Efficient construction of an interference-free region and tool orientation planning for the robotic grinding of blisks

For robotic grinding of blisks, the tool and workpiece easily interfere with each other in the grinding process, which results in severe damage to the tool and workpiece. Therefore, interference-free tool orientation planning is a core issue of robotic grinding. Currently, most interference detection techniques are based on the discretization of geometric elements, but the surface discretization accuracy and computational efficiency conflict with each other, which results in low calculation efficiency to realize acceptable accuracy. In this paper, with the aim of addressing the interference problem in the grinding of complex components, an algorithm is developed for the efficient construction of an interference-free region and tool orientation planning in robotic grinding. First, the critical points on the edge of the checking surface are solved by the quadratic Newton-Raphson method. Then, the special critical point of the edge is taken as the search starting point on the checking surface, and the equal step and variable scale methods are combined to search the remaining critical points. The obtained critical points are sorted to construct the closed interference-free region. To improve the quality of the machining surface and material removal accuracy, the grinding tool orientations are generated with the target of optimal conformity between the tool and machining surface in the interference-free region. Robotic grinding experiments on the blade integrated disk reveal that the developed method can effectively avoid interference in the robotic grinding process, the material removal accuracy of the processed workpiece profile is improved by 44.2 %, and the surface roughness is reduced by 61.1 %.