Velocity Feedback Control System for a Rotor of a Toy Helicopter

• US 20110155843A1
• Filed: 05/21/2010
• 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 8,123,176 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 toy helicopter, the helicopter having a first rotor and a second rotor, the first rotor being driven by a first motor, and the second rotor being driven by a second motor, power being provided to the first motor and the second motor using pulse width modulation;

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 adjusted second rotor speed defining a target ratio;

the method comprising the steps of;

(a) measuring the first rotor speed, measuring the second rotor speed and determining a ratio of the first rotor speed to the second rotor speed;

(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;

wherein measuring the first rotor speed comprises measuring a feedback voltage of the first motor and measuring the second rotor speed comprises measuring a feedback voltage of the second motor.

2. The method according to claim 1, wherein one of the first rotor and 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 target ratio is determined by a trim position.

5. The method according to claim 1, the method further comprising the steps of:

(e) reading a throttle position;

(f) determining a target rotor speed for at least one of the first rotor and the second rotor based on the throttle position;

(g) measuring the speed of the at least one of the first rotor and the second rotor;

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

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

(j) repeating steps (a) to (c) and (g) to (i), until the speed of the at least one of the first rotor and the second rotor and the target motor speed are within a first predetermined margin, and the ratio and the target ratio are within a second predetermined margin.

6. The method of claim 5, wherein the step of reading a throttle position comprises receiving a wireless command, wherein the wireless command specifies the throttle position.

7. The method according to claim 1, the method further comprising the steps of:

(e) reading a steering position;

(f) determining a new target ratio based on the steering position; and

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

8. The method according to claim 7, wherein the step of determining the new target ratio comprises using a relationship associated with the steering position.

9. The method according to claim 8 wherein the relationship is represented by a lookup table.

10. A toy 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 the method of claim 1.