Pointing method, a device and system for the same

• US 9,372,549 B2
• Filed: 03/07/2012
• Issued: 06/21/2016
• Est. Priority Date: 03/14/2011
• Status: Active Grant

• Current Assignee: Murata Manufacturing Co Limited
• Original Assignee: Murata Electronics OY (Murata Manufacturing Co Limited)
• Inventors: Merihein, Ulf, Stockmann, Sten, Kauppinen, Ossi, Kostiainen, Pekka, Blomqvist, Anssi
• Primary Examiner(s): Yodichkas, Aneeta
• Application Number:
  US13/414,068
• Publication Number:
  US 20120235905A1
• Time in Patent Office: 1,567 Days
• Field of Search: 345/158, 345/160, 345/145, 345/157, 345/159, 345/161, 345/163, 345/164
• US Class Current: 1/1
• 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

The invention shows a method to control a pointing device with an angular, rate sensor, that comprises generating an ensemble of orthogonal unit vector associated signals by at least one angular rate sensor to represent angular rates in a dimensional space for each mutually orthogonal unit vector direction of said dimensional space, amplifying the at least one of said signal non-linearly for determination of cursor on a screen for (x,y) coordinates of the screen, applying a decision criterion to determine the state of the pointing device as based on said unit vector associated signals. The invention also shows a pointer utilizing the method and a system comprising such a pointer.

Claims

1. A method to control a pointing device with an angular rate sensor (ars), said method comprising:

generating an ensemble of orthogonal unit vector associated angular rate signals by at least one angular rate sensor, each angular rate signal representing an angular rate in a dimensional space for a mutually orthogonal unit vector direction of said dimensional space;

amplifying at least one of said angular rate signals with an amplification function that is a non-linear function of at least one of said angular rate signals;

determining (x,y) coordinates of a cursor on a screen from said angular rate signals, one of said (x,y) coordinates corresponding to one of said angular rate signals;

applying a decision criterion to determine a stationary state of the pointing device from said unit vector associated angular rate signals, and

updating, in response to determining the stationary state of the pointing device, a zero point offset of the angular rate sensor.

2. The method according to claim 1, wherein said decision criterion comprises:

determining the integral of the amplified angular rate signal for determination of the position of the cursor on said screen,

determining the stationary state of the pointing device, as defined by the function of ω

²=ω

²(z)+ω

²(y) relative to a preset threshold, where ω

(z) and ω

(y) are angular rates around z- and y-axis respectively,

updating the zero point offset of the angular rate sensor, when it is stationary, so as ω

₀(z, y)=ω

(z=0, y=0) and/or

ω

₀(z, y, x)=ω

(z=0, y=0, x=0).

3. The method according to claim 2, wherein the zero point offset has offset values ω

₀(z, y), and averages (ave) ω

_0ave(z, y) recursively updated as ω

_0ave(z, y)=ω

_0ave(z, y)*(n−

1)/n+ω

₀(z, y)/n, where ω

represents angular rate and n is the effective number of samples for averaging.

4. The method of claim 1, wherein the angular rate sensor comprises at least one 2- or 3-axis angular rate sensor to correspond said dimensional space.

5. The method of claim 1, wherein said amplifying comprises amplifying by an amplification factor of the angular rate signal defined at least partly by at least one of the following equations:

6. The method of claim 5, wherein the amplifications in z- and y-directions are the same.

7. The method of claim 5, wherein at least one of the unit vector direction associated angular rate signal is formed by using a slice-wise linear function.

8. The method of claim 7, wherein the slice-wise slicing comprises at least 3 slices there between the zero value and the maximum value of said angular rate sensor used for generating said angular rate signal.

9. The method of claim 8, wherein said slicing is adaptive in at least one direction of unit vector.

10. The method of claim 5, wherein a function ω

is defined by a conic section curve.

11. The method of claim 5, wherein the function ω

² is further defined by the z and y components as ω

²=ω

(z)·

ω

²(z)+ω

(y)·

ω

²(y) as applied for z- and y-axis respectively, where ω

represents angular rate.

12. The method of claim 1, wherein a zero point correction of the angular rate sensor is based on an average of the output angular rate values of a stationary angular rate sensor.

13. The method according to claim 1, wherein a zero point offset correction is made as update based on a digitally low pass filtered angular rate output value of a stationary angular rate sensor.

14. The method according to claim 13, further comprising using a filter function comprising ω

₀filt(n)=ω

₀filt(n−

1)*(1−

1/k)+ω

₀/k, where ω

₀filt(n) is the new filtered value, ω

₀filt(n−

1) the old filtered value and k a filter constant, respectively, and where n is the effective number of samples for averaging.

15. The method according to claim 1, wherein the method comprises

detecting at the beginning the stationary state,

detecting an opportunity to make initial angular rate zero offset cancelling

comparing the variances of the angular rate function around axes z and y to preset threshold values, according to the criterion var(ω

(z))<

var(th(z)) and/or var(ω

(y))<

var(th(y)) respectively, where ω

represents angular rate.

16. The method according to claim 1, wherein the method comprises detecting the stationary state as the combination of comparing the function ω

² and variances var(ω

(z)) and var(ω

(y)) to respective preset thresholds, where ω

represents angular rate.

17. The method according to claim 1 to control a pointing device with a 2- or 3-axis angular rate sensor, wherein the method comprises

keeping the angular rate sensor in stand-by state while not on duty,

detecting according to a preset criterion the need for wake up,

waking up for taking two or more angular rate readings for diagnostics and to give a proper estimate for the angular rate.

18. A pointer system, comprising:

a pointer including an angular rate sensor configured to generate an ensemble of orthogonal unit vector associated angular rate signals, each angular rate signal representing an angular rate in a dimensional space for a mutually orthogonal unit vector direction of said dimensional space;

an amplifier configured to amplify at least one of said angular rate signals with an amplification function that is a non-linear function of at least one of said angular rate signals; and

a processor configured to determine(x,y) coordinates of cursor on a screen, one of said (x,y) coordinates corresponding to one of said angular rate signals,

wherein the processor is configured to apply a decision criterion to determine a stationary state of the pointer from said unit vector associated angular rate signals, and update, in response to determining the stationary state of the pointing device, a zero point offset of the angular rate sensor.

19. The pointer system of claim 18, wherein the pointer comprises the amplifier and the processor.

20. The pointer system of claim 19, wherein the pointer comprises at least one of the following:

a memory for saving certain positions and/or the configuration associated to said position,

a marker to save a certain position and/or the related configuration,

wireless means to communicate the position data to a presentation system, and

recalling means to restore certain position and/or the related configuration.

21. The pointer system of claim 20, wherein the pointer is configured to be used with a screen that comprises a display.

22. The pointer system of claim 18, comprising a presentation system server that includes the amplifier and the processor.

23. The pointer system according to claim 18, wherein the pointer comprises a laser beam generating means for producing a light spot on a side screen.

24. A pointer comprising:

an angular rate sensor configured to generate an ensemble of orthogonal unit vector associated angular rate signals, each angular rate signal representing an angular rate in a dimensional space for a mutually orthogonal unit vector direction of said dimensional space;

an amplifier configured to amplify at least one of said angular rate signals non-linearly; and

a processor configured to determine (x,y) coordinates of a cursor on a screen from said angular rate signals, the processor being configured to apply a decision criterion to determine a stationary state of the pointer from said unit vector associated angular rate signals, and update, in response to determining the stationary state of the pointing device, a zero point offset of the angular rate sensor.