Layered Preparation Method for Cracked Tooth Preparation Robot Based on Iso-MRR Algorithm

Tooth preparation robots have the potential to markedly improve the precision and efficiency of dental procedures, concurrently minimizing human error. Nevertheless, these robotic systems encounter challenges, including excessive grinding forces and chatter during actual tooth preparation, which can result in restoration failures. Drawing inspiration from the practices of clinical dentists, we propose an iso-material removal rate trajectory optimization algorithm to address these issues. The optimization method develop produces a layered preparation trajectory by using the inherent characteristics of the tooth and the desired preparation depth, while also adjusting the feed speed rate to optimize the material removal volume between the tool and the defective tooth. A key contribution of our approach is the establishment of a safe maximum preparation depth for each layer, enabling the creation of a layered preparation trajectory that minimizes force and heat exerted on the tooth, ultimately enhancing preparation efficiency. One additional contribution is the ability to calculate the optimal preparation parameters for the robot by inputting established trajectory parameters and tool outline information, thereby addressing the issue of crack extension due to end chatter. In our experimental setup, a test platform is constructed to facilitate end force control, chatter optimization, and the preparation of cracked teeth. Despite the presence of cracks in the teeth, the optimized trajectory allows for effective collaboration between the robotic arm and dental handpiece in the preparation of hard and brittle cracked teeth.