5.E MOTOR SIZING AND BATTERY SIZING OF THE SYSTEM - M-Division-2020-2021-Even/Repo_12 GitHub Wiki

5.E MOTOR SIZING

1. Servo Motor

Mass of body it holds (m) = 0.4 Kg

Diameter(D) = 0.03 m

Acceleration due to gravity(g) = 9.8 m/s^2

μ = 0.4

F = m * g

F = 0.4 * 9.8

F = 3.92 N

Friction

F = mg * μ

F = 3.92 * 0.4

F = 1.568 N

Now Torque : T = F * (D/2)

T = 1.568 * (0.03/2)

T = 0.02352 Kg-m

T = 0.02352 * (100/9.8)

T = 0.24 Kg-cm

Considering Factor Of safety i.e., FOS = 1.5

Final Torque = T * FOS

Final Torque = 0.24 * 1.5

Final Torque = 0.360 Kg-cm

We require Servo Motor Of Specification Tower Pro SG-90.

Operating Voltage : (3.0– 7.2 )V.

Stall current : 650 mA.

∴ No. Of SG 90 Servo Motors Required : 2.

2) DC Motor :

Mass of body it holds (m) = 0.3 Kg

Diameter(D) = 0.08 m

Acceleration due to gravity(g) = 9.8 m/s^2

μ = 0.45

F = m * g

F = 0.4 * 9.8

F = 3.92 N

Now considering friction

F = mg * μ

F = 3.92 * 0.45

F = 1.764 N

Now Torque : T = F * (D/2)

T = 1.764 * (0.08/2)

T = 0.07056 Kg-m

T = 0.07056 * (100/9.8)

T = 0.720 Kg-cm

Considering Factor Of safety = 1.5

Final Torque = T * FOS(Factor Of safety)

Final Torque = 0.72 * 1.5

Final Torque = 1.08 Kg-cm

We required DC Motor Of 150 RPM @ 12V for torque about 1.08 kg-cm.

∴ No. Of DC Geared Motors Required : 2.

3) Battery Sizing :

SL No.	Components	Quantity	Voltage Required	Current Drawn
1.	PIR Sensor	1	5 V	40mA
2.	SG 90 Servo Motor	2	5 V	1400 mA
3.	DC Geared Motor	2	5 V	40 mA
4.	Arduino Mega 2560	1	5 V	100 mA

So, for 12 V Current Drawn(C1) = 600 mA So, for 5 V Current Drawn(C2) = 1400+40+100+80 = 1620 mA

Now Considering Factor Of Safety i.e., FOS = 1.2

C1 = 600 * 1.2

C1 = 720 mA = 0.720 A

C2 = 1620 * 1.2

C2 = 1944 mA = 1.944 A

For Time(T) = 3 Hrs For 12 V

Battery Required : 0.720 * 3 = 2.16 Ah. For 5 V

Battery Required : 1.944 * 3 = 5.832 Ah.