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Drop select guess variables from the KinematicsSolver object


removeInitialGuessVariables(ks,ids) drops from the KinematicsSolver object ks the guess variables named in ids. Guess variables provide a starting point for the solution of a kinematic problem and serve to bias the solver toward one of equally plausible alternatives when several exist. Use this function to remove just one or a few guess variables if they become obsolete.

The output is an updated table with the guess variables—those that remain—in rows. Each row gives the ID of a variable, the type and block path of the joint to which it belongs if a joint variable, the base and follower frames from which it spawns if a frame variable, and the unit for its numerical value. The variables rank in the order added.

Most variables can be assigned individually. A few must be assigned in groups—axis components alongside rotation angle in spherical primitives; bend angle alongside azimuth angle in constant-velocity primitives. (A bend angle can be assigned individually but the azimuth angle cannot.)

Input Arguments

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Kinematics solver object, specified as a KinematicsSolver object that is the representation of the Simscape Multibody model used for kinematic analysis.

Example: ks = simscape.multibody.KinematicsSolver('sm_double_pendulum')

Identifiers of the kinematic variables, specified as either a cell array of characters or string vector. The cell array of character and string vector can be 1-by-N or N-by-1, where N is a positive integer. Use the jointPositionVariables or jointVelocityVariables object function to show the IDs for joint variables. Use the frameVariables object function to show the IDs for frame variables.

Example: "j1.Rz.q", ["j1.Rz.q", "j2.Rz.q"], {'j1.Rz.q'}, or {'j1.Rz.q'; 'j2.Rz.q'};

Version History

Introduced in R2019a