CalcJointT

avicohen

Hi,<?: prefix = o ns = "urn:schemas-microsoft-com:office:office" />

I use CalcJointT to
check if a Cartesian point is Reachable, and if yes, to keep its equivalent
joints values.

I have a problem
that sometime I get error (ERR_ROBLIMIT) when I use it.

To investigate
it I took a point in Cartesian value which the robot give ERR_ROBLIMIT

I run a program which
move the robot to that position :

The position was
:

[[273.7763,-297.6656,707.4647],[0.161286955593029,0.145771576665284,-0.0468260793419564,0.974958708707968],[0,1,0,0],[8.999999E+09,8.999999E+09,8.999999E+09,8.999999E+09,8.999999E+09,8.999999E+09]]

 

So now, after running
the program, this point is his current position.

Now if I ask the
robot it current position, I get the same result but with different configuration
: [0,2,0,-1]

If I run CalcJointT with the current position values [0,2,0,-1] I get error. Even if this point is his
current position ?

If I run CalcJointT with (with the values [0,1,0,0]) I get ok.

 

I seem that:

A?        
When the robot ask to move with a specific configuration sometime
it ignore it and use his current configuration.

A?        
The configuration may change the result.

 

Is there a way to run CalcJointT and ask to ignore configuration?

I need to check for a giving path (which
may include 10 -50 robot position) if the robot can move in this path (all the point
in the path are reachable for him) is there a better way to do it ?

Thanks

Avi

John Wiberg

Hi avicohen,

 

From the manual

[quote]The calculation always selects the robot configuration according
to the specified configuration data in the input robtarget data. Instructions ConfL and ConfJ do not affect this
calculation principle. When wrist singularity is used, robot axis 4 will be set
to 0 degrees.[/quote] so no, you can't tell it to ignore configuration. Then check that 0 degrees thing.

 

Also a note on singularities, check out the RAPID reference manual [Data types > confdata - Robot configuration data] or your robot manual. There you have a summary of how those configs are used etc.

 

And yes, since you are creating a JointTarget then the exact positions of the joints, ie configuration, is what you are asking for. So If you send in a [0,1,0,0] configuration then that is the positions of the arm that you are going to get, with the problem that, no the robot won't usually twist 180A? in a single move like that. Especially if you are within the singularity quarter.

 

But how come you are asking RAPID questions in the Developer Center Forum?