1,590 Days
• Field of Search: 345/157
• 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 of at least one accelerometer contained in a device in three axes, wherein the three axes are three axes of a three-dimensional coordinate system in the 3D space;

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

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

2. The method of claim 1, wherein using the rotation radius of the device and the plurality of values of the gyroscope in the two axes to generate the tangential accelerations of the device in the two axes is performed according to:

3. The method of claim 2, wherein using the plurality of values of the accelerometer in the two axes and the tangential accelerations of the device in the two axes to generate the gravity components of the device in the two axes 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.

4. The method of claim 3, wherein using the gravity components of the device in the two axes 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:

5. The method of claim 4, wherein using the plurality of values of the gyroscope in the two axes, 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

.

6. The method of claim 4, wherein using the plurality of values of the gyroscope in the two axes, 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

.