TRIBHUVAN UNIVERSITY
INSTITUTE OF ENGINEERING
THAPATHALI CAMPUS
A PROPOSAL
ON
MECHANICAL ROBOT
SUBMITTED BY
KRISHNA KHATRI
073/BAME/616
SUBMITTED TO
DEPARTMENT OF AUTOMOBILE AND MECHANICAL ENGINEERING
Table of contents
1. Title
2. Objective
3. Literature Review
4. System description
5. Calculation
6. Cost estimation
7. Limitation
8. Reference
1. Title
Mechanical Robot is used for making garbage out of any place. This mechanical robot is four
wheeled and collects the whole garbage into the place. In this project I will control this vehicle
with controller. In this project, the controller will control the robot like forward backward right
and left.
2. Objective
The main objectives of this project are:
To collect recyclable wastes for recycling purpose.
To dispose non recyclable waste in one place.
Reference purpose
3. Literature review
As a result of the accumulation of waste in recent times researchers. Are working to find the best
solutions to reduce environmental pollution caused by the wastes. Some of those solutions are
related with robotics, such as Zen Robotic Recycling, which has multiple sensors for accurate
analysis. Zen Robotic Recycling can be used only in recycling factories and some commercial
establishments, but it has high cost and it is unusable in different environments. I decided to
design my own mechanical robot. In this work, some factors have been considered such as cost,
size, weight. The main purpose of this machine is to pick the wastes in a container.
The main target is to design and make mechanical robot .This robot is built on the caterpillar
wheels sizes 52*74*17 cm and the power is supplied from 12v 30Ah battery. The user can use
remote control to control the direction of the robot.
4. System description
4.1Working operation
The mechanical robot is that type of machine which collects recyclable materials and use for
future reference. The energy stored in the battery is used so far to run the motor. The two
motors are used to run this robot. The first motor is used in the backside of wheel to run the
wheel by rotating the spur gears. The second robot is used along with the rack and pinion to
collect the waste in vertical direction. Rack and pinion is used to convert vertical to horizontal
and vice versa. The waste is collected in the container. Controller is used to control the
movements of the robot in right direction.
5. Calculation
1. Design of frame
Frame design for safety for 25*25*3 L mild steel channel
b=25mm,d=25mm, t=3mm
Consider the maximum load on the frame to be 50 kg
Max. bending moment =force *perpendicular distance=15*9.81*325
M=47823.75
We know,
M/I = αb / y
M= Bending moment
I = Moment of inertia about axis of bending that is Ixx
y= distance of the layer at which bending stress is considered
E= modulus of elasticity of beam material
I = bd^3/ 12
= 25*25^3/12
I= 32552.08 mm4
αb= 18.36N/mm^2
The allowable shear stress for material is α allow = Syt/fos
Where, Syt= yield stress= 210mpa
Fos=2
αallow =210/2= 105 mpa
Comparing we get,
αb<αallow
2. Motor selection for wheels
Given,
R= 100mm
Weight of assembly with frame = 5kg
Torque required for motor = force * radius of wheel
= 5*9.81*200/2= 4.905 Nm
We are using two motors for wheels so torque required for one motor is half of total torque =
24.525 kg cm
Therefore, we are selecting motor with 25kgcm torque
Power output of dc motor = voltage * current
= 12*0.8= 9.6W
Power = 2*π * N* 24.5252/60
N= 3.75 rpm
We are selecting motor with 10 rpm
3. Design of shaft
Consider the maximum load on the frame to be 5kg
Maximum bending moment = force * perpendicular distance
= 5*9.81*225
M= 11036.25 Nmm
We know,
M/I= αb/y
I= moment of inertia about X axis
Y= distance of the layer at which bending stress is considered
I= (π/64)*d^4
I= 2485.04mm^4
αb=33.308N/mm^2
The allowable shear stress for material is α allow = Syt/fos
Syt= 210Mpa
Fos = 2
αallow = 210/2=105Mpa
33.308 < 105
So, design is safe.
4. Rack And Pinion Design:
1. Load(w)=m=50 kg
2. Load acceleration(a)=0.1(m/sec)/0.1(sec)=1m/sec^2
3. Force due to acceleration=m*a=50*1=50N
4. Force due to gravity=m*g*sinα=50*9.81*sin60=424.785N
5. Force due to friction=m*µ*g*cosα=245.25N
Total force=720.035N
Total force with shock further (ft)=720.035*1.2=864.042N
1. Required pinion torque=ft*meshing pitch circle diameter=864.042*80=69.12 Nm
2. Pinion rpm=60000*0.1/250=24rpm
5. Spur gear design
Gear ratio (GR) = no. of teeth on driven gear/no. of teeth on driving gear
=30/15
=2/1
Velocity ratio = velocity of driving rear / velocity of driven gear
= 2/1
Mechanical advantage (MA) = load / effort
=30/15
=2
6. Cost Estimation
SN Materials Quantity Cost
1. Wire 4
2. Controller 1
3. Battery 1
4. Collecting box 1
5. Spur gear 2
6. Rack and pinion 1
7. Dc motor 2
8. Frame 1
9. wheels 4
10. shaft 2
7. Limitation
Periodic maintenance is required
Needs practice to learn movements pneumatically
Pressure must be consistent and supply must be continuous
8. Reference
1. Dr. Kirpal Singh Automobile Vol. 1,2, “Automobile Engineering”
2. P.S. Gill, “Automobile Engineering” ,
3. www.slideshare.net
4. www.gearseds.com
5. R.S. Khurmi J.K. Gupta , “Theory Of Machines”,
6.
www.robots.com/articles/mechanical-engineering-for-robots
