A Normal Force Estimation Model for a Robotic Belt-grinding System

Belt grinding is a commonly used finishing process that can reduce defects and burrs created by previous machining procedures. While it has been studied for a long time, researchers have mostly focused on methods that use grinding wheels, while other methods have seldom been addressed. Aiming to develop a force-sensorless grinding system, we propose a new 3-dimensional (3D) model that estimates the normal force being generated between workpieces and the grinding belt with a free strand of abrasive belt. The 3D model was constructed using integrated 2D interaction forces between the workpieces and the abrasive belt, and the latter force derived based on the tension force of the abrasive belt and the geometric contact configuration. A virtual simulator was developed and added to the geometric-based digital twin of the grinding system, forming a physics engine. The model was experimentally evaluated using spheres, cylinders, and frustums grinding specimens. The results confirm that the model can successfully predict normal forces.