Fall 2015 MicroBiped Servo

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MICROSERVO TRADE-OFF

By Michael Balagtas (Manufacturing Engineer)
Approved by Paul Oo (Project Manager)
Approved by Railly Mateo (Systems Engineer)

servoImage provided by Banggood.com

Servo

Price (unit)

Torque

Speed

Weight

Dimensions

MG90S

$4.35

4.8V = 1.8kg/cm 6.0V = 2.2kg/cm

4.8V = 0.10sec/60deg  6.0V = 0.08sec/60deg

13.4 g

22.8 x 12.2 x 28.5mm

MG92B

$7.00

4.8V = 3.1kg/cm 6.0V = 3.5kg/cm

4.8V = 0.15sec/60deg 6.0V = 0.11sec/60deg

13.8 g

22.0 x 12.0 x 31.0mm

SG90

$4.31

4.8V = 1.0kg/cm

4.8V = 0.12sec/60deg

9.0 g

22.0 x 11.5 x 22.5mm

The table above compares 3 possible servos to use for the µBiPed project. The chart compares torque, speed, weight, rotation, and price.

    1. Torque is important because if the servos do not have enough torque the µBiPed will not move.
      • Heavier servos means larger batteries.
      • Slower servos means larger batteries due to a larger operation time to complete the course.
    2. Speed and weight are important for the sizing of batteries.
    3. Rotation of 180 degrees is needed to complete the required range of motion.
    4. Pricing is a desired to lower the cost of the total budget.

After comparing the servos, the group decided on using MG92B for the purpose of having a higher torque rating.

    1. Although MG90S and SG90 have less weight and lower cost than MG90S, they don’t have as much torque to move the µBiPed. 
    2. The MG92B is also a U.S. products and thus can be delivered much faster than other servos not listed in the chart.