Trajectory planning of multi-robot coordination platform for locating large subassembly

In the manufacturing engineering field, a multi-robot coordination platform is often used to adjust a large subassembly's location (including position and orientation). This paper introduces an open spherical joint coupling between the subassembly and every robot manipulator and presents a B-spline interpolation trajectory planning method for the manipulators. The location of the subassembly can be described with an element of the group of spatial displacement in Euclidean space. The trajectory of every manipulator can be obtained through finding a smooth motion of the subassembly and then mapping it to the corresponding axes of every manipulator. Unit quaternion is adopted for describing a given set of orientations, and then a cubic B-spline interpolation method is applied to calculate the position and orientation curves, respectively. Finally, the two curves are fused. This paper proves that all the motion points of the subassembly are continuous in the same order as the B-spline function.