Attitude detecting device

• US 10,551,939 B2
• Filed: 04/10/2016
• Issued: 02/04/2020
• 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
• Primary Examiner(s): Ahn, Sejoon
• Application Number:
  US15/557,528
• Publication Number:
  US 20180088685A1
• Time in Patent Office: 1,395 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 configured to be operated in a 3-dimensional movement, orientation of the device being translated into a mathematical 3-dimensional representation and then further into a mathematical 2-dimensional presentation to remove movement effects of an unused degree of freedom, the device comprising:

attitude, or orientation, detecting sensors; and

a processor operatively connected to the attitude, or orientation, detecting sensors;

wherein the processor is configured to iteratively estimate the present orientation of the device through changes in orientation as registered by the attitude, or orientation, detecting sensors, the processor estimating a mathematical transition operator between two orientations, where the mathematical transition operator is estimated on the basis of measured sensor data registered by the attitude, or orientation, detecting sensors, the mathematical transition operator being a quaternion q, and where iteration calculations of the new quaternion q_i+1 representing the latest change in position of the device as measured by the attitude, or orientation, detecting sensors are calculated according to an equation

q_i+1=q_i+(dq<sub>ω

,i</sub>−

η

×

dq_a,i−

ζ

×

dq_m,i)×

dT

where q_i is the quaternion before the latest change in position of the device as measured by the attitude, or orientation, detecting sensors, 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; and

wherein the processor dynamically calculates the two gain values η and

ζ

based on the measured sensor data registered by the attitude, or orientation, detecting sensors according to the equations;

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

3. The device according to claim 2, where said detecting sensors include an accelerometer and gyroscope and 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 being fixed and a sensor frame being a rotation of the world frame, and where an object orientation is represented by the vector F in the sensor frame.

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 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.

8. The device according to claim 7, where the vector V is used to project the vector F representing the present object orientation to the two used degrees of freedom.

9. The device according to claim 7, where the vector V is used to initialize or configure the sensor system.

10. 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.

11. The device according to claim 1, where the device includes a recover from Interrupt system configured to make 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.

12. The device according to claim 1, where detecting sensors are, in any data communication to a processer, capable of performing the required calculations and storing the required data.

13. 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.

16. The device according to claim 2, where the mathematical representation includes a world frame being a basic reference frame coordinate system being fixed and a sensor frame being a rotation of the world frame, and where the device orientation is represented by the vector F in the sensor frame.

17. The device according to claim 2, where said detecting sensors include an accelerometer and gyroscope.

18. The device according to claim 1, where the measured sensor data is an acceleration vector A=(Ax, Ay, Az), gyroscope vector ω

=(ω

x, ω

y, ω

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

14. A method of operating a device in a 3-dimensional movement, the device includes attitude, or orientation, detecting sensors, orientation of the device being translated into a mathematical 3-dimensional representation and then further into a mathematical 2-dimensional presentation, to remove movement effects of an unused degree of freedom, the method comprising:

estimating the present orientation of the device iteratively through changes in orientation as registered by the attitude, or orientation, detecting sensors, the estimating including the steps of estimating a mathematical transition operator between two orientations, where the mathematical transition operator is estimated on the basis of measured sensor data registered by the attitude, or orientation, detecting sensors, the mathematical transition operator being a quaternion q, and where iteration calculations of the new quaternion q_i+1 representing the latest change in position of the device as measured by the attitude, or orientation, detecting sensors are calculated according to an equation

q_i+1=q_i+(dq<sub>ω

,i−

η

×</sub>

dq_a,i−

ζ

×

dq_m,i)×

dT

where q_i is the quaternion before the latest change in position of the device as measured by the attitude, or orientation, detecting sensors, 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; and

dynamically calculating the two gain values η and

ζ

based on the measured sensor data registered by the attitude, or orientation detecting sensors;

wherein the gain values η and

ζ

are calculated according to the equations

15. The method of operating the device according to claim 14, where the 2-dimensional representation is calculated based on an object orientation vector F seen on the two used degrees of freedom.

19. The method according to claim 14, where the measured sensor data is an acceleration vector A =(Ax, Ay, Az), gyroscope vector ω

=(ω

x, ω

y, ω

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