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8/8/2019 Prabhat (73)Robotics..
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Robotics
-Prabhat Chandra Bajpai
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Different Types of Robots
1. Ro b o t Arms (Fixed Ro b o ts)2 . Mo bile Ro b o ts
Hu man o id Ro b o tsLegged Ro b o ts
Wheel Ro b o ts3 wheels
2 Driver wheels, 1 Caster 1 Driver wheel, 2 Casters
4 wheelsCasters make diverse pr o blems in the c o ntr o l of the r o b o t
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Wh eel Robot Main Components
M ain C o mp o nentsM echanics
WheelsDriver Mo to r (s)P o wer Transmissi o n System
Electr o nicsCo ntr o ller B o ard
Needingf eedback
f r
om envir
onment
Sens o rsWe are now discussing some of the above
topics
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Different Types of Motors
DC Mo to rs Yo u can simply c o ntr o l it
AC Mo to rsIts di ff ic u lt t o be c o ntr o lled b u t it canbe u sed in high p o wer applicati o ns
Serv o Mo to rs Yo u have c o mplete c o ntr o l o n the sha f t
angle
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Different Types of Feed Back Sens o rs
IR Sens o rsPress u re Sens o rsLight Sens o rs
Temperat u re Sens o rsEnc o der
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Wh at is Encoder
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Wh y do we use Power Transmission Systems?
1.T
ored
uce Ang
ular Vel
ocity2 . To increase T o rq u e
Diff erent Transmissi o n SystemsG ear
H ard man u f act u ringand adj u stment
P u lley
S o [ => T
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GearG ears are u sed t o change the speed andfo rce of the m o to r . Yo u can u se gears t o:
1. Speed u p o r sl o w d o wn y o u r r o b o t .
2 . M ake y o u r r o b o t str o nger o r weaker .
There are many di ff erent types of gearsSp u r G ear Bevel G ear Wo rm G ear R ack & Pini o n
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GearSp u r gears are wheels with teeth
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GearBevel gears mesh at right angles, s o
they change the directi o n of r o tati o n .
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GearWo rm gears l oo k like screws . They have
many special pr o perties .
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GearR ack & pini o n gears t u rn r o tati o nal m o tio n
int o straight-line m o tio n .
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Where does all this torque come from?
Consider a pair of gears that are meshed together.
FX
T he moment arm is the radius of the gear.Remember: X = F x r
r
A torque
on thisaxle...
producesa force at the tooth.
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F
Xr
T he force from the small gear s tooth pushes against
the large gear s tooth. T his creates an equal (and opposite)force in the large gear. T his is Newton s 3rd Law.
andproduces alarger torqueon this axle.
T he force acts through this larger moment arm ...
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F1 = -F 2
X
r 2
X
r 1
A nalyzing the forces... X1 = F1 x r 1 X2 = F2 x r 2
F1 = X1 / r 1F2 = X2 / r 2
F1 = - F 2
X1 / r 1 = -X2 / r 2
X2 / X1 = r 2 / r 1
T he ratio of torques is the ratio of the gear radii.T his is the g ear ratio!
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GearThe gear ratio of this gear box is 75 to 1
T hat meansthe last axlerotates 75
times slowerthanthe first axle.It also meansthe last axlehas 75 timesthe torque asthe first axle.
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T ry this experiment.
Have one person turnthis wheel.
A nd have another persontry to hold on to this wheel.
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Gears can increase the torque (and force) that they exert
on something.T
his is known as mechanical advanta g e .
BUT , it comes at a price. Do you know what it is?
torque increases
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Belt Drives
U ses f ricti o n t o transmit p o wer
2
1
C
[2 [ 1
D2D1
2
1
[
[!VR
Velocity Ratio:
D 1. [ D2 .[
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Shaft Size for DR,can use NEMA frame
Belt Drive Basics
Motor Nameplate
Center Distance(center shaft to center shaft)
T ake-up/Installation Allowance
SizeSize
DR DN
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Belt Drive Basics
R N
R N Speed Speed--UpUp
Speed Speed--Down Down 1010
1750 rpm1750 rpm
1010 44
44
700 rpm700 rpm
4375 rpm4375 rpm
Ratio always greater than 1
Sp eed Ratio = 2.5
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How to assemble our RobotH ere is o u r package
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How to assemble our Robot
1 2
3
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How to assemble our RobotBo tt o m view of the r o b o t
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How to assemble our RobotSens o r b o ard assembly
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Th ank You!
.