servo drive match in terms of dynamc load (industrial robot )

[3688761]

Hello!
I do not know how to calculate Servo drive for traverse robot. There are 3 axis (as You can see on the pictures bellow) I want them to work with 0.8m/s velocity, the strokes starting from first one - the biggest are: 1200mm, 800mm and vertical - 1000mm. Construction will be based on steel profiles so robot will be heavy - about 180 kilos. How should I match Servo Drive Torque to provide acceleration about 1m/s^2 or better? (i know velocity or carriages so i know also required r/pm for servo drive) I know also moment of inertia of hole mechine according to driving shaft of first motor(when calculating first axis drive). What is the formula for required Torque (taking dynamics under concideration)? Every sugestions from You Guys are more than welcome. Sorry for my Pol-glish and have a good day!

http://files.engineering.com/getfile.aspx?folder=34ca6ebf-b12d-44f9-a776-3b04d0026149&file=Robot.JPG

http://files.engineering.com/getfil...-3f44-4f95-a64d-294ea25bf51a&file=Robot11.JPG

 

[3688761]

its better now:
Hello!
I do not know how to calculate Servo drive for traverse robot. There are 3 axes (as You can see on the pictures bellow) I want them to work with 0.8m/s velocity. The strokes, starting from first one - the biggest - are: 1200mm, 800mm and vertical - 1000mm. Construction will be based on steel profiles so robot will be heavy - about 180 kilos. How should I match Servo Drive Torque to provide acceleration about 1m/s^2 or higher? (I know velocity or carriages so i know also required r/pm for servo drive) I know also Moment of Inertia for a whole mechine according to driving shaft of first motor(when calculating first axis drive). What is the formula for required Torque? (taking dynamics under concideration) Every sugestions from You Guys are more than welcome. Sorry for my Pol-glish and have a good day!
Tomas.

http://files.engineering.com/getfile.aspx?folder=229fb2a7-c3fa-4129-b046-1002610466df&file=Robot.JPG

 

[tygerdawg]

The short answer is: go purchase what you need from Yamaha Robotics.

The long answer is: you must do a full dynamics analysis of your system for all expected motions. Your goal is to identify the Peak Torque for your motors. So you must identify velocity profiles, accelerations of translational & rotational masses, etc etc etc. Once you have Peak Torque, then you can start specifying motors necessary to provide this.

If you need the dynamics equations, my favorite recommendation is to websearch & download "The Smart Motion Cheat Sheet" which summarizes most of the equations.

But if you do this all by yourself, then you run the risk of not providing sufficient torque; having mechanical vibration due to structural issues; accuracy problems because of position feedback issues. A purchased solution has already figured that stuff out and that is why you pay for it.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com

 

[waross]

When you have solved your torque problems you may want to RMS HP load on the motor to assure that your selected motor will not overheat when run at your expected duty cycle.
See the Cowern papers for information on RMS HP loading.

http://baldor.com/support/literature_load.asp?LitNumber=PR2525

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[3688761]

The initial project of my machine is here:

http://www.youtube.com/watch?v=N3GbBgOL2Lc

It will be used to remove molder from injection molding machine.
For this moment I have calculate required power, it is 2,4 kW (~3.22HP) for the first one - biggest drive, basing only at Newtons formula "Force=mass X acceleration" Torque=Force x (pinion diameter)/2. I know mass and required linear acceleration, i multiplayed calculated power by 2 ( a safety factor) and that is how I got 2.4 kw - this is verry initial calculation and i think - a bit naive, but nothing more makes no sens at this stage. At worst, company which will provide a servodrive can calculate it better than me. I will start matching the drives when i will know all masses starting from gripper, vertical actuator, guides(i did not calculate guides yet, i think they could be smaller than in aniamtion)
Now I do not have an exact idea of a third axis - the vertical one (no gripper also, but this is next step) I think that best solution would be belt driven linear module to reduce moving masses. Screw is too slow, something like here:

http://www.youtube.com/watch?v=LXn98AjNuMM&playnext_from=TL&videos=tEv3_UkVSn0

__The question__: How do You think what kind of a linear module is used in vertical direction in movie above. In my animation I innitially applied "funny" LM module with belt (you can see photos bellow)

but now i know that it is not strong enough for this machine - so the vertical axis will be changed. The carriage and motor stays stil, but the beam with gripper is moving in vertical direction, so it is oposite situation to the other 2 axes. does the regular LM actuator with belt can work like this?(beam is moving and carriage not)