Why is my robot arm jerking during motion?

[GPP]

Dear Friends,
I have designed a robotic arm driven by servo motor via a planetary gear box.I have used taper roller bearing & deep groove bearing to hold the driven shaft.The distance between two bearings is 10 mm .We I turn ON the motor, the motion of arm is jerky.Also, I've used lamina coupling to couple the drive shaft.
The rpm of rotation is very very slow.Some say this may be due to unbalanced load or may be due to less distance between two bearings & improper pre-loading of bearings.

I've also fine tuned the motor.

Please can anyone help me to resolve this problem

 

[StevieTNZ]

Hi GPP

Welcome to PF!

This area of the forum is for introductions about yourself. Please pose your question in the appropriate homework forum if it is homework or course-related. Thanks!

- Stevie

 

[GPP]

Oh sorry about that.
Hi Everyone,
I would like to introduce myself as a mechanical engineer. Presently working as a design engineer in welding automation field.
Wish we would have great time .