Update ur5 kinematics #5
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rafaelsqueiroz
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src/ur5_simulation/ur5_kinematics.py
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| return self._teta4 | ||
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| def calculate_inverse_kinematics(self, tf, shoulder='left', wrist='up', elbow='up', short=True): |
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How do I know where is shoulder, wrist and elbow in the moment of inverse kinematics? They always will be in this position left, up and up respectively?
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These are geometric factors that depend on how the robot was modeled. For the way the DH matrix was set, the sequence will always be left, up, up. If the user inputs shoulder='right', for example, the links length and orientation need to be reassessed. Same is valid for elbow and wrist.
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I have studied the Spong Book to understand better this "problem" and the position of components doesn't depend on how the arm was modeled but how is the configuration to the arm end-effector reaches some pose. If you have Spong book first edition, see figures 3.17, 3.18, and 3.20. But anyway, I'm not sure that all positions chosen to validate the kinematics methods are with the arm configuration shoulder = left and elbow = up. But I think wrist varies between up and down. Please, see the pictures in our document to see the end effector poses which we are using.
Changed the name of some functions and add some methods to calculate the inverse kinematics of the UR5, given a homogeneous transformation matrix (tf)