Generate overload JntToJac function in ChainJntToJacSolver Class to return Jacobians for all segments#492
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… jacobians JntToJac(const JntArray& q_in, Jacobian& jac, int seg_nr) in ChainJntToJacSolver Class only returns the Jacobian for the specified input segment. Because this function internally calculates all of the Jacobians leading up to seg_nr, the modified JntToJac() returns all of the intermediate Jacobians by encapsulating them in a std vector <Jacobian>. Note that this is analogous to overloaded function JntToCart() in the ChainFkSolverPos_recursive Class which returns Cartesian frames for all of the intermediate segments in std::vector<Frame>.
… jacs Unit test 'JacAllSegments()' was added to solvertest.cpp for the new jnttojac() function that returns the Jacobians for all of the segments. It uses the (current) JntToJac function to test the return value of the Jacobian for each individual segment. Note that the index starts at 0 so that segment N has the index N-1 in the Jacobian vector.
MatthijsBurgh
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Jul 24, 2025
This adds the description for the new array of Jacobian outputs.
removed white space Co-authored-by: Matthijs van der Burgh <matthijs.vander.burgh@live.nl>
Jacobians generally have 6 rows corresponding to the 6 Cartesian degrees of freedom, but this makes it explicit that the indexing is based on the number of rows of the Jacobian.
MatthijsBurgh
requested changes
Aug 5, 2025
formatting change only Co-authored-by: Matthijs van der Burgh <matthijs.vander.burgh@live.nl>
formatting change only Co-authored-by: Matthijs van der Burgh <matthijs.vander.burgh@live.nl>
Added member function to output array of Jacobians
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JntToJac() in the ChainJntToJacSolver Class only returns the Jacobian for the specified input segment seg_nr. Some inverse kinematics algorithms require Jacobians for multiple segments in a chain such as those used for commanding self-motion. Because JntToJac already calculates all of the Jacobians leading up to seg_nr, it does not cost anything computationally to return the intermediate Jacobians. The modified JntToJac() returns Jacobians for all of the segments by encapsulating them in a std vector . Note that this is analogous to overloaded function JntToCart() in the ChainFkSolverPos_recursive Class which returns Cartesian frames for all of the intermediate segments in std::vector. JntToJac() follows JntToCart() as a model to generate the same functionality.