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misan / dcservo

Position control of DC motors
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Question: Servo logic vs H-Bridge? #62

Closed cbpdk closed 5 years ago

cbpdk commented 5 years ago

I have a continious rotating MG395 servo connected to a Freescale 100 slot disc and optical quadrature encoder module. A near destructive hw mod rotating the optical encoder module 90 degrees was needed before it acted as a quadrature encoder. Using the encoder gives a resolution of 360/400 = 0.9 degrees.

The MG395 only contains a servo control board.

The specs say it moves 60 degrees in 180 ms without load. However, the servo has a deadband around the 90 degrees signal, approx. +/- 15 degrees.

For tests I am using an Uno and a sketch based on a modified verion of dcservo_magencoder_servo360_MKR1000.ino

This to quickly adjust PID parameters and view the position errors using a serial connection.

Is there any advantage replacing the servo logic board with a h-bridge(like TB6612FNG) with regard to position precision?

misan commented 5 years ago

I do not think so.

El jue., 25 jul. 2019 8:19, cbpdk notifications@github.com escribió:

I have a continious rotating MG395 servo connected to a Freescale 100 slot disc and optical quadrature encoder module. A near destructive hw mod rotating the optical encoder module 90 degrees was needed before it acted as a quadrature encoder. Using the encoder gives a resolution of 360/400 = 0.9 degrees.

The MG395 only contains a servo control board.

The specs say it moves 60 degrees in 180 ms without load. However, the servo has a deadband around the 90 degrees signal, approx. +/- 15 degrees.

For tests I am using an Uno and a sketch based on a modified verion of dcservo_magencoder_servo360_MKR1000.ino

This to quickly adjust PID parameters and view the position errors using a serial connection.

Is there any advantage replacing the servo logic board with a h-bridge(like TB6612FNG) with regard to position precision?

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cbpdk commented 5 years ago

Thank you very much, saves me for the trouble of testing to no avail.