Velocity Feedback Control System for a Rotor of a Toy Helicopter

• US 20110155842A1
• Filed: 12/24/2009
• Published: 06/30/2011
• Est. Priority Date: 12/24/2009
• Status: Active Grant

• Current Assignee: Spin Master Limited (Spin Master Corp.)
• Original Assignee: Spin Master Limited (Spin Master Corp.)
• Inventors: Mak, Paul
• Granted Patent: US 8,123,175 B2
• Time in Patent Office: Days
• US Class Current: 244/17.13
• CPC Class Codes: G05D 1/0858 specially adapted for vertical take-off of aircraft

Abstract

There is provided a method and apparatus for controlling a toy helicopter in flight. The toy helicopter is powered by a first rotor and a second rotor. A target speed ratio is determined for the speed of the first rotor and the speed of the second rotor. The speed of the rotors is adjusted incrementally until the target ratio is achieved.

Claims

1. A method for controlling a helicopter, the helicopter having a first rotor and a second rotor, the method comprising the steps of:

(a) measuring the speed of the first rotor;

(b) determining the target second rotor speed based on the speed of the first rotor;

(c) measuring the speed of the second rotor;

(d) if the speed of the second rotor is greater than the target second rotor speed, decreasing the power to the second rotor by a fixed increment;

(e) if the speed of the second rotor is less than the target second rotor speed, increasing the power to the second rotor by a fixed increment;

(f) repeating steps (c), (d) and (e), until the speed of the second rotor and the target second rotor speed are within a predetermined margin.

2. The method according to claim 1, wherein the second rotor is a tail rotor.

3. The method according to claim 1, wherein the second rotor is coaxial with the first rotor.

4. The method according to claim 1, wherein the first rotor is driven by a first motor, and the second rotor is driven by a second motor, and wherein power is provided to the first motor and the second motor using pulse width modulation (PWM).

5. The method according to claim 4, wherein the step of measuring the speed of the first rotor comprises measuring the feedback voltage of the first motor.

6. The method according to claim 5, wherein the step of measuring the speed of the second rotor comprises measuring the feedback voltage of the second motor.

7. The method according to claim 1, wherein the step of determining the target second rotor speed depends on a trim position.

8. A method for controlling a helicopter, the helicopter having a rotor, the method comprising the steps of:

(a) reading a throttle position;

(b) determining the target rotor speed based on the throttle position;

(c) measuring the speed of the rotor;

(d) if the speed of the rotor is greater than the target rotor speed, decreasing the power to the rotor by a fixed increment;

(e) if the speed of the rotor is less than the target rotor speed, increasing the power to the rotor by a fixed increment;

(f) repeating steps (c), (d) and (e), until the speed of the rotor and the target motor speed are within a predetermined margin.

9. The method of claim 8, wherein the step of reading a throttle position comprises receiving a wireless command, wherein the wireless command specifies the throttle position.

10. The method of claim 8, wherein the rotor is driven by a motor, and wherein power is provided to the rotor using pulse width modulation (PWM).

11. The method of claim 10, wherein the step of measuring the speed of the rotor comprises measuring the voltage feedback of the motor.

12. A method of steering a helicopter, the helicopter having a first rotor and a second rotor, the method comprising the steps of:

(a) reading a steering position;

(b) measuring a first rotor speed;

(c) determining a target second rotor speed based on the first rotor speed and the steering position;

(d) measuring the second rotor speed;

(e) if the second rotor speed is greater than the target second rotor speed, decreasing the power to the second rotor by a fixed increment;

(f) if the second rotor speed is less than the target second rotor speed, increasing the power to the second rotor by a fixed increment;

(g) repeating steps (d), (e) and (f), until the second rotor speed and the target second rotor speed are within a predetermined margin.

13. The method of claim 12, wherein the first rotor is driven by a first motor, and the second rotor is driven by a second motor, and wherein power is provided to the first motor and the second motor using pulse width modulation (PWM).

14. The method according to claim 13, wherein the step of measuring the speed of the first rotor comprises measuring the feedback voltage of the first motor.

15. The method according to claim 14, wherein the step of measuring the speed of the second rotor comprises measuring the feedback voltage of the second motor.

16. The method according to claim 12, wherein the step of determining the target second rotor speed comprises using a relationship associated with the steering level to compute the target second rotor speed from the first rotor speed.

17. The method according to claim 16 wherein the relationship is represented by a lookup table.

18. The method according to claim 16 wherein the relationship consists of multiplying the first rotor speed by a factor α

.

19. A method for controlling a helicopter, the helicopter having a first rotor and a second rotor, the first rotor having a first rotor speed and the second rotor having a second rotor speed, the first rotor speed and the second rotor speed being adjusted such that the helicopter is stable in flight, the ratio of the adjusted first rotor speed to the

(b) if the ratio is greater than the target ratio, performing at least one of decreasing the power to the first rotor by a fixed increment and increasing the power to the second rotor by a fixed increment;

(c) if the ratio is less than the target ratio, performing at least one of increasing the power to the first rotor by a fixed increment and decreasing the power to the second rotor by a fixed increment; and

(d) repeating steps (a) to (c) until the ratio and the target ratio are within a predetermined margin.

20. A helicopter comprising:

a first rotor powered by a first motor;

a second rotor powered by a second motor;

a power source to provide power to the first rotor and the second rotor; and

a microprocessor configured to perform a method of controlling the helicopter, the method comprising the steps of

(a) measuring the speed of the first rotor;

(b) determining the target second rotor speed based on the speed of the first rotor;

(c) measuring the speed of the second rotor;

(d) if the speed of the second rotor is greater than the target second rotor speed, decreasing the power to the second rotor by a fixed increment;

(e) if the speed of the second rotor is less than the target second rotor speed, increasing the power to the second rotor by a fixed increment;

repeating steps (c), (d) and (e), until the speed of the second rotor and the target second rotor speed are within a predetermined margin.