Motion effector controller for use in a virtual reality system

• US 6,195,596 B1
• Filed: 08/11/1998
• Issued: 02/27/2001
• Est. Priority Date: 10/24/1997
• Status: Expired due to Fees

• Current Assignee: Daewoo Electronics Company Limited (Dayou Holdings Co.,Ltd.)
• Original Assignee: Daewoo Electronics Company Limited (Dayou Holdings Co.,Ltd.)
• Inventors: Kim, Jeoung Tae
• Primary Examiner(s): Sheikh, Ayaz
• Assistant Examiner(s): Backer, Firmin
• Application Number:
  US09/132,411
• Time in Patent Office: 931 Days
• Field of Search: 700/245, 708/420, 708/571, 364/718, 364/722, 364/728
• US Class Current: 700/245
• CPC Class Codes: G05B 13/042 in which a parameter or coefficient is automatically adjusted to optimise the performance

Abstract

In a motion effector for use in a virtual reality system, a plant is a target of control and for producing an output signal reflecting the actual movement of a moving part therein and a reference input provider provides a reference input signal which reflects a desired motion of the plant. In addition, a subtractor produces an error signal by subtracting the output signal from the reference input signal. A feedback compensator generates a first control signal by using the error signal and a feed-forward compensator generates a second control signal by using the reference input signal. An adder generates a final control signal by adding the first and the second control signals and provides the final control signal to the plant, wherein the final control signal is used to control the plant.

Claims

1. A motion effector for use in a virtual reality system, comprising:

a plant for producing an output signal reflecting actual movement of a moving part therein;

means for providing a reference input signal which reflects a desired motion of the plant;

subtracting means for producing an error signal by subtracting an output signal from the reference input signal, wherein the output signal is generated from the plant and reflects the actual movement of the plant;

first compensating means for generating a first control signal by using the error signal;

second compensating means for generating a second control signal by using the reference input signal; and

adding means for generating a final control signal by adding the first and the second control signals and providing the final control signal to the plant, wherein;

the first compensating means is capable of reducing external disturbances to the motion effector and the modeling ciTors of the motion effector and stabilizing the second compensating means,

the second compensating means is capable of reducing the time gap between the reference input signal and the output signal, and

the first compensating means is characterized by the function H_b(z<sup>−

1</sup>) represented by;

$H_b<br><br>\left(z^{-1}\right)=\frac{1+b_1<br><br>z^{-1}+b_2<br><br>z^{-2}}{a_0+a_1<br><br>z^{-1}+a_2<br><br>z^{-2}},$

wherein a₀, a₁, a₂, b₁ and b₂ are real coefficients and z is the complex variable according to the z transform.

2. The motion effector of claim 1, wherein the second compensating means is characterized by the function H_f(z⁻

1) represented by;

$H_f<br><br>\left(z^{-1}\right)=\frac{{\mathrm{bz}}^{-1}}{1+{\mathrm{az}}^{-1}}$

wherein a and b are real coefficients.

3. The motion effector of claim 2, wherein the plant includes:

a first amplifier for receiving and amplifying the final control signal;

an actuator controlled by the amplified final control signal;

a motion simulator as the moving part driven by the actuator;

a sensor for generating the output signal by sensing the movement of the motion simulator and converting the movement into an electrical signal; and

a second amplifier for amplifying the electrical signal to produce the output signal.

4. The motion effector of claim 3, wherein the actuator is operated by using a hydraulic mechanism.

5. The motion effector of claim 4, wherein the hydraulic mechanism has hydraulic pumps, valves, cylinders and a reservoir therein.

6. The motion effector of claim 3, wherein the actuator is operated by using electrical motors.

7. The motion effector of claim 6, wherein the motion simulator is an entertainment chair to sit on, to thereby allow a user to feel a movement in synchronism with a display on a screen.

8. A motion effector for use in a virtual reality system, comprising:

a plant configured to produce an output signal reflecting actual movement of a moving part therein;

a reference provider configured to provide a reference input signal which reflects a desired motion of the plant;

a subtractor configured to produce an error signal by subtracting the output signal from the reference input signal,

a first compensator configured to generate a first control signal by using the error signal;

a second compensator configured to generate a second control signal by using the reference input signal; and

an adder configured to generate a final control signal by adding the first and the second control signals and to provide the final control signal to the plant, wherein the final control signal is used to control the plant, wherein;

the first compensator is capable of reducing external disturbances to the motion effector and the modeling errors of the motion effector and stabilizing the second compensator,

the second compensator is capable of reducing the time gap between the reference input signal and the output signal, and

the first compensator is characterized by the function H_b(z<sup>−

1</sup>)represented by;

$H_b<br><br>\left(z^{-1}\right)=\frac{1+b_1<br><br>z^{-1}+b_2<br><br>z^{-2}}{a_0+a_1<br><br>z^{-1}+a_2<br><br>z^{-2}},$

wherein a₀, a₁, a₂, b₁ and b₂ are real coefficients and z is the complex variable according to the z transform.

9. The motion effector of claim 8, wherein the second compensator is characterized by the function H_f(z⁻

1) represented by;

$H_f<br><br>\left(z^{-1}\right)=\frac{{\mathrm{bz}}^{-1}}{1+{\mathrm{az}}^{-1}}$

wherein a and b are real coefficients.

10. The motion effector of claim 9, wherein the plant includes:

a first amplifier for receiving and amplifying the final control signal;

an actuator controlled by the amplified final control signal;

a motion simulator as the moving part driven by the actuator;

a sensor for generating the output signal by sensing the movement of the motion simulator and converting the movement into an electrical signal; and

a second amplifier for amplifying the electrical signal to produce the output signal.

11. The motion effector of claim 10, wherein the actuator is operated by using a hydraulic mechanism.

12. The motion effector of claim 11, wherein the hydraulic mechanism has hydraulic pumps, valves, cylinders and a reservoir therein.

13. The motion effector of claim 10, wherein the actuator is operated by using electrical motors.

14. The motion effector of claim 13, wherein the motion simulator is an entertainment chair to sit on, to thereby allow a user to feel a movement in synchronism with a display on a screen.