NATIONAL TECHNICAL UNIVERSITY OF ATHENS

MECHANICAL ENGINEERING DEPARTMENT

MECHATRONIC SYSTEMS

3-DOF BICOPTER

Supervisor : Professor E. Papadopoulos, (NTUA).

ΔΠΜΣ «AUTOMATION SYSTEMS» 2011-12

TEAM 3

Stathopoulos Christos Papanikolaou Thomas

Kampras Nikos

2 Mechatronic Systems- 2012

Contents

• System Description

• Modeling - Control

• Implementation

• Problems - Improvements

3-DOF BICOPTER

Mechatronic Systems- 2012 3

Unmanned Aerial Vehicles ( UAV ) • Quadrotors

• Helicopters

4 Mechatronic Systems- 2012

Idea

• 3 revolute joints

• 2 propeller motors

• 3 angle sensors

• Underactuated System

• Microcontroller

• Workspace

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System Description

• Physical system analysis – Dynamic Equations

• Linearization around operation position – 1st Lyapunov method

• Linearization position:

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Modeling (1)

1 1 3 2 2 1 2

2 2 3 2 1 2

3 3 3 1 2

sin cos

cos

Ι θ (θ ) (θ ) l (F F )

Ι θ (θ ) l (F F )

Ι θ l (F F )

1 2 3, , 0,0,0

0 0

( , )

( , ) ( , )

x x

x f x u

f x u f x ux x u Ax Bu

x u

7 Mechatronic Systems- 2012

Modeling (2)

11

22

33

11 2 21

2 222

3 3 33

3 3

0 00 0 0 1 0 0

0 00 0 0 0 1 0

0 00 0 0 0 0 1

0 0

0 0 0 0 0

0 0 0 0 0 0

0 0 0 0 0 0

c

Ax x

l mgl l

I I

l l

I I

1

2

1

2

3

1

2

3

1 0 0 0 0 0

0 1 0 0 0 0

0 0 1 0 0 0

B

u

u

u

x

C

y

6

6

rank Ob ή

rank Cb έ

8 Mechatronic Systems- 2012

Modeling (3) • Modeling of motor and propeller system F = λ∙u + b

• Measuring λ

• Underactuated: 2 inputs – 3 degrees of freedom • Control of the Yaw angle through the Roll angle • 3 PID

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Control

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Simulation • Control Signals • System response

• Aluminum Frame • Light • Easy to manipulate

• Potensiometer:

• angle measurement • enough prescision • simple use • parallel usage as joints • low cost

11 Mechatronic Systems- 2012

Implementation (1)

12

Implementation (2) • Brushless DC motors – (high power/mass, durable, simple to operate)

• ESC Controllers – Rpm Control– PWM

• Microcontroller Arduino Mega : • Atmel AVR, 8bit, 16Mhz • Measurements – Control Law – Motor Control signals • Comunication via USB with the PC User Interface • Simple to program. • Open Source – community support.

Mechatronic Systems- 2012

• Signal Plotting – Command Box • Processing – Open Source, easy to create graphics. • Serial Command protocol (control and debugging)

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INTERFACE - COCKPIT

• High noise levels in signal measurements → LCD οθόνη

• Performance degrading due to battery discharging → power unit • Motors large vibrations → 2 x power units 5Α

• Unstable behavior → Tuning of the PID gains → Tuning the delay of the control loop → Digital Filter • Target Step transition → smooth transitions

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Problems Faced

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Future Improvements

• More robust construction

• Replacement of the potentiometers with Encoders

• Nonlinear – Adaptive Control

• Fly-by-wire Control

End of Presentation

16 Mechatronic Systems- 2012