Aerobotics Tutorial

8/2/2019 Aerobotics Tutorial

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AEROBOTICSTUTORIAL & GUIDELINES

This is just for reference of participantsand should be used at own discretion


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AEROBOTICS is an event which adds a verticaldimension to Robotics, making it all the more

adventurous and challenging.

The event aims to merge principles of aviationwith those of robotics.

Aero + Robotics= AEROBOTICS

INTRODUCTION


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Make a hovercraft

Move straight within a defined path

Count the number of lines and use it forperforming the various tasks.

Hovercraft has to fly autonomously . It

cannot be controlled manually. No RCequipment can be used

PROBLEM STATEMENT


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MODULES


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HOVERCRAFT

MATERIAL

THRUST AND AIR CUSHION

TORQUE & WEIGHT BALANCE

DRIFTING & ROTATION

NAVIGATION


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A SAMPLE DESIGN


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Considering the fact that the vehicle should be air

borne it has to be light

Material should have good resistance to bending

moments

The Material that can be considered to build the

chassis could be

-High/Medium Density Foam-Balsa Wood

-Any other suitable material

Cost of the material under consideration

MATERIAL


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The thrust to be provided depends on the weight of theAerobot. The static thrust of the motor can be lesser than the weight

of the Aerobot. Primary importance is maintaining a goodair-cushion to make the vehicle float.

This thrust can be provided by-Standard RC Brushless Motors

-Duct-fans

THRUST AND AIR CUSHION


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Out runners

High RPM

Power Requirement

ESC (Electronic Speed Controller)

Control is via PWM (Pulse Width Modulation), following

certain specifications

Time Period = 20ms

On time = 1 ms 2 ms

Cost

BRUSHLESS MOTORS


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Processor ESC Motor


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Control by PWM

Simple DC Motor

High Power Requirements

Requires Large Current rating IC to

control it

Cost

DUCT FAN


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TORQUE & WEIGHT BALANCE

THRUST

Weight Distribution


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Placement of the components decides CG of the

vehicle

The CG should be perfectly aligned with the Thrust

line

Since the system is afloat it will experience some

rogue torque caused by this misalignment of

components

Too many actuators may also provide torque and add

to the instability

PLACEMENT


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The system has an inherent property of drifting

This can only be controlled effectively by a good

mechanical design of the system

Not all defects in the design can be countered by a

electronic system

Rotation can however be regulated by an effectiveControl system

Rotation is due to the principle of Conservation of

angular momentum

DRIFTING & ROTATION


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Horizontal thrust providers with control surfaces .

Thrust provider can be fans or propellers

For control surfaces we need to implement

aerodynamically effective solutions which would

be rudders

Rotatable horizontal thrust providers.

Can be implemented in either pusher or puller form

NAVIGATION


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The horizontal thrust is being provided by a propeller placedat the rear end of the system

This means the bot is being pushed horizontally

There might be mismatch between the horizontal thrust line

and the bots horizontal symmetry axis causing rotation andhence needs to be implemented carefully.

PUSHER

CG


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The horizontal thrust is being provided by a propeller placed

at the front end of the system

This means the bot is being pulled horizontally

The advantage in doing so is: in the case of mismatch the bot

will still continue moving forward without rotation.

PULLER

CG


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Lithium polymer

This is the most preferred Power pack used

in RC Planes

Provides high current

One pack of Lipo Battery contains a group

of cells in series, each cell can provide 3.7 V

Standard Specifications are

3 cell pack : 11.2 V

LITHIUM POLYMER BATTERIES


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Factors to be considered before buying a

battery:

Voltage Ampere Hour Rating

No. Of Cells

BATTERY SPECIFIATIONS


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Sensors IR

Ultrasonic

Processor Atmega

Arduino

Actuator Fans

Control

Surfaces

ELECTRONICS


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Sensors are to be used to sense the line on the arenaand the side barricades.

The ideal sensors for this purpose will be IR sensors

though a variety of sensors can be used.

IR sensors are cheap and decently reliable.

Ultra Sound sensors can also be used to detect the

walls on the sides.

These are costlier than IR but more reliable.

The major challenge lies in placing the Optimal

number of sensors in the right position In the case when IR sensors are affected by the

ambient light interference then TSOP sensors can be

used.

SENSORS


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Processors

For onboard processing several processors are

available in the market like

Microcontroller: PIC, Atmega

Arduino board Any other development board

Development boards like Arduino Board provide an

user friendly interface butits costlier than sparemicrocontroller.

PROCESSORS


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PWM may be used to control the speed ofthe motor

This is done by controlling the ON time of

the Square Voltage signal given to the

motor

Processor

ESC

Motor Driver Motor

PULSE WIDTH MODULATION


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The current required to drive any motor is very high

Hence an appropriate motor driver is required

For example L293D : max rating 1 amp

L298 : max rating 2 amp

The current by them may not be sufficient hence insuch a case high Power Transistors can also be

used.

MOTOR DRIVERS


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THANK YOU

Documents

Aerobotics Tutorial