Efficient interference-free inspection path planning for impeller blades based on non-vertical on-machine measurement

Abstract On-machine measurement (OMM) has emerged as a critical technology for in situ monitoring and machining error identification in impeller blade manufacturing. Non-vertical OMM offers significant advantages by further reducing probe posture adjustment frequency and enhancing inspection efficiency. However, the complex impeller structure and non-vertical OMM process result in highly time-consuming path planning. To address this issue, an efficient interference-free inspection path planning strategy is proposed in this paper. Firstly, the probe posture is discretized. And its feasibility is represented by a feasible matrix of probe posture ( FMPP ). To reduce the number of interference checks, the ranges of approaching direction and probe posture are constrained by physical limitations and machine workspace. Considering the similarity of adjacent FMPP , a fast calculation algorithm is developed by iteratively calculating the feasibility of boundary pixels based on the known FMPP . To avoid calculating FMPP s of all inspection points, measurable regions of each probe posture are established by FMPP s of a small number of uniformly distributed sampling points. Thus, feasible probe postures for any inspection point can be rapidly determined by identifying which probe posture’s measurable region contains it. Finally, the feasible region’s center pixel of the feasible matrix of approaching direction is selected as the optimal approaching direction. Compared to the exhaustive calculation method, the proposed strategy achieves a 95.0% reduction in path planning time. The feasibility is verified by the impeller blade OMM experiment.