RV-4AJL-S311 5-axis Robot rebuild project

[sement]

Hi there!

I am completely new to Robots and robot programming so I realize this is a very difficult hobby for me to pick up

I want to use an old Robot arm as a stop motion/live motion camera rig. I had originally thought I would create something similar to this:

http://sites.google.com/site/srdjancrnjanski/hardwareprojects

I find it quite daunting to start with something so complex so I started looking around for used robots and found a very cheap RV-4AJL-S311 5-axis Robot. My idea is to be able to control it directly and just use the arm as a hardware base to build upon. Rewiring the servos to a more open software based system where I can control it like I want to. Is there anything in Mitsubishi robots that would make this difficult? Also Is there a "raw" serial communications protocol where I can just stream movements directly to each servo so I dont need to rewire?


RV-4AJL-S311 5-axis Robot
http://www.rixan.com/Products2/tabid/64/CategoryID/3/Category2ID/17/List/1/Level/2/ProductID/31/Default.aspx?SortField=DateCreated%2CDateCreated+DESC



Best Regards

Ludvig Friberg

[Werner Hampel]

the Robotcontroller from Mitsubishi is perfekt, so why do you want it to rebuild ? 

Just send to the Controller your needs like Positiondata and the Robot will do 

[sement]

Thanks for the swift reply Werner!

As I said before I am a total beginner in this field so really thanks for bearing with my ignorance an wild ideas!

The reason why I started thinking about rebuilding it that I thought my application is different than most robot programming. To me it is most interesting to tell the robot where to be 24 or more times per second. I am not going from point A to B, instead its all about the movement, acceleration and deacceleration. I was under the impression, hopefully wrongly that this would be difficult with the usual programming tools. If I can plot a 3dimensional path through time with unlimited waypoints or Bezier functions for both spatial and temporal for the toolhead and let the controller deal with the InverseKinematics that would be perfect. Also I wanted to resarch ways to control it directly with analogue controls so I can "fly" with it smoothly and record its movements and then play them back.

reference
http://www.redpinestudios.com/cmocos.html

Best regards

Ludvig Friberg

[Werner Hampel]

24 Positions per Second ?

this might be impossible for an Robot 

[sement]

I probably dont make a lot of sense using the wrong words.

I will try to explain it more detailed. What I want is for the camera robot to move the camera head along a predefined 3D bezier path with specific timing. Moving slower and faster at different parts along this path. The way I see it there is only three ways I can do this.

1. If the Robot can be fed the bezier path and timing keyframes as to where it should be along the path and follow my predefined smoothing interpolation on those keyframes. Then I could upload that data to the controller and the controller takes care of both interpolation of smoothing and the InverseKinematics.

2 I Create the movement in a simulation( probably 3ds max or Maya) the position of the head in XYZ on that path at any given time in whatever frequency fits best with the robot is written to an ASCII file. This file is fed to the controller and the controler works out the InverseKinematics

3. I Create the movement in a simulation( probably 3ds max or Maya) and write out all the positions on all the servos at any given time in whatever frequency fits best with the robot in a ASCII file. This file then either is being read by the Mitsubishi controller or by my homebuilt controller and tells the servos what to do.

Here is a small example of what I want to accomplish, what I try to show here is the predefined path and the smooth acceleration and deacceleration.
<a href="http://vimeo.com/moogaloop.swf?clip_id=9493909&amp;server=vimeo.com&amp;fullscreen=1&amp;show_title=1&amp;show_byline=1&amp;show_portrait=0&amp;color=01AAEA" target="_blank">http://vimeo.com/moogaloop.swf?clip_id=9493909&amp;server=vimeo.com&amp;fullscreen=1&amp;show_title=1&amp;show_byline=1&amp;show_portrait=0&amp;color=01AAEA</a>
Would this be possible with the standard Mitsubishi controller or with maybe a special realtime control software to run on a computer is that what WINE can do?

Again, thanks a lot for your valuable insight.

Best Regards

Ludvig Friberg

[Werner Hampel]

well, a big Project, but at least possible, i think.

You will need to read a lot of Documentations to solve all your Problems.

I think Point 2 is your solution.

[sement]

Yes I will start in august and hopefully I will have something working after a year. I realize that I am trying to do something these controllers wasnt really ment to do. Do you think it matters what brand of robot I choose? Are the smaller motoman, fanuc etc. easier or harder to progam? Just out of interest, how does a cnc machine store all the movements of a program? That must be a lot of data on a complex shape. Maybe an avenue for me to explore?

Best regards and thanks!

[Werner Hampel]

well, for that what you want, Mitsubishi is perfect, not every Robot can do this.
But which Controller do you have ? The older Controllers can not do this ;)

[sement]

I dont have any controller yet, or a robot for that matter. which is the latest controller/robot I should look for?

Ludvig

[Werner Hampel]

For Mitsubishi look for a CR2B or higher Controller with Networkcard.

[sement]

CR2D has 13000 max position points per program, does that really mean that I can define 13000 points in 3d space for the tool head? If I sample 24 times per second that is still more than 8 minutes! More than I will ever use. Most moves will be 1 minute. So that sounds good.

Is the CR2B similar in specs I tried finding specs but didnt find anything?