C²-Continuous Orientation Planning for Robot End-Effector with B-Spline Curve Based on Logarithmic Quaternion

Table 1

Initial information of the four key orientations.

No.	Quaternion Qi	Rotation angle θi	Rotation axis ni
1	[0.866, 0, 0, 0.500]	π/3	(0, 0, 1)
2	[0.924, 0, 0.383, 0]	π/4	(0, 1, 0)
3	[0.707, 0.707, 0, 0]	π/2	(1, 0, 0)
4	[0.707, 0.211, 0.422, 0.527]	π/2	(0.298, 0.596, 0.745)