#include <chainiksolvervel_wdls.hpp>
Public Member Functions | |
| virtual int | CartToJnt (const JntArray &q_in, const Twist &v_in, JntArray &qdot_out) |
| virtual int | CartToJnt (const JntArray &, const FrameVel &, JntArrayVel &) |
| ChainIkSolverVel_wdls (const Chain &chain, double eps=0.00001, int maxiter=150) | |
| double | getEps () const |
| double | getLambda () const |
| double | getLambdaScaled () const |
| unsigned int | getNrZeroSigmas () const |
| int | getSigma (Eigen::VectorXd &Sout) |
| double | getSigmaMin () const |
| int | getSVDResult () const |
| void | setEps (const double eps_in) |
| void | setLambda (const double lambda) |
| void | setMaxIter (const int maxiter_in) |
| int | setWeightJS (const Eigen::MatrixXd &Mq) |
| int | setWeightTS (const Eigen::MatrixXd &Mx) |
| virtual const char * | strError (const int error) const |
| virtual void | updateInternalDataStructures () |
| ~ChainIkSolverVel_wdls () | |
 Public Member Functions inherited from KDL::ChainIkSolverVel | |
| virtual | ~ChainIkSolverVel () |
| Public Member Functions inherited from KDL::SolverI | |
| virtual int | getError () const |
| Return the latest error. More... | |
| SolverI () | |
| Initialize latest error to E_NOERROR. More... | |
| virtual | ~SolverI () |
Static Public Attributes | |
| static const int | E_CONVERGE_PINV_SINGULAR = +100 |
| solution converged but (pseudo)inverse is singular More... | |
Private Attributes | |
| const Chain & | chain |
| double | eps |
| Jacobian | jac |
| ChainJntToJacSolver | jnt2jac |
| double | lambda |
| double | lambda_scaled |
| int | maxiter |
| unsigned int | nj |
| unsigned int | nrZeroSigmas |
| Eigen::VectorXd | S |
| double | sigmaMin |
| int | svdResult |
| Eigen::VectorXd | tmp |
| Eigen::MatrixXd | tmp_jac |
| Eigen::MatrixXd | tmp_jac_weight1 |
| Eigen::MatrixXd | tmp_jac_weight2 |
| Eigen::MatrixXd | tmp_js |
| Eigen::MatrixXd | tmp_ts |
| Eigen::MatrixXd | U |
| Eigen::MatrixXd | V |
| Eigen::MatrixXd | weight_js |
| Eigen::MatrixXd | weight_ts |
Additional Inherited Members | |
| Public Types inherited from KDL::SolverI | |
| enum | { E_DEGRADED = +1, E_NOERROR = 0, E_NO_CONVERGE = -1, E_UNDEFINED = -2, E_NOT_UP_TO_DATE = -3, E_SIZE_MISMATCH = -4, E_MAX_ITERATIONS_EXCEEDED = -5, E_OUT_OF_RANGE = -6, E_NOT_IMPLEMENTED = -7, E_SVD_FAILED = -8 } |
| Protected Attributes inherited from KDL::SolverI | |
| int | error |
| Latest error, initialized to E_NOERROR in constructor. More... | |
Detailed Description
Implementation of a inverse velocity kinematics algorithm based on the weighted pseudo inverse with damped least-square to calculate the velocity transformation from Cartesian to joint space of a general KDL::Chain. It uses a svd-calculation based on householders rotations.
J# = M_q*Vb*pinv_dls(Db)*Ub'*M_x
where B = Mx*J*Mq
and B = Ub*Db*Vb' is the SVD decomposition of B
Mq and Mx represent, respectively, the joint-space and task-space weighting matrices. Please refer to the documentation of setWeightJS(const Eigen::MatrixXd& Mq) and setWeightTS(const Eigen::MatrixXd& Mx) for details on the effects of these matrices.
For more details on Weighted Pseudo Inverse, see : 1) [Ben Israel 03] A. Ben Israel & T.N.E. Greville. Generalized Inverses : Theory and Applications, second edition. Springer, 2003. ISBN 0-387-00293-6.
2) [Doty 93] K. L. Doty, C. Melchiorri & C. Boniveto. A theory of generalized inverses applied to Robotics. The International Journal of Robotics Research, vol. 12, no. 1, pages 1-19, february 1993.
Definition at line 63 of file chainiksolvervel_wdls.hpp.
Constructor & Destructor Documentation
◆ ChainIkSolverVel_wdls()
|
explicit |
Constructor of the solver
- Parameters
-
chain the chain to calculate the inverse velocity kinematics for eps if a singular value is below this value, its inverse is set to zero, default: 0.00001 maxiter maximum iterations for the svd calculation, default: 150
Definition at line 28 of file chainiksolvervel_wdls.cpp.
◆ ~ChainIkSolverVel_wdls()
| KDL::ChainIkSolverVel_wdls::~ChainIkSolverVel_wdls | ( | ) |
Definition at line 72 of file chainiksolvervel_wdls.cpp.
Member Function Documentation
◆ CartToJnt() [1/2]
|
virtual |
Find an output joint velocity qdot_out, given a starting joint pose q_init and a desired cartesian velocity v_in
- Returns
- E_NOERROR=svd solution converged in maxiter E_SVD_FAILED=svd solution failed E_CONVERGE_PINV_SINGULAR=svd solution converged but (pseudo)inverse singular
- Note
- if E_CONVERGE_PINV_SINGULAR returned then converged and can continue motion, but have degraded solution
- If E_SVD_FAILED returned, then getSvdResult() returns the error code from the SVD algorithm.
Implements KDL::ChainIkSolverVel.
Definition at line 116 of file chainiksolvervel_wdls.cpp.
◆ CartToJnt() [2/2]
|
inlinevirtual |
not (yet) implemented.
Implements KDL::ChainIkSolverVel.
Definition at line 105 of file chainiksolvervel_wdls.hpp.
◆ getEps()
|
inline |
Request the value of eps
Definition at line 193 of file chainiksolvervel_wdls.hpp.
◆ getLambda()
|
inline |
Request the value of lambda for the minimum
Definition at line 198 of file chainiksolvervel_wdls.hpp.
◆ getLambdaScaled()
|
inline |
Request the scaled value of lambda for the minimum singular value 1-6
Definition at line 204 of file chainiksolvervel_wdls.hpp.
◆ getNrZeroSigmas()
|
inline |
Request the number of singular values of the jacobian that are < eps; if the number of near zero singular values is > jac.col()-jac.row(), then the jacobian pseudoinverse is singular
Definition at line 178 of file chainiksolvervel_wdls.hpp.
◆ getSigma()
| int KDL::ChainIkSolverVel_wdls::getSigma | ( | Eigen::VectorXd & | Sout | ) |
Request the six singular values of the Jacobian
Definition at line 108 of file chainiksolvervel_wdls.cpp.
◆ getSigmaMin()
|
inline |
Request the minimum of the first six singular values
Definition at line 183 of file chainiksolvervel_wdls.hpp.
◆ getSVDResult()
|
inline |
Retrieve the latest return code from the SVD algorithm
- Returns
- 0 if CartToJnt() not yet called, otherwise latest SVD result code.
Definition at line 210 of file chainiksolvervel_wdls.hpp.
◆ setEps()
| void KDL::ChainIkSolverVel_wdls::setEps | ( | const double | eps_in | ) |
Set eps
Definition at line 98 of file chainiksolvervel_wdls.cpp.
◆ setLambda()
| void KDL::ChainIkSolverVel_wdls::setLambda | ( | const double | lambda | ) |
Set lambda
Definition at line 93 of file chainiksolvervel_wdls.cpp.
◆ setMaxIter()
| void KDL::ChainIkSolverVel_wdls::setMaxIter | ( | const int | maxiter_in | ) |
Set maxIter
Definition at line 103 of file chainiksolvervel_wdls.cpp.
◆ setWeightJS()
| int KDL::ChainIkSolverVel_wdls::setWeightJS | ( | const Eigen::MatrixXd & | Mq | ) |
Set the joint space weighting matrix
- Parameters
-
weight_js joint space weighting symmetric matrix, default : identity. M_q : This matrix being used as a weight for the norm of the joint space speed it HAS TO BE symmetric and positive definite. We can actually deal with matrices containing a symmetric and positive definite block and 0s otherwise. Taking a diagonal matrix as an example, a 0 on the diagonal means that the corresponding joints will not contribute to the motion of the system. On the other hand, the bigger the value, the most the corresponding joint will contribute to the overall motion. The obtained solution q_dot will actually minimize the weighted norm sqrt(q_dot'*(M_q^-2)*q_dot). In the special case we deal with, it does not make sense to invert M_q but what is important is the physical meaning of all this : a joint that has a zero weight in M_q will not contribute to the motion of the system and this is equivalent to saying that it gets an infinite weight in the norm computation. For more detailed explanation : vincent.padois@upmc.fr
- Returns
- success/error code
Definition at line 76 of file chainiksolvervel_wdls.cpp.
◆ setWeightTS()
| int KDL::ChainIkSolverVel_wdls::setWeightTS | ( | const Eigen::MatrixXd & | Mx | ) |
Set the task space weighting matrix
- Parameters
-
weight_ts task space weighting symmetric matrix, default: identity M_x : This matrix being used as a weight for the norm of the error (in terms of task space speed) it HAS TO BE symmetric and positive definite. We can actually deal with matrices containing a symmetric and positive definite block and 0s otherwise. Taking a diagonal matrix as an example, a 0 on the diagonal means that the corresponding task coordinate will not be taken into account (ie the corresponding error can be really big). If the rank of the jacobian is equal to the number of task space coordinates which do not have a 0 weight in M_x, the weighting will actually not impact the results (ie there is an exact solution to the velocity inverse kinematics problem). In cases without an exact solution, the bigger the value, the most the corresponding task coordinate will be taken into account (ie the more the corresponding error will be reduced). The obtained solution will minimize the weighted norm sqrt(|x_dot-Jq_dot|'*(M_x^2)*|x_dot-Jq_dot|). For more detailed explanation : vincent.padois@upmc.fr
- Returns
- success/error code
Definition at line 86 of file chainiksolvervel_wdls.cpp.
◆ strError()
|
virtual |
Return a description of the latest error
- Returns
- if error is known then a description of error, otherwise "UNKNOWN ERROR"
Reimplemented from KDL::SolverI.
Definition at line 218 of file chainiksolvervel_wdls.cpp.
◆ updateInternalDataStructures()
|
virtual |
Update the internal data structures. This is required if the number of segments or number of joints of a chain/tree have changed. This provides a single point of contact for solver memory allocations.
Implements KDL::ChainIkSolverVel.
Definition at line 54 of file chainiksolvervel_wdls.cpp.
Member Data Documentation
◆ chain
|
private |
Definition at line 219 of file chainiksolvervel_wdls.hpp.
◆ E_CONVERGE_PINV_SINGULAR
|
static |
solution converged but (pseudo)inverse is singular
Definition at line 67 of file chainiksolvervel_wdls.hpp.
◆ eps
|
private |
Definition at line 226 of file chainiksolvervel_wdls.hpp.
◆ jac
|
private |
Definition at line 222 of file chainiksolvervel_wdls.hpp.
◆ jnt2jac
|
private |
Definition at line 220 of file chainiksolvervel_wdls.hpp.
◆ lambda
|
private |
Definition at line 236 of file chainiksolvervel_wdls.hpp.
◆ lambda_scaled
|
private |
Definition at line 237 of file chainiksolvervel_wdls.hpp.
◆ maxiter
|
private |
Definition at line 227 of file chainiksolvervel_wdls.hpp.
◆ nj
|
private |
Definition at line 221 of file chainiksolvervel_wdls.hpp.
◆ nrZeroSigmas
|
private |
Definition at line 238 of file chainiksolvervel_wdls.hpp.
◆ S
|
private |
Definition at line 224 of file chainiksolvervel_wdls.hpp.
◆ sigmaMin
|
private |
Definition at line 240 of file chainiksolvervel_wdls.hpp.
◆ svdResult
|
private |
Definition at line 239 of file chainiksolvervel_wdls.hpp.
◆ tmp
|
private |
Definition at line 228 of file chainiksolvervel_wdls.hpp.
◆ tmp_jac
|
private |
Definition at line 229 of file chainiksolvervel_wdls.hpp.
◆ tmp_jac_weight1
|
private |
Definition at line 230 of file chainiksolvervel_wdls.hpp.
◆ tmp_jac_weight2
|
private |
Definition at line 231 of file chainiksolvervel_wdls.hpp.
◆ tmp_js
|
private |
Definition at line 233 of file chainiksolvervel_wdls.hpp.
◆ tmp_ts
|
private |
Definition at line 232 of file chainiksolvervel_wdls.hpp.
◆ U
|
private |
Definition at line 223 of file chainiksolvervel_wdls.hpp.
◆ V
|
private |
Definition at line 225 of file chainiksolvervel_wdls.hpp.
◆ weight_js
|
private |
Definition at line 235 of file chainiksolvervel_wdls.hpp.
◆ weight_ts
|
private |
Definition at line 234 of file chainiksolvervel_wdls.hpp.
The documentation for this class was generated from the following files: