HAND HELD POINTING DEVICE WITH ROLL COMPENSATION

• US 20090326857A1
• Filed: 06/27/2008
• Published: 12/31/2009
• 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.
• Granted Patent: US 8,010,313 B2
• Time in Patent Office: Days
• 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 first rotational sensor providing a first rotational velocity signal R_X for rotational movement about a first axis;

a second rotational sensor providing a second rotational velocity signal R_Z for rotational movement about a second axis;

a first accelerometer providing a first acceleration signal A_X in response to a gravitational acceleration in a first direction along the first axis;

a second accelerometer providing a second acceleration signal A_Z in response to a gravitational acceleration in a second direction along the second axis;

a processing unit that (a) receives R_X, R_Z, A_X and A_Z from the respective rotational sensors and accelerometers, (b) calculates a vector sum A_XZ of A_X and A_Z, (c) calculates roll-compensated cursor movement signals by solving;

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

Y_comp=[A_X*R_Z−

A_Z*R_X]/A_XZ, and

(d) transmits the roll-compensated cursor movement signals to a receiver associated with movement of the cursor on the electronic display.

2. The pointing device of claim 1,

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 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.

3. The pointing device of claim 1 wherein the processing unit comprises an 8 bit or a 16 bit processor that operates at less than 4 MHz.

4. The pointing device of claim 1 wherein the processing unit samples the first rotational sensor, the second rotational sensor, the first accelerometer and the second accelerometer more than once every 6 milliseconds.

5. The pointing device of claim 5 wherein the processing unit provides the roll compensated cursor movement signals more than once every 10 milliseconds.

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

a first rotational sensor providing a first rotational velocity signal R_X for rotational movement about a first axis;

a second rotational sensor providing a second rotational velocity signal R_Z for rotational movement about a second axis;

a first accelerometer providing a first acceleration signal A_X in response to a gravitational acceleration in a first direction along the first axis;

a second accelerometer providing a second acceleration signal A_Z in response to a gravitational acceleration in a second direction along the second axis;

a third accelerometer providing a third acceleration signal A_Y in response to a gravitational acceleration in a third direction along a third axis;

a processing unit that (a) receives R_X, R_Z, A_X A_Y and A_Z from the respective rotational sensors and accelerometers, (b) calculates a vector sum A_XZ of A_X and A_Z, (c) (c) calculates a vector sum A_XYZ of A_X, A_Y and A_Z, (d) calculates pitch-and-roll-compensated cursor movement signals by solving;

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

Y_comp=[A_X*R_Z−

A_Z*R_X]/A_XZ, and

(d) transmits the pitch-and-roll-compensated cursor movement signals to a receiver associated with movement of the cursor on the electronic display.

7. The pointing device of claim 6,

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 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.

8. The pointing device of claim 6 wherein the processing unit comprises an 8 bit or a 16 bit processor that operates at less than 4 MHz.

9. The pointing device of claim 6 wherein the processing unit samples the first rotational sensor, the second rotational sensor, the first accelerometer and the second accelerometer more than once every 6 milliseconds.

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

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

detecting a first rotational velocity R_X for rotational movement about a first axis;

detecting a second rotational velocity R_Z for rotational movement about a second axis;

detecting a first acceleration signal A_X in response to a gravitational acceleration in a first direction along the first axis;

detecting a second acceleration signal A_Z in response to a gravitational acceleration in a second direction along the second axis;

calculating a vector sum, A_XZ of A_X and A_Z;

calculating a first roll-compensated cursor movement signal X_comp=[A_X*R_X+A_Z* R_Z]/A_XZ;

calculating a second roll-compensated cursor movement signal Y_comp=[A_X*R_Z−

A_Z* R_X]/A_XZ; and

transmitting the roll-compensated cursor movement signals to a receiver associated with movement of the cursor on the electronic display.

12. The method of claim 11 further comprising:

correcting 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 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 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.

13. The method of claim 11, further comprising:

providing an 8 bit or a 16 bit processor that operates at less than 4 MHz and performs the detecting and calculating steps.

14. The method of claim 11, further comprising:

providing a processing unit that samples the first rotational sensor, the second rotational sensor, the first accelerometer and the second accelerometer more than once every 6 milliseconds.

15. The method of claim 11, further comprising:

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

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

detecting a first rotational velocity R_X for rotational movement about a first axis;

detecting a second rotational velocity R_Z for rotational movement about a second axis;

detecting a first acceleration signal A_X in response to a gravitational acceleration in a first direction along the first axis;

detecting a second acceleration signal A_Z in response to a gravitational acceleration in a second direction along the second axis;

detecting a third acceleration signal A_Y in response to a gravitational acceleration in a third direction along a third axis;

calculating a vector sum, A_XZ of A_X and A_Z;

calculating a vector sum A_XYZ of A_X, A_Y and A_Z;

calculating a first roll-compensated cursor movement signal X_comp=[A_X*R_X+A_Z* R_Z]/A_XZ*A_XYZ/A_XZ;

calculating a second roll compensated cursor movement signal Y_comp=[A_X*R_Z−

A_Z* R_X]/A_XZ; and

transmitting the roll-compensated cursor movement signals to a receiver associated with movement of the cursor on the electronic display.

17. The method of claim 16 further comprising:

correcting 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 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 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.

18. A pointing device comprising:

a first rotational sensor providing a first rotational velocity signal R_X for rotational movement about a first axis;

a second rotational sensor providing a second rotational velocity signal R_Z for rotational movement about a second axis;

a first accelerometer providing a first acceleration signal A_X in response to a gravitational acceleration in a first direction along the first axis;

a second accelerometer providing a second acceleration signal A_Z in response to a gravitational acceleration in a second direction along the second axis; and

a processing unit that (a) receives R_X, R_Z, A_X and A_Z from the respective rotational sensors and accelerometers, (b) calculates a vector sum A_XZ of A_X and A_Z, (c) calculates algebraic algorithms to provide roll-compensation cursor movement signals X_comp and Y_comp; and

(d) transmits the roll-compensated cursor movement signals to a receiver associated with movement of the cursor on the electronic display.

19. The pointing device of claim 18,

wherein the first acceleration signal A_X is adjusted 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 adjusted 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 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.

20. The pointing device of claim 18 wherein the processing unit comprises an 8 bit or a 16 bit processor that operates at less than 4 MHz.

21. A pointing device comprising:

a first rotational sensor providing a first rotational velocity signal R_X for rotational movement about a first axis;

a second rotational sensor providing a second rotational velocity signal R_Z for rotational movement about a second axis;

a first accelerometer providing a first acceleration signal A_X in response to a gravitational acceleration in a first direction along the first axis;

a second accelerometer providing a second acceleration signal A_Z in response to a gravitational acceleration in a second direction along the second axis;

a third accelerometer providing a third acceleration signal A_Y providing a third acceleration signal A_Y in response to a gravitational acceleration in a third direction along a third axis, and

a processing unit that (a) receives R_X, R_Z, A_X, A_Y and A_Z from the respective rotational sensors and accelerometers, (b) calculates a vector sum A_XZ of A_X and A_Z, (c) calculates a vector sum A_XYZ of A_X, A_Y and A_Z, (d) calculates algebraic algorithms to solve pitch-and-roll-compensated cursor movement signals X_comp and Y_comp; and

(e) transmits the pitch-and-roll-compensated cursor movement signals to a receiver associated with movement of the cursor on the electronic display.

22. The pointing device of claim 21 wherein the first acceleration signal A_X is adjusted 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 adjusted 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 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.

23. The pointing device of claim 21 wherein the processing unit comprises an 8 bit or a 16 bit processor that operates at less than 4 MHz.