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petercorke / robotics-toolbox-matlab

Robotics Toolbox for MATLAB
GNU Lesser General Public License v2.1
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Panda forward kinematics is WRONG #125

Open fjakob opened 1 year ago

fjakob commented 1 year ago

The forward kinematics of rtb.models.Panda() is wrong. This can be easily verified by comparing the Denavit-Hartenberg values or just looking at the zero configuration:

panda = rtb.models.Panda()
print(panda.fkine(np.zeros(7))

which yiels 

   0.7071    0.7071    0         0.088     
   0.7071   -0.7071    0         0         
   0         0        -1         0.8226    
   0         0         0         1

and not 

   1         0         0         0.088     
   0        -1         0         0         
   0         0        -1         0.926     
   0         0         0         1
Zheng-JIA commented 1 year ago

Not sure if you solved it or not. The difference is because the rtb assumes the panda hand is attached, so an extra 0.104 mm is subtracted from 0.926, and the hand has 45 degrees of offset.