When solving the kinematics problem for a robot using DH parameters, if there are some passive joints between the actuator and the end effector, do I have to define the axis and transformations of passive joints too just like for active joints?
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2$\begingroup$ Short answer: yes. For a longer answer: Do you have passive joints because you have a parallel structure (Stewart platform, hexapod, tripod) or do you have a serial structure with e.g. passive compliant joints? For parallel structures you might get away with not modelling the joints as DH. For serial structures you should probably model them as DH. $\endgroup$– 50k4Jul 27, 2017 at 9:50
1 Answer
Yes. Geometrically computing the static joint-space coordinates in terms of Cartesian coordinates (for example), it is irrelevant if a joint is active or passive. For non-serial chains, some coordinates may be expressible in terms of others, so may be omitted from the IK calculation and computed by substitution afterward.