ATTITUDE DETECTING DEVICE

• US 20180088685A1
• Filed: 03/10/2016
• Published: 03/29/2018
• Est. Priority Date: 03/13/2015
• Status: Active Grant

• Current Assignee: SYD Dynamics ApS
• Original Assignee: SYD Dynamics ApS
• Inventors: Sang, Yinan, Gong, Zhuocheng, Shi, Liping
• Granted Patent: US 10,551,939 B2
• Time in Patent Office: Days
• CPC Class Codes: G01B 21/22 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01C 21/1654 with electromagnetic compass
• CPC Class Codes: G06F 3/017 Gesture based interaction, e.g. based on a set of recognized hand gestures interaction based on gestures traced on a digitiser G06F3/04883
• 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
• CPC Class Codes: G06F 3/0383 Signal control means within the pointing device
• CPC Class Codes: H04N 21/42222 Additional components integrated in the remote control device, e.g. timer, speaker, sensors for detecting position, direction or movement of the remote control, microphone or battery charging device

Abstract

The present invention relates to an attitude detecting device requiring no optical nor visual sensors but instead using an advanced processing method, which can be used in applications such as data-login, measurements, motion control, cursor pointing on graphic user interfaces, gaming, etc. The device includes inertial measurement units (IMU) such as accelerometers, gyroscopes and may also include magnetometers. The method utilizes the IMU'"'"'s sensor data and uses a revised method to transfer 3-dimensional rotations into a representation, such as quaternions, Euler angles, yaw, pitch, and roll. The method also provides better performance when the device recovers from interrupts. The method further utilizes the above mentioned representation and turns it into 2-dimensional values in a precise way while intentionally remove the effects caused by rotation in the other unused degree of freedom.

Claims

1. A device being operated in a 3-dimensional movement and where its orientation is translated into a mathematical 3D representation that then further is transformed into a mathematical 2D presentation, where the device includes an attitude, or orientation, detecting means, where the mathematical representation transformation uses to remove the effects of an unused degree of freedom.

2. The device according to claim 1, where the 2D representation is calculated based on the object orientation vector F seen on the two used degrees of freedom.

3. The device according to claim 2, where said detecting means includes an accelerometer and gyroscope and optionally a magnetometer.

4. The device according to claim 3, where the device comprises least three of one or some of the said accelerometer, gyroscope and/or magnetometer positioned to generate a measured sensor data vector, such as a measurement acceleration vector A=(Ax, Ay, Az), gyroscope vector ω

=(ω

x, ω

y, ω

z) and/or magnetic vector M=(Mx, My, Mz).

5. The device according to claim 1, where the mathematical representation includes a world frame being a basic reference frame coordinate system (X, Y, Z) being fixed and a sensor frame (X′

, Y′

, Z′

) being a rotation of the world frame (X, Y, Z), and where the object orientation is represented by the vector F (X1, Y1, Z1) in the sensor frame (X′

, Y′

, Z′

).

6. The device according to claim 5, where the vector F it is parallel to the unused degree of freedom.

7. The device according to claim 1, where the present orientation of the object is estimated through the changes in orientation as registered by the sensors including the steps of estimating a mathematical transition operator between two orientation, where this transition operator is estimated on the basis the measured sensor data, such as acceleration vector A=(Ax, Ay, Az), gyroscope vector ω

=(ω

x, ω

y, ω

z) and/or magnetic vector M=(Mx, My, Mz) and where the mathematical representation of the object is calculated based on such iterations of calculations, where the calculated object orientation is used as the input orientation of the object at the next iteration when a new transition operator is estimated based on new sensor data and were the embodiment includes dynamical calculations of the two gain parameters based on the following equations.

8. The device according to claim 7, where in the calculation some of the measured sensor data are weighted by dynamically changing gain parameters being the dynamically calculated depending on the actual measured sensor data parameters.

9. The device according to claim 8, where one mathematical representation of the orientation changes of the device is represented in quaternions and the transition operator being a quaternion q, and where iteration calculations of the new quaternion representing the latest change in position of the object as measured by the detecting means is calculated according to an equation

q_i+1=q_i+(dq_ω

,i−

η

×

dq_a,i−

ζ

×

dq_m,i)×

dT

where η and

ζ

are gain values, or weights, dT is the time elapsed since last measurement and dq<sub>ω

, i</sub> dq_a,i and dq_m,i are the gradient, or correction, of the respective quaternions solution during the iteration.

10. The device according to claim 9, where the gain comprises two values calculated according to the equations and

11. The device according to claim 1, where the mathematical representation of the system further includes a base vector V defined in either the world frame or the sensor frame and chosen such that it is parallel to the axis around which the rotation of the object being measured is to be neglected, the unused degree of freedom.

12. The device according to claim 11, where the vector V is used to project the vector F representing the present object orientation to the two used degrees of freedom.

13. The device according to claim 11, where the vector V is used to initialize or configure the sensor system (X′

, Y′

, Z′

).

14. The device according to claim 1, where the angles α

and β

of the vector F to axis of the used degrees of freedom of freedom seen in the sensor system is calculated and used in one of the following applications;

angle measurement, X-Y plotting and/or computer mouse cursor control.

15. The device according to claim 1, where the device includes a recover from Interrupt algorithm including the steps of measuring sensor data for a few times, meaning making a plural of immediate initializing measurements of the sensor data, and subsequently to produce multiple fast iterations of calculation through the mathematical transfer operator without further reading of the actual sensor data until the output is stable.

16. The device according to claim 1, where detecting means is in any data communication to a processer capable of performing the required calculations and store the required data.

17. The device according to claim 1, wherein the device includes a shift between separate mathematical representations when the orientation crosses a critical angel above a horizontal plane being defined as the plane orthogonal to the direction of gravity.

20. The device according to claim 2, where the mathematical representation includes a world frame being a basic reference frame coordinate system (X, Y, Z) being fixed and a sensor frame (X′

, Y′

, Z′

) being a rotation of the world frame (X, Y, Z), and where the object orientation is represented by the vector F (X1, Y1, Z1) in the sensor frame (X′

, Y′

, Z′

).

18. A method of operating a device in a 3-dimensional movement and where its orientation is translated into a mathematical 3D representation that then further is transformed into a mathematical 2D presentation, where the device includes an attitude, or orientation, detecting means, where the mathematical representation transformation uses to remove the effects of an unused degree of freedom.

19. The method of operating the device according to claim 18.