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AEROBOTICS Tutorial. AEROBOTICS is an event which adds a vertical dimension to Robotics, making it all the more adventurous and challenging. The event.

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Presentation on theme: "AEROBOTICS Tutorial. AEROBOTICS is an event which adds a vertical dimension to Robotics, making it all the more adventurous and challenging. The event."— Presentation transcript:

1 AEROBOTICS Tutorial

2 AEROBOTICS is an event which adds a vertical dimension to Robotics, making it all the more adventurous and challenging. The event aims to merge principles of aviation with those of robotics. AERO + robotics= Aerobotics AEROBOTICS Introduction

3 AEROBOTICS TUTORIAL AEROBOTICS

4 Arena

5 AEROBOTICS Arena – various zones

6 Hover-Craft AEROBOTICS

7 HOVERCRAFT MATERIAL THRUST AND AIR CUSHION TORQUE & WEIGHT BALANCE DRIFTING & ROTATION NAVIGATION AEROBOTICS

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9 Another possible way by using a rudder…… AEROBOTICS

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11 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, depron -Balsa Wood Cost of the material under consideration AEROBOTICS Material

12 The thrust to be provided depends on the weight of the Aerobot. The static thrust of the motor can be lesser than the weight of the Aerobot. Primary importance is maintaining a good air-cushion to make the vehicle float. This thrust can be provided by -Standard RC Brushless Motors -Duct-fans AEROBOTICS Thrust and Air cushion

13 AEROBOTICS

14 Control by PWM Simple DC Motor High Power Requirements Requires Large Current rating IC to control it. Relays can also be used. Cost AEROBOTICS Duct Fan

15 THRUST Weight Distribution AEROBOTICS Torque & Weight balance

16 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 AEROBOTICS Placement

17 Imbalance Moment Instability AEROBOTICS Placement

18 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 effective Control system Rotation is due to the principle of Conservation of angular momentum AEROBOTICS Drifting & Rotation

19 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 AEROBOTICS Navigation

20 The horizontal thrust is being provided by a propeller placed at 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 bot’s horizontal symmetry axis causing rotation and hence needs to be implemented carefully. CG AEROBOTICS Pusher

21 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. CG AEROBOTICS Puller

22 Li-Poly ESC POWER SPECs AEROBOTICS

23 This is the most preferred Power pack used in RC Planes because of high power rating and duration longing. 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 AEROBOTICS Lithium Polymer Batteries

24 Factors to be considered before buying a battery: Voltage Ampere Hour Rating No. Of Cells AEROBOTICS Battery Specifications

25 Sensors IR sensor LDR (Light Dependent Resistor) Ultrasound Sensor (optional) Processor Atmega Arduino PIC Actuator Fans Control Surfaces AEROBOTICS Electronics

26 Sensors are necessary to sense the lines on the arena and 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. AEROBOTICS Sensors

27 Light Dependent Resistor (LDR) has a property of changing its resistance when illuminated with light. When placed in dark it has a very high resistance. Resistance drops dramatically when light falls on it. It can be used to detect if the bulb is ON or OFF. AEROBOTICS Sensors

28 LDR Sensor Circuit In poor light conditions, Resistance of LDR is large and hence more potential drop. This increases the voltage at 3 more than that at 2. Output voltage of the op-amp is HIGH and LED across 1 and 4 glows. In bright light conditions due to lesser potential drop across LDR, output of op-amp would be LOW. LED across 8 and 1 glows. AEROBOTICS

29 The circuit switches LED on in the dark The LED remains off as long as LDR is illuminated The 10K potentiometer shown can be used to adjust the sensitivity(calibration) of the sensor circuit Transistor can be replaced with an op-amp as a comparator which was shown in the previous slide. AEROBOTICS LDR Sensor Circuit

30 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. AEROBOTICS Sensors

31 RF Communication can be used for controlling the hovercraft wirelessly. Methods to employ RF Communication RF Module Hacking open a RF toy car AEROBOTICS RF Communication

32 It consists of two parts Transmitter Receiver The transmitter should be given serial data as input, which is received by the receiver Transmitter Receiver AEROBOTICS RF Module

33 We strongly recommend that you go through the following links:- between-microcontrollers-part-i/ communication-between-microcontrollers-part-ii/ communication-between-microcontrollers-%e2%80%93- part-iii/ AEROBOTICS RF Module

34 A cheap 4 channel RF controlled car maybe hacked open and used The channels are independent so all the four channels can be directly used for controlling four movements of the hovercraft. Since the channels are independent, upto 16 unique controls can be generated using various combinations of the channels if required. AEROBOTICS Hacking open a toy car

35 For onboard processing several processors are available in the market like  microcontroller  Arduino board  Any other development board An important specification of microcontroller is that it should have many PWM channels. Development boards like Arduino Board provide an user friendly interface but it’s costlier than spare microcontroller. AEROBOTICS Processors

36 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 AEROBOTICS Brushless Motors

37 ProcessorESCMotor Interfacing motor with microcontroller AEROBOTICS

38 PWM is used to control the speed of the motor This is done by controlling the ON time of the rectangular Voltage signal given to the motor Processor ESC Motor Driver Motor AEROBOTICS Pulse Width Modulation

39 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  Relays for high current duct fan. The current by them may not be sufficient hence in such a case high Power Transistors can also be used. AEROBOTICS Motor Drivers

40 Please keep the following aspects in mind :- Hovercraft may drift outward at curves. Natural tendency of the hovercraft to drift and rotate Sufficient momentum might be required to climb the ramp At the Y junction the hovercraft may tend to turn in one direction preferentially because of the angular momentum of the lift fan. AEROBOTICS Problems that might surface

41 Consider your own safety. Work carefully with propellers and brushless motors. Fix the motors properly on the chassis. Be careful with LiPo, both while charging and working. Use according to specification by the manufacturer. AEROBOTICS Safety Issues

42 The following are some videos of RC hovercrafts that may be useful for you in building your own hovercraft:- Uk&feature=related Uk&feature=related &NR=1 &NR=1 k&feature=related k&feature=related AEROBOTICS Video links


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