Non-uniform material removal in robotic compliant grinding for flexible free-form surfaces

Abstract In a convolution material removal process, taking grinding free-form surfaces as an example, the workpiece’s complex shape may lead to dynamic tool–workpiece contact state, and the curved tool path results in an uneven dwell time distribution. These factors contribute to non-uniform material removal (NMR), causing over-grinding or under-grinding in localized areas. This work aims to model NMR accurately and propose a method to enhance material removal uniformity. First, a dynamic tool–workpiece contact model integrating the workpiece’s complex shape, contact force, and the mechanical properties of the tool and the workpiece is proposed by introducing the measured workpiece point cloud. Second, path geodesic curvature is employed to calculate the dwell time distribution. Third, a material removal model that combines the dynamic tool–workpiece contact and the uneven dwell time distribution is introduced. Then, the tool influence function is optimized by adjusting the tool orientation to improve material removal uniformity. Finally, the proposed material removal model and optimization method are validated through experiments, with results showing a remarkable improvement in material removal uniformity using this approach.