Cursor tracking

• US 6,040,821 A
• Filed: 01/19/1993
• Issued: 03/21/2000
• Est. Priority Date: 09/26/1989
• Status: Expired due to Term

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Incontrol Solutions, Inc.
• Inventors: Straayer, David H., Dodier, Robert H., Franz, Patrick J., Biehl, Philip D.
• Primary Examiner(s): Liang, Regina
• Application Number:
  US08/006,139
• Time in Patent Office: 2,618 Days
• Field of Search: 340/706, 340/709, 340/710, 340/712, 341/22, 341/23, 345/156, 345/157, 345/159, 345/168, 345/172, 345/160, 345/145
• US Class Current: 345/159
• CPC Class Codes: G05G 9/047 the controlling member being movable by hand about orthogonal axes, e.g. joysticks for switches H01H25/04
• CPC Class Codes: G06F 3/0213 Arrangements providing an integrated pointing device in a keyboard, e.g. trackball, mini-joystick for pointing devices integrated in a laptop computer G06F1/169; joysticks G05G9/047; constructional details of pointing devices G06F3/033
• CPC Class Codes: G06F 3/023 Arrangements for converting discrete items of information into a coded form, e.g. arrangements for interpreting keyboard generated codes as alphanumeric codes, operand codes or instruction codes
• CPC Class Codes: G06F 3/0338 with detection of limited linear or angular displacement of an operating part of the device from a neutral position, e.g. isotonic or isometric joysticks
• CPC Class Codes: H01H 2003/0293 with an integrated touch switch
• CPC Class Codes: H01H 2221/012 Joy stick type
• CPC Class Codes: H01H 2239/006 Containing a capacitive switch or usable as such

Abstract

In a cursor tracking system (FIG. 11), a pointing device includes a plurality of force sensors (304), optionally integrated with a keyswitch on a computer keyboard. The force sensors detect lateral and vertical forces applied to the keycap (300) by a user (302) for cursor control. Raw force data is acquired by A/D apparatus (306) and transmitted (310,312) to a host processor. Driver level software in the host linearizes the raw force values (316, FIG. 12D) to compensate for anomolies and nonlinearities in the force sensors, keyboard mechanics, and A/D. The resulting linear force values are adjusted (320) to compensate for preloading bias forces (318) on the sensors. The unbiased, linear force values and sensor configuration (322) are used to determine a net XY vector (324, FIG. 16). A speed value is determined by a quadratic mapping of the XY vector magnitude (328), taking mouse button status into account. The speed value is scaled by a speed factor, clamped according to a speed limit value, and the result used to determine a total displacement value which, in turn, is used to scale the XY vectors to determine X and Y cursor displacement for repositioning the cursor. The quadratic mapping coefficients, as well as the speed factor and speed limit values, are user-alterable at run time, to allow customizing the response of the cursor tracking system. The result is a low-cost pointing system having excellent responsiveness for ergonomic efficiency. The system is useful in most computer systems, such as IBM AT-compatible systems, to allow pointing operations without use of a separate pointing device such as a mouse.

Claims

1. In an integrated keyboard coupled to a display having a cursor, the keyboard having an array of typing keyswitches that includes a multi-purpose pointing key and a plurality of force sensors coupled to the pointing key, each force sensor having an associated direction and the force sensors providing sensor signals having a non-inear relationship to force applied to the force sensors, a method of acquiring pointing signals for repositioning the cursor comprising the steps of:

providing means in the keyboard for selecting one at a time of a typing mode of operation for acquiring typing signals and a pointing mode of operation for acquiring pointing signals;

when the keyboard is not in pointing mode, periodically scanning each of the force sensors to acquire a corresponding force signal defining a sensor bias signal;

during a pointing operation, periodically scanning each of the force sensors to acquire a corresponding force signal defining a pointing signal;

linearizing the acquired sensor bias signals and the acquired pointing signals so that the linearized signals have a generally linear relationship to force applied to the sensors at the time said signals were acquired;

deducting each linearized force sensor bias signal from the corresponding linearized pointing signal to form respective net pointing signals;

combining the net pointing signals according to the associated directions of the corresponding force sensors; and

repositioning the cursor responsive to the combined net pointing signals.

2. In a cursor control system, a method of converting forces applied by a user to cursor displacement data for controlling cursor repositioning on a display screen, comprising the steps of:

providing a force-sensitive pointing device including a plurality of force sensors each having a respective associated direction, for receiving external forces applied by a user pressing on the pointing device;

applying a bias force to each of the force sensors so that each sensor exhibits a bias electrical signal while no external force is applied to the pointing device by the user;

while no external force is applied to the pointing device, acquiring sensor signals from each of the pointing device force sensors, thereby determining respective force sensor bias signals;

while an external force is applied to the pointing device by the user, acquiring sensor signals from each of the pointing device force sensors, thereby determining respective raw force signals, the raw force sensor signals having a non-linear relationship to the applied external force;

linearizing the force sensor bias signals and the raw force signals so as to form linearized bias signals and linearized raw force signals, respectively, each having a generally linear relationship to the bias signals and the raw force signals, respectively;

compensating each of the linearized raw force signals responsive to the corresponding linearized bias signals to form linearized, unbiased force values;

combining the linearized, unbiased force values according to their associated directions so as to form a horizontal signal and a vertical signal; and

repositioning the cursor in the horizontal and vertical directions on the display screen, responsive to the horizontal and vertical signals, respectively.

3. A method according to claim 2 wherein said combining step includes:

combining the linearized, unbiased force values according to their associated directions so as to form a net XY vector;

computing a magnitude M of the net XY vector to represent a total lateral force applied by the user;

computing a speed value according to a formula;

space="preserve" listing-type="equation">speed=SQUARE×

(M--NULL).sup.2 +LINEAR×

(M--NULL)

where

SQUARE is a predetermined square term coefficient,

M is the magnitude of the net XY vector,

NULL is a predetermined minimum force to initiate cursor motion, and

LINEAR is a predetermined linear term coefficient, thereby converting the force sensor data to form the speed value;

repositioning the cursor on the display screen by a distance proportional to the speed value; and

repeating said repositioning step periodically thereby moving the cursor with an apparent velocity proportional to the speed value.

4. A method according to claim 3, the system also having a mouse button for distinguishing dragging operations from cursor repositioning operations, and further comprising:

providing a first value for use as the SQUARE term coefficient during repositioning operations and a second value for use as the SQUARE term coefficient during dragging operations;

checking status of the mouse button to determine whether the user is repositioning or dragging;

if repositioning, selecting the first value for use as the SQUARE term coefficient for computing the speed value; and

if dragging, selecting the second value for use as the SQUARE term coefficient for computing the speed value, thereby adjusting the cursor tracking responsive to the mouse button status.

5. A method according to claim 4 wherein the first value is greater than the second value so that the computed speed value is greater for a repositioning operation than for a dragging operation.

6. A method according to claim 3 further comprising:

providing a first value for use as the LINEAR term coefficient during repositioning operations and a second value for use as the LINEAR term coefficient during dragging operations;

checking status of the mouse buttons; and

selecting one of the first and second values responsive to the mouse button status for use as the LINEAR term coefficient in said computing the speed value.

7. A method according to claim 3 further comprising:

providing a first value for use as the NULL force value during repositioning operations and a second value for use as the NULL force value during dragging operations;

checking status of the mouse buttons; and

selecting one of the first and second values responsive to the mouse button status for use as the NULL force value in said computing the speed value.

8. A method according to claim 3 further comprising:

providing a predetermined speed factor for user control of the overall apparent cursor speed; and

scaling the speed value according to the speed factor to form a cursor speed value;

and wherein

the horizontal and vertical signals are adjusted according to the cursor speed value rather than the speed value.

9. A method according to claim 8 further comprising:

providing a predetermined cursor speed limit value for limiting the apparent cursor speed to a desired maximum to control overshoot of the cursor on the display screen;

comparing the cursor speed value to the cursor speed limit value; and

if the cursor speed value exceeds the cursor speed limit value, reducing the cursor speed value to the cursor speed limit value, thereby determining a total cursor displacement value.

10. A method according to claim 8 further comprising:

determining a ratio of the cursor speed value to the magnitude M of the net XY vector, thereby forming a scaling factor; and

scaling each of the unbiased force values by the scaling factor to form X displacement and Y displacement values, respectively; and

wherein said repositioning the cursor includes updating cursor position by the X and Y displacement values; and

repeating the foregoing steps to control cursor motion responsive to the acquired sensor data.

11. A method according to claim 3 wherein computing the magnitude of the net XY vector comprises:

determining a larger one of the X vector and the Y vector; and

summing the magnitude of the larger vector together with one-half the magnitude of the other (smaller) vector to form an approximation of the magnitude of the net XY vector.

12. A graphic cursor positioning device comprising:

force sensor means responsive to operator actuation to generate a first pair of cursor movement electrical signals, each of the first pair of cursor movement electrical signals having an associated direction;

signal processing means acting upon the first pair of cursor movement signals to produce a corresponding second pair of cursor movement signals;

display means for presenting a moveable cursor;

cursor generating means connected to said display means so as to cause movement of said cursor in correspondence to said second pair of cursor movement signals;

said signal processing means including means for providing differing time response characteristics of said cursor movement in correspondence to said operator actuation, the time response including a faster cursor movement while the operator actuation is a repositioning operation and a slower cursor movement while the operator actuation is a dragging operation.

13. A graphic cursor positioning device according to claim 12 wherein said signal processing means includes a mouse button status memory for determining a present state of a mouse button, a mouse button down state indicating a dragging operation and a mouse button up state indicating a repositioning operation, so that the response of the cursor to the operator actuation depends upon the state of the mouse button status memory.

14. In a cursor control system, a method of converting forces applied by a user to cursor displacement data for controlling cursor motion on a display screen, comprising the steps of:

providing a force-sensitive pointing device including a plurality of force sensors each having a respective associated direction, for receiving external forces applied by a user;

biasing the pointing device by applying a bias force to each of the force sensors so that each sensor exhibits a bias force when no force is applied by the user;

while no external force is applied to the pointing device, acquiring sensor data from each of the pointing device force sensors, thereby determining force sensor bias values;

while external force is applied to the pointing device by the user, acquiring sensor data comprising raw force values from each of the pointing device force sensors;

linearizing each raw force value to form a linear force value, said linearizing step including;

providing a predetermined linearization square coefficient (LINSQ);

providing a predetermined linearization offset coefficient, (LINOFF); and

computing the linear force value according to the formula;

space="preserve" listing-type="equation">LFV=(RAW.sup.2 ×

LINSQ)+LINOFF

where LFV represents the linear force value,

RAW represents the raw force value,

LINSQ represents the linearization square factor, and

LINOFF represents the linearization offset factor;

compensating each of the linear force values responsive to the corresponding force sensor bias value to form a corresponding unbiased force value; and

then combining the unbiased force values according to their associated directions so as to form a horizontal signal and a vertical signal for repositioning the cursor in the horizontal and vertical directions, respectively, on tbhe display screen.

15. In a cursor control system, a method of converting forces applied by a user to cursor displacement data for controlling cursor motion on a display screen, comprising the steps of:

providing a force-sensitive pointing device for receiving external forces applied by the use, the pointing device having four orthogonal force sensors disposed offset forty-five degrees from a predetermined cartesian coordinate system, so that each of the force sensors corresponds to one of NE,SE,SW and NW directions relative to the cartesian coordinate system;

biasing the pointing device by applying a bias force to each of the force sensors so that each sensor exhibits a bias force when no force is applied by the user

while no external force is applied to the pointing device, acquiring sensor data from each of the pointing device force sensors, thereby determining force sensor bias values;

while external force is applied to the pointing device by the user acquiring sensor data comprising raw force values from each of the pointing device force sensors;

compensating each of the force values responsive to the corresponding force sensor bias value to form a corresponding unbiased force value; and

combining the unbiased sensor force values to form X and Y vectors by computing the X and Y vectors according to the formulae;

space="preserve" listing-type="equation">X=(NE+SE)-(NW+SW) and Y=(NE+NW)-(SW+SE)

for repositioning the cursor in the horizontal and vertical directions, respectively, on the display screen.

16. A method of controlling cursor motion on a display screen to move the cursor in an ergonomically efficient manner responsive to a lateral force applied by a user pressing a pointing device, the method comprising:

providing first and second force sensors in the pointing device, the first sensor responsive to force applied in a first direction and the second sensor responsive to force applied in a second direction angularly offset from the first direction;

sensing the user-applied force in the first sensor to form a first analog electrical signal representing force applied along the first direction;

converting the first analog electrical signal to a first digital signal representing a first raw force sensor value;

sensing the user-applied force in the second sensor to form a second analog electrical signal representing force applied along the second direction;

converting the second analog electrical signal to a second digital signal representing a second raw force sensor value;

linearizing each of the first and second raw force sensor values so as to compensate for non-linearities inherent in the force sensors, keycap mechanics and in said converting step, thereby forming first and second linear force values, respectively, that are substantially linearly related to the force applied to the pointing device by the user;

converting the first and second linear force values to form net X and net Y force values, where the net X force value represents a component of the user-applied force along a horizontal axis corresponding to a horizontal line on the display screen and the net Y force value represents a component of the user-applied force along a vertical axis corresponding to a vertical line on the display screen;

combining the net X force value and the net Y force value to form an XY magnitude value that reflects the total lateral force applied by the user;

determining a speed factor;

multiplying each of the net X force value and net Y force value by the speed factor to determine x and y cursor displacement values, respectively;

repositioning the cursor on the display screen by a horizontal and vertical offsets corresponding to the x and y displacement values, respectively; and

periodically repeating said repositioning step, thereby moving the cursor on the display screen with an apparent speed and direction responsive to the user-applied force.

17. A method according to claim 16 further comprising:

providing third and fourth force sensors coupled to the pointing device;

arranging the third force sensor opposite the first force sensor in the pointing device, so that force applied along the first direction increases force in the first force sensor and decreases force in the third force sensor;

arranging the fourth force sensor opposite the second force sensor in the pointing device, so that force applied along the second direction increases force in the second force sensor and decreases force in the fourth force sensor;

sensing the user-applied force in the third sensor to form a third analog electrical signal representing force applied opposite to the first direction;

converting the third analog electrical signal to a third digital signal representing a third raw force sensor value;

sensing the user-applied force in the fourth sensor to form a fourth analog electrical signal representing force applied opposite to the second direction;

converting the fourth analog electrical signal to a fourth digital signal representing a fourth raw force sensor value;

linearizing each of the third and fourth raw force sensor values so as to compensate for non-linearities inherent in the force sensors, pointing device mechanics and in said converting steps, thereby forming third and fourth linear force values, respectively, that are substantially linearly related to the force applied by the user;

subtracting the third linear force sensor value from the first linear force sensor value to determine the net X force value; and

subtracting the fourth linear force sensor value from the second linear force sensor value to determine the net Y force value.

18. A method according to claim 16 further comprising:

biasing the force sensors to a standby operating point so that the force sensor values exhibit a non-zero bias value in the absence of any force applied by the user; and

adjusting each of the linear force values by subtracting the corresponding bias value so that the adjusted linear force values represent only the force applied by the user.

19. A method according to claim 16 wherein said determining a speed factor includes the steps of:

for low net X and net Y force values, selecting a first speed factor for lower apparent cursor speeds; and

for higher net X and net Y force values, selecting a second speed factor greater than the first speed factor for faster apparent cursor speeds.

20. A method according to claim 16 further comprising limiting the speed factor to a predetermined speed limit value thereby limiting the apparent cursor motion speed on the display screen.

21. A method according to claim 16 wherein said determining a speed factor includes computing a speed value according to a formula:

space="preserve" listing-type="equation">speed=SQUARE×

(M--NULL).sup.2 LINEAR×

(M--NULL), where

SQUARE is a predetermined square term coefficient,

M is the XY magnitude value,

NULL is a predetermined minimum force to initiate cursor motion, and

LINEAR is a predetermined linear term coefficient.

22. A method according to claim 21 further comprising:

providing a first value for use as the SQUARE term coefficient during repositioning operations and a second value for use as the SQUARE term coefficient during dragging operations;

checking status of the mouse buttons to determine whether the user is repositioning or dragging; and

if repositioning, selecting the first value for use as the SQUARE term coefficient for computing the speed value; and

if dragging, selecting the second value for use as the SQUARE term coefficient for computing the speed value, thereby adjusting the cursor tracking responsive to the mouse button status.

23. A method according to claim 21 wherein the first value is greater than the second value so that the computed speed value is greater for a repositioning operation than for a dragging operation.

24. A method according to claim 21 further comprising:

providing a first value for use as the LINEAR term coefficient during repositioning operations and a second value for use as the LINEAR term coefficient during dragging operations;

checking status of the mouse buttons; and

selecting one of the first and second values responsive to the mouse button status for use as the LINEAR term coefficient in said computing the speed value.

25. A method according to claim 17 further comprising:

arranging the four force sensors offset by forty-five degrees from a predetermined cartesian coordinate system having an X direction corresponding to horizontal dimension on the display screen and a Y direction normal to the X direction, so that each of the force values corresponds to one of NE,SE,SW and NW directions relative to the cartesian coordinate system; and

wherein

combining the sensor force values to form X and Y force values includes computing the X and Y force values according to the formulae;

space="preserve" listing-type="equation">X=(NE+SE)-(NW+SW) and Y=(NE+NW)-(SW+SE).

26.

26. A keyboard for use in combination with a computer having a cursor visible on a display screen, the keyboard comprising:

an array of keyswitches each having a keycap;

force sensor means coupled to a selected one of the keycaps and responsive to a user pressing on the selected keycap for generating at least two electrical signals, each electrical signal associated with a corresponding direction; and

signal processing means for controlling movement of the cursor on the display screen responsive to the electrical signals;

said signal processing means including means for providing differing time response characteristics of said cursor movement responsive to the said user pressing on the keycap, the time response including a faster cursor movement while the user is a conducting a cursor repositioning operation and a slower cursor movement while the user is conducting a cursor dragging operation.

27. A computer system comprising:

a display screen having means for displaying a cursor;

a keyboard having an array of keyswitches, each of the keyswitches having a keycap coupled thereto;

force sensor means in the keyboard coupled to a selected one of the keycaps and responsive to a user pressing on the selected keycap for generating at least two electrical signals, each electrical signal associated with a corresponding direction on the display screen; and

signal processing means coupled to the force sensor means for repositioning the cursor on the display screen in the corresponding directions in response to the electrical signals;

said signal processing means including means for providing differing time response characteristics of said cursor movement responsive to the said user pressing on the keycap, the time response including a faster cursor movement while the user is a conducting a cursor repositioning operation and a slower cursor movement while the user is conducting a cursor dragging operation.