Hi Panyixiao
Yesterday my friend and I found a way to identify the configuration 'UP/DOWN' based on the joint values.
From our test we found that whenever the sum of J2 and J3 axis value is in the range of -80 to 80, then the configuration is always 'UP' and if the result is out of this range then its always 'Down' config.
For example if J2=-30 and J3= 100, then J2+J3 = 70 which is in the range of -80 to 80, so the configuration will be 'UP'.
We tested and confirmed this practically on a R2000ib robot manipulator and I'm sure the same relationship holds good for any mate robots also.
Today I will work on Top/bottom and if I find any relationship then I'll let know.
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