Method of finding feasible joint trajectories for an n-dof robot with rotation invariant process (n>5)

A computer-implemented method for determining feasible joint trajectories for an n-dof (n>5) robot in a rotation invariant processing of an object, said method comprising the steps:

• receiving geometric data representing the object;
• receiving geometric data representing the processing tool;
• receiving a tool path X(t), where t is time;
• searching for feasible paths qRobot (t) using IK (t) and qTool (t) as set of possible solutions at time t, wherein qRobot (t) defines positions of all the joints in the robot as function of time, qTool (t) defines the rotation of a tool flange around the tool axis at time t, and IK (t) defines the inverse kinematics solutions for a given X(t) and qTool (t), said qTool runs from 0 to 360 degrees;
• determining, from the geometric data and X(t), how the joint path qRobot (t) should be chosen so as to comply with one or more optimisation criteria;
• and
• determining how qTool (t) can be controlled in order to meet a plurality of the optimisation criteria;
• wherein the searching for feasible paths is performed globally in time, discretizing the time interval of the complete path into t1<t2. . . <tN−1<tN.