Hand held pointing device with roll compensation

• US 8,442,798 B2
• Filed: 05/20/2011
• Issued: 05/14/2013
• Est. Priority Date: 06/27/2008
• Status: Active Grant

• Current Assignee: Movea SA (TDK Corporation)
• Original Assignee: Movea SA (TDK Corporation)
• Inventors: Mathews, Michael, Mason, Walter M.
• Primary Examiner(s): LE, TOAN M
• Application Number:
  US13/112,742
• Publication Number:
  US 20120194426A1
• Time in Patent Office: 725 Days
• Field of Search: 702/141, 702 33- 36, 702/41, 702/81, 702 84- 85, 702/92, 702 94- 97, 702/127, 702/142, 702145-147, 702149-153, 702/155, 702157-158, 702/179, 702182-183, 702188-189, 702198-199, 345156-159, 345/163, 73/13.7, 73/17.5, 73/17.9, 335/74, 335/79, 340/500, 340/540, 340669-671
• US Class Current: 702/141
• 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 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry

Abstract

A pointing device includes accelerometers and rotational sensors that are coupled to a processor. The processor samples the accelerometers and rotational sensors to detect gravity and pointing device motion and uses algebraic algorithms to calculate roll compensated cursor control signals. The processor transmits the cursor control signals to a receiver that is coupled to an electronic device that moves the cursor on the visual display.

Claims

1. A pointing device for controlling movement of a cursor on an electronic display comprising:

a processing unit containing executable instructions for;

(a) receiving a first rotational velocity signal R_X, a second rotational velocity signal R_Z, a first acceleration signal A_X in response to a gravitational acceleration in a first direction along the first axis and a second acceleration signal A_Z in response to a gravitational acceleration in a second direction along the second axis, (b) calculating a vector sum A_XZ of A_X and A_Z, (c) calculating roll-compensation cursor movement signals X_comp and Y_comp using roll-compensation algorithms that do not include trigonometry functions and using signals R_X, R_Z, A_X, and A_Z and the vector sum A_XZ as inputs to the roll-compensation algorithms, and (d) transmitting the roll-compensated cursor movement signals to a receiver coupled to an electronic device having a display.

2. The pointing device of claim 1, wherein the algorithms used to provide the roll-compensated cursor movement signals include:

X_comp=[A_Z*R_X+A_X*R_Z]/A_XZ, and

Y_comp=[A_X*R_X−

A_Z*R_Z]/A_XZ.

3. The pointing device of claim 2, further comprising:

a first rotational sensor providing the first rotational velocity signal R_X;

a second rotational sensor providing the second rotational velocity signal R_Z;

wherein the first acceleration signal A_X is corrected for rotational acceleration of the first accelerometer about the second axis by the equation;

A_Xcorrected=A_X−

Δ

R_Z/Δ

time*l_X,

wherein the second acceleration signal A_Z is corrected for rotational acceleration of the second accelerometer about the first axis by the equation;

A_Zcorrected=A_Z−

Δ

R_X/Δ

time*l_Z, and

wherein Δ

R_X/Δ

time is a rotational acceleration about the first axis, Δ

R_Z/Δ

time is a rotational acceleration about the second axis, l_X is a perpendicular length between a line through the first accelerometer in the first direction and the second axis and l_Z is a perpendicular length between a line through the second accelerometer in the second direction and the first axis.

4. The pointing device of claim 1 wherein the processing unit comprises a 16 bit processor that operates at less than 4 MHz.

5. The pointing device of claim 1 wherein the processing unit receives the first rotational velocity signal R_X, the second rotational velocity signal R_Z, the first acceleration signal A_X and the second acceleration signal A_Z more than once every 6 milliseconds.

6. The pointing device of claim 1 wherein the processing unit provides the roll compensated cursor movement signals more than once every 10 milliseconds.

7. A pointing device for controlling movement of a cursor on an electronic display comprising:

a processing unit containing executable instructions for;

(a) receiving a first rotational velocity signal R_X, a second rotational velocity signal R_Z, a first acceleration signal A_X in response to a gravitational acceleration in a first direction along the first axis, a second acceleration signal A_Z in response to a gravitational acceleration in a second direction along the second axis and a third acceleration signal A_y in response to a gravitational acceleration in a third direction along a third axis, (b) calculating a vector sum A_XZ of A_X and A_Z, (c) calculating a vector sum A_XYZ of A_X, A_Y and A_Z, (d) calculating pitch-and-roll-compensated cursor movement signals to provide roll-compensation cursor movement signals X_comp and Y_comp using pitch-and-roll-compensation algorithms that do not include trigonometry functions and using signals R_X, R_Z, A_X, and A_Z and the vector sum A_XYZ as inputs to the pitch-and-roll-compensation algorithms, and (e) transmitting the pitch-and-roll-compensated cursor movement signals to a receiver coupled to an electronic device having a display.

8. The pointing device of claim 7, wherein the algorithms used to provide the pitch-and-roll-compensated cursor movement signals include:

X_comp=[A_Z*R_X+A_X*R_Z]/A_XY*A_XYZ/A_XZ

Y_comp=[A_X*R_X−

A_Z*R_Z]/A_XZ.

9. The pointing device of claim 8, further comprising:

a first rotational sensor providing the first rotational velocity signal R_X;

a second rotational sensor providing the second rotational velocity signal R_Z;

wherein the first acceleration signal A_X is corrected for rotational acceleration of the first accelerometer about the second axis by the equation A_Xcorrected=A_X−

Δ

R_Z/Δ

time*l_X,

wherein the second acceleration signal A_Z is corrected for rotational acceleration of the second accelerometer about the first axis by the equation;

A_Zcorrected=A_Z−

Δ

R_X/Δ

time*l_Z, and

wherein Δ

R_X/Δ

time is a rotational acceleration about the first axis, Δ

R_Z/Δ

time is a rotational acceleration about the second axis, l_X is a perpendicular length between a line through the first accelerometer in the first direction and the Z axis and l_Z is a perpendicular length between a line through the second accelerometer in the second direction and the first axis.

10. The pointing device of claim 7 wherein the processing unit comprises a 16 bit processor that operates at less than 4 MHz.

11. The pointing device of claim 7 wherein the processing unit receives the first rotational velocity signal R_X, the second rotational velocity signal R_Z, the first acceleration signal A_X, the second acceleration signal A_Z and the third acceleration signal A_Y more than once every 6 milliseconds.

12. The pointing device of claim 7 wherein the processing unit provides the roll compensated cursor movement signals more than once every 10 milliseconds.

13. A method for providing roll compensation signals for controlling movement of a cursor on an electronic display comprising:

receiving by processing unit, a first rotational velocity R_X for rotational movement about a first axis, a second rotational velocity R_Z for rotational movement about a second axis, a first acceleration signal A_X in response to a gravitational acceleration in a first direction along the first axis, and a second acceleration signal A_Z in response to a gravitational acceleration in a second direction along the second axis;

calculating by the processing unit, a vector sum, A_XZ of A_X and A_Z;

calculating by the processing unit, a first roll-compensated cursor movement signal X_comp using a first roll-compensated cursor movement signal algorithm that does not include the trigonometry functions and a second roll-compensated cursor movement signal Y_comp using a second roll-compensated cursor movement signal algorithm that does not include the trigonometry functions and using signals R_X, R_Z, A_X, and A_Z and the vector sum A_XZ as inputs to the first roll-compensation cursor movement signal algorithm and the second roll-compensation cursor movement signal algorithm; and

transmitting by the processing unit, the roll-compensated cursor movement signals to a receiver coupled to an electronic device having a display.

14. The method of claim 13, wherein the first roll-compensated cursor movement signal algorithm for X_comp is X_comp=[A_Z*R_X+A_X*R_Z]/A_XZ and the second roll-compensated cursor movement signal algorithm for Y_comp is Y_comp=[A_X*R_X−

A_Z* R_Z]/A_XZ.

15. The method of claim 14 further comprising:

generating by a first accelerometer the first rotational velocity signal R_X;

generating by a second accelerometer the second rotational velocity signal R_Z;

correcting by the processing unit, the first acceleration signal A_X for rotational acceleration of the a accelerometer about the second axis by the equation A_Xcorrected=A_X−

Δ

R_Z/Δ

time*l_X; and

correcting by the processing unit, the second acceleration signal A_Z for rotational acceleration of a second accelerometer about the first axis by A_Zcorrected=A_Z−

Δ

R_X*Δ

time*l_Z;

wherein Δ

R_X/Δ

time is a rotational acceleration about the first axis, Δ

R_Z/Δ

time is a rotational acceleration about the second axis, l_X is a perpendicular length between a line through a first accelerometer in the first direction and the second axis and l_Z is a perpendicular length between a line through the second accelerometer in the second direction and the first axis.

16. The method of claim 13, further comprising:

operating the processor at less than 4 MHz.

17. The method of claim 13, further comprising:

receiving by the processing unit, the first rotational velocity signal R_X, the second rotational velocity signal R_Z, the first acceleration signal A_X, and the second acceleration signal A_Z more than once every 6 milliseconds.

18. The method of claim 13, further comprising:

providing by the processing unit, the roll-compensated cursor movement signals X_comp and Y_comp more than once every 10 milliseconds.

19. A method for providing roll-compensation signals for controlling movement of a cursor on an electronic display comprising:

receiving by processing unit, a first rotational velocity R_X for rotational movement about a first axis, a second rotational velocity R_Z for rotational movement about a second axis, a first acceleration signal A_X in response to a gravitational acceleration in a first direction along the first axis, a second acceleration signal A_Z in response to a gravitational acceleration in a second direction along the second axis and a third acceleration signal A_Y in response to a gravitational acceleration in a third direction along a third axis;

calculating by a processing unit, a vector sum, A_XZ of A_X and A_Z;

calculating by the processing unit, a vector sum A_XYZ of A_X, A_Y and A_Z;

calculating by the processing unit, a first pitch-and-roll-compensated cursor movement signal X_comp using a first pitch-and-roll-compensated cursor movement signal algorithm that does not include the trigonometry functions and a second pitch-and-roll-compensated cursor movement signal Y_comp using a second pitch-and-roll-compensated cursor movement signal algorithm that does not include trigonometry functions and using signals R_X, R_Z, A_X, and A_Z and the vector sum A_XYZ as inputs to the first pitch-and-roll-compensation algorithms; and

transmitting by the processing unit, the roll-compensated cursor movement signals to a receiver coupled to an electronic device having a display.

20. The method of claim 19, wherein the first roll-compensated cursor movement signal algorithm for X_comp is X_comp=[A_Z*R_X+A_X*R_Z]/A_XZ*A_XYZ/A_XZ and the second roll-compensated cursor movement signal algorithm for Y_comp is Y_comp=[A_X*R_X−

A_Z*R_Z]/A_XZ.

21. The method of claim 20 further comprising:

generating by a first accelerometer the first rotational velocity signal R_X;

generating by a second accelerometer the second rotational velocity signal R_Z;

correcting by the processing unit, the first acceleration signal A_X for rotational acceleration of the first accelerometer about the second axis by the equation A_Xcorrected=A_X−

Δ

R_Z/Δ

time *l_X; and

correcting by the processing unit, the second acceleration signal A_Z for rotational acceleration of the second accelerometer about the first axis by the equation A_Zcorrected=A_Z−

Δ

R_X/Δ

time*l_Z;

wherein Δ

R_X/Δ

time is a rotational acceleration about the first axis, Δ

R_Z/Δ

time is a rotational acceleration about the second axis, l_X is a perpendicular length between a line through the first accelerometer in the first direction and the second axis and l_Z is a perpendicular length between a line through the second accelerometer in the second direction and the first axis.

22. The method of claim 19, further comprising:

operating the processor at less than 4 MHz.

23. The method of claim 19, further comprising:

receiving by the processing unit, the first rotational velocity signal R_X, the second rotational velocity signal R_Z, the first acceleration signal A_X, and the second acceleration signal A_Z more than once every 6 milliseconds.