me451a: btech project modular aerial vehicle (modav)home.iitk.ac.in/~mandeeps/btp modav.pdf ·...
TRANSCRIPT
ME451A: BTech Project
Modular Aerial Vehicle(ModAV)
Team Members: Rohit Gupta (14567) | Mandeep Singh (14363) | Rohit Choudhary(14565)Supervisor: Dr. Ashish DuttaDepartment of Mechanical EngineeringIndian Institute of Technology Kanpur
Motivation
Design a modular configurable aerial robot which would address following problems and is a remedy of such problems :
- Optimum resource allocation for given payload.- Different configurations of the aerial vehicle can be advantageous for different
applications.- Scalable to payload needs.- Compact packing and transportability of the aerial vehicle.
Deliverables
- Modular docking robots in controlled environment.- Aerial Vehicle capable of delivering light weight objects (payload of 10-50
gram) to a distance of around 5 m.- Flight height of more than 5 meter- Flight time of more than 1 minutes.
DESIGN CALCULATIONS
Weight CalculationsS. No. Part Name Quantity Weight (g)
1 Block 4 3.62
2 Rotor Base 8 21.33
3 Pinion 16 8.65
4 Docker Block 8 17.5
5 Docker Face 8 6.65
6 Wire Frame 8 2.7
7 Wedge 1 16 0.04
8 Central Unit Base 1 40.58
9 Central Unit Side 1 2 25.07
10 Central Unit Side 2 2 24.81
11 Central Unit Cover 1 39.24
12 Wedge 2 4 0.51
13 Lock 4 12.09
17 Motor Shaft 4 3.05
Total 780.0
(Excluding electronic components)
Selection of motor and propellers:
Setup:Total weight of the aerial vehicle (W)~= 1700g Number of motors (n) = 4Average Efficiency of motors ()=80%Now, total thrust required at full throttle assuming = 100% (using MCCORMICK METHOD)
= 2 * W = 2 * 1700 = 3400g
Taking into account efficiency of motors, we calculate thrust at 80% throttle which roughly corresponds to 80% power/efficiencyTherefore, thrust required at 80% throttle (T) = 3400gThrust required per motor = T / n
= 3400/4 = 850g
Thrust Calculations
(THRUST CALCULATIONS ECALC BY MCCORMICK METHODS-
http://www.calvin.edu/academic/engineering/2014-15-team02/content/THRUST%20Calculations%20eCalc%20by%20McCormick%20Methods.pdf)
(Performance of Propellers - http://web.mit.edu/16.unified/www/FALL/thermodynamics/notes/node86.html)
Comparison of thrust produced by given rotor & propeller combinations are shown below
Dimension of propeller are given as (Diameter in inches) X (Pitch in inches)
http://rcbazaar.com/product.aspx?productid=4746https://www.kdedirect.com/collections/uas-multi-rotor-brushless-motors/products/kde2315xf-965
Thrust Calculations
Rotor Propeller Throttle Current(A)
Voltage(V)
Thrust(g)
Cost(Rs)
1 Avionic 3506 12x3.8 83% 12.9 11.1 870g 1350
2 Avionic PRO C3536 9x3.8 100% 17 11.1 1070g 1535
3 KDE2315XF-965 10x3.3 87.5% 10.7 11.6 900g 4000
4 KDE2814XF-775 12.5x4.3 87.5% 11.0 11.6 1060g 4600
Formula for thrust (T)obtained using momentum theory
T = 2ρAω2
for the selected motor is calculated by multiplying rated KV(RPM/V) rating by rated voltage.
ω= KV (RPM/V) * V = 850 * 11.1 = 9435 RPMA = pi *(12.5/2 * 2.52 * 0.01)^2
Therefore, T = 2 * 10^-3 *pi *(12.5/2 * 2.52 * 0.01)^2 * (9435)^2 = 15.4N
Thrust Calculations using momentum theory
Control Volume for air flow
Selection of Battery:Total discharge rate required: 12.9*4 = 51.6A = 51.6C
Voltage required: 11.1
Desired Flight Time: around 5 minutes
Desired mAh of the battery > (Total Discharge Rate / Discharge Efficiency) * Desired Flight Time(in hours) * 1000 mAh
= (51.6 / 0.67 ) * (5/60) *1000
= 5160 mAh
Thrust Calculations
Battery mAh Flight Time Price(Rs)
Turnigy Graphene 2700 ~3min 3200
LiPo 4850 3S 4850 ~5 min 8100
https://hobbyking.com/en_us/graphene-2200mah-4s-65c-w-xt60.html4.https://www.maxamps.com/lipo-4850-3s-11-1v-battery-pack
Bill of MaterialsElectronic Items Quantity Weight
(g/unit)Price
(Rs/unit)Assembly
Rotor: Avionic 3506 850kv 4 80 1350 Rotor Unit
Propellor: APC 12 x 6 E1 4 5 150 Rotor Unit
Servo Motor2 12 9 195 Platform
Big Battery: LiPo 4850 3S4 1 355 8100 Central Unit
Arduino Mini3 4 10 250 Platform
Wifi Module5 5 5 300 Platform+ Central Unit
Small Battery: 500mah 7.4V6 4 36 415 Platform
Pixhawk Controller7 1 38 12000 Central Unit
ESC8 1 50 700 Central Unit
Raspberry Pi9 1 15 3000 Central Unit
Omni Wheels10 8 60 600 Platform
Total(weight excluding Platform) 803 41100
Electronic Items
Bill of Materials
Item Estimated Cost (Rs)
Balsa Wood 3000
Adhesive 400
Glass Fibre 400
Velcro Straps 200
Miscellaneous ItemsBalsa Wood, Adhesive, Glass Fibre, Velcro Straps to be purchased locally.
Cost Estimation
Manufacturing cost: Cost of Laser cutting : 2 hrs of cutting * Rs 800/hr = Rs1600Cost of 3D printing: 2 hrs of printing * Rs300/hr = Rs 600
Total Manufacturing Cost : Rs 2200
Total estimated cost: Rs 41100 + Rs 4000 + Rs2200 = Rs 47300
Isometric Views
ModAVNet Weight: 1700 g
Rotor Module
Material: Balsa Wood with cross frame of fibre compositeManufacturing Process: Cutting, Fitting Rapid Prototyping
Platform
Central Module
Material: Balsa WoodManufacturing Process: Cutting, Fitting
Docking Mechanism
CRITICAL DESIGNMaterial: Nylon fibre or Onyx fibreManufacturing Process: Rapid prototyping, Fitting
Stress Analysis
Stress Analysis
Concept of Modularity
Concept of Modularity
References 1.Propellor: http://rcbazaar.com/product.aspx?productid=24832.Servo Motor - https://www.amazon.in/Robodo-Electronics-Tower-Micro-Servo/dp/B00MTFFAE0/ref=sr_1_1?ie=UTF8&qid=1509749507&sr=8-1&keywords=servo+motor3.Arduino Mini: https://www.amazon.in/Arduino-Atmega-Compatible-Board-Smaller/dp/B00H8MYAGI5.Wifi Module - https://www.amazon.in/ESP8266-Serial-Wireless-Transceiver-Module/dp/B00O34AGSU/ref=sr_1_4?s=industrial&ie=UTF8&qid=1509749820&sr=1-4&keywords=wifi+module+for+arduino
6.Small Battery: http://rcbazaar.com/product.aspx?productid=4848
7. PIXHAWK flight ontroller: https://www.inf.ethz.ch/personal/pomarc/pubs/MeierICRA11.pdf
8.ESC: http://rcbazaar.com/product.aspx?productid=4792
9.Raspberry pi: https://www.amazon.in/RASPBERRY-PI-MODEL-INBULT-BLUETOOTH/dp/B01G882L3G/ref=sr_1_2?s=industrial&ie=UTF8&qid=1509750158&sr=1-2&keywords=raspberry+pi+3
10.Omni Wheels: https://robokits.co.in/robot-parts/robot-wheels/omni-wheels/omni-wheel-58mm-servo-lego-nxt-compatible