ikin (with iteration threshold)

This function returns the joint position corresponding to the target TCP position (fSourcePos) while allowing the user to specify iteration thresholds for the IK solver. This extended version provides finer control over the numerical convergence behavior compared to the standard ikin() function.

Definition
DRFLEx.h within class CDRFLEx, public section

LPINVERSE_KINEMATIC_RESPONSE ikin(
    float fSourcePos[NUM_TASK],
    unsigned char iSolutionSpace,
    COORDINATE_SYSTEM eTargetRef,
    float fIterThreshold[NUMBER_OF_ITER_THRESHOULD]
) {
    return _ikin_add_iter_threshold(_rbtCtrl, fSourcePos, iSolutionSpace, eTargetRef, fIterThreshold);
};

Parameter

Parameter Name	Data Type	Default Value	Description
fSourcePos	float[6]		Target TCP position (x, y, z, Rx, Ry, Rz) in task space.
iSolutionSpace	unsigned char		Solution space index (0-7), or 255 to let the controller choose the reachable solution. Selects one of eight inverse-kinematics configurations.
eTargetRef	COORDINATE_SYSTEM		Reference coordinate system for the TCP pose.
fIterThreshold	float[NUMBER_OF_ITER_THRESHOULD]		Iteration threshold values used in the IK solver to define convergence precision or tolerance for each joint dimension. NUMBER_OF_ITER_THRESHOULD = 2

Return

Value	Description
LPINVERSE_KINEMATIC_RESPONSE	Extended inverse-kinematics response structure containing the calculated joint positions and solver convergence information.

Note

This call waits for the controller to answer.

Example

float tcp_target[6] = { 400.0f, 500.0f, 600.0f, 90.0f, 0.0f, 180.0f };

// Iteration threshold for IK solver
// NUMBER_OF_ITER_THRESHOULD = 2
float iter_th[NUMBER_OF_ITER_THRESHOULD] = { 0.01f, 0.001f };

LPINVERSE_KINEMATIC_RESPONSE result =
    drfl.ikin(tcp_target, 2, COORDINATE_SYSTEM_BASE, iter_th);

if (result && result->_iStatus == 0)
{
    float q[6] = {0};
    for (int i = 0; i < 6; ++i)
        q[i] = result->_fTargetPos[i];

    drfl.movej(q, 60, 30);
}

In this example, the function calculates an inverse kinematics solution with a tighter iteration threshold, improving solver precision when working with high-accuracy motion requirements or sensitive tasks such as calibration or assembly.