Need help in designing cylindrical robot arm

[kennykck]

I'm currently designing the mechanism for a basic cylindrical robot arm. It must be capable of lifting max 2kg of item. The robot arm looks like ST Robotic R19 model. It moves in X and Z direction plus rotation at base and arm. The robot should looks like the attachment below. Can u please suggest some of the mechanism that is suitable for my project. Thank you very much.

 

[Danger]

Welcome to PF, Kenny.
There are a lot of different mechanisms available, from pneumatics through to complex gear trains to chain drives and screwjacks. I'm not entirely clear about how you want it to move. The 'Z' displacement, for instance—does it pivot up or climb up the support column? A more complete description would be helpful. Even the size, although I can give it a good guess from the picture and the lifting requirement, is a bit vague. That will help determine what sort of machinery can meet your needs.

 

[kennykck]

I prefer to use gearing(ex:- rack and pinion) or belt system(ex:- timing belt to pull the arm up) for my robotic mechanism. The robot must be able to move displacement of 1 meter at x znd z direction. So the robot is around 1m ++ height and 1m ++ tall. And it must be able to support 2kg item at the end tip of the fully extended arm. The speed of the movement does not really matters in my design. I hope my description here can help u to identify the mechanism suitable for my robot arm.

 

[ank_gl]

have you thought of screw jacks or lead screws or feed screws(as used in lathes). they can be used for linear displacement

 

[Danger]

Hmmm... this thing is about twice as big as I'd estimated. Since you've declared your preference for gears and belts, which are both very serviceable approaches, your question then would be a matter of how to implement the design. Since Ank and I both suggested screwjacks, you might consider that as a good option. It's still technically 'gearing', since it's essentially a linear worm-and-roller train. Outside of hydraulics, it's my personal favourite where a lot of force is needed in a small package. Also, like hydraulics, the movement is non-reversible by the load; once you stop the drive motor, that thing is locked in position. With regular gears, chains, pulleys, belts, etc., you have to either maintain input power or build in an auxilliary locking device. It's particularly effective for situations like yours where the load is held at the end of a significant lever-arm. If it matters, it's also very smooth and quiet.