5E. Motor sizing and Battery sizing of the system - M-Division-2020-2021-Even/Repo_13 GitHub Wiki

5.6 MOTOR SIZING :

5.6.1 DC MOTOR :

Mass of body (m) = 0.3kg
Diameter (D) = 0.08 m
Acceleration due to gravity = 9.8 m/s^2
Coefficient of friction = 0.45

F = m * g
F = 0.3 * 9.8
F = 2.94 N

Now considering friction

F = m * g * u
F = 2.94 * 0.45
F = 1.323 N

Torque : T = F * (D/2)
T = 1.323 * (0.08/2)
T = 0.05292 Kg-m
T = 0.05292 * (100/9.8)
T = 0.54 Kg-cm

Considering the factor of safety i.e FOS = 1.5
Final torque = T * FOS
Final torque = 0.54 * 1.5
Final torque = 0.81 Kg-cm
By comparing with table of specification for 0.81 Kg-cm Rated torque, We need DC motor of 300 rpm @ 12V

5.6.2 SERVO MOTOR :

Mass of body (m) = 0.3kg
Diameter (D) = 0.03 m
Acceleration due to gravity = 9.8 m/s^2
Coefficient of friction = 0.4

F = m * g
F = 0.3 * 9.8
F = 2.94 N

Now considering friction

F = m * g * u
F = 2.94 N * 0.45
F = 1.176 N

Torque : T = F * (D/2)
T = 1.176 * (0.03/2)
T = 0.01764 Kg-m
T = 0.01764 * (100/9.8)
T = 0.18 Kg-cm

Considering the factor of safety i.e FOS = 1.5
Final torque = T * FOS
Final torque = 0.18 * 1.5
Final torque = 0.27 Kg-cm
By comparing with the table of specifications for 0.27 Kg-cm Stall Torque, We need Servo Motor Of Specification Tower Pro SG-90.
Operating Voltage = 3.0 - 7.2 V
Stall current = 650 mA

BATTERY SIZING :

SL No.	Components	Quantity	Voltage required	Current Drawn
1.	DC motor	1	12V	300 mA
2.	SG 90 Servo motor	1	5V	650 mA
3.	PIR Sensor	1	5V	40 mA
4.	Arduino UNO R3	1	5V	100 mA
5.	Double Channel Relay	1	5V	80 mA

So, for 12V
Current Drawn(C1) = 300 mA
So, for 5V
Current Drawn(C2) = 650 + 40 + 100 + 80 = 870 mA

Now considering Factor Of Safety i.e FOS = 1.2
C1 = 300 mA * 1.2
C1 = 360 mA = 0.36 A
C2 = 870 mA * 1.2
C2 = 1044 mA = 1.044 A

For time(T) = 3 hrs
For 12V
Battery Required : 3 * 0.36 = 1.08 Ah
For 5V
Battery Required : 3 * 1.044 = 3.132 Ah

Therefore, No. of battery required : 1.